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of: reserved_mem: only support one <base size> entry in reg property

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A /reserved-memory child node may have multiple <base size> tuples in
'reg' property, but multiple entries in 'reg' have never been fully
functional:
 - fdt_scan_reserved_mem() in the early pass loops over every
   tuple and reserves them all.

 - fdt_scan_reserved_mem_late() reads 'reg' by
   of_flat_dt_get_addr_size(), which returns false if entries != 1.
   So 'reg' property with multiple <base size> entries will be
   skipped, no reserved_mem entry is created in reserved_mem[].

Supporting multiple <base size> tuples is not a good idea:
  - It requires reserved_mem_ops->node_init support. Currently,
    CMA(rmem_cma_setup) and DMA(rmem_dma_setup) are not supported.

  - of_reserved_mem_lookup() is name-based, only the first entry in
    multiple <base size> tuples will be found.

So change to support one <base size> entry in 'reg' property.

Also update dt binding:
  https://github.com/devicetree-org/dt-schema/pull/197

Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wandun Chen <chenwandun@lixiang.com>
Tested-by: Meijing Zhao <zhaomeijing@lixiang.com>
Link: https://lore.kernel.org/all/20260506014752.GA280279-robh@kernel.org/
Link: https://patch.msgid.link/20260525121700.2706141-1-chenwandun1@gmail.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
This commit is contained in:
Wandun Chen
2026-05-25 20:17:00 +08:00
committed by Rob Herring (Arm)
parent 26afc4dff2
commit 7b9f263909
1 changed files with 24 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/of/of_reserved_mem.c
View File

@@ -128,42 +128,43 @@ static int __init early_init_dt_reserve_memory(phys_addr_t base,
}
/*
* __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
* __reserved_mem_reserve_reg() - reserve memory described in the
* first entry in 'reg' property
*/
static int __init __reserved_mem_reserve_reg(unsigned long node,
const char *uname)
{
phys_addr_t base, size;
int i, len, err;
int len, err;
const __be32 *prop;
bool nomap;
u64 b, s;
prop = of_flat_dt_get_addr_size_prop(node, "reg", &len);
if (!prop)
if (!prop || !len)
return -ENOENT;
if (len > 1)
pr_warn("Reserved memory: node '%s' has %d <base size> entries, only the first is used\n",
uname, len);
nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
err = fdt_validate_reserved_mem_node(node, NULL);
if (err && err != -ENODEV)
return err;
for (i = 0; i < len; i++) {
u64 b, s;
of_flat_dt_read_addr_size(prop, 0, &b, &s);
base = b;
size = s;
of_flat_dt_read_addr_size(prop, i, &b, &s);
base = b;
size = s;
if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
fdt_fixup_reserved_mem_node(node, base, size);
pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
} else {
pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
}
if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
fdt_fixup_reserved_mem_node(node, base, size);
pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
} else {
pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
}
return 0;
}
@@ -274,20 +275,24 @@ void __init fdt_scan_reserved_mem_late(void)
}
fdt_for_each_subnode(child, fdt, node) {
const __be32 *prop;
const char *uname;
u64 b, s;
int ret;
int len;
if (!of_fdt_device_is_available(fdt, child))
continue;
if (!of_flat_dt_get_addr_size(child, "reg", &b, &s))
prop = of_flat_dt_get_addr_size_prop(child, "reg", &len);
if (!prop || !len)
continue;
ret = fdt_validate_reserved_mem_node(child, NULL);
if (ret && ret != -ENODEV)
continue;
of_flat_dt_read_addr_size(prop, 0, &b, &s);
base = b;
size = s;