> -----Original Message----- > From: Adrian Hunter [mailto:adrian.hunter@xxxxxxxxx] > Sent: Tuesday, April 18, 2017 5:38 PM > To: Bough Chen <haibo.chen@xxxxxxx>; ulf.hansson@xxxxxxxxxx; A.S. Dong > <aisheng.dong@xxxxxxx> > Cc: linux-mmc@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] mmc: sdhci-esdhc-imx: reset tuning circuit when power > on mmc card > > On 18/04/17 11:16, Bough Chen wrote: > >> -----Original Message----- > >> From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- > >> owner@xxxxxxxxxxxxxxx] On Behalf Of Adrian Hunter > >> Sent: Tuesday, April 18, 2017 3:16 PM > >> To: Bough Chen <haibo.chen@xxxxxxx>; ulf.hansson@xxxxxxxxxx; A.S. > >> Dong <aisheng.dong@xxxxxxx> > >> Cc: linux-mmc@xxxxxxxxxxxxxxx > >> Subject: Re: [PATCH] mmc: sdhci-esdhc-imx: reset tuning circuit when > >> power on mmc card > >> > >> On 17/04/17 14:45, Haibo Chen wrote: > >>> USDHC tuning circuit should be reset before every time card > >>> enumeration or re-enumeration. > >>> > >>> SD3.0 card need tuning. For SDR104 card, when system suspend in > >>> standby mode, and then resume back, the IO timing is still > >>> SDR104(tuned) which may result in card re-enumeration fail in low > >>> card > >>> speed(400khz) for some cards. And we did meet the issue that in > >>> certain probability, SDR104 card meet mmc command CRC/Timeout error > >>> when send CMD2 during mmc bus resume. > >>> > >>> This patch reset the tuning circuit when the ios timing is > >>> MMC_TIMING_LEGACY/MMC_TIMING_MMC_HS/MMC_TIMING_SD_HS, > >> which means both > >>> mmc_power_up() and mmc_power_off() will reset the tuning circuit. > >>> > >>> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx> > >>> --- > >>> drivers/mmc/host/sdhci-esdhc-imx.c | 26 > ++++++++++++++++++++++++++ > >>> 1 file changed, 26 insertions(+) > >>> > >>> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c > >>> b/drivers/mmc/host/sdhci-esdhc-imx.c > >>> index abad67a..8960833 100644 > >>> --- a/drivers/mmc/host/sdhci-esdhc-imx.c > >>> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c > >>> @@ -889,6 +889,28 @@ static void esdhc_set_strobe_dll(struct > >>> sdhci_host > >> *host) > >>> } > >>> } > >>> > >>> +static void esdhc_reset_tuning(struct sdhci_host *host) { > >>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); > >>> + struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host); > >>> + u16 ctrl; > >>> + > >>> + /* Rest the tuning circurt */ > >>> + if (esdhc_is_usdhc(imx_data)) { > >>> + if (imx_data->socdata->flags & ESDHC_FLAG_MAN_TUNING) { > >>> + ctrl = readl(host->ioaddr + ESDHC_MIX_CTRL); > >>> + ctrl &= ~ESDHC_MIX_CTRL_SMPCLK_SEL; > >> > >> So ESDHC_MIX_CTRL_SMPCLK_SEL is bit-23 but ctrl is 16-bit? > >> > > > > The bit-23 of both register ESDHC_MIX_CTRL and SDHCI_ACMD12_ERR is > named ESDHC_MIX_CTRL_SMPCLK_SEL , define whether tuned clock or fixed > clock is used to sample data. > > The bit-23 of register ESDHC_MIX_CTRL works when STD_TUNING_EN is 0, > which means use MAN tuning. > > The bit-23 of register SDHCI_ACMD12_ERR works when STD_TUNING_EN is > set. > > I meant it looks very weird to try to change bit-23 in a 16-bit variable. > Should 'ctrl' be u32? > Oh, yes, my mistake. Will change in V2 > > > >>> + ctrl &= ~ESDHC_MIX_CTRL_FBCLK_SEL; > >>> + writel(ctrl, host->ioaddr + ESDHC_MIX_CTRL); > >>> + writel(0 << 8, host->ioaddr + > >> ESDHC_TUNE_CTRL_STATUS); > >> > >> 0 << 8 is still zero. > > > > Yes, this code want to clear the bit8~bit14 of register > > ESDHC_TUNE_CTRL_STATUS Here is the define of these bits in RM: > > [14-8] DLY_CELL_SET_PRE[6:0] Set the number of delay cells on the feedback > clock between the feedback clock and CLK_PRE. > > I just meant use 0 not 0 << 8. Yes, seems better. Haibo > > > > > Haibo > >> > >>> + } else if (imx_data->socdata->flags & > >> ESDHC_FLAG_STD_TUNING) { > >>> + ctrl = readl(host->ioaddr + SDHCI_ACMD12_ERR); > >>> + ctrl &= ~ESDHC_MIX_CTRL_SMPCLK_SEL; > >>> + writel(ctrl, host->ioaddr + SDHCI_ACMD12_ERR); > >>> + } > >>> + } > >>> +} > >>> + > >>> static void esdhc_set_uhs_signaling(struct sdhci_host *host, > >>> unsigned > >>> timing) { > >>> u32 m; > >>> @@ -932,6 +954,10 @@ static void esdhc_set_uhs_signaling(struct > >> sdhci_host *host, unsigned timing) > >>> host->ops->set_clock(host, host->clock); > >>> esdhc_set_strobe_dll(host); > >>> break; > >>> + case MMC_TIMING_LEGACY: > >>> + default: > >>> + esdhc_reset_tuning(host); > >>> + break; > >>> } > >>> > >>> esdhc_change_pinstate(host, timing); > >>> > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-mmc" > >> in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo > >> info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
