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fdt: Add resource parsing functions

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Add the fdt_get_resource() and fdt_get_named_resource() functions which
can be used to parse resources (memory regions) from an FDT. A helper to
compute the size of a region is also provided.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Thierry Reding 2014-08-26 17:33:53 +02:00 committed by Simon Glass
parent 5094eb408a
commit 56f42242f0
2 changed files with 109 additions and 0 deletions
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52
include/fdtdec.h
View file

@ -40,6 +40,27 @@ struct fdt_memory {
fdt_addr_t end;
};
/*
* Information about a resource. start is the first address of the resource
* and end is the last address (inclusive). The length of the resource will
* be equal to: end - start + 1.
*/
struct fdt_resource {
fdt_addr_t start;
fdt_addr_t end;
};
/**
* Compute the size of a resource.
*
* @param res the resource to operate on
* @return the size of the resource
*/
static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
{
return res->end - res->start + 1;
}
/**
* Compat types that we know about and for which we might have drivers.
* Each is named COMPAT_<dir>_<filename> where <dir> is the directory
@ -597,4 +618,35 @@ struct fmap_entry {
*/
int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
struct fmap_entry *entry);
/**
* Obtain an indexed resource from a device property.
*
* @param fdt FDT blob
* @param node node to examine
* @param property name of the property to parse
* @param index index of the resource to retrieve
* @param res returns the resource
* @return 0 if ok, negative on error
*/
int fdt_get_resource(const void *fdt, int node, const char *property,
unsigned int index, struct fdt_resource *res);
/**
* Obtain a named resource from a device property.
*
* Look up the index of the name in a list of strings and return the resource
* at that index.
*
* @param fdt FDT blob
* @param node node to examine
* @param property name of the property to parse
* @param prop_names name of the property containing the list of names
* @param name the name of the entry to look up
* @param res returns the resource
*/
int fdt_get_named_resource(const void *fdt, int node, const char *property,
const char *prop_names, const char *name,
struct fdt_resource *res);
#endif

57
lib/fdtdec.c
View file

@ -708,4 +708,61 @@ int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
return 0;
}
static u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells)
{
u64 number = 0;
while (cells--)
number = (number << 32) | fdt32_to_cpu(*ptr++);
return number;
}
int fdt_get_resource(const void *fdt, int node, const char *property,
unsigned int index, struct fdt_resource *res)
{
const fdt32_t *ptr, *end;
int na, ns, len, parent;
unsigned int i = 0;
parent = fdt_parent_offset(fdt, node);
if (parent < 0)
return parent;
na = fdt_address_cells(fdt, parent);
ns = fdt_size_cells(fdt, parent);
ptr = fdt_getprop(fdt, node, property, &len);
if (!ptr)
return len;
end = ptr + len / sizeof(*ptr);
while (ptr + na + ns <= end) {
if (i == index) {
res->start = res->end = fdtdec_get_number(ptr, na);
res->end += fdtdec_get_number(&ptr[na], ns) - 1;
return 0;
}
ptr += na + ns;
i++;
}
return -FDT_ERR_NOTFOUND;
}
int fdt_get_named_resource(const void *fdt, int node, const char *property,
const char *prop_names, const char *name,
struct fdt_resource *res)
{
int index;
index = fdt_find_string(fdt, node, prop_names, name);
if (index < 0)
return index;
return fdt_get_resource(fdt, node, property, index, res);
}
#endif