Re: [PATCH v2 18/19] riscv: errata: andes: limit the IOCP workaround to RZ/Five

[Conor Dooley <conor@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 2605 bytes --]

On Fri, Nov 13, 2026 at 03:11:42PM +0800, Mina Hui-Min Chou wrote:
> The SBI-based IOCP check was added for Renesas RZ/Five (R9A07G043F),
> the only upstream-supported SoC whose AX45MP has no IOCP. It matches
> the AX45MP marchid and the mimpid of the RZ/Five core, but it is built
> into every kernel with ERRATA_ANDES_CMO, so the SBI call is issued even
> when the kernel does not support RZ/Five.
> 
> Move the match into soc_is_r9a07g043f() and make it also require
> ARCH_R9A07G043. Kernels without RZ/Five support then skip the SBI call
> and take the generic Andes cache errata path. No other upstream-
> supported SoC uses this AX45MP mimpid, so their behavior does not
> change.

But a device using this soc that doesn't have a dts in mainline won't
function properly, so this is fragile. Why not just do it properly and
check for RZ/Five specifically?
Can check for of_machine_is_compatible() probably?

> 
> While at it, rename ax45mp_iocp_sw_workaround() to
> r9a07g043f_iocp_sw_workaround(), as the check is only used for RZ/Five.
> 
> Signed-off-by: Mina Hui-Min Chou <minachou@andestech.com>
> ---
>  arch/riscv/errata/andes/errata.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/riscv/errata/andes/errata.c b/arch/riscv/errata/andes/errata.c
> index 530d2df216e0..f2535a81b1e2 100644
> --- a/arch/riscv/errata/andes/errata.c
> +++ b/arch/riscv/errata/andes/errata.c
> @@ -25,7 +25,7 @@
>  
>  #define ANDES_SBI_EXT_IOCP_SW_WORKAROUND	1
>  
> -static long ax45mp_iocp_sw_workaround(void)
> +static long r9a07g043f_iocp_sw_workaround(void)
>  {
>  	struct sbiret ret;
>  
> @@ -39,6 +39,13 @@ static long ax45mp_iocp_sw_workaround(void)
>  	return ret.error ? 0 : ret.value;
>  }
>  
> +static bool soc_is_r9a07g043f(unsigned long arch_id, unsigned long impid)
> +{
> +	return IS_ENABLED(CONFIG_ARCH_R9A07G043) &&
> +	       arch_id == ANDES_AX45MP_MARCHID &&
> +	       impid == ANDES_AX45MP_MIMPID;
> +}
> +
>  static void errata_probe_andes_cache(unsigned int stage, unsigned long arch_id, unsigned long impid)
>  {
>  	static bool done;
> @@ -51,8 +58,8 @@ static void errata_probe_andes_cache(unsigned int stage, unsigned long arch_id,
>  
>  	done = true;
>  
> -	if (arch_id == ANDES_AX45MP_MARCHID && impid == ANDES_AX45MP_MIMPID) {
> -		if (!ax45mp_iocp_sw_workaround())
> +	if (soc_is_r9a07g043f(arch_id, impid)) {
> +		if (!r9a07g043f_iocp_sw_workaround())
>  			return;
>  	} else if (riscv_isa_extension_available(NULL, ZICBOM)) {
>  		return;
> -- 
> 2.34.1
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]