[PATCH 3/3] fdt.c: Refactor unflatten_device_tree and add fdt_unflatten_tree
Stephen Neuendorffer
stephen.neuendorffer at xilinx.com
Thu Nov 18 06:15:45 EST 2010
unflatten_device_tree has two dependencies on things that happen
during boot time. Firstly, it references the initial device tree
directly. Secondly, it allocates memory using the early boot
allocator. This patch factors out these dependencies and uses
the new __unflatten_device_tree function to implement a driver-visible
fdt_unflatten_tree function, which can be used to unflatten a
blob after boot time.
Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer at xilinx.com>
---
drivers/of/fdt.c | 147 ++++++++++++++++++++++++++++++++----------------
include/linux/of_fdt.h | 2 +
2 files changed, 100 insertions(+), 49 deletions(-)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index c448b2f..e98ee59 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -11,10 +11,12 @@
#include <linux/kernel.h>
#include <linux/initrd.h>
+#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/string.h>
#include <linux/errno.h>
+#include <linux/slab.h>
#ifdef CONFIG_PPC
#include <asm/machdep.h>
@@ -316,6 +318,94 @@ unsigned long unflatten_dt_node(unsigned long mem,
return mem;
}
+/**
+ * __unflatten_device_tree - create tree of device_nodes from flat blob
+ *
+ * unflattens a device-tree, creating the
+ * tree of struct device_node. It also fills the "name" and "type"
+ * pointers of the nodes so the normal device-tree walking functions
+ * can be used.
+ * @blob: The blob to expand
+ * @mynodes: The device_node tree created by the call
+ * @dt_alloc: An allocator that provides memory for the resulting tree
+ */
+void __unflatten_device_tree(struct boot_param_header *blob,
+ struct device_node **mynodes,
+ unsigned long (*dt_alloc)(u64 size, u64 align))
+{
+ unsigned long start, mem, size;
+ struct device_node **allnextp = mynodes;
+
+ pr_debug(" -> unflatten_device_tree()\n");
+
+ if (!blob) {
+ pr_debug("No device tree pointer\n");
+ return;
+ }
+
+ pr_debug("Unflattening device tree:\n");
+ pr_debug("magic: %08x\n", be32_to_cpu(blob->magic));
+ pr_debug("size: %08x\n", be32_to_cpu(blob->totalsize));
+ pr_debug("version: %08x\n", be32_to_cpu(blob->version));
+
+ if (be32_to_cpu(blob->magic) != OF_DT_HEADER) {
+ pr_err("Invalid device tree blob header\n");
+ return;
+ }
+
+ /* First pass, scan for size */
+ start = ((unsigned long)blob) +
+ be32_to_cpu(blob->off_dt_struct);
+ size = unflatten_dt_node(0, &start, NULL, NULL, 0, blob);
+ size = (size | 3) + 1;
+
+ pr_debug(" size is %lx, allocating...\n", size);
+
+ /* Allocate memory for the expanded device tree */
+ mem = (unsigned long) dt_alloc(size + 4,
+ __alignof__(struct device_node));
+ mem = (unsigned long) __va(mem);
+
+ ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
+
+ pr_debug(" unflattening %lx...\n", mem);
+
+ /* Second pass, do actual unflattening */
+ start = ((unsigned long)blob) +
+ be32_to_cpu(blob->off_dt_struct);
+ unflatten_dt_node(mem, &start, NULL, &allnextp, 0, blob);
+ if (be32_to_cpup((__be32 *)start) != OF_DT_END)
+ pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
+ if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
+ pr_warning("End of tree marker overwritten: %08x\n",
+ be32_to_cpu(((__be32 *)mem)[size / 4]));
+ *allnextp = NULL;
+
+ pr_debug(" <- unflatten_device_tree()\n");
+}
+
+static unsigned long kernel_tree_alloc(u64 size, u64 align)
+{
+ return (unsigned long) kzalloc(size, GFP_KERNEL);
+}
+
+/**
+ * fdt_unflatten_tree - create tree of device_nodes from flat blob
+ *
+ * unflattens the device-tree passed by the firmware, creating the
+ * tree of struct device_node. It also fills the "name" and "type"
+ * pointers of the nodes so the normal device-tree walking functions
+ * can be used.
+ */
+void fdt_unflatten_tree(unsigned long *blob,
+ struct device_node **mynodes)
+{
+ struct boot_param_header *device_tree =
+ (struct boot_param_header *)blob;
+ __unflatten_device_tree(device_tree, mynodes, &kernel_tree_alloc);
+}
+EXPORT_SYMBOL_GPL(fdt_unflatten_tree);
+
/* Everything below here references initial_boot_params directly. */
int __initdata dt_root_addr_cells;
int __initdata dt_root_size_cells;
@@ -577,6 +667,12 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
return 1;
}
+static unsigned long __init early_device_tree_alloc(u64 size, u64 align)
+{
+ unsigned long mem = early_init_dt_alloc_memory_arch(size, align);
+ return (unsigned long) __va(mem);
+}
+
/**
* unflatten_device_tree - create tree of device_nodes from flat blob
*
@@ -587,58 +683,11 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
*/
void __init unflatten_device_tree(void)
{
- unsigned long start, mem, size;
- struct device_node **allnextp = &allnodes;
-
- pr_debug(" -> unflatten_device_tree()\n");
-
- if (!initial_boot_params) {
- pr_debug("No device tree pointer\n");
- return;
- }
-
- pr_debug("Unflattening device tree:\n");
- pr_debug("magic: %08x\n", be32_to_cpu(initial_boot_params->magic));
- pr_debug("size: %08x\n", be32_to_cpu(initial_boot_params->totalsize));
- pr_debug("version: %08x\n", be32_to_cpu(initial_boot_params->version));
-
- if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
- pr_err("Invalid device tree blob header\n");
- return;
- }
-
- /* First pass, scan for size */
- start = ((unsigned long)initial_boot_params) +
- be32_to_cpu(initial_boot_params->off_dt_struct);
- size = unflatten_dt_node(0, &start, NULL, NULL, 0, initial_boot_params);
- size = (size | 3) + 1;
-
- pr_debug(" size is %lx, allocating...\n", size);
-
- /* Allocate memory for the expanded device tree */
- mem = early_init_dt_alloc_memory_arch(size + 4,
- __alignof__(struct device_node));
- mem = (unsigned long) __va(mem);
-
- ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
-
- pr_debug(" unflattening %lx...\n", mem);
-
- /* Second pass, do actual unflattening */
- start = ((unsigned long)initial_boot_params) +
- be32_to_cpu(initial_boot_params->off_dt_struct);
- unflatten_dt_node(mem, &start, NULL, &allnextp, 0, initial_boot_params);
- if (be32_to_cpup((__be32 *)start) != OF_DT_END)
- pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
- if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
- pr_warning("End of tree marker overwritten: %08x\n",
- be32_to_cpu(((__be32 *)mem)[size / 4]));
- *allnextp = NULL;
+ __unflatten_device_tree(initial_boot_params, &allnodes,
+ early_device_tree_alloc);
/* Get pointer to OF "/chosen" node for use everywhere */
of_chosen = of_find_node_by_path("/chosen");
if (of_chosen == NULL)
of_chosen = of_find_node_by_path("/chosen at 0");
-
- pr_debug(" <- unflatten_device_tree()\n");
}
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 864ec47..5b0e2f3 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -66,6 +66,8 @@ extern void *fdt_get_property(unsigned long node, const char *name,
struct boot_param_header *blob);
extern int fdt_is_compatible(unsigned long node, const char *name,
struct boot_param_header *blob);
+extern void fdt_unflatten_tree(unsigned long *blob,
+ struct device_node **mynodes);
/* TBD: Temporary export of fdt globals - remove when code fully merged */
extern int __initdata dt_root_addr_cells;
--
1.5.6.6
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