of/fdt: run soc memory setup when early_init_dt_scan_memory fails

commit 2a12187d5853d9fd5102278cecef7dac7c8ce7ea upstream.

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: stable@vger.kernel.org
Signed-off-by: Andreas Rammhold <andreas@rammhold.de>
Link: https://lore.kernel.org/r/20221223112748.2935235-1-andreas@rammhold.de
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/mips/ralink/of.c b/arch/mips/ralink/of.c
index 01c132b..4d06de7 100644 (file)
--- a/arch/mips/ralink/of.c
+++ b/arch/mips/ralink/of.c
@@ -64,7 +64,7 @@ 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 7b571a6..4f88e8b 100644 (file)
--- 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)