2022-12-23 11:52:14

by Andreas Rammhold

Subject: [PATCH] of/fdt: run soc memory setup when early_init_dt_scan_memory fails

From: Andreas Rammhold <[email protected]>

If memory has been found early_init_dt_scan_memory now returns 1. If
it hasn't found any memory it will return 0, allowing other memory
setup mechanisms to carry on.

Previously early_init_dt_scan_memory always returned 0 without
distinguishing between any kind of memory setup being done or not. Any
code path after the early_init_dt_scan memory call in the ramips
plat_mem_setup code wouldn't be executed anymore. Making
early_init_dt_scan_memory the only way to initialize the memory.

Some boards, including my mt7621 based Cudy X6 board, depend on memory
initialization being done via the soc_info.mem_detect function
pointer. Those wouldn't be able to obtain memory and panic the kernel
during early bootup with the message "early_init_dt_alloc_memory_arch:
Failed to allocate 12416 bytes align=0x40".

Fixes: 1f012283e936 ("of/fdt: Rework early_init_dt_scan_memory() to call directly")
Cc: [email protected]
Signed-off-by: Andreas Rammhold <[email protected]>
---
arch/mips/ralink/of.c | 2 +-
drivers/of/fdt.c | 6 ++++--
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/mips/ralink/of.c b/arch/mips/ralink/of.c
index ea8072acf8d94..6873b02634219 100644
--- a/arch/mips/ralink/of.c
+++ b/arch/mips/ralink/of.c
@@ -63,7 +63,7 @@ void __init plat_mem_setup(void)
dtb = get_fdt();
__dt_setup_arch(dtb);

- if (!early_init_dt_scan_memory())
+ if (early_init_dt_scan_memory())
return;

if (soc_info.mem_detect)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 7b571a6316397..4f88e8bbdd279 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1099,7 +1099,7 @@ u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
*/
int __init early_init_dt_scan_memory(void)
{
- int node;
+ int node, found_memory = 0;
const void *fdt = initial_boot_params;

fdt_for_each_subnode(node, fdt, 0) {
@@ -1139,6 +1139,8 @@ int __init early_init_dt_scan_memory(void)

early_init_dt_add_memory_arch(base, size);

+ found_memory = 1;
+
if (!hotpluggable)
continue;

@@ -1147,7 +1149,7 @@ int __init early_init_dt_scan_memory(void)
base, base + size);
}
}
- return 0;
+ return found_memory;
}

int __init early_init_dt_scan_chosen(char *cmdline)
--
2.38.1

2023-01-04 01:20:45

by Rob Herring (Arm)

Subject: Re: [PATCH] of/fdt: run soc memory setup when early_init_dt_scan_memory fails

On Fri, 23 Dec 2022 12:27:47 +0100, [email protected] wrote:
> From: Andreas Rammhold <[email protected]>
>
> If memory has been found early_init_dt_scan_memory now returns 1. If
> it hasn't found any memory it will return 0, allowing other memory
> setup mechanisms to carry on.
>
> Previously early_init_dt_scan_memory always returned 0 without
> distinguishing between any kind of memory setup being done or not. Any
> code path after the early_init_dt_scan memory call in the ramips
> plat_mem_setup code wouldn't be executed anymore. Making
> early_init_dt_scan_memory the only way to initialize the memory.
>
> Some boards, including my mt7621 based Cudy X6 board, depend on memory
> initialization being done via the soc_info.mem_detect function
> pointer. Those wouldn't be able to obtain memory and panic the kernel
> during early bootup with the message "early_init_dt_alloc_memory_arch:
> Failed to allocate 12416 bytes align=0x40".
>
> Fixes: 1f012283e936 ("of/fdt: Rework early_init_dt_scan_memory() to call directly")
> Cc: [email protected]
> Signed-off-by: Andreas Rammhold <[email protected]>
> ---
> arch/mips/ralink/of.c | 2 +-
> drivers/of/fdt.c | 6 ++++--
> 2 files changed, 5 insertions(+), 3 deletions(-)
>

Applied, thanks!