mmc: host: sdhci-esdhc-imx: async sdio interrupt and hardware auto-tuning

[Bough Chen]

> -----Original Message-----
> From: Marcel Ziswiler <marcel.ziswiler at toradex.com>
> Sent: 2022年11月3日 4:43
> To: linux-arm-kernel at lists.infradead.org; linux-mmc at vger.kernel.org;
> linux-kernel at vger.kernel.org
> Cc: dl-linux-imx <linux-imx at nxp.com>; kernel at pengutronix.de;
> s.hauer at pengutronix.de; Bough Chen <haibo.chen at nxp.com>;
> ulf.hansson at linaro.org; shawnguo at kernel.org; adrian.hunter at intel.com;
> festevam at gmail.com
> Subject: mmc: host: sdhci-esdhc-imx: async sdio interrupt and hardware
> auto-tuning
> 
> Hi there
> 
> When we investigated an SDIO Wi-Fi stability issue I discovered the following
> downstream-only commit in NXP's latest downstream BSP
> 5.15.52_2.1.0 [1]. The asynchronous SDIO interrupt seems to adversly affect the
> hardware auto-tuning. As a workaround what got implemented is an fsl-custom
> device tree property that limits the auto-tuning to
> 1 bit only (e.g. on DAT[0]) while the SDIO interrupt stays on DAT[1].
> 
> Does anybody know any further details about this?
> 
> Would this be a reasonable thing to also implement upstream?

Hi Marcel,

I send these patches to community few month ago, get some comments related to dts part. 
I will continue to do the upstream work for these patches.

Best Regards
Haibo Chen
> 
> Unfortunately, so far we have not really done any extensive SDIO validation
> using upstream but I plan to set something like that up so we may see whether
> or not we are also hitting such issue.
> 
> Thanks!
> 
> [1]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.co
> m%2Fnxp-imx%2Flinux-imx%2Fcommit%2F84c529a1474a9f6614e475e178ca5fe
> 23b6177de&data=05%7C01%7Chaibo.chen%40nxp.com%7C5b75121c05a
> d48c362d708dabd12e507%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0
> %7C638030186093684545%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAw
> MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7
> C&sdata=PX17UiGkQHfMxHd9Sf2jEbIsZgWO5MCp5pF%2BIDXQIn4%3D&a
> mp;reserved=0
> 
> Cheers
> 
> Marcel