At present fdt_read_prop() can only handle 1 or 2 cells. It is
called by fdt_read_range() which may be used to read PCI address
from <ranges> for a PCI bus node where the number of PCI address
cell is 3. The <ranges> property is an array of:
{ <child address> <parent address> <size in child address space> }
When trying to read <child address> from a PCI bus node using
fdt_read_prop(), as the codes below:
/* Read <child address> */
if (child_addr) {
r = fdt_read_prop(ranges, ranges_len, cell, child_addr,
acells);
if (r)
return r;
}
it will fail, because the PCI child address is made up of 3 cells
but fdt_read_prop() cannot handle it. We advance the cell offset
by 1 so that the <child address> can be correctly read.
This adds the special handling of such case.
Signed-off-by: Bin Meng <bmeng...@gmail.com>
---
Changes in v2:
- add more details in the commit message, and put some comments
in the codes to explain why
common/fdt_support.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/common/fdt_support.c b/common/fdt_support.c
index 638eca9..17c54a3 100644
--- a/common/fdt_support.c
+++ b/common/fdt_support.c
@@ -1602,22 +1602,36 @@ u64 fdt_get_base_address(const void *fdt, int node)
}
/*
- * Read a property of size <prop_len>. Currently only supports 1 or 2 cells.
+ * Read a property of size <prop_len>. Currently only supports 1 or 2 cells,
+ * or 3 cells specially for a PCI address.
*/
static int fdt_read_prop(const fdt32_t *prop, int prop_len, int cell_off,
uint64_t *val, int cells)
{
- const fdt32_t *prop32 = &prop[cell_off];
- const unaligned_fdt64_t *prop64 = (const fdt64_t *)&prop[cell_off];
+ const fdt32_t *prop32;
+ const unaligned_fdt64_t *prop64;
if ((cell_off + cells) > prop_len)
return -FDT_ERR_NOSPACE;
+ prop32 = &prop[cell_off];
+
+ /*
+ * Special handling for PCI address in PCI bus <ranges>
+ *
+ * PCI child address is made up of 3 cells. Advance the cell offset
+ * by 1 so that the PCI child address can be correctly read.
+ */
+ if (cells == 3)
+ cell_off += 1;
+ prop64 = (const fdt64_t *)&prop[cell_off];
+
switch (cells) {
case 1:
*val = fdt32_to_cpu(*prop32);
break;
case 2:
+ case 3:
*val = fdt64_to_cpu(*prop64);
break;
default:
--
2.7.4
