Let early_init_dt_scan() fall-back to the built-in DT if no DT was passed,
or if it's invalid, so architectures don't have to duplicate this logic.
Suggested-by: Rob Herring <rob.herring@xxxxxxxxxxx>
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
drivers/of/fdt.c | 24 +++++++++++++++++-------
include/linux/of_fdt.h | 1 +
2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 2fa024b97c43..a797cd43bc8b 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -868,18 +868,28 @@ void * __init __weak early_init_dt_alloc_memory_arch(u64 size, u64 align)
bool __init early_init_dt_scan(void *params)
{
- if (!params)
- return false;
-
/* Setup flat device-tree pointer */
initial_boot_params = params;
- /* check device tree validity */
- if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
- initial_boot_params = NULL;
- return false;
+ /* check passed device tree validity */
+ if (initial_boot_params &&
+ be32_to_cpu(initial_boot_params->magic) == OF_DT_HEADER) {
+ pr_info("FDT at %p\n", initial_boot_params);
+ goto found;
+ }
+
+ /* check built-in device tree validity */
+ initial_boot_params = &__dtb_start;
+ if (__dtb_end != (void *)&__dtb_start &&
+ be32_to_cpu(initial_boot_params->magic) == OF_DT_HEADER) {
+ pr_info("Compiled-in FDT at %p\n", initial_boot_params);
+ goto found;
}
+ initial_boot_params = NULL;
+ return false;
+
+found:
/* Retrieve various information from the /chosen node */
of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index aabc49f3e403..6c4a60454854 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -59,6 +59,7 @@ struct boot_param_header {
/* For kernels with a built-in device tree */
extern struct boot_param_header __dtb_start;
+extern char __dtb_end[];
#if defined(CONFIG_OF_FLATTREE)
--
1.7.9.5
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