Hi Haibo, On Thu, Oct 21, 2021 at 08:00:43AM +0000, Bough Chen wrote: > > -----Original Message----- > > From: Chester Lin [mailto:clin@xxxxxxxx] > > Sent: 2021年10月21日 15:31 > > To: Ulf Hansson <ulf.hansson@xxxxxxxxxx>; dl-S32 <S32@xxxxxxx>; dl-linux-imx > > <linux-imx@xxxxxxx>; Bough Chen <haibo.chen@xxxxxxx>; Aisheng Dong > > <aisheng.dong@xxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx > > Cc: Rob Herring <robh+dt@xxxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; > > Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>; Pengutronix Kernel Team > > <kernel@xxxxxxxxxxxxxx>; Fabio Estevam <festevam@xxxxxxxxx>; > > devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; Radu-nicolae Pirea (OSS) > > <radu-nicolae.pirea@xxxxxxxxxxx>; Andreas Färber <afaerber@xxxxxxx>; > > Matthias Brugger <mbrugger@xxxxxxxx>; Ivan T . Ivanov <iivanov@xxxxxxx>; > > Lee, Chun-Yi <jlee@xxxxxxxx> > > Subject: Re: [RFC PATCH 2/3] mmc: sdhci-esdhc-imx: add NXP S32G2 support > > > > Hi NXP S32 and i.MX Linux teams, > > > > On Thu, Oct 21, 2021 at 03:13:32PM +0800, Chester Lin wrote: > > > Support the SDHCI controller found on NXP S32G2 platform. The new flag > > > ESDHC_FLAG_SKIP_ERR004536 is used because the hardware erratum bit is > > > not applicable for S32G2. > > > > > > Signed-off-by: Chester Lin <clin@xxxxxxxx> > > > --- > > > drivers/mmc/host/sdhci-esdhc-imx.c | 17 +++++++++++++++-- > > > 1 file changed, 15 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c > > > b/drivers/mmc/host/sdhci-esdhc-imx.c > > > index f18d169bc8ff..d0f7d46a0354 100644 > > > --- a/drivers/mmc/host/sdhci-esdhc-imx.c > > > +++ b/drivers/mmc/host/sdhci-esdhc-imx.c > > > @@ -196,6 +196,9 @@ > > > */ > > > #define ESDHC_FLAG_BROKEN_AUTO_CMD23 BIT(16) > > > > > > +/* ERR004536 is not applicable for the IP */ > > > +#define ESDHC_FLAG_SKIP_ERR004536 BIT(17) > > > + > > > enum wp_types { > > > ESDHC_WP_NONE, /* no WP, neither controller nor gpio */ > > > ESDHC_WP_CONTROLLER, /* mmc controller internal WP */ > > > @@ -289,6 +292,13 @@ static const struct esdhc_soc_data > > usdhc_imx7d_data = { > > > | ESDHC_FLAG_BROKEN_AUTO_CMD23, > > > }; > > > > > > +static struct esdhc_soc_data usdhc_s32g2_data = { > > > + .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_MAN_TUNING > > > + | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200 > > > + | ESDHC_FLAG_HS400 | ESDHC_FLAG_HS400_ES > > > + | ESDHC_FLAG_SKIP_ERR004536, > > > +}; > > > + > > > static struct esdhc_soc_data usdhc_imx7ulp_data = { > > > .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING > > > | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200 @@ -347,6 > > +357,7 @@ > > > static const struct of_device_id imx_esdhc_dt_ids[] = { > > > { .compatible = "fsl,imx7ulp-usdhc", .data = &usdhc_imx7ulp_data, }, > > > { .compatible = "fsl,imx8qxp-usdhc", .data = &usdhc_imx8qxp_data, }, > > > { .compatible = "fsl,imx8mm-usdhc", .data = &usdhc_imx8mm_data, }, > > > + { .compatible = "nxp,s32g2-usdhc", .data = &usdhc_s32g2_data, }, > > > { /* sentinel */ } > > > }; > > > MODULE_DEVICE_TABLE(of, imx_esdhc_dt_ids); @@ -1359,8 +1370,10 > > @@ > > > static void sdhci_esdhc_imx_hwinit(struct sdhci_host *host) > > > * erratum ESDHC_FLAG_ERR004536 fix for MX6Q TO1.2 and MX6DL > > > * TO1.1, it's harmless for MX6SL > > > */ > > > - writel(readl(host->ioaddr + 0x6c) & ~BIT(7), > > > - host->ioaddr + 0x6c); > > > + if (!(imx_data->socdata->flags & ESDHC_FLAG_SKIP_ERR004536)) { > > > + writel(readl(host->ioaddr + 0x6c) & ~BIT(7), > > > + host->ioaddr + 0x6c); > > > + } > > > > Hope you don't might that I raise this question here. Is it really necessary to > > unconditionally apply the erratum bit even if some SoCs might not need this > > workaround? From the S32 implementation in CodeAurora[1], I noticed that > > this bit is not required by S32V/S32G so I wonder if there's any better way to > > refine this part? > > > > I confirmed with IP owner before, for SoC contain this errata fixup, clear this bit 7 > will enable the fixup, set the bit 7 will disable the fixup. > For SoC which do not contain this errata fixup, this bit 7 has no definition. > So it's okay to clear this bit 7 unconditionally. > Thanks for your reply. If I understand correctly, this bit should be almost the same even if the IP can be used in different SoCs. Actually I haven't found an issue even if I have tried to clear the bit-7 on S32G274A although this patch just gets the driver working on S32G, which still has limited functions [e.g. pins_100mhz and pins_200mhz are missing]. I just wonder if any case should avoid touching this bit since the s32 downstream kernel has a specific handling for this part. @NXP S32 team: Please let us know if any concern about this bit. Thanks, Chester > > > > Thanks, > > Chester > > > > [1] > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsource. > > codeaurora.org%2Fexternal%2Fautobsps32%2Flinux%2Ftree%2Fdrivers%2Fm > > mc%2Fhost%2Fsdhci-esdhc-imx.c%3Fh%3Drelease%2Fbsp30.0-5.4-rt%23n1268 > > &data=04%7C01%7Chaibo.chen%40nxp.com%7Cec36a273354b4b66c45b > > 08d99464c449%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63770 > > 3982782606697%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ > > QIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=hvzsy > > 3W%2FpKXBmXxS8%2F73huzb157a%2FuHa5G4lFWj5ABQ%3D&reserved= > > 0 > > > > > > > > /* disable DLL_CTRL delay line settings */ > > > writel(0x0, host->ioaddr + ESDHC_DLL_CTRL); > > > -- > > > 2.30.0 > > > >
