Mailing List Archive

[PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers
The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
address space. The mapping's address is returned as struct dma_buf_map.
Each function is a simplified version of TTM's existing kmap code. Both
functions respect the memory's location ani/or writecombine flags.

On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
two helpers that convert a GEM object into the TTM BO and forward the call
to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
callbacks.

v4:
* drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
Christian)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
drivers/gpu/drm/ttm/ttm_bo_util.c | 72 ++++++++++++++++++++++++++++
include/drm/drm_gem_ttm_helper.h | 6 +++
include/drm/ttm/ttm_bo_api.h | 28 +++++++++++
include/linux/dma-buf-map.h | 20 ++++++++
5 files changed, 164 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
index 0e4fb9ba43ad..db4c14d78a30 100644
--- a/drivers/gpu/drm/drm_gem_ttm_helper.c
+++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
@@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
}
EXPORT_SYMBOL(drm_gem_ttm_print_info);

+/**
+ * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
+ * @gem: GEM object.
+ * @map: [out] returns the dma-buf mapping.
+ *
+ * Maps a GEM object with ttm_bo_vmap(). This function can be used as
+ * &drm_gem_object_funcs.vmap callback.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int drm_gem_ttm_vmap(struct drm_gem_object *gem,
+ struct dma_buf_map *map)
+{
+ struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+
+ return ttm_bo_vmap(bo, map);
+
+}
+EXPORT_SYMBOL(drm_gem_ttm_vmap);
+
+/**
+ * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
+ * @gem: GEM object.
+ * @map: dma-buf mapping.
+ *
+ * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
+ * &drm_gem_object_funcs.vmap callback.
+ */
+void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
+ struct dma_buf_map *map)
+{
+ struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+
+ ttm_bo_vunmap(bo, map);
+}
+EXPORT_SYMBOL(drm_gem_ttm_vunmap);
+
/**
* drm_gem_ttm_mmap() - mmap &ttm_buffer_object
* @gem: GEM object.
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index bdee4df1f3f2..80c42c774c7d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -32,6 +32,7 @@
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/drm_vma_manager.h>
+#include <linux/dma-buf-map.h>
#include <linux/io.h>
#include <linux/highmem.h>
#include <linux/wait.h>
@@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
}
EXPORT_SYMBOL(ttm_bo_kunmap);

+int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
+{
+ struct ttm_resource *mem = &bo->mem;
+ int ret;
+
+ ret = ttm_mem_io_reserve(bo->bdev, mem);
+ if (ret)
+ return ret;
+
+ if (mem->bus.is_iomem) {
+ void __iomem *vaddr_iomem;
+ unsigned long size = bo->num_pages << PAGE_SHIFT;
+
+ if (mem->bus.addr)
+ vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
+ else if (mem->placement & TTM_PL_FLAG_WC)
+ vaddr_iomem = ioremap_wc(mem->bus.offset, size);
+ else
+ vaddr_iomem = ioremap(mem->bus.offset, size);
+
+ if (!vaddr_iomem)
+ return -ENOMEM;
+
+ dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
+
+ } else {
+ struct ttm_operation_ctx ctx = {
+ .interruptible = false,
+ .no_wait_gpu = false
+ };
+ struct ttm_tt *ttm = bo->ttm;
+ pgprot_t prot;
+ void *vaddr;
+
+ BUG_ON(!ttm);
+
+ ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
+ if (ret)
+ return ret;
+
+ /*
+ * We need to use vmap to get the desired page protection
+ * or to make the buffer object look contiguous.
+ */
+ prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
+ vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
+ if (!vaddr)
+ return -ENOMEM;
+
+ dma_buf_map_set_vaddr(map, vaddr);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(ttm_bo_vmap);
+
+void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
+{
+ if (dma_buf_map_is_null(map))
+ return;
+
+ if (map->is_iomem)
+ iounmap(map->vaddr_iomem);
+ else
+ vunmap(map->vaddr);
+ dma_buf_map_clear(map);
+
+ ttm_mem_io_free(bo->bdev, &bo->mem);
+}
+EXPORT_SYMBOL(ttm_bo_vunmap);
+
static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
bool dst_use_tt)
{
diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
index 118cef76f84f..7c6d874910b8 100644
--- a/include/drm/drm_gem_ttm_helper.h
+++ b/include/drm/drm_gem_ttm_helper.h
@@ -10,11 +10,17 @@
#include <drm/ttm/ttm_bo_api.h>
#include <drm/ttm/ttm_bo_driver.h>

+struct dma_buf_map;
+
#define drm_gem_ttm_of_gem(gem_obj) \
container_of(gem_obj, struct ttm_buffer_object, base)

void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
const struct drm_gem_object *gem);
+int drm_gem_ttm_vmap(struct drm_gem_object *gem,
+ struct dma_buf_map *map);
+void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
+ struct dma_buf_map *map);
int drm_gem_ttm_mmap(struct drm_gem_object *gem,
struct vm_area_struct *vma);

diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 37102e45e496..2c59a785374c 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -48,6 +48,8 @@ struct ttm_bo_global;

struct ttm_bo_device;

+struct dma_buf_map;
+
struct drm_mm_node;

struct ttm_placement;
@@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
*/
void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);

+/**
+ * ttm_bo_vmap
+ *
+ * @bo: The buffer object.
+ * @map: pointer to a struct dma_buf_map representing the map.
+ *
+ * Sets up a kernel virtual mapping, using ioremap or vmap to the
+ * data in the buffer object. The parameter @map returns the virtual
+ * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid range.
+ */
+int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
+
+/**
+ * ttm_bo_vunmap
+ *
+ * @bo: The buffer object.
+ * @map: Object describing the map to unmap.
+ *
+ * Unmaps a kernel map set up by ttm_bo_vmap().
+ */
+void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
+
/**
* ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
*
diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
index fd1aba545fdf..2e8bbecb5091 100644
--- a/include/linux/dma-buf-map.h
+++ b/include/linux/dma-buf-map.h
@@ -45,6 +45,12 @@
*
* dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
*
+ * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
+ *
+ * .. code-block:: c
+ *
+ * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
+ *
* Test if a mapping is valid with either dma_buf_map_is_set() or
* dma_buf_map_is_null().
*
@@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
map->is_iomem = false;
}

+/**
+ * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
+ * @map: The dma-buf mapping structure
+ * @vaddr_iomem: An I/O-memory address
+ *
+ * Sets the address and the I/O-memory flag.
+ */
+static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
+ void __iomem *vaddr_iomem)
+{
+ map->vaddr_iomem = vaddr_iomem;
+ map->is_iomem = true;
+}
+
/**
* dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
* @lhs: The dma-buf mapping structure
--
2.28.0
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
> The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
> address space. The mapping's address is returned as struct dma_buf_map.
> Each function is a simplified version of TTM's existing kmap code. Both
> functions respect the memory's location ani/or writecombine flags.
>
> On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
> two helpers that convert a GEM object into the TTM BO and forward the call
> to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
> callbacks.
>
> v4:
> * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
> Christian)

Bunch of minor comments below, but over all look very solid to me.

>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
> drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
> drivers/gpu/drm/ttm/ttm_bo_util.c | 72 ++++++++++++++++++++++++++++
> include/drm/drm_gem_ttm_helper.h | 6 +++
> include/drm/ttm/ttm_bo_api.h | 28 +++++++++++
> include/linux/dma-buf-map.h | 20 ++++++++
> 5 files changed, 164 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
> index 0e4fb9ba43ad..db4c14d78a30 100644
> --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> }
> EXPORT_SYMBOL(drm_gem_ttm_print_info);
>
> +/**
> + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
> + * @gem: GEM object.
> + * @map: [out] returns the dma-buf mapping.
> + *
> + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
> + * &drm_gem_object_funcs.vmap callback.
> + *
> + * Returns:
> + * 0 on success, or a negative errno code otherwise.
> + */
> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> + struct dma_buf_map *map)
> +{
> + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> +
> + return ttm_bo_vmap(bo, map);
> +
> +}
> +EXPORT_SYMBOL(drm_gem_ttm_vmap);
> +
> +/**
> + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
> + * @gem: GEM object.
> + * @map: dma-buf mapping.
> + *
> + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
> + * &drm_gem_object_funcs.vmap callback.
> + */
> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> + struct dma_buf_map *map)
> +{
> + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> +
> + ttm_bo_vunmap(bo, map);
> +}
> +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
> +
> /**
> * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
> * @gem: GEM object.
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index bdee4df1f3f2..80c42c774c7d 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -32,6 +32,7 @@
> #include <drm/ttm/ttm_bo_driver.h>
> #include <drm/ttm/ttm_placement.h>
> #include <drm/drm_vma_manager.h>
> +#include <linux/dma-buf-map.h>
> #include <linux/io.h>
> #include <linux/highmem.h>
> #include <linux/wait.h>
> @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
> }
> EXPORT_SYMBOL(ttm_bo_kunmap);
>
> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> +{
> + struct ttm_resource *mem = &bo->mem;
> + int ret;
> +
> + ret = ttm_mem_io_reserve(bo->bdev, mem);
> + if (ret)
> + return ret;
> +
> + if (mem->bus.is_iomem) {
> + void __iomem *vaddr_iomem;
> + unsigned long size = bo->num_pages << PAGE_SHIFT;

Please use uint64_t here and make sure to cast bo->num_pages before
shifting.

We have an unit tests of allocating a 8GB BO and that should work on a
32bit machine as well :)

> +
> + if (mem->bus.addr)
> + vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> + else if (mem->placement & TTM_PL_FLAG_WC)

I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
mem->bus.caching enum as replacement.

> + vaddr_iomem = ioremap_wc(mem->bus.offset, size);
> + else
> + vaddr_iomem = ioremap(mem->bus.offset, size);
> +
> + if (!vaddr_iomem)
> + return -ENOMEM;
> +
> + dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> +
> + } else {
> + struct ttm_operation_ctx ctx = {
> + .interruptible = false,
> + .no_wait_gpu = false
> + };
> + struct ttm_tt *ttm = bo->ttm;
> + pgprot_t prot;
> + void *vaddr;
> +
> + BUG_ON(!ttm);

I think we can drop this, populate will just crash badly anyway.

> +
> + ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> + if (ret)
> + return ret;
> +
> + /*
> + * We need to use vmap to get the desired page protection
> + * or to make the buffer object look contiguous.
> + */
> + prot = ttm_io_prot(mem->placement, PAGE_KERNEL);

The calling convention has changed on drm-misc-next as well, but should
be trivial to adapt.

Regards,
Christian.

> + vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> + if (!vaddr)
> + return -ENOMEM;
> +
> + dma_buf_map_set_vaddr(map, vaddr);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(ttm_bo_vmap);
> +
> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> +{
> + if (dma_buf_map_is_null(map))
> + return;
> +
> + if (map->is_iomem)
> + iounmap(map->vaddr_iomem);
> + else
> + vunmap(map->vaddr);
> + dma_buf_map_clear(map);
> +
> + ttm_mem_io_free(bo->bdev, &bo->mem);
> +}
> +EXPORT_SYMBOL(ttm_bo_vunmap);
> +
> static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> bool dst_use_tt)
> {
> diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
> index 118cef76f84f..7c6d874910b8 100644
> --- a/include/drm/drm_gem_ttm_helper.h
> +++ b/include/drm/drm_gem_ttm_helper.h
> @@ -10,11 +10,17 @@
> #include <drm/ttm/ttm_bo_api.h>
> #include <drm/ttm/ttm_bo_driver.h>
>
> +struct dma_buf_map;
> +
> #define drm_gem_ttm_of_gem(gem_obj) \
> container_of(gem_obj, struct ttm_buffer_object, base)
>
> void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> const struct drm_gem_object *gem);
> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> + struct dma_buf_map *map);
> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> + struct dma_buf_map *map);
> int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> struct vm_area_struct *vma);
>
> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> index 37102e45e496..2c59a785374c 100644
> --- a/include/drm/ttm/ttm_bo_api.h
> +++ b/include/drm/ttm/ttm_bo_api.h
> @@ -48,6 +48,8 @@ struct ttm_bo_global;
>
> struct ttm_bo_device;
>
> +struct dma_buf_map;
> +
> struct drm_mm_node;
>
> struct ttm_placement;
> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
> */
> void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
>
> +/**
> + * ttm_bo_vmap
> + *
> + * @bo: The buffer object.
> + * @map: pointer to a struct dma_buf_map representing the map.
> + *
> + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> + * data in the buffer object. The parameter @map returns the virtual
> + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
> + *
> + * Returns
> + * -ENOMEM: Out of memory.
> + * -EINVAL: Invalid range.
> + */
> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> +
> +/**
> + * ttm_bo_vunmap
> + *
> + * @bo: The buffer object.
> + * @map: Object describing the map to unmap.
> + *
> + * Unmaps a kernel map set up by ttm_bo_vmap().
> + */
> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> +
> /**
> * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> *
> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> index fd1aba545fdf..2e8bbecb5091 100644
> --- a/include/linux/dma-buf-map.h
> +++ b/include/linux/dma-buf-map.h
> @@ -45,6 +45,12 @@
> *
> * dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> *
> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> + *
> + * .. code-block:: c
> + *
> + * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> + *
> * Test if a mapping is valid with either dma_buf_map_is_set() or
> * dma_buf_map_is_null().
> *
> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
> map->is_iomem = false;
> }
>
> +/**
> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
> + * @map: The dma-buf mapping structure
> + * @vaddr_iomem: An I/O-memory address
> + *
> + * Sets the address and the I/O-memory flag.
> + */
> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> + void __iomem *vaddr_iomem)
> +{
> + map->vaddr_iomem = vaddr_iomem;
> + map->is_iomem = true;
> +}
> +
> /**
> * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
> * @lhs: The dma-buf mapping structure
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian K?nig wrote:
> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
> > The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
> > address space. The mapping's address is returned as struct dma_buf_map.
> > Each function is a simplified version of TTM's existing kmap code. Both
> > functions respect the memory's location ani/or writecombine flags.
> >
> > On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
> > two helpers that convert a GEM object into the TTM BO and forward the call
> > to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
> > callbacks.
> >
> > v4:
> > * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
> > Christian)
>
> Bunch of minor comments below, but over all look very solid to me.

Yeah I think just duplicating the ttm bo map stuff for vmap is indeed the
cleanest. And then we can maybe push the combinatorial monster into
vmwgfx, which I think is the only user after this series. Or perhaps a
dedicated set of helpers to map an invidual page (again using the
dma_buf_map stuff).

I'll let Christian with the details, but at a high level this is
definitely

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Thanks a lot for doing all this.
-Daniel

>
> >
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > ---
> > drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
> > drivers/gpu/drm/ttm/ttm_bo_util.c | 72 ++++++++++++++++++++++++++++
> > include/drm/drm_gem_ttm_helper.h | 6 +++
> > include/drm/ttm/ttm_bo_api.h | 28 +++++++++++
> > include/linux/dma-buf-map.h | 20 ++++++++
> > 5 files changed, 164 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > index 0e4fb9ba43ad..db4c14d78a30 100644
> > --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> > }
> > EXPORT_SYMBOL(drm_gem_ttm_print_info);
> > +/**
> > + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: [out] returns the dma-buf mapping.
> > + *
> > + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + *
> > + * Returns:
> > + * 0 on success, or a negative errno code otherwise.
> > + */
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map)
> > +{
> > + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > + return ttm_bo_vmap(bo, map);
> > +
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vmap);
> > +
> > +/**
> > + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: dma-buf mapping.
> > + *
> > + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + */
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map)
> > +{
> > + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > + ttm_bo_vunmap(bo, map);
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
> > +
> > /**
> > * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
> > * @gem: GEM object.
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > index bdee4df1f3f2..80c42c774c7d 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > @@ -32,6 +32,7 @@
> > #include <drm/ttm/ttm_bo_driver.h>
> > #include <drm/ttm/ttm_placement.h>
> > #include <drm/drm_vma_manager.h>
> > +#include <linux/dma-buf-map.h>
> > #include <linux/io.h>
> > #include <linux/highmem.h>
> > #include <linux/wait.h>
> > @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
> > }
> > EXPORT_SYMBOL(ttm_bo_kunmap);
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > + struct ttm_resource *mem = &bo->mem;
> > + int ret;
> > +
> > + ret = ttm_mem_io_reserve(bo->bdev, mem);
> > + if (ret)
> > + return ret;
> > +
> > + if (mem->bus.is_iomem) {
> > + void __iomem *vaddr_iomem;
> > + unsigned long size = bo->num_pages << PAGE_SHIFT;
>
> Please use uint64_t here and make sure to cast bo->num_pages before
> shifting.
>
> We have an unit tests of allocating a 8GB BO and that should work on a 32bit
> machine as well :)
>
> > +
> > + if (mem->bus.addr)
> > + vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> > + else if (mem->placement & TTM_PL_FLAG_WC)
>
> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
> mem->bus.caching enum as replacement.
>
> > + vaddr_iomem = ioremap_wc(mem->bus.offset, size);
> > + else
> > + vaddr_iomem = ioremap(mem->bus.offset, size);
> > +
> > + if (!vaddr_iomem)
> > + return -ENOMEM;
> > +
> > + dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> > +
> > + } else {
> > + struct ttm_operation_ctx ctx = {
> > + .interruptible = false,
> > + .no_wait_gpu = false
> > + };
> > + struct ttm_tt *ttm = bo->ttm;
> > + pgprot_t prot;
> > + void *vaddr;
> > +
> > + BUG_ON(!ttm);
>
> I think we can drop this, populate will just crash badly anyway.
>
> > +
> > + ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > + if (ret)
> > + return ret;
> > +
> > + /*
> > + * We need to use vmap to get the desired page protection
> > + * or to make the buffer object look contiguous.
> > + */
> > + prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
>
> The calling convention has changed on drm-misc-next as well, but should be
> trivial to adapt.
>
> Regards,
> Christian.
>
> > + vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> > + if (!vaddr)
> > + return -ENOMEM;
> > +
> > + dma_buf_map_set_vaddr(map, vaddr);
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vmap);
> > +
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > + if (dma_buf_map_is_null(map))
> > + return;
> > +
> > + if (map->is_iomem)
> > + iounmap(map->vaddr_iomem);
> > + else
> > + vunmap(map->vaddr);
> > + dma_buf_map_clear(map);
> > +
> > + ttm_mem_io_free(bo->bdev, &bo->mem);
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vunmap);
> > +
> > static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> > bool dst_use_tt)
> > {
> > diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
> > index 118cef76f84f..7c6d874910b8 100644
> > --- a/include/drm/drm_gem_ttm_helper.h
> > +++ b/include/drm/drm_gem_ttm_helper.h
> > @@ -10,11 +10,17 @@
> > #include <drm/ttm/ttm_bo_api.h>
> > #include <drm/ttm/ttm_bo_driver.h>
> > +struct dma_buf_map;
> > +
> > #define drm_gem_ttm_of_gem(gem_obj) \
> > container_of(gem_obj, struct ttm_buffer_object, base)
> > void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> > const struct drm_gem_object *gem);
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map);
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map);
> > int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> > struct vm_area_struct *vma);
> > diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> > index 37102e45e496..2c59a785374c 100644
> > --- a/include/drm/ttm/ttm_bo_api.h
> > +++ b/include/drm/ttm/ttm_bo_api.h
> > @@ -48,6 +48,8 @@ struct ttm_bo_global;
> > struct ttm_bo_device;
> > +struct dma_buf_map;
> > +
> > struct drm_mm_node;
> > struct ttm_placement;
> > @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
> > */
> > void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> > +/**
> > + * ttm_bo_vmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: pointer to a struct dma_buf_map representing the map.
> > + *
> > + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> > + * data in the buffer object. The parameter @map returns the virtual
> > + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
> > + *
> > + * Returns
> > + * -ENOMEM: Out of memory.
> > + * -EINVAL: Invalid range.
> > + */
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > +
> > +/**
> > + * ttm_bo_vunmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: Object describing the map to unmap.
> > + *
> > + * Unmaps a kernel map set up by ttm_bo_vmap().
> > + */
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > +
> > /**
> > * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> > *
> > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> > index fd1aba545fdf..2e8bbecb5091 100644
> > --- a/include/linux/dma-buf-map.h
> > +++ b/include/linux/dma-buf-map.h
> > @@ -45,6 +45,12 @@
> > *
> > * dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> > *
> > + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> > + *
> > + * .. code-block:: c
> > + *
> > + * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> > + *
> > * Test if a mapping is valid with either dma_buf_map_is_set() or
> > * dma_buf_map_is_null().
> > *
> > @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
> > map->is_iomem = false;
> > }
> > +/**
> > + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
> > + * @map: The dma-buf mapping structure
> > + * @vaddr_iomem: An I/O-memory address
> > + *
> > + * Sets the address and the I/O-memory flag.
> > + */
> > +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> > + void __iomem *vaddr_iomem)
> > +{
> > + map->vaddr_iomem = vaddr_iomem;
> > + map->is_iomem = true;
> > +}
> > +
> > /**
> > * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
> > * @lhs: The dma-buf mapping structure
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
Hi

On Thu, 15 Oct 2020 18:49:09 +0200 Daniel Vetter <daniel@ffwll.ch> wrote:

> On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian König wrote:
> > Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
> > > The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in
> > > kernel address space. The mapping's address is returned as struct
> > > dma_buf_map. Each function is a simplified version of TTM's existing
> > > kmap code. Both functions respect the memory's location ani/or
> > > writecombine flags.
> > >
> > > On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
> > > two helpers that convert a GEM object into the TTM BO and forward the
> > > call to TTM's vmap/vunmap. These helpers can be dropped into the rsp
> > > GEM object callbacks.
> > >
> > > v4:
> > > * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers
> > > (Daniel, Christian)
> >
> > Bunch of minor comments below, but over all look very solid to me.
>
> Yeah I think just duplicating the ttm bo map stuff for vmap is indeed the
> cleanest. And then we can maybe push the combinatorial monster into
> vmwgfx, which I think is the only user after this series. Or perhaps a
> dedicated set of helpers to map an invidual page (again using the
> dma_buf_map stuff).

From a quick look, I'd say it should be possible to have the same interface
for kmap/kunmap as for vmap/vunmap (i.e., parameters are bo and dma-buf-map).
All mapping state can be deduced from this. And struct ttm_bo_kmap_obj can be
killed off entirely.

Best regards
Thomas

>
> I'll let Christian with the details, but at a high level this is
> definitely
>
> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
> Thanks a lot for doing all this.
> -Daniel
>
> >
> > >
> > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > > ---
> > > drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
> > > drivers/gpu/drm/ttm/ttm_bo_util.c | 72 ++++++++++++++++++++++++++++
> > > include/drm/drm_gem_ttm_helper.h | 6 +++
> > > include/drm/ttm/ttm_bo_api.h | 28 +++++++++++
> > > include/linux/dma-buf-map.h | 20 ++++++++
> > > 5 files changed, 164 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > > b/drivers/gpu/drm/drm_gem_ttm_helper.c index 0e4fb9ba43ad..db4c14d78a30
> > > 100644 --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > > +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > > @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,
> > > unsigned int indent, }
> > > EXPORT_SYMBOL(drm_gem_ttm_print_info);
> > > +/**
> > > + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
> > > + * @gem: GEM object.
> > > + * @map: [out] returns the dma-buf mapping.
> > > + *
> > > + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
> > > + * &drm_gem_object_funcs.vmap callback.
> > > + *
> > > + * Returns:
> > > + * 0 on success, or a negative errno code otherwise.
> > > + */
> > > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > > + struct dma_buf_map *map)
> > > +{
> > > + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > > +
> > > + return ttm_bo_vmap(bo, map);
> > > +
> > > +}
> > > +EXPORT_SYMBOL(drm_gem_ttm_vmap);
> > > +
> > > +/**
> > > + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
> > > + * @gem: GEM object.
> > > + * @map: dma-buf mapping.
> > > + *
> > > + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used
> > > as
> > > + * &drm_gem_object_funcs.vmap callback.
> > > + */
> > > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > > + struct dma_buf_map *map)
> > > +{
> > > + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > > +
> > > + ttm_bo_vunmap(bo, map);
> > > +}
> > > +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
> > > +
> > > /**
> > > * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
> > > * @gem: GEM object.
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > b/drivers/gpu/drm/ttm/ttm_bo_util.c index bdee4df1f3f2..80c42c774c7d
> > > 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > > @@ -32,6 +32,7 @@
> > > #include <drm/ttm/ttm_bo_driver.h>
> > > #include <drm/ttm/ttm_placement.h>
> > > #include <drm/drm_vma_manager.h>
> > > +#include <linux/dma-buf-map.h>
> > > #include <linux/io.h>
> > > #include <linux/highmem.h>
> > > #include <linux/wait.h>
> > > @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
> > > }
> > > EXPORT_SYMBOL(ttm_bo_kunmap);
> > > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > > +{
> > > + struct ttm_resource *mem = &bo->mem;
> > > + int ret;
> > > +
> > > + ret = ttm_mem_io_reserve(bo->bdev, mem);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + if (mem->bus.is_iomem) {
> > > + void __iomem *vaddr_iomem;
> > > + unsigned long size = bo->num_pages << PAGE_SHIFT;
> >
> > Please use uint64_t here and make sure to cast bo->num_pages before
> > shifting.
> >
> > We have an unit tests of allocating a 8GB BO and that should work on a
> > 32bit machine as well :)
> >
> > > +
> > > + if (mem->bus.addr)
> > > + vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> > > + else if (mem->placement & TTM_PL_FLAG_WC)
> >
> > I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
> > mem->bus.caching enum as replacement.
> >
> > > + vaddr_iomem = ioremap_wc(mem->bus.offset,
> > > size);
> > > + else
> > > + vaddr_iomem = ioremap(mem->bus.offset, size);
> > > +
> > > + if (!vaddr_iomem)
> > > + return -ENOMEM;
> > > +
> > > + dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> > > +
> > > + } else {
> > > + struct ttm_operation_ctx ctx = {
> > > + .interruptible = false,
> > > + .no_wait_gpu = false
> > > + };
> > > + struct ttm_tt *ttm = bo->ttm;
> > > + pgprot_t prot;
> > > + void *vaddr;
> > > +
> > > + BUG_ON(!ttm);
> >
> > I think we can drop this, populate will just crash badly anyway.
> >
> > > +
> > > + ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + /*
> > > + * We need to use vmap to get the desired page
> > > protection
> > > + * or to make the buffer object look contiguous.
> > > + */
> > > + prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
> >
> > The calling convention has changed on drm-misc-next as well, but should be
> > trivial to adapt.
> >
> > Regards,
> > Christian.
> >
> > > + vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> > > + if (!vaddr)
> > > + return -ENOMEM;
> > > +
> > > + dma_buf_map_set_vaddr(map, vaddr);
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +EXPORT_SYMBOL(ttm_bo_vmap);
> > > +
> > > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
> > > *map) +{
> > > + if (dma_buf_map_is_null(map))
> > > + return;
> > > +
> > > + if (map->is_iomem)
> > > + iounmap(map->vaddr_iomem);
> > > + else
> > > + vunmap(map->vaddr);
> > > + dma_buf_map_clear(map);
> > > +
> > > + ttm_mem_io_free(bo->bdev, &bo->mem);
> > > +}
> > > +EXPORT_SYMBOL(ttm_bo_vunmap);
> > > +
> > > static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> > > bool dst_use_tt)
> > > {
> > > diff --git a/include/drm/drm_gem_ttm_helper.h
> > > b/include/drm/drm_gem_ttm_helper.h index 118cef76f84f..7c6d874910b8
> > > 100644 --- a/include/drm/drm_gem_ttm_helper.h
> > > +++ b/include/drm/drm_gem_ttm_helper.h
> > > @@ -10,11 +10,17 @@
> > > #include <drm/ttm/ttm_bo_api.h>
> > > #include <drm/ttm/ttm_bo_driver.h>
> > > +struct dma_buf_map;
> > > +
> > > #define drm_gem_ttm_of_gem(gem_obj) \
> > > container_of(gem_obj, struct ttm_buffer_object, base)
> > > void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int
> > > indent, const struct drm_gem_object *gem);
> > > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > > + struct dma_buf_map *map);
> > > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > > + struct dma_buf_map *map);
> > > int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> > > struct vm_area_struct *vma);
> > > diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> > > index 37102e45e496..2c59a785374c 100644
> > > --- a/include/drm/ttm/ttm_bo_api.h
> > > +++ b/include/drm/ttm/ttm_bo_api.h
> > > @@ -48,6 +48,8 @@ struct ttm_bo_global;
> > > struct ttm_bo_device;
> > > +struct dma_buf_map;
> > > +
> > > struct drm_mm_node;
> > > struct ttm_placement;
> > > @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
> > > unsigned long start_page, */
> > > void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> > > +/**
> > > + * ttm_bo_vmap
> > > + *
> > > + * @bo: The buffer object.
> > > + * @map: pointer to a struct dma_buf_map representing the map.
> > > + *
> > > + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> > > + * data in the buffer object. The parameter @map returns the virtual
> > > + * address as struct dma_buf_map. Unmap the buffer with
> > > ttm_bo_vunmap().
> > > + *
> > > + * Returns
> > > + * -ENOMEM: Out of memory.
> > > + * -EINVAL: Invalid range.
> > > + */
> > > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > > +
> > > +/**
> > > + * ttm_bo_vunmap
> > > + *
> > > + * @bo: The buffer object.
> > > + * @map: Object describing the map to unmap.
> > > + *
> > > + * Unmaps a kernel map set up by ttm_bo_vmap().
> > > + */
> > > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
> > > *map); +
> > > /**
> > > * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> > > *
> > > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> > > index fd1aba545fdf..2e8bbecb5091 100644
> > > --- a/include/linux/dma-buf-map.h
> > > +++ b/include/linux/dma-buf-map.h
> > > @@ -45,6 +45,12 @@
> > > *
> > > * dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> > > *
> > > + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> > > + *
> > > + * .. code-block:: c
> > > + *
> > > + * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> > > + *
> > > * Test if a mapping is valid with either dma_buf_map_is_set() or
> > > * dma_buf_map_is_null().
> > > *
> > > @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
> > > dma_buf_map *map, void *vaddr) map->is_iomem = false;
> > > }
> > > +/**
> > > + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to
> > > an address in I/O memory
> > > + * @map: The dma-buf mapping structure
> > > + * @vaddr_iomem: An I/O-memory address
> > > + *
> > > + * Sets the address and the I/O-memory flag.
> > > + */
> > > +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> > > + void __iomem
> > > *vaddr_iomem) +{
> > > + map->vaddr_iomem = vaddr_iomem;
> > > + map->is_iomem = true;
> > > +}
> > > +
> > > /**
> > > * dma_buf_map_is_equal - Compares two dma-buf mapping structures for
> > > equality
> > > * @lhs: The dma-buf mapping structure
> >
>



--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
Hi

On Thu, 15 Oct 2020 16:08:13 +0200 Christian König <christian.koenig@amd.com>
wrote:

> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
> > The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
> > address space. The mapping's address is returned as struct dma_buf_map.
> > Each function is a simplified version of TTM's existing kmap code. Both
> > functions respect the memory's location ani/or writecombine flags.
> >
> > On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
> > two helpers that convert a GEM object into the TTM BO and forward the call
> > to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
> > callbacks.
> >
> > v4:
> > * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
> > Christian)
>
> Bunch of minor comments below, but over all look very solid to me.
>
> >
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > ---
> > drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
> > drivers/gpu/drm/ttm/ttm_bo_util.c | 72 ++++++++++++++++++++++++++++
> > include/drm/drm_gem_ttm_helper.h | 6 +++
> > include/drm/ttm/ttm_bo_api.h | 28 +++++++++++
> > include/linux/dma-buf-map.h | 20 ++++++++
> > 5 files changed, 164 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > b/drivers/gpu/drm/drm_gem_ttm_helper.c index 0e4fb9ba43ad..db4c14d78a30
> > 100644 --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,
> > unsigned int indent, }
> > EXPORT_SYMBOL(drm_gem_ttm_print_info);
> >
> > +/**
> > + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: [out] returns the dma-buf mapping.
> > + *
> > + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + *
> > + * Returns:
> > + * 0 on success, or a negative errno code otherwise.
> > + */
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map)
> > +{
> > + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > + return ttm_bo_vmap(bo, map);
> > +
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vmap);
> > +
> > +/**
> > + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: dma-buf mapping.
> > + *
> > + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + */
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map)
> > +{
> > + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > + ttm_bo_vunmap(bo, map);
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
> > +
> > /**
> > * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
> > * @gem: GEM object.
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > b/drivers/gpu/drm/ttm/ttm_bo_util.c index bdee4df1f3f2..80c42c774c7d
> > 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > @@ -32,6 +32,7 @@
> > #include <drm/ttm/ttm_bo_driver.h>
> > #include <drm/ttm/ttm_placement.h>
> > #include <drm/drm_vma_manager.h>
> > +#include <linux/dma-buf-map.h>
> > #include <linux/io.h>
> > #include <linux/highmem.h>
> > #include <linux/wait.h>
> > @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
> > }
> > EXPORT_SYMBOL(ttm_bo_kunmap);
> >
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > + struct ttm_resource *mem = &bo->mem;
> > + int ret;
> > +
> > + ret = ttm_mem_io_reserve(bo->bdev, mem);
> > + if (ret)
> > + return ret;
> > +
> > + if (mem->bus.is_iomem) {
> > + void __iomem *vaddr_iomem;
> > + unsigned long size = bo->num_pages << PAGE_SHIFT;
>
> Please use uint64_t here and make sure to cast bo->num_pages before
> shifting.
>
> We have an unit tests of allocating a 8GB BO and that should work on a
> 32bit machine as well :)
>
> > +
> > + if (mem->bus.addr)
> > + vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> > + else if (mem->placement & TTM_PL_FLAG_WC)
>
> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
> mem->bus.caching enum as replacement.
>
> > + vaddr_iomem = ioremap_wc(mem->bus.offset, size);
> > + else
> > + vaddr_iomem = ioremap(mem->bus.offset, size);
> > +
> > + if (!vaddr_iomem)
> > + return -ENOMEM;
> > +
> > + dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> > +
> > + } else {
> > + struct ttm_operation_ctx ctx = {
> > + .interruptible = false,
> > + .no_wait_gpu = false
> > + };
> > + struct ttm_tt *ttm = bo->ttm;
> > + pgprot_t prot;
> > + void *vaddr;
> > +
> > + BUG_ON(!ttm);
>
> I think we can drop this, populate will just crash badly anyway.
>
> > +
> > + ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > + if (ret)
> > + return ret;
> > +
> > + /*
> > + * We need to use vmap to get the desired page protection
> > + * or to make the buffer object look contiguous.
> > + */
> > + prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
>
> The calling convention has changed on drm-misc-next as well, but should
> be trivial to adapt.

Thanks for quickly reviewing these patches. My drm-tip seems out of date
(last Sunday). TTM is moving fast these days and I still have to get used to
that. :)

Best regards
Thomas

>
> Regards,
> Christian.
>
> > + vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> > + if (!vaddr)
> > + return -ENOMEM;
> > +
> > + dma_buf_map_set_vaddr(map, vaddr);
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vmap);
> > +
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > + if (dma_buf_map_is_null(map))
> > + return;
> > +
> > + if (map->is_iomem)
> > + iounmap(map->vaddr_iomem);
> > + else
> > + vunmap(map->vaddr);
> > + dma_buf_map_clear(map);
> > +
> > + ttm_mem_io_free(bo->bdev, &bo->mem);
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vunmap);
> > +
> > static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> > bool dst_use_tt)
> > {
> > diff --git a/include/drm/drm_gem_ttm_helper.h
> > b/include/drm/drm_gem_ttm_helper.h index 118cef76f84f..7c6d874910b8 100644
> > --- a/include/drm/drm_gem_ttm_helper.h
> > +++ b/include/drm/drm_gem_ttm_helper.h
> > @@ -10,11 +10,17 @@
> > #include <drm/ttm/ttm_bo_api.h>
> > #include <drm/ttm/ttm_bo_driver.h>
> >
> > +struct dma_buf_map;
> > +
> > #define drm_gem_ttm_of_gem(gem_obj) \
> > container_of(gem_obj, struct ttm_buffer_object, base)
> >
> > void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> > const struct drm_gem_object *gem);
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map);
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > + struct dma_buf_map *map);
> > int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> > struct vm_area_struct *vma);
> >
> > diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> > index 37102e45e496..2c59a785374c 100644
> > --- a/include/drm/ttm/ttm_bo_api.h
> > +++ b/include/drm/ttm/ttm_bo_api.h
> > @@ -48,6 +48,8 @@ struct ttm_bo_global;
> >
> > struct ttm_bo_device;
> >
> > +struct dma_buf_map;
> > +
> > struct drm_mm_node;
> >
> > struct ttm_placement;
> > @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
> > unsigned long start_page, */
> > void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> >
> > +/**
> > + * ttm_bo_vmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: pointer to a struct dma_buf_map representing the map.
> > + *
> > + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> > + * data in the buffer object. The parameter @map returns the virtual
> > + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
> > + *
> > + * Returns
> > + * -ENOMEM: Out of memory.
> > + * -EINVAL: Invalid range.
> > + */
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > +
> > +/**
> > + * ttm_bo_vunmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: Object describing the map to unmap.
> > + *
> > + * Unmaps a kernel map set up by ttm_bo_vmap().
> > + */
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
> > *map); +
> > /**
> > * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> > *
> > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> > index fd1aba545fdf..2e8bbecb5091 100644
> > --- a/include/linux/dma-buf-map.h
> > +++ b/include/linux/dma-buf-map.h
> > @@ -45,6 +45,12 @@
> > *
> > * dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> > *
> > + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> > + *
> > + * .. code-block:: c
> > + *
> > + * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> > + *
> > * Test if a mapping is valid with either dma_buf_map_is_set() or
> > * dma_buf_map_is_null().
> > *
> > @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
> > dma_buf_map *map, void *vaddr) map->is_iomem = false;
> > }
> >
> > +/**
> > + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an
> > address in I/O memory
> > + * @map: The dma-buf mapping structure
> > + * @vaddr_iomem: An I/O-memory address
> > + *
> > + * Sets the address and the I/O-memory flag.
> > + */
> > +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> > + void __iomem *vaddr_iomem)
> > +{
> > + map->vaddr_iomem = vaddr_iomem;
> > + map->is_iomem = true;
> > +}
> > +
> > /**
> > * dma_buf_map_is_equal - Compares two dma-buf mapping structures for
> > equality
> > * @lhs: The dma-buf mapping structure
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel



--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
Am 15.10.20 um 19:52 schrieb Thomas Zimmermann:
> Hi
>
> On Thu, 15 Oct 2020 18:49:09 +0200 Daniel Vetter <daniel@ffwll.ch> wrote:
>
>> On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian König wrote:
>>> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
>>>> The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in
>>>> kernel address space. The mapping's address is returned as struct
>>>> dma_buf_map. Each function is a simplified version of TTM's existing
>>>> kmap code. Both functions respect the memory's location ani/or
>>>> writecombine flags.
>>>>
>>>> On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
>>>> two helpers that convert a GEM object into the TTM BO and forward the
>>>> call to TTM's vmap/vunmap. These helpers can be dropped into the rsp
>>>> GEM object callbacks.
>>>>
>>>> v4:
>>>> * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers
>>>> (Daniel, Christian)
>>> Bunch of minor comments below, but over all look very solid to me.
>> Yeah I think just duplicating the ttm bo map stuff for vmap is indeed the
>> cleanest. And then we can maybe push the combinatorial monster into
>> vmwgfx, which I think is the only user after this series. Or perhaps a
>> dedicated set of helpers to map an invidual page (again using the
>> dma_buf_map stuff).
> From a quick look, I'd say it should be possible to have the same interface
> for kmap/kunmap as for vmap/vunmap (i.e., parameters are bo and dma-buf-map).
> All mapping state can be deduced from this. And struct ttm_bo_kmap_obj can be
> killed off entirely.

Yes, that would be rather nice to have.

Thanks,
Christian.

>
> Best regards
> Thomas
>
>> I'll let Christian with the details, but at a high level this is
>> definitely
>>
>> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>>
>> Thanks a lot for doing all this.
>> -Daniel
>>
>>>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>>>> ---
>>>> drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
>>>> drivers/gpu/drm/ttm/ttm_bo_util.c | 72 ++++++++++++++++++++++++++++
>>>> include/drm/drm_gem_ttm_helper.h | 6 +++
>>>> include/drm/ttm/ttm_bo_api.h | 28 +++++++++++
>>>> include/linux/dma-buf-map.h | 20 ++++++++
>>>> 5 files changed, 164 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c
>>>> b/drivers/gpu/drm/drm_gem_ttm_helper.c index 0e4fb9ba43ad..db4c14d78a30
>>>> 100644 --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
>>>> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
>>>> @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,
>>>> unsigned int indent, }
>>>> EXPORT_SYMBOL(drm_gem_ttm_print_info);
>>>> +/**
>>>> + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
>>>> + * @gem: GEM object.
>>>> + * @map: [out] returns the dma-buf mapping.
>>>> + *
>>>> + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
>>>> + * &drm_gem_object_funcs.vmap callback.
>>>> + *
>>>> + * Returns:
>>>> + * 0 on success, or a negative errno code otherwise.
>>>> + */
>>>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
>>>> + struct dma_buf_map *map)
>>>> +{
>>>> + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
>>>> +
>>>> + return ttm_bo_vmap(bo, map);
>>>> +
>>>> +}
>>>> +EXPORT_SYMBOL(drm_gem_ttm_vmap);
>>>> +
>>>> +/**
>>>> + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
>>>> + * @gem: GEM object.
>>>> + * @map: dma-buf mapping.
>>>> + *
>>>> + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used
>>>> as
>>>> + * &drm_gem_object_funcs.vmap callback.
>>>> + */
>>>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
>>>> + struct dma_buf_map *map)
>>>> +{
>>>> + struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
>>>> +
>>>> + ttm_bo_vunmap(bo, map);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
>>>> +
>>>> /**
>>>> * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
>>>> * @gem: GEM object.
>>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
>>>> b/drivers/gpu/drm/ttm/ttm_bo_util.c index bdee4df1f3f2..80c42c774c7d
>>>> 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
>>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
>>>> @@ -32,6 +32,7 @@
>>>> #include <drm/ttm/ttm_bo_driver.h>
>>>> #include <drm/ttm/ttm_placement.h>
>>>> #include <drm/drm_vma_manager.h>
>>>> +#include <linux/dma-buf-map.h>
>>>> #include <linux/io.h>
>>>> #include <linux/highmem.h>
>>>> #include <linux/wait.h>
>>>> @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
>>>> }
>>>> EXPORT_SYMBOL(ttm_bo_kunmap);
>>>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
>>>> +{
>>>> + struct ttm_resource *mem = &bo->mem;
>>>> + int ret;
>>>> +
>>>> + ret = ttm_mem_io_reserve(bo->bdev, mem);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + if (mem->bus.is_iomem) {
>>>> + void __iomem *vaddr_iomem;
>>>> + unsigned long size = bo->num_pages << PAGE_SHIFT;
>>> Please use uint64_t here and make sure to cast bo->num_pages before
>>> shifting.
>>>
>>> We have an unit tests of allocating a 8GB BO and that should work on a
>>> 32bit machine as well :)
>>>
>>>> +
>>>> + if (mem->bus.addr)
>>>> + vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
>>>> + else if (mem->placement & TTM_PL_FLAG_WC)
>>> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
>>> mem->bus.caching enum as replacement.
>>>
>>>> + vaddr_iomem = ioremap_wc(mem->bus.offset,
>>>> size);
>>>> + else
>>>> + vaddr_iomem = ioremap(mem->bus.offset, size);
>>>> +
>>>> + if (!vaddr_iomem)
>>>> + return -ENOMEM;
>>>> +
>>>> + dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
>>>> +
>>>> + } else {
>>>> + struct ttm_operation_ctx ctx = {
>>>> + .interruptible = false,
>>>> + .no_wait_gpu = false
>>>> + };
>>>> + struct ttm_tt *ttm = bo->ttm;
>>>> + pgprot_t prot;
>>>> + void *vaddr;
>>>> +
>>>> + BUG_ON(!ttm);
>>> I think we can drop this, populate will just crash badly anyway.
>>>
>>>> +
>>>> + ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + /*
>>>> + * We need to use vmap to get the desired page
>>>> protection
>>>> + * or to make the buffer object look contiguous.
>>>> + */
>>>> + prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
>>> The calling convention has changed on drm-misc-next as well, but should be
>>> trivial to adapt.
>>>
>>> Regards,
>>> Christian.
>>>
>>>> + vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
>>>> + if (!vaddr)
>>>> + return -ENOMEM;
>>>> +
>>>> + dma_buf_map_set_vaddr(map, vaddr);
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +EXPORT_SYMBOL(ttm_bo_vmap);
>>>> +
>>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>>>> *map) +{
>>>> + if (dma_buf_map_is_null(map))
>>>> + return;
>>>> +
>>>> + if (map->is_iomem)
>>>> + iounmap(map->vaddr_iomem);
>>>> + else
>>>> + vunmap(map->vaddr);
>>>> + dma_buf_map_clear(map);
>>>> +
>>>> + ttm_mem_io_free(bo->bdev, &bo->mem);
>>>> +}
>>>> +EXPORT_SYMBOL(ttm_bo_vunmap);
>>>> +
>>>> static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
>>>> bool dst_use_tt)
>>>> {
>>>> diff --git a/include/drm/drm_gem_ttm_helper.h
>>>> b/include/drm/drm_gem_ttm_helper.h index 118cef76f84f..7c6d874910b8
>>>> 100644 --- a/include/drm/drm_gem_ttm_helper.h
>>>> +++ b/include/drm/drm_gem_ttm_helper.h
>>>> @@ -10,11 +10,17 @@
>>>> #include <drm/ttm/ttm_bo_api.h>
>>>> #include <drm/ttm/ttm_bo_driver.h>
>>>> +struct dma_buf_map;
>>>> +
>>>> #define drm_gem_ttm_of_gem(gem_obj) \
>>>> container_of(gem_obj, struct ttm_buffer_object, base)
>>>> void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int
>>>> indent, const struct drm_gem_object *gem);
>>>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
>>>> + struct dma_buf_map *map);
>>>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
>>>> + struct dma_buf_map *map);
>>>> int drm_gem_ttm_mmap(struct drm_gem_object *gem,
>>>> struct vm_area_struct *vma);
>>>> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
>>>> index 37102e45e496..2c59a785374c 100644
>>>> --- a/include/drm/ttm/ttm_bo_api.h
>>>> +++ b/include/drm/ttm/ttm_bo_api.h
>>>> @@ -48,6 +48,8 @@ struct ttm_bo_global;
>>>> struct ttm_bo_device;
>>>> +struct dma_buf_map;
>>>> +
>>>> struct drm_mm_node;
>>>> struct ttm_placement;
>>>> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
>>>> unsigned long start_page, */
>>>> void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
>>>> +/**
>>>> + * ttm_bo_vmap
>>>> + *
>>>> + * @bo: The buffer object.
>>>> + * @map: pointer to a struct dma_buf_map representing the map.
>>>> + *
>>>> + * Sets up a kernel virtual mapping, using ioremap or vmap to the
>>>> + * data in the buffer object. The parameter @map returns the virtual
>>>> + * address as struct dma_buf_map. Unmap the buffer with
>>>> ttm_bo_vunmap().
>>>> + *
>>>> + * Returns
>>>> + * -ENOMEM: Out of memory.
>>>> + * -EINVAL: Invalid range.
>>>> + */
>>>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
>>>> +
>>>> +/**
>>>> + * ttm_bo_vunmap
>>>> + *
>>>> + * @bo: The buffer object.
>>>> + * @map: Object describing the map to unmap.
>>>> + *
>>>> + * Unmaps a kernel map set up by ttm_bo_vmap().
>>>> + */
>>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>>>> *map); +
>>>> /**
>>>> * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
>>>> *
>>>> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
>>>> index fd1aba545fdf..2e8bbecb5091 100644
>>>> --- a/include/linux/dma-buf-map.h
>>>> +++ b/include/linux/dma-buf-map.h
>>>> @@ -45,6 +45,12 @@
>>>> *
>>>> * dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
>>>> *
>>>> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
>>>> + *
>>>> + * .. code-block:: c
>>>> + *
>>>> + * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
>>>> + *
>>>> * Test if a mapping is valid with either dma_buf_map_is_set() or
>>>> * dma_buf_map_is_null().
>>>> *
>>>> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
>>>> dma_buf_map *map, void *vaddr) map->is_iomem = false;
>>>> }
>>>> +/**
>>>> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to
>>>> an address in I/O memory
>>>> + * @map: The dma-buf mapping structure
>>>> + * @vaddr_iomem: An I/O-memory address
>>>> + *
>>>> + * Sets the address and the I/O-memory flag.
>>>> + */
>>>> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
>>>> + void __iomem
>>>> *vaddr_iomem) +{
>>>> + map->vaddr_iomem = vaddr_iomem;
>>>> + map->is_iomem = true;
>>>> +}
>>>> +
>>>> /**
>>>> * dma_buf_map_is_equal - Compares two dma-buf mapping structures for
>>>> equality
>>>> * @lhs: The dma-buf mapping structure
>
>
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
Hi Christian

On 15.10.20 16:08, Christian König wrote:
> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
>> The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
>> address space. The mapping's address is returned as struct dma_buf_map.
>> Each function is a simplified version of TTM's existing kmap code. Both
>> functions respect the memory's location ani/or writecombine flags.
>>
>> On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
>> two helpers that convert a GEM object into the TTM BO and forward the
>> call
>> to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM
>> object
>> callbacks.
>>
>> v4:
>>     * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
>>       Christian)
>
> Bunch of minor comments below, but over all look very solid to me.
>
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
>>   drivers/gpu/drm/ttm/ttm_bo_util.c    | 72 ++++++++++++++++++++++++++++
>>   include/drm/drm_gem_ttm_helper.h     |  6 +++
>>   include/drm/ttm/ttm_bo_api.h         | 28 +++++++++++
>>   include/linux/dma-buf-map.h          | 20 ++++++++
>>   5 files changed, 164 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c
>> b/drivers/gpu/drm/drm_gem_ttm_helper.c
>> index 0e4fb9ba43ad..db4c14d78a30 100644
>> --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
>> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
>> @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,
>> unsigned int indent,
>>   }
>>   EXPORT_SYMBOL(drm_gem_ttm_print_info);
>>   +/**
>> + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
>> + * @gem: GEM object.
>> + * @map: [out] returns the dma-buf mapping.
>> + *
>> + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
>> + * &drm_gem_object_funcs.vmap callback.
>> + *
>> + * Returns:
>> + * 0 on success, or a negative errno code otherwise.
>> + */
>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
>> +             struct dma_buf_map *map)
>> +{
>> +    struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
>> +
>> +    return ttm_bo_vmap(bo, map);
>> +
>> +}
>> +EXPORT_SYMBOL(drm_gem_ttm_vmap);
>> +
>> +/**
>> + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
>> + * @gem: GEM object.
>> + * @map: dma-buf mapping.
>> + *
>> + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be
>> used as
>> + * &drm_gem_object_funcs.vmap callback.
>> + */
>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
>> +            struct dma_buf_map *map)
>> +{
>> +    struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
>> +
>> +    ttm_bo_vunmap(bo, map);
>> +}
>> +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
>> +
>>   /**
>>    * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
>>    * @gem: GEM object.
>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
>> b/drivers/gpu/drm/ttm/ttm_bo_util.c
>> index bdee4df1f3f2..80c42c774c7d 100644
>> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
>> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
>> @@ -32,6 +32,7 @@
>>   #include <drm/ttm/ttm_bo_driver.h>
>>   #include <drm/ttm/ttm_placement.h>
>>   #include <drm/drm_vma_manager.h>
>> +#include <linux/dma-buf-map.h>
>>   #include <linux/io.h>
>>   #include <linux/highmem.h>
>>   #include <linux/wait.h>
>> @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
>>   }
>>   EXPORT_SYMBOL(ttm_bo_kunmap);
>>   +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
>> +{
>> +    struct ttm_resource *mem = &bo->mem;
>> +    int ret;
>> +
>> +    ret = ttm_mem_io_reserve(bo->bdev, mem);
>> +    if (ret)
>> +        return ret;
>> +
>> +    if (mem->bus.is_iomem) {
>> +        void __iomem *vaddr_iomem;
>> +        unsigned long size = bo->num_pages << PAGE_SHIFT;
>
> Please use uint64_t here and make sure to cast bo->num_pages before
> shifting.

I thought the rule of thumb is to use u64 in source code. Yet TTM only
uses uint*_t types. Is there anything special about TTM?

>
> We have an unit tests of allocating a 8GB BO and that should work on a
> 32bit machine as well :)
>
>> +
>> +        if (mem->bus.addr)
>> +            vaddr_iomem = (void *)(((u8 *)mem->bus.addr));

I after reading the patch again, I realized that this is the
'ttm_bo_map_premapped' case and it's missing from _vunmap(). I see two
options here: ignore this case in _vunmap(), or do an ioremap()
unconditionally. Which one is preferable?

Best regards
Thomas

>> +        else if (mem->placement & TTM_PL_FLAG_WC)
>
> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
> mem->bus.caching enum as replacement.
>
>> +            vaddr_iomem = ioremap_wc(mem->bus.offset, size);
>> +        else
>> +            vaddr_iomem = ioremap(mem->bus.offset, size);
>> +
>> +        if (!vaddr_iomem)
>> +            return -ENOMEM;
>> +
>> +        dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
>> +
>> +    } else {
>> +        struct ttm_operation_ctx ctx = {
>> +            .interruptible = false,
>> +            .no_wait_gpu = false
>> +        };
>> +        struct ttm_tt *ttm = bo->ttm;
>> +        pgprot_t prot;
>> +        void *vaddr;
>> +
>> +        BUG_ON(!ttm);
>
> I think we can drop this, populate will just crash badly anyway.
>
>> +
>> +        ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
>> +        if (ret)
>> +            return ret;
>> +
>> +        /*
>> +         * We need to use vmap to get the desired page protection
>> +         * or to make the buffer object look contiguous.
>> +         */
>> +        prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
>
> The calling convention has changed on drm-misc-next as well, but should
> be trivial to adapt.
>
> Regards,
> Christian.
>
>> +        vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
>> +        if (!vaddr)
>> +            return -ENOMEM;
>> +
>> +        dma_buf_map_set_vaddr(map, vaddr);
>> +    }
>> +
>> +    return 0;
>> +}
>> +EXPORT_SYMBOL(ttm_bo_vmap);
>> +
>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>> *map)
>> +{
>> +    if (dma_buf_map_is_null(map))
>> +        return;
>> +
>> +    if (map->is_iomem)
>> +        iounmap(map->vaddr_iomem);
>> +    else
>> +        vunmap(map->vaddr);
>> +    dma_buf_map_clear(map);
>> +
>> +    ttm_mem_io_free(bo->bdev, &bo->mem);
>> +}
>> +EXPORT_SYMBOL(ttm_bo_vunmap);
>> +
>>   static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
>>                    bool dst_use_tt)
>>   {
>> diff --git a/include/drm/drm_gem_ttm_helper.h
>> b/include/drm/drm_gem_ttm_helper.h
>> index 118cef76f84f..7c6d874910b8 100644
>> --- a/include/drm/drm_gem_ttm_helper.h
>> +++ b/include/drm/drm_gem_ttm_helper.h
>> @@ -10,11 +10,17 @@
>>   #include <drm/ttm/ttm_bo_api.h>
>>   #include <drm/ttm/ttm_bo_driver.h>
>>   +struct dma_buf_map;
>> +
>>   #define drm_gem_ttm_of_gem(gem_obj) \
>>       container_of(gem_obj, struct ttm_buffer_object, base)
>>     void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int
>> indent,
>>                   const struct drm_gem_object *gem);
>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
>> +             struct dma_buf_map *map);
>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
>> +            struct dma_buf_map *map);
>>   int drm_gem_ttm_mmap(struct drm_gem_object *gem,
>>                struct vm_area_struct *vma);
>>   diff --git a/include/drm/ttm/ttm_bo_api.h
>> b/include/drm/ttm/ttm_bo_api.h
>> index 37102e45e496..2c59a785374c 100644
>> --- a/include/drm/ttm/ttm_bo_api.h
>> +++ b/include/drm/ttm/ttm_bo_api.h
>> @@ -48,6 +48,8 @@ struct ttm_bo_global;
>>     struct ttm_bo_device;
>>   +struct dma_buf_map;
>> +
>>   struct drm_mm_node;
>>     struct ttm_placement;
>> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
>> unsigned long start_page,
>>    */
>>   void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
>>   +/**
>> + * ttm_bo_vmap
>> + *
>> + * @bo: The buffer object.
>> + * @map: pointer to a struct dma_buf_map representing the map.
>> + *
>> + * Sets up a kernel virtual mapping, using ioremap or vmap to the
>> + * data in the buffer object. The parameter @map returns the virtual
>> + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
>> + *
>> + * Returns
>> + * -ENOMEM: Out of memory.
>> + * -EINVAL: Invalid range.
>> + */
>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
>> +
>> +/**
>> + * ttm_bo_vunmap
>> + *
>> + * @bo: The buffer object.
>> + * @map: Object describing the map to unmap.
>> + *
>> + * Unmaps a kernel map set up by ttm_bo_vmap().
>> + */
>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>> *map);
>> +
>>   /**
>>    * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
>>    *
>> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
>> index fd1aba545fdf..2e8bbecb5091 100644
>> --- a/include/linux/dma-buf-map.h
>> +++ b/include/linux/dma-buf-map.h
>> @@ -45,6 +45,12 @@
>>    *
>>    *    dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
>>    *
>> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
>> + *
>> + * .. code-block:: c
>> + *
>> + *    dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
>> + *
>>    * Test if a mapping is valid with either dma_buf_map_is_set() or
>>    * dma_buf_map_is_null().
>>    *
>> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
>> dma_buf_map *map, void *vaddr)
>>       map->is_iomem = false;
>>   }
>>   +/**
>> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to
>> an address in I/O memory
>> + * @map:        The dma-buf mapping structure
>> + * @vaddr_iomem:    An I/O-memory address
>> + *
>> + * Sets the address and the I/O-memory flag.
>> + */
>> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
>> +                           void __iomem *vaddr_iomem)
>> +{
>> +    map->vaddr_iomem = vaddr_iomem;
>> +    map->is_iomem = true;
>> +}
>> +
>>   /**
>>    * dma_buf_map_is_equal - Compares two dma-buf mapping structures
>> for equality
>>    * @lhs:    The dma-buf mapping structure
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
Hi Thomas,

[SNIP]
>>>   +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
>>> +{
>>> +    struct ttm_resource *mem = &bo->mem;
>>> +    int ret;
>>> +
>>> +    ret = ttm_mem_io_reserve(bo->bdev, mem);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    if (mem->bus.is_iomem) {
>>> +        void __iomem *vaddr_iomem;
>>> +        unsigned long size = bo->num_pages << PAGE_SHIFT;
>> Please use uint64_t here and make sure to cast bo->num_pages before
>> shifting.
> I thought the rule of thumb is to use u64 in source code. Yet TTM only
> uses uint*_t types. Is there anything special about TTM?

My last status is that you can use both and my personal preference is to
use the uint*_t types because they are part of a higher level standard.

>> We have an unit tests of allocating a 8GB BO and that should work on a
>> 32bit machine as well :)
>>
>>> +
>>> +        if (mem->bus.addr)
>>> +            vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> I after reading the patch again, I realized that this is the
> 'ttm_bo_map_premapped' case and it's missing from _vunmap(). I see two
> options here: ignore this case in _vunmap(), or do an ioremap()
> unconditionally. Which one is preferable?

ioremap would be very very bad, so we should just do nothing.

Thanks,
Christian.

>
> Best regards
> Thomas
>
>>> +        else if (mem->placement & TTM_PL_FLAG_WC)
>> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
>> mem->bus.caching enum as replacement.
>>
>>> +            vaddr_iomem = ioremap_wc(mem->bus.offset, size);
>>> +        else
>>> +            vaddr_iomem = ioremap(mem->bus.offset, size);
>>> +
>>> +        if (!vaddr_iomem)
>>> +            return -ENOMEM;
>>> +
>>> +        dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
>>> +
>>> +    } else {
>>> +        struct ttm_operation_ctx ctx = {
>>> +            .interruptible = false,
>>> +            .no_wait_gpu = false
>>> +        };
>>> +        struct ttm_tt *ttm = bo->ttm;
>>> +        pgprot_t prot;
>>> +        void *vaddr;
>>> +
>>> +        BUG_ON(!ttm);
>> I think we can drop this, populate will just crash badly anyway.
>>
>>> +
>>> +        ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
>>> +        if (ret)
>>> +            return ret;
>>> +
>>> +        /*
>>> +         * We need to use vmap to get the desired page protection
>>> +         * or to make the buffer object look contiguous.
>>> +         */
>>> +        prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
>> The calling convention has changed on drm-misc-next as well, but should
>> be trivial to adapt.
>>
>> Regards,
>> Christian.
>>
>>> +        vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
>>> +        if (!vaddr)
>>> +            return -ENOMEM;
>>> +
>>> +        dma_buf_map_set_vaddr(map, vaddr);
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL(ttm_bo_vmap);
>>> +
>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>>> *map)
>>> +{
>>> +    if (dma_buf_map_is_null(map))
>>> +        return;
>>> +
>>> +    if (map->is_iomem)
>>> +        iounmap(map->vaddr_iomem);
>>> +    else
>>> +        vunmap(map->vaddr);
>>> +    dma_buf_map_clear(map);
>>> +
>>> +    ttm_mem_io_free(bo->bdev, &bo->mem);
>>> +}
>>> +EXPORT_SYMBOL(ttm_bo_vunmap);
>>> +
>>>   static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
>>>                    bool dst_use_tt)
>>>   {
>>> diff --git a/include/drm/drm_gem_ttm_helper.h
>>> b/include/drm/drm_gem_ttm_helper.h
>>> index 118cef76f84f..7c6d874910b8 100644
>>> --- a/include/drm/drm_gem_ttm_helper.h
>>> +++ b/include/drm/drm_gem_ttm_helper.h
>>> @@ -10,11 +10,17 @@
>>>   #include <drm/ttm/ttm_bo_api.h>
>>>   #include <drm/ttm/ttm_bo_driver.h>
>>>   +struct dma_buf_map;
>>> +
>>>   #define drm_gem_ttm_of_gem(gem_obj) \
>>>       container_of(gem_obj, struct ttm_buffer_object, base)
>>>     void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int
>>> indent,
>>>                   const struct drm_gem_object *gem);
>>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
>>> +             struct dma_buf_map *map);
>>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
>>> +            struct dma_buf_map *map);
>>>   int drm_gem_ttm_mmap(struct drm_gem_object *gem,
>>>                struct vm_area_struct *vma);
>>>   diff --git a/include/drm/ttm/ttm_bo_api.h
>>> b/include/drm/ttm/ttm_bo_api.h
>>> index 37102e45e496..2c59a785374c 100644
>>> --- a/include/drm/ttm/ttm_bo_api.h
>>> +++ b/include/drm/ttm/ttm_bo_api.h
>>> @@ -48,6 +48,8 @@ struct ttm_bo_global;
>>>     struct ttm_bo_device;
>>>   +struct dma_buf_map;
>>> +
>>>   struct drm_mm_node;
>>>     struct ttm_placement;
>>> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
>>> unsigned long start_page,
>>>    */
>>>   void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
>>>   +/**
>>> + * ttm_bo_vmap
>>> + *
>>> + * @bo: The buffer object.
>>> + * @map: pointer to a struct dma_buf_map representing the map.
>>> + *
>>> + * Sets up a kernel virtual mapping, using ioremap or vmap to the
>>> + * data in the buffer object. The parameter @map returns the virtual
>>> + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
>>> + *
>>> + * Returns
>>> + * -ENOMEM: Out of memory.
>>> + * -EINVAL: Invalid range.
>>> + */
>>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
>>> +
>>> +/**
>>> + * ttm_bo_vunmap
>>> + *
>>> + * @bo: The buffer object.
>>> + * @map: Object describing the map to unmap.
>>> + *
>>> + * Unmaps a kernel map set up by ttm_bo_vmap().
>>> + */
>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>>> *map);
>>> +
>>>   /**
>>>    * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
>>>    *
>>> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
>>> index fd1aba545fdf..2e8bbecb5091 100644
>>> --- a/include/linux/dma-buf-map.h
>>> +++ b/include/linux/dma-buf-map.h
>>> @@ -45,6 +45,12 @@
>>>    *
>>>    *    dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
>>>    *
>>> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
>>> + *
>>> + * .. code-block:: c
>>> + *
>>> + *    dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
>>> + *
>>>    * Test if a mapping is valid with either dma_buf_map_is_set() or
>>>    * dma_buf_map_is_null().
>>>    *
>>> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
>>> dma_buf_map *map, void *vaddr)
>>>       map->is_iomem = false;
>>>   }
>>>   +/**
>>> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to
>>> an address in I/O memory
>>> + * @map:        The dma-buf mapping structure
>>> + * @vaddr_iomem:    An I/O-memory address
>>> + *
>>> + * Sets the address and the I/O-memory flag.
>>> + */
>>> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
>>> +                           void __iomem *vaddr_iomem)
>>> +{
>>> +    map->vaddr_iomem = vaddr_iomem;
>>> +    map->is_iomem = true;
>>> +}
>>> +
>>>   /**
>>>    * dma_buf_map_is_equal - Compares two dma-buf mapping structures
>>> for equality
>>>    * @lhs:    The dma-buf mapping structure
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Re: [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers [ In reply to ]
On Mon, Oct 19, 2020 at 11:45:05AM +0200, Christian K?nig wrote:
> Hi Thomas,
>
> [SNIP]
> > > > ? +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > > > +{
> > > > +??? struct ttm_resource *mem = &bo->mem;
> > > > +??? int ret;
> > > > +
> > > > +??? ret = ttm_mem_io_reserve(bo->bdev, mem);
> > > > +??? if (ret)
> > > > +??????? return ret;
> > > > +
> > > > +??? if (mem->bus.is_iomem) {
> > > > +??????? void __iomem *vaddr_iomem;
> > > > +??????? unsigned long size = bo->num_pages << PAGE_SHIFT;
> > > Please use uint64_t here and make sure to cast bo->num_pages before
> > > shifting.
> > I thought the rule of thumb is to use u64 in source code. Yet TTM only
> > uses uint*_t types. Is there anything special about TTM?
>
> My last status is that you can use both and my personal preference is to use
> the uint*_t types because they are part of a higher level standard.

Yeah the only hard rule is that in uapi headers you need to use the __u64
and similar typedefs, to avoid cluttering the namespace for unrelated
stuff in userspace.

In the kernel c99 types are perfectly fine, and I think slowly on the
rise.
-Daniel

>
> > > We have an unit tests of allocating a 8GB BO and that should work on a
> > > 32bit machine as well :)
> > >
> > > > +
> > > > +??????? if (mem->bus.addr)
> > > > +??????????? vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> > I after reading the patch again, I realized that this is the
> > 'ttm_bo_map_premapped' case and it's missing from _vunmap(). I see two
> > options here: ignore this case in _vunmap(), or do an ioremap()
> > unconditionally. Which one is preferable?
>
> ioremap would be very very bad, so we should just do nothing.
>
> Thanks,
> Christian.
>
> >
> > Best regards
> > Thomas
> >
> > > > +??????? else if (mem->placement & TTM_PL_FLAG_WC)
> > > I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
> > > mem->bus.caching enum as replacement.
> > >
> > > > +??????????? vaddr_iomem = ioremap_wc(mem->bus.offset, size);
> > > > +??????? else
> > > > +??????????? vaddr_iomem = ioremap(mem->bus.offset, size);
> > > > +
> > > > +??????? if (!vaddr_iomem)
> > > > +??????????? return -ENOMEM;
> > > > +
> > > > +??????? dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> > > > +
> > > > +??? } else {
> > > > +??????? struct ttm_operation_ctx ctx = {
> > > > +??????????? .interruptible = false,
> > > > +??????????? .no_wait_gpu = false
> > > > +??????? };
> > > > +??????? struct ttm_tt *ttm = bo->ttm;
> > > > +??????? pgprot_t prot;
> > > > +??????? void *vaddr;
> > > > +
> > > > +??????? BUG_ON(!ttm);
> > > I think we can drop this, populate will just crash badly anyway.
> > >
> > > > +
> > > > +??????? ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > > > +??????? if (ret)
> > > > +??????????? return ret;
> > > > +
> > > > +??????? /*
> > > > +???????? * We need to use vmap to get the desired page protection
> > > > +???????? * or to make the buffer object look contiguous.
> > > > +???????? */
> > > > +??????? prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
> > > The calling convention has changed on drm-misc-next as well, but should
> > > be trivial to adapt.
> > >
> > > Regards,
> > > Christian.
> > >
> > > > +??????? vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> > > > +??????? if (!vaddr)
> > > > +??????????? return -ENOMEM;
> > > > +
> > > > +??????? dma_buf_map_set_vaddr(map, vaddr);
> > > > +??? }
> > > > +
> > > > +??? return 0;
> > > > +}
> > > > +EXPORT_SYMBOL(ttm_bo_vmap);
> > > > +
> > > > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
> > > > *map)
> > > > +{
> > > > +??? if (dma_buf_map_is_null(map))
> > > > +??????? return;
> > > > +
> > > > +??? if (map->is_iomem)
> > > > +??????? iounmap(map->vaddr_iomem);
> > > > +??? else
> > > > +??????? vunmap(map->vaddr);
> > > > +??? dma_buf_map_clear(map);
> > > > +
> > > > +??? ttm_mem_io_free(bo->bdev, &bo->mem);
> > > > +}
> > > > +EXPORT_SYMBOL(ttm_bo_vunmap);
> > > > +
> > > > ? static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> > > > ?????????????????? bool dst_use_tt)
> > > > ? {
> > > > diff --git a/include/drm/drm_gem_ttm_helper.h
> > > > b/include/drm/drm_gem_ttm_helper.h
> > > > index 118cef76f84f..7c6d874910b8 100644
> > > > --- a/include/drm/drm_gem_ttm_helper.h
> > > > +++ b/include/drm/drm_gem_ttm_helper.h
> > > > @@ -10,11 +10,17 @@
> > > > ? #include <drm/ttm/ttm_bo_api.h>
> > > > ? #include <drm/ttm/ttm_bo_driver.h>
> > > > ? +struct dma_buf_map;
> > > > +
> > > > ? #define drm_gem_ttm_of_gem(gem_obj) \
> > > > ????? container_of(gem_obj, struct ttm_buffer_object, base)
> > > > ? ? void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int
> > > > indent,
> > > > ????????????????? const struct drm_gem_object *gem);
> > > > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > > > +???????????? struct dma_buf_map *map);
> > > > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > > > +??????????? struct dma_buf_map *map);
> > > > ? int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> > > > ?????????????? struct vm_area_struct *vma);
> > > > ? diff --git a/include/drm/ttm/ttm_bo_api.h
> > > > b/include/drm/ttm/ttm_bo_api.h
> > > > index 37102e45e496..2c59a785374c 100644
> > > > --- a/include/drm/ttm/ttm_bo_api.h
> > > > +++ b/include/drm/ttm/ttm_bo_api.h
> > > > @@ -48,6 +48,8 @@ struct ttm_bo_global;
> > > > ? ? struct ttm_bo_device;
> > > > ? +struct dma_buf_map;
> > > > +
> > > > ? struct drm_mm_node;
> > > > ? ? struct ttm_placement;
> > > > @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
> > > > unsigned long start_page,
> > > > ?? */
> > > > ? void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> > > > ? +/**
> > > > + * ttm_bo_vmap
> > > > + *
> > > > + * @bo: The buffer object.
> > > > + * @map: pointer to a struct dma_buf_map representing the map.
> > > > + *
> > > > + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> > > > + * data in the buffer object. The parameter @map returns the virtual
> > > > + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
> > > > + *
> > > > + * Returns
> > > > + * -ENOMEM: Out of memory.
> > > > + * -EINVAL: Invalid range.
> > > > + */
> > > > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > > > +
> > > > +/**
> > > > + * ttm_bo_vunmap
> > > > + *
> > > > + * @bo: The buffer object.
> > > > + * @map: Object describing the map to unmap.
> > > > + *
> > > > + * Unmaps a kernel map set up by ttm_bo_vmap().
> > > > + */
> > > > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
> > > > *map);
> > > > +
> > > > ? /**
> > > > ?? * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> > > > ?? *
> > > > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> > > > index fd1aba545fdf..2e8bbecb5091 100644
> > > > --- a/include/linux/dma-buf-map.h
> > > > +++ b/include/linux/dma-buf-map.h
> > > > @@ -45,6 +45,12 @@
> > > > ?? *
> > > > ?? *??? dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> > > > ?? *
> > > > + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> > > > + *
> > > > + * .. code-block:: c
> > > > + *
> > > > + *??? dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> > > > + *
> > > > ?? * Test if a mapping is valid with either dma_buf_map_is_set() or
> > > > ?? * dma_buf_map_is_null().
> > > > ?? *
> > > > @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
> > > > dma_buf_map *map, void *vaddr)
> > > > ????? map->is_iomem = false;
> > > > ? }
> > > > ? +/**
> > > > + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to
> > > > an address in I/O memory
> > > > + * @map:??????? The dma-buf mapping structure
> > > > + * @vaddr_iomem:??? An I/O-memory address
> > > > + *
> > > > + * Sets the address and the I/O-memory flag.
> > > > + */
> > > > +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> > > > +?????????????????????????? void __iomem *vaddr_iomem)
> > > > +{
> > > > +??? map->vaddr_iomem = vaddr_iomem;
> > > > +??? map->is_iomem = true;
> > > > +}
> > > > +
> > > > ? /**
> > > > ?? * dma_buf_map_is_equal - Compares two dma-buf mapping structures
> > > > for equality
> > > > ?? * @lhs:??? The dma-buf mapping structure
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel@lists.freedesktop.org
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>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch