[PATCH] lib: utils/regmap: Fix reg_stride calculation in syscon regmap

[Anup Patel]

On Sat, Apr 4, 2026 at 1:59 AM David E. Garcia Porras
<david.garcia at aheadcomputing.com> wrote:
>
> The reg_stride field represents the address stride in bytes between
> consecutive registers. The Linux kernel regmap framework validates
> register accesses using IS_ALIGNED(reg, map->reg_stride) as an address
> alignment check (drivers/base/regmap/regmap.c). The Linux kernel syscon
> driver (drivers/mfd/syscon.c) sets reg_stride directly to reg_io_width:
>
>   syscon_config.reg_stride = reg_io_width;
>
> The current OpenSBI code incorrectly multiplies reg_io_width by 8,
> converting a byte value to bits. Fix this by using reg_io_width directly
> as the stride value, consistent with the Linux kernel.
>
> Signed-off-by: David E. Garcia Porras <david.garcia at aheadcomputing.com>

Fixes tag is missing but I will add this at the time of merging.

Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

> ---
>  lib/utils/regmap/fdt_regmap_syscon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/utils/regmap/fdt_regmap_syscon.c b/lib/utils/regmap/fdt_regmap_syscon.c
> index 1309a55c..59cd5ee5 100644
> --- a/lib/utils/regmap/fdt_regmap_syscon.c
> +++ b/lib/utils/regmap/fdt_regmap_syscon.c
> @@ -190,7 +190,7 @@ static int regmap_syscon_init(const void *fdt, int nodeoff,
>
>         srm->rmap.id = nodeoff;
>         srm->rmap.reg_shift = 0;
> -       srm->rmap.reg_stride = srm->reg_io_width * 8;
> +       srm->rmap.reg_stride = srm->reg_io_width;
>         srm->rmap.reg_base = 0;
>         srm->rmap.reg_max = size / srm->reg_io_width;
>         switch (srm->reg_io_width) {
> --
> 2.43.0
>
>
> --
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