Re: [PATCH 1/3] of/fdt: Scan the root node properties earlier

Frank Rowand
2018-09-05T01:49:52Z

On 08/30/18 12:05, Rob Herring wrote:
> Scan the root node properties (#{size,address}-cells) earlier,

^^^^^^^
before mdesc->dt_fixup() is called

> so that
> the dt_root_addr_cells and dt_root_size_cells variables are initialized
> and can be used.
by mdesc->dt_fixup()
>
> Cc: Frank Rowand <frowand.list@gmail.com>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
> drivers/of/fdt.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
Moving early_init_dt_scan_root() to inside early_init_dt_verify()
puts something that has nothing to do with verifying the fdt
into a function whose purpose is the verify. It hides the side
effect of initializing the dt_root_addr_cells and dt_root_size_cells
variables.

I suggest creating a new function early_init_dt_scan_init_pre_dt_fixup(),
move the chunk of code there instead of to early_init_dt_scan_nodes(),
and call the new function from setup_machine_fdt(), just before
calling mdesc->dt_fixup(). This would be a little bit more code,
but more clearly showing the intent.

-Frank

> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 800ad252cf9c..49abe18f1bde 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -1215,6 +1215,10 @@ bool __init early_init_dt_verify(void *params)
> initial_boot_params = params;
> of_fdt_crc32 = crc32_be(~0, initial_boot_params,
> fdt_totalsize(initial_boot_params));
> +
> + /* Initialize {size,address}-cells info */
> + of_scan_flat_dt(early_init_dt_scan_root, NULL);
> +
> return true;
> }
>
> @@ -1224,9 +1228,6 @@ void __init early_init_dt_scan_nodes(void)
> /* Retrieve various information from the /chosen node */
> of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
>
> - /* Initialize {size,address}-cells info */
> - of_scan_flat_dt(early_init_dt_scan_root, NULL);
> -
> /* Setup memory, calling early_init_dt_add_memory_arch */
> of_scan_flat_dt(early_init_dt_scan_memory, NULL);
> }
>