回复: [PATCH] firmware: scmi: Drop mmu_set_region_dcache_behaviour() misuse

[Alice Guo (OSS)]

> -----邮件原件-----
> 发件人: U-Boot <u-boot-bounces at lists.denx.de> 代表 Marek Vasut
> 发送时间: 2025年10月26日 5:35
> 收件人: u-boot at lists.denx.de
> 抄送: Marek Vasut <marek.vasut+renesas at mailbox.org>; Alice Guo
> <alice.guo at nxp.com>; Etienne Carriere <etienne.carriere at linaro.org>; Patrick
> Delaunay <patrick.delaunay at foss.st.com>; Peng Fan <peng.fan at nxp.com>;
> Tom Rini <trini at konsulko.com>; Vinh Nguyen <vinh.nguyen.xz at renesas.com>;
> Viorel Suman <viorel.suman at nxp.com>; Ye Li <ye.li at nxp.com>
> 主题: [PATCH] firmware: scmi: Drop mmu_set_region_dcache_behaviour()
> misuse
> 
> MMU region cache behavior configuration for SCMI/SMT mailboxes is platform
> specific. Even on ARM systems, the mailbox memory may not even be located in
> any cacheable MMU region and may instead reside in some SRAM. Remove this
> non-generic cache behavior configuration code from generic code path.
> 
> It is unlikely that any platform is affected by this change if it did configure its
> MMU regions correctly on start up. Platforms which might be affected are
> i.MX94/95 and STM32MP.
> 
> Fixes: 240720e9052f ("firmware: scmi: mailbox/smt agent device")
> Fixes: 2a3f161c8b16 ("scmi: correctly configure MMU for SCMI buffer")
> Fixes: b2ae10970d40 ("firmware: scmi: use PAGE_SIZE alignment for ARM64")
> Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
> ---
> Cc: Alice Guo <alice.guo at nxp.com>
> Cc: Etienne Carriere <etienne.carriere at linaro.org>
> Cc: Patrick Delaunay <patrick.delaunay at foss.st.com>
> Cc: Peng Fan <peng.fan at nxp.com>
> Cc: Tom Rini <trini at konsulko.com>
> Cc: Vinh Nguyen <vinh.nguyen.xz at renesas.com>
> Cc: Viorel Suman <viorel.suman at nxp.com>
> Cc: Ye Li <ye.li at nxp.com>
> Cc: u-boot at lists.denx.de
> ---
>  drivers/firmware/scmi/smt.c | 14 --------------
>  1 file changed, 14 deletions(-)
> 
> diff --git a/drivers/firmware/scmi/smt.c b/drivers/firmware/scmi/smt.c index
> 237871559f0..cd1c0801f72 100644
> --- a/drivers/firmware/scmi/smt.c
> +++ b/drivers/firmware/scmi/smt.c
> @@ -61,20 +61,6 @@ int scmi_dt_get_smt_buffer(struct udevice *dev, struct
> scmi_smt *smt)
>  	if (device_is_compatible(dev, "arm,scmi") &&
> ofnode_has_property(dev_ofnode(dev), "mboxes"))
>  		scmi_smt_enable_intr(smt, true);
> 
> -#ifdef CONFIG_ARM
> -	if (dcache_status()) {
> -		u32 align_size;
> -
> -		if (IS_ENABLED(CONFIG_ARM64))
> -			align_size = PAGE_SIZE;
> -		else
> -			align_size = MMU_SECTION_SIZE;
> -
> -
> 	mmu_set_region_dcache_behaviour(ALIGN_DOWN((uintptr_t)smt->buf,
> align_size),
> -						ALIGN(smt->size, align_size), DCACHE_OFF);
> -	}
> -#endif
> -
>  	return 0;
>  }
> 
> --
> 2.51.0

Tested-by: Alice Guo <alice.guo at nxp.com>

Tested on two boards: IMX94 and IMX95. No regressions were observed during boot. Looks good to me.

Best regards,
Alice Guo