linux-kernel - Re: [PATCH 4/5] mmc: mtk-sd: enable internal card-detect logic.

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Message-ID: <1555569583.18628.29.camel@mhfsdcap03>
Date:   Thu, 18 Apr 2019 14:39:43 +0800
From:   Chaotian Jing <chaotian.jing@...iatek.com>
To:     NeilBrown <neil@...wn.name>
CC:     Ulf Hansson <ulf.hansson@...aro.org>, <linux-mmc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <thirtythreeforty@...il.com>
Subject: Re: [PATCH 4/5] mmc: mtk-sd: enable internal card-detect logic.

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 <neil@...wn.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;
> 
>