[PATCH 4/7] fdt.c: Add non-boottime device tree functions
Stephen Neuendorffer
stephen.neuendorffer at xilinx.com
Fri Nov 19 10:54:59 EST 2010
In preparation for providing run-time handling of device trees, factor
out some of the basic functions so that they take an arbitrary blob,
rather than relying on the single boot-time tree.
Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer at xilinx.com>
--
V2: functions have of_fdt_* names
removed find_flat_dt_string
blob argument is first
---
drivers/of/fdt.c | 133 ++++++++++++++++++++++++++++-------------------
include/linux/of_fdt.h | 11 ++++
2 files changed, 90 insertions(+), 54 deletions(-)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 4d71b29..190e26c 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -22,6 +22,82 @@
#include <asm/page.h>
+char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
+{
+ return ((char *)blob) +
+ be32_to_cpu(blob->off_dt_strings) + offset;
+}
+
+/**
+ * of_fdt_get_property - Given a node in the given flat blob, return
+ * the property ptr
+ */
+void *of_fdt_get_property(struct boot_param_header *blob,
+ unsigned long node, const char *name,
+ unsigned long *size)
+{
+ unsigned long p = node;
+
+ do {
+ u32 tag = be32_to_cpup((__be32 *)p);
+ u32 sz, noff;
+ const char *nstr;
+
+ p += 4;
+ if (tag == OF_DT_NOP)
+ continue;
+ if (tag != OF_DT_PROP)
+ return NULL;
+
+ sz = be32_to_cpup((__be32 *)p);
+ noff = be32_to_cpup((__be32 *)(p + 4));
+ p += 8;
+ if (be32_to_cpu(blob->version) < 0x10)
+ p = ALIGN(p, sz >= 8 ? 8 : 4);
+
+ nstr = of_fdt_get_string(blob, noff);
+ if (nstr == NULL) {
+ pr_warning("Can't find property index name !\n");
+ return NULL;
+ }
+ if (strcmp(name, nstr) == 0) {
+ if (size)
+ *size = sz;
+ return (void *)p;
+ }
+ p += sz;
+ p = ALIGN(p, 4);
+ } while (1);
+}
+
+/**
+ * of_fdt_is_compatible - Return true if given node from the given blob has
+ * compat in its compatible list
+ * @blob: A device tree blob
+ * @node: node to test
+ * @compat: compatible string to compare with compatible list.
+ */
+int of_fdt_is_compatible(struct boot_param_header *blob,
+ unsigned long node, const char *compat)
+{
+ const char *cp;
+ unsigned long cplen, l;
+
+ cp = of_fdt_get_property(blob, node, "compatible", &cplen);
+ if (cp == NULL)
+ return 0;
+ while (cplen > 0) {
+ if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
+ return 1;
+ l = strlen(cp) + 1;
+ cp += l;
+ cplen -= l;
+ }
+
+ return 0;
+}
+
+/* Everything below here references initial_boot_params directly. */
int __initdata dt_root_addr_cells;
int __initdata dt_root_size_cells;
@@ -29,12 +105,6 @@ struct boot_param_header *initial_boot_params;
#ifdef CONFIG_EARLY_FLATTREE
-char *find_flat_dt_string(u32 offset)
-{
- return ((char *)initial_boot_params) +
- be32_to_cpu(initial_boot_params->off_dt_strings) + offset;
-}
-
/**
* of_scan_flat_dt - scan flattened tree blob and call callback on each.
* @it: callback function
@@ -123,38 +193,7 @@ unsigned long __init of_get_flat_dt_root(void)
void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
unsigned long *size)
{
- unsigned long p = node;
-
- do {
- u32 tag = be32_to_cpup((__be32 *)p);
- u32 sz, noff;
- const char *nstr;
-
- p += 4;
- if (tag == OF_DT_NOP)
- continue;
- if (tag != OF_DT_PROP)
- return NULL;
-
- sz = be32_to_cpup((__be32 *)p);
- noff = be32_to_cpup((__be32 *)(p + 4));
- p += 8;
- if (be32_to_cpu(initial_boot_params->version) < 0x10)
- p = ALIGN(p, sz >= 8 ? 8 : 4);
-
- nstr = find_flat_dt_string(noff);
- if (nstr == NULL) {
- pr_warning("Can't find property index name !\n");
- return NULL;
- }
- if (strcmp(name, nstr) == 0) {
- if (size)
- *size = sz;
- return (void *)p;
- }
- p += sz;
- p = ALIGN(p, 4);
- } while (1);
+ return of_fdt_get_property(initial_boot_params, node, name, size);
}
/**
@@ -164,21 +203,7 @@ void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
*/
int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
{
- const char *cp;
- unsigned long cplen, l;
-
- cp = of_get_flat_dt_prop(node, "compatible", &cplen);
- if (cp == NULL)
- return 0;
- while (cplen > 0) {
- if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
- return 1;
- l = strlen(cp) + 1;
- cp += l;
- cplen -= l;
- }
-
- return 0;
+ return of_fdt_is_compatible(initial_boot_params, node, compat);
}
static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
@@ -303,7 +328,7 @@ unsigned long __init unflatten_dt_node(unsigned long mem,
if (be32_to_cpu(initial_boot_params->version) < 0x10)
*p = ALIGN(*p, sz >= 8 ? 8 : 4);
- pname = find_flat_dt_string(noff);
+ pname = of_fdt_get_string(initial_boot_params, noff);
if (pname == NULL) {
pr_info("Can't find property name in list !\n");
break;
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 7bbf5b3..70c5b73 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -58,6 +58,17 @@ struct boot_param_header {
};
#if defined(CONFIG_OF_FLATTREE)
+
+/* For scanning an arbitrary device-tree at any time */
+extern char *of_fdt_get_string(struct boot_param_header *blob, u32 offset);
+extern void *of_fdt_get_property(struct boot_param_header *blob,
+ unsigned long node,
+ const char *name,
+ unsigned long *size);
+extern int of_fdt_is_compatible(struct boot_param_header *blob,
+ unsigned long node,
+ const char *compat);
+
/* TBD: Temporary export of fdt globals - remove when code fully merged */
extern int __initdata dt_root_addr_cells;
extern int __initdata dt_root_size_cells;
--
1.5.6.6
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