On Wed, Nov 17, 2010 at 11:15:43AM -0800, Stephen Neuendorffer wrote:
> 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 <[email protected]>
> ---
> drivers/of/fdt.c | 129 ++++++++++++++++++++++++++++++-----------------
> include/linux/of_fdt.h | 9 +++
> 2 files changed, 91 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index c1360e0..6ae207a 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -22,6 +22,86 @@
>
> #include <asm/page.h>
>
> +char *fdt_get_string(u32 offset,
> + struct boot_param_header *blob)
nitpicking: Encouraged naming convention is of_flat_dt_* for this
file. Also, I think it makes more sense for blob to be the first
argument in all of these functions.
> +{
> + return ((char *)blob) +
> + be32_to_cpu(blob->off_dt_strings) + offset;
> +}
> +
> +/**
> + * of_get_flat_dt_prop_blob - Given a node in the given flat blob, return
> + * the property ptr
> + *
> + * This function can be used within scan_flattened_dt callback to get
> + * access to properties
> + */
> +void *fdt_get_property(unsigned long node, const char *name,
> + unsigned long *size,
> + struct boot_param_header *blob)
Colocate this function with the defintiion of
of_flat_dt_get_property()
> +{
> + unsigned long p = node;
I think 'p' can be made type void* to eliminate all the casting in
this function (although I understand that this patch just moves code;
so that change doesn't need to be in this patch.
> +
> + 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);
If you change p to void*, then PTR_ALIGN can be used.
> +
> + nstr = fdt_get_string(noff, blob);
> + 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);
> +}
> +
> +/**
> + * fdt_is_compatible - Return true if given node from the given blob has
> + * compat in its compatible list
> + * @node: node to test
> + * @compat: compatible string to compare with compatible list.
> + * @blob: A device tree blob
> + */
> +int fdt_is_compatible(unsigned long node, const char *compat,
> + struct boot_param_header *blob)
Colocate this definition with of_flat_dt_is_compatible.
> +{
> + const char *cp;
> + unsigned long cplen, l;
> +
> + cp = fdt_get_property(node, "compatible", &cplen, blob);
> + 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;
>
> @@ -121,38 +201,7 @@ 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 fdt_get_property(node, name, size, initial_boot_params);
> }
>
> /**
> @@ -162,21 +211,7 @@ 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 fdt_is_compatible(node, compat, initial_boot_params);
> }
>
> static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long
> size,
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 7bbf5b3..864ec47 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -58,6 +58,15 @@ struct boot_param_header {
> };
>
> #if defined(CONFIG_OF_FLATTREE)
> +/* For scanning an arbitrary device-tree at any time */
> +extern char *fdt_get_string(u32 offset,
> + struct boot_param_header *blob);
> +extern void *fdt_get_property(unsigned long node, const char *name,
> + unsigned long *size,
> + struct boot_param_header *blob);
> +extern int fdt_is_compatible(unsigned long node, const char *name,
> + struct boot_param_header *blob);
> +
Other than renaming the functions to match the existing naming
convention, and making 'blob' the first argument, this patch looks
good to me.
g.
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