On Tue, 2019-04-16 at 14:47 +1000, NeilBrown wrote:
> The mtk-sd silicon has integrated card-detect logic that is
> enabled, at least, on the MT7621 as used in the GNUBEE NAS.
> 
> If the sdhci isn't marked non-removable and doesn't have a
> cd-gpio configured, assume the internal cd logic should be used.
> 
> Signed-off-by: NeilBrown <n...@brown.name>
> ---
>  drivers/mmc/host/mtk-sd.c |   58 
> ++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 54 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index d379f2ece305..341cf5f03429 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -300,6 +300,8 @@
>  #define CMD_TIMEOUT         (HZ/10 * 5)      /* 100ms x5 */
>  #define DAT_TIMEOUT         (HZ    * 5)      /* 1000ms x5 */
>  
> +#define DEFAULT_DEBOUNCE     (8)     /* 8 cycles CD debounce */
> +
>  #define PAD_DELAY_MAX        32 /* PAD delay cells */
>  
> /*--------------------------------------------------------------------------*/
>  /* Descriptor Structure                                                     
> */
> @@ -430,6 +432,7 @@ struct msdc_host {
>       bool hs400_cmd_resp_sel_rising;
>                                /* cmd response sample selection for HS400 */
>       bool hs400_mode;        /* current eMMC will run at hs400 mode */
> +     bool internal_cd;       /* Use internal card-detect logic */
>       struct msdc_save_para save_para; /* used when gate HCLK */
>       struct msdc_tune_para def_tune_para; /* default tune setting */
>       struct msdc_tune_para saved_tune_para; /* tune result of CMD21/CMD19 */
> @@ -1430,6 +1433,11 @@ static irqreturn_t msdc_irq(int irq, void *dev_id)
>                       sdio_signal_irq(host->mmc);
>               }
>  
> +             if ((events & event_mask) & MSDC_INT_CDSC) {
> +                     mmc_detect_change(host->mmc, msecs_to_jiffies(20));
> +                     events &= ~MSDC_INT_CDSC;
> +             }
> +
>               if (!(events & (event_mask & ~MSDC_INT_SDIOIRQ)))
>                       break;
>  
> @@ -1463,14 +1471,24 @@ static void msdc_init_hw(struct msdc_host *host)
>       /* Reset */
>       msdc_reset_hw(host);
>  
> -     /* Disable card detection */
> -     sdr_clr_bits(host->base + MSDC_PS, MSDC_PS_CDEN);
> -
>       /* Disable and clear all interrupts */
>       writel(0, host->base + MSDC_INTEN);
>       val = readl(host->base + MSDC_INT);
>       writel(val, host->base + MSDC_INT);
>  
> +     /* Configure card detection */
> +     if (host->internal_cd) {
> +             sdr_set_field(host->base + MSDC_PS, MSDC_PS_CDDEBOUNCE,
> +                           DEFAULT_DEBOUNCE);
> +             sdr_set_bits(host->base + MSDC_PS, MSDC_PS_CDEN);
> +             sdr_set_bits(host->base + MSDC_INTEN, MSDC_INTEN_CDSC);
> +             sdr_set_bits(host->base + SDC_CFG, SDC_CFG_INSWKUP);
> +     } else {
> +             sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_INSWKUP);
> +             sdr_clr_bits(host->base + MSDC_PS, MSDC_PS_CDEN);
> +             sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_CDSC);
> +     }
> +
>       if (host->top_base) {
>               writel(0, host->top_base + EMMC_TOP_CONTROL);
>               writel(0, host->top_base + EMMC_TOP_CMD);
> @@ -1580,6 +1598,11 @@ static void msdc_init_hw(struct msdc_host *host)
>  static void msdc_deinit_hw(struct msdc_host *host)
>  {
>       u32 val;
> +
> +     /* Disabled card-detect */
> +     sdr_clr_bits(host->base + MSDC_PS, MSDC_PS_CDEN);
> +     sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_INSWKUP);
> +
>       /* Disable and clear all interrupts */
>       writel(0, host->base + MSDC_INTEN);
>  
> @@ -2078,13 +2101,31 @@ static void msdc_ack_sdio_irq(struct mmc_host *mmc)
>       __msdc_enable_sdio_irq(mmc, 1);
>  }
>  
> +static int msdc_get_cd(struct mmc_host *mmc)
> +{
> +     struct msdc_host *host = mmc_priv(mmc);
> +     int val;
> +
> +     if (mmc->caps & MMC_CAP_NONREMOVABLE)
> +             return 1;
> +
> +     if (!host->internal_cd)
> +             return mmc_gpio_get_cd(mmc);
> +
> +     val = readl(host->base + MSDC_PS) & MSDC_PS_CDSTS;
> +     if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> +             return !!val;
> +     else
> +             return !val;
> +}
> +
>  static const struct mmc_host_ops mt_msdc_ops = {
>       .post_req = msdc_post_req,
>       .pre_req = msdc_pre_req,
>       .request = msdc_ops_request,
>       .set_ios = msdc_ops_set_ios,
>       .get_ro = mmc_gpio_get_ro,
> -     .get_cd = mmc_gpio_get_cd,
> +     .get_cd = msdc_get_cd,
>       .enable_sdio_irq = msdc_enable_sdio_irq,
>       .ack_sdio_irq = msdc_ack_sdio_irq,
>       .start_signal_voltage_switch = msdc_ops_switch_volt,
> @@ -2206,6 +2247,15 @@ static int msdc_drv_probe(struct platform_device *pdev)
>               goto host_free;
>       }
>  
> +     if (!(mmc->caps & MMC_CAP_NONREMOVABLE) &&
> +         !mmc_can_gpio_cd(mmc)) {

Should not do this assume!
better to add "mediatek,internal-cd" in your DTS, then no impact to
other Soc.
> +             /*
> +              * Is removable but no GPIO declared, so
> +              * use internal functionality.
> +              */
> +             host->internal_cd = true;
> +     }
> +
>       msdc_of_property_parse(pdev, host);
>  
>       host->dev = &pdev->dev;
> 
> 


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