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

[Marek Vasut]

On 10/28/25 9:00 AM, Alice Guo (OSS) wrote:
>> -----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.
Thank you !