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The bootloader should populate /chosen/modules/module@<N>/ for each
module it wishes to pass to the hypervisor. The content of these nodes
is described in docs/misc/arm/device-tree/booting.txt

The hypervisor parses for 2 types of module, linux zImages and linux
initrds. Currently we don't do anything with them.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
v4: Use /chosen/modules/module@N
Identify module type by compatible property not number.
v3: Use a reg = < > property for the module address/length.
v2: Reserve the zeroeth module for Xen itself (not used yet)
Use a more idiomatic DT layout
Document said layout
---
docs/misc/arm/device-tree/booting.txt | 25 ++++++++++
xen/common/device_tree.c | 86 +++++++++++++++++++++++++++++++++
xen/include/xen/device_tree.h | 14 +++++
3 files changed, 125 insertions(+), 0 deletions(-)
create mode 100644 docs/misc/arm/device-tree/booting.txt

diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt
new file mode 100644
index 0000000..94cd3f1
--- /dev/null
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -0,0 +1,25 @@
+Xen is passed the dom0 kernel and initrd via a reference in the /chosen
+node of the device tree.
+
+Each node has the form /chosen/modules/module@<N> and contains the following
+properties:
+
+- compatible
+
+ Must be:
+
+ "xen,<type>", "xen,multiboot-module"
+
+ where <type> must be one of:
+
+ - "linux-zimage" -- the dom0 kernel
+ - "linux-initrd" -- the dom0 ramdisk
+
+- reg
+
+ Specifies the physical address of the module in RAM and the
+ length of the module.
+
+- bootargs (optional)
+
+ Command line associated with this module
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index da0af77..4bb640e 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -270,6 +270,90 @@ static void __init process_cpu_node(const void *fdt, int node,
cpumask_set_cpu(start, &cpu_possible_map);
}

+static int __init process_chosen_modules_node(const void *fdt, int node,
+ const char *name, int *depth,
+ u32 address_cells, u32 size_cells)
+{
+ const struct fdt_property *prop;
+ const u32 *cell;
+ int nr, nr_modules = 0;
+ struct dt_mb_module *mod;
+ int len;
+
+ for ( *depth = 1;
+ *depth >= 1;
+ node = fdt_next_node(fdt, node, depth) )
+ {
+ name = fdt_get_name(fdt, node, NULL);
+ if ( strncmp(name, "module@", strlen("module@")) == 0 ) {
+
+ if ( fdt_node_check_compatible(fdt, node,
+ "xen,multiboot-module" ) != 0 )
+ early_panic("%s not a compatible module node\n", name);
+
+ if ( fdt_node_check_compatible(fdt, node,
+ "xen,linux-zimage") == 0 )
+ nr = 1;
+ else if ( fdt_node_check_compatible(fdt, node,
+ "xen,linux-initrd") == 0)
+ nr = 2;
+ else
+ early_panic("%s not a known xen multiboot byte\n");
+
+ if ( nr > nr_modules )
+ nr_modules = nr;
+
+ mod = &early_info.modules.module[nr];
+
+ prop = fdt_get_property(fdt, node, "reg", NULL);
+ if ( !prop )
+ early_panic("node %s missing `reg' property\n", name);
+
+ cell = (const u32 *)prop->data;
+ device_tree_get_reg(&cell, address_cells, size_cells,
+ &mod->start, &mod->size);
+
+ prop = fdt_get_property(fdt, node, "bootargs", &len);
+ if ( prop )
+ {
+ if ( len > sizeof(mod->cmdline) )
+ early_panic("module %d command line too long\n", nr);
+
+ safe_strcpy(mod->cmdline, prop->data);
+ }
+ else
+ mod->cmdline[0] = 0;
+ }
+ }
+
+ for ( nr = 1 ; nr < nr_modules ; nr++ )
+ {
+ mod = &early_info.modules.module[nr];
+ if ( !mod->start || !mod->size )
+ early_panic("module %d missing / invalid\n", nr);
+ }
+
+ early_info.modules.nr_mods = nr_modules;
+ return node;
+}
+
+static void __init process_chosen_node(const void *fdt, int node,
+ const char *name,
+ u32 address_cells, u32 size_cells)
+{
+ int depth;
+
+ for ( depth = 0;
+ depth >= 0;
+ node = fdt_next_node(fdt, node, &depth) )
+ {
+ name = fdt_get_name(fdt, node, NULL);
+ if ( depth == 1 && strcmp(name, "modules") == 0 )
+ node = process_chosen_modules_node(fdt, node, name, &depth,
+ address_cells, size_cells);
+ }
+}
+
static int __init early_scan_node(const void *fdt,
int node, const char *name, int depth,
u32 address_cells, u32 size_cells,
@@ -279,6 +363,8 @@ static int __init early_scan_node(const void *fdt,
process_memory_node(fdt, node, name, address_cells, size_cells);
else if ( device_tree_type_matches(fdt, node, "cpu") )
process_cpu_node(fdt, node, name, address_cells, size_cells);
+ else if ( device_tree_node_matches(fdt, node, "chosen") )
+ process_chosen_node(fdt, node, name, address_cells, size_cells);

return 0;
}
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 4d010c0..c383677 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -15,6 +15,7 @@
#define DEVICE_TREE_MAX_DEPTH 16

#define NR_MEM_BANKS 8
+#define NR_MODULES 2

struct membank {
paddr_t start;
@@ -26,8 +27,21 @@ struct dt_mem_info {
struct membank bank[NR_MEM_BANKS];
};

+struct dt_mb_module {
+ paddr_t start;
+ paddr_t size;
+ char cmdline[1024];
+};
+
+struct dt_module_info {
+ int nr_mods;
+ /* Module 0 is Xen itself, followed by the provided modules-proper */
+ struct dt_mb_module module[NR_MODULES + 1];
+};
+
struct dt_early_info {
struct dt_mem_info mem;
+ struct dt_module_info modules;
};

typedef int (*device_tree_node_func)(const void *fdt,
--
1.7.9.1


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