Mailing List Archive

Introduce a find_compatible_node function that can be used by device
drivers to find the node corresponding to their device in the device
tree.

Initialize device_tree_flattened early in start_xen, so that it is
available before setup_mm. Get rid of fdt in the process.

Also add device_tree_node_compatible to device_tree.h, that is currently
missing.

Changes in v4:
- stop iterating over the DT nodes in device_tree_for_each_node if func
returns a value != 0;
- return 1 from _find_compatible_node when a node is found.

Changes in v2:
- remove fdt;
- return early from _find_compatible_node, if a node has already been
found.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
xen/arch/arm/setup.c | 7 ++---
xen/common/device_tree.c | 56 +++++++++++++++++++++++++++++++++++++++-
xen/include/xen/device_tree.h | 3 ++
3 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 8882514..89ef3df 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -196,7 +196,6 @@ void __init start_xen(unsigned long boot_phys_offset,
unsigned long atag_paddr,
unsigned long cpuid)
{
- void *fdt;
size_t fdt_size;
int cpus, i;

@@ -204,12 +203,12 @@ void __init start_xen(unsigned long boot_phys_offset,

smp_clear_cpu_maps();

- fdt = (void *)BOOT_MISC_VIRT_START
+ device_tree_flattened = (void *)BOOT_MISC_VIRT_START
+ (atag_paddr & ((1 << SECOND_SHIFT) - 1));
- fdt_size = device_tree_early_init(fdt);
+ fdt_size = device_tree_early_init(device_tree_flattened);

cpus = smp_get_max_cpus();
- cmdline_parse(device_tree_bootargs(fdt));
+ cmdline_parse(device_tree_bootargs(device_tree_flattened));

setup_pagetables(boot_phys_offset, get_xen_paddr());
setup_mm(atag_paddr, fdt_size);
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 8b4ef2f..68be270 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -137,7 +137,7 @@ u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name)
* Any nodes nested at DEVICE_TREE_MAX_DEPTH or deeper are ignored.
*
* Returns 0 if all nodes were iterated over successfully. If @func
- * returns a negative value, that value is returned immediately.
+ * returns a value different from 0, that value is returned immediately.
*/
int device_tree_for_each_node(const void *fdt,
device_tree_node_func func, void *data)
@@ -166,12 +166,64 @@ int device_tree_for_each_node(const void *fdt,

ret = func(fdt, node, name, depth,
address_cells[depth-1], size_cells[depth-1], data);
- if ( ret < 0 )
+ if ( ret != 0 )
return ret;
}
return 0;
}

+struct find_compat {
+ const char *compatible;
+ int found;
+ int node;
+ int depth;
+ u32 address_cells;
+ u32 size_cells;
+};
+
+static int _find_compatible_node(const void *fdt,
+ int node, const char *name, int depth,
+ u32 address_cells, u32 size_cells,
+ void *data)
+{
+ struct find_compat *c = (struct find_compat *) data;
+
+ if ( c->found )
+ return 1;
+
+ if ( device_tree_node_compatible(fdt, node, c->compatible) )
+ {
+ c->found = 1;
+ c->node = node;
+ c->depth = depth;
+ c->address_cells = address_cells;
+ c->size_cells = size_cells;
+ return 1;
+ }
+ return 0;
+}
+
+int find_compatible_node(const char *compatible, int *node, int *depth,
+ u32 *address_cells, u32 *size_cells)
+{
+ int ret;
+ struct find_compat c;
+ c.compatible = compatible;
+ c.found = 0;
+
+ ret = device_tree_for_each_node(device_tree_flattened, _find_compatible_node, &c);
+ if ( !c.found )
+ return ret;
+ else
+ {
+ *node = c.node;
+ *depth = c.depth;
+ *address_cells = c.address_cells;
+ *size_cells = c.size_cells;
+ return 1;
+ }
+}
+
/**
* device_tree_bootargs - return the bootargs (the Xen command line)
* @fdt flat device tree.
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index a0e3a97..5a75f0e 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -54,6 +54,9 @@ void device_tree_set_reg(u32 **cell, u32 address_cells, u32 size_cells,
u64 start, u64 size);
u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name);
bool_t device_tree_node_matches(const void *fdt, int node, const char *match);
+bool_t device_tree_node_compatible(const void *fdt, int node, const char *match);
+int find_compatible_node(const char *compatible, int *node, int *depth,
+ u32 *address_cells, u32 *size_cells);
int device_tree_for_each_node(const void *fdt,
device_tree_node_func func, void *data);
const char *device_tree_bootargs(const void *fdt);
--
1.7.2.5


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