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fdt: call fdt_parent_offset fewer times while translating addresses 

fdt_parent_offset() is an expensive operation, so we'd like to reduce
unnecessary calls to it.

Further, the practice of iterating up to the root if address/size cells
aren't found was apparently done for Linux for compatibility with certain
buggy Open Firmware implementations, and U-Boot inherited the code.  The
compliant behavior is to treat a missing #address-cells as 2, and a missing
#size-cells as 1 -- never looking anywhere but the immediate parent of the
node of interest.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Scott Wood 2010-08-12 18:37:39 -05:00 committed by Kumar Gala
parent b80d30546e
commit 6395f318e9
1 changed files with 21 additions and 37 deletions
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58
common/fdt_support.c
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@ -874,35 +874,6 @@ static inline u64 of_read_number(const __be32 *cell, int size)
return r;
}
static int of_n_cells(const void *blob, int nodeoffset, const char *name)
{
int np;
const int *ip;
do {
np = fdt_parent_offset(blob, nodeoffset);
if (np >= 0)
nodeoffset = np;
ip = (int *)fdt_getprop(blob, nodeoffset, name, NULL);
if (ip)
return be32_to_cpup(ip);
} while (np >= 0);
/* No #<NAME>-cells property for the root node */
return 1;
}
int of_n_addr_cells(const void *blob, int nodeoffset)
{
return of_n_cells(blob, nodeoffset, "#address-cells");
}
int of_n_size_cells(const void *blob, int nodeoffset)
{
return of_n_cells(blob, nodeoffset, "#size-cells");
}
#define PRu64 "%llx"
/* Max address size we deal with */
@ -928,7 +899,7 @@ static void of_dump_addr(const char *s, const u32 *addr, int na) { }
struct of_bus {
const char *name;
const char *addresses;
void (*count_cells)(void *blob, int offset,
void (*count_cells)(void *blob, int parentoffset,
int *addrc, int *sizec);
u64 (*map)(u32 *addr, const u32 *range,
int na, int ns, int pna);
@ -936,13 +907,26 @@ struct of_bus {
};
/* Default translator (generic bus) */
static void of_bus_default_count_cells(void *blob, int offset,
static void of_bus_default_count_cells(void *blob, int parentoffset,
int *addrc, int *sizec)
{
if (addrc)
*addrc = of_n_addr_cells(blob, offset);
if (sizec)
*sizec = of_n_size_cells(blob, offset);
const u32 *prop;
if (addrc) {
prop = fdt_getprop(blob, parentoffset, "#address-cells", NULL);
if (prop)
*addrc = be32_to_cpup(prop);
else
*addrc = 2;
}
if (sizec) {
prop = fdt_getprop(blob, parentoffset, "#size-cells", NULL);
if (prop)
*sizec = be32_to_cpup(prop);
else
*sizec = 1;
}
}
static u64 of_bus_default_map(u32 *addr, const u32 *range,
@ -1068,7 +1052,7 @@ u64 __of_translate_address(void *blob, int node_offset, const u32 *in_addr,
bus = &of_busses[0];
/* Cound address cells & copy address locally */
bus->count_cells(blob, node_offset, &na, &ns);
bus->count_cells(blob, parent, &na, &ns);
if (!OF_CHECK_COUNTS(na, ns)) {
printf("%s: Bad cell count for %s\n", __FUNCTION__,
fdt_get_name(blob, node_offset, NULL));
@ -1095,7 +1079,7 @@ u64 __of_translate_address(void *blob, int node_offset, const u32 *in_addr,
/* Get new parent bus and counts */
pbus = &of_busses[0];
pbus->count_cells(blob, node_offset, &pna, &pns);
pbus->count_cells(blob, parent, &pna, &pns);
if (!OF_CHECK_COUNTS(pna, pns)) {
printf("%s: Bad cell count for %s\n", __FUNCTION__,
fdt_get_name(blob, node_offset, NULL));