On 20/01/2025 20:43, Sam Day wrote:
> commit fc37a73e6679 ("fdt: Swap the signature for
> board_fdt_blob_setup()") introduced a subtle change to the Snapdragon
> implementation, removing the assignment to gd->fdt_blob partway through
> the function.
>
> This breaks qcom_parse_memory() which was also called during
> board_fdt_blob_setup().
>
> The underlying issue here is that qcom_parse_memory is using the of_ api
> to traverse a devicetree, which relies on the fdt_blob in global data.
>
> Rather than relying on this subtle behaviour, explicitly pass the FDT
> that should be consulted for a /memory node.
>
> Using the OF API is typically preferable because it's easier to read,
> but using the lower level fdt_ methods instead here doesn't add too much
> complexity, I think.
>
> Finally, a minor tweak was made to board_fdt_blob_setup to use the
> passed fdt blob pointer instead of gd->fdt_blob, which removes the last
> of the references to global data in this area.
>
> Fixes: fc37a73e6679 (fdt: Swap the signature for board_fdt_blob_setup())
> Signed-off-by: Sam Day <[email protected]>
Reviewed-by: Caleb Connolly <[email protected]>
Thanks so much for sending this! I'm pretty sure the whole reason we
called qcom_parse_memory() from board_fdt_blob_setup() originally was to
allow for the usecase you add in patch 2, so it's nice to see that
fulfilled :>
> ---
> arch/arm/mach-snapdragon/board.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm/mach-snapdragon/board.c
> b/arch/arm/mach-snapdragon/board.c
> index
> f1319df4314783622bb5f4f2410d1d4fd28a1c83..2ef936aab757c7045729a2dd91944f4f9bff917e
> 100644
> --- a/arch/arm/mach-snapdragon/board.c
> +++ b/arch/arm/mach-snapdragon/board.c
> @@ -88,20 +88,21 @@ int dram_init_banksize(void)
> return 0;
> }
>
> -static void qcom_parse_memory(void)
> +static void qcom_parse_memory(const void *fdt)
> {
> - ofnode node;
> + int offset;
> const fdt64_t *memory;
> int memsize;
> phys_addr_t ram_end = 0;
> int i, j, banks;
>
> - node = ofnode_path("/memory");
> - if (!ofnode_valid(node)) {
> + offset = fdt_path_offset(fdt, "/memory");
> + if (offset < 0) {
> log_err("No memory node found in device tree!\n");
> return;
> }
> - memory = ofnode_read_prop(node, "reg", &memsize);
> +
> + memory = fdt_getprop(fdt, offset, "reg", &memsize);
> if (!memory) {
> log_err("No memory configuration was provided by the previous
> bootloader!\n");
> return;
> @@ -158,7 +159,7 @@ int board_fdt_blob_setup(void **fdtp)
>
> fdt = (struct fdt_header *)get_prev_bl_fdt_addr();
> external_valid = fdt && !fdt_check_header(fdt);
> - internal_valid = !fdt_check_header(gd->fdt_blob);
> + internal_valid = !fdt_check_header(*fdtp);
>
> /*
> * There is no point returning an error here, U-Boot can't do anything
> useful in this situation.
> @@ -181,7 +182,7 @@ int board_fdt_blob_setup(void **fdtp)
> * Parse the /memory node while we're here,
> * this makes it easy to do other things early.
> */
> - qcom_parse_memory();
> + qcom_parse_memory(*fdtp);
>
> return ret;
> }
>
--
// Caleb (they/them)
