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common: fdt_support: Support special case of PCI address in fdt_read_prop()

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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.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
This commit is contained in:
Bin Meng 2021-02-25 17:22:24 +08:00 committed by Priyanka Jain
parent 5cd1ecb994
commit a932aa3c69
1 changed files with 17 additions and 3 deletions
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20
common/fdt_support.c
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@ -1668,22 +1668,36 @@ 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, static int fdt_read_prop(const fdt32_t *prop, int prop_len, int cell_off,
uint64_t *val, int cells) uint64_t *val, int cells)
{ {
const fdt32_t *prop32 = &prop[cell_off]; const fdt32_t *prop32;
const unaligned_fdt64_t *prop64 = (const fdt64_t *)&prop[cell_off]; const unaligned_fdt64_t *prop64;
if ((cell_off + cells) > prop_len) if ((cell_off + cells) > prop_len)
return -FDT_ERR_NOSPACE; 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) { switch (cells) {
case 1: case 1:
*val = fdt32_to_cpu(*prop32); *val = fdt32_to_cpu(*prop32);
break; break;
case 2: case 2:
case 3:
*val = fdt64_to_cpu(*prop64); *val = fdt64_to_cpu(*prop64);
break; break;
default: default: