Re: [PATCH 1/9] dt: Handle passed/built-in DT selection in early_init_dt_scan()

From: Rob Herring
Date: Wed Nov 20 2013 - 15:51:04 EST


On Tue, Nov 19, 2013 at 5:12 AM, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> wrote:
> 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>
> ---

Looks good to me. I can take this series if you want to send me a pull
request. In any case, for the series:

Reviewed-by: Rob Herring <rob.herring@xxxxxxxxxxx>

Rob

> 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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