Date:   Mon, 17 Jan 2022 11:50:33 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Axe Yang <axe.yang@...iatek.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Chaotian Jing <chaotian.jing@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Cc:     Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Satya Tangirala <satyat@...gle.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Lucas Stach <dev@...xeye.de>,
        Eric Biggers <ebiggers@...gle.com>,
        Andrew Jeffery <andrew@...id.au>,
        Stephen Boyd <swboyd@...omium.org>,
        Kiwoong Kim <kwmad.kim@...sung.com>,
        Yue Hu <huyue2@...ong.com>, Tian Tao <tiantao6@...ilicon.com>,
        linux-mmc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Yong Mao <yong.mao@...iatek.com>
Subject: Re: [PATCH 3/3] mmc: mediatek: add support for SDIO eint IRQ

Il 17/01/22 08:12, Axe Yang ha scritto:
> Add support for eint IRQ when MSDC is used as an SDIO host. This
> feature requires SDIO device support async IRQ function. With this
> feature, SDIO host can be awakened by SDIO card in suspend state,
> without additional pin.
> 
> MSDC driver will time-share the SDIO DAT1 pin. During suspend, MSDC
> turn off clock and switch SDIO DAT1 pin to GPIO mode. And during
> resume, switch GPIO function back to DAT1 mode then turn on clock.
> 
> Some device tree property should be added or modified in MSDC node
> to support SDIO eint IRQ. Pinctrls named state_dat1 and state_eint
> are mandatory. And cap-sdio-async-irq flag is necessary since this
> feature depends on asynchronous interrupt:
>          &mmcX {
>                  ...
>                  pinctrl-names = "default", "state_uhs", "state_eint",
>                                  "state_dat1";
>                  ...
>                  pinctrl-2 = <&mmc2_pins_eint>;
>                  pinctrl-3 = <&mmc2_pins_dat1>;
>                  ...
>                  cap-sdio-async-irq;
>                  ...
>          };
> 
> Signed-off-by: Axe Yang <axe.yang@...iatek.com>
> Signed-off-by: Yong Mao <yong.mao@...iatek.com>
> ---
>   drivers/mmc/host/mtk-sd.c | 125 +++++++++++++++++++++++++++++++++++---
>   1 file changed, 117 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 65037e1d7723..cbdbcce99fd9 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -1,6 +1,6 @@
>   // SPDX-License-Identifier: GPL-2.0-only
>   /*
> - * Copyright (c) 2014-2015 MediaTek Inc.
> + * Copyright (c) 2022 MediaTek Inc.
>    * Author: Chaotian.Jing <chaotian.jing@...iatek.com>
>    */
>   
> @@ -9,6 +9,7 @@
>   #include <linux/clk.h>
>   #include <linux/delay.h>
>   #include <linux/dma-mapping.h>
> +#include <linux/gpio/consumer.h>
>   #include <linux/iopoll.h>
>   #include <linux/ioport.h>
>   #include <linux/irq.h>
> @@ -440,8 +441,12 @@ struct msdc_host {
>   	struct pinctrl *pinctrl;
>   	struct pinctrl_state *pins_default;
>   	struct pinctrl_state *pins_uhs;
> +	struct pinctrl_state *pins_eint;
> +	struct pinctrl_state *pins_dat1;
>   	struct delayed_work req_timeout;
>   	int irq;		/* host interrupt */
> +	int eint_irq;		/* device interrupt */
> +	int sdio_irq_cnt;	/* irq enable cnt */
>   	struct reset_control *reset;
>   
>   	struct clk *src_clk;	/* msdc source clock */
> @@ -465,6 +470,7 @@ struct msdc_host {
>   	bool hs400_tuning;	/* hs400 mode online tuning */
>   	bool internal_cd;	/* Use internal card-detect logic */
>   	bool cqhci;		/* support eMMC hw cmdq */
> +	bool sdio_eint_ready;	/* Ready to support SDIO eint interrupt */
>   	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 */
> @@ -1527,10 +1533,12 @@ static void msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)
>   	__msdc_enable_sdio_irq(host, enb);
>   	spin_unlock_irqrestore(&host->lock, flags);
>   
> -	if (enb)
> -		pm_runtime_get_noresume(host->dev);
> -	else
> -		pm_runtime_put_noidle(host->dev);
> +	if (mmc->card && !mmc->card->cccr.enable_async_irq) {
> +		if (enb)
> +			pm_runtime_get_noresume(host->dev);
> +		else
> +			pm_runtime_put_noidle(host->dev);
> +	}
>   }
>   
>   static irqreturn_t msdc_cmdq_irq(struct msdc_host *host, u32 intsts)
> @@ -2461,6 +2469,50 @@ static const struct mmc_host_ops mt_msdc_ops = {
>   	.hw_reset = msdc_hw_reset,
>   };
>   
> +static irqreturn_t msdc_sdio_eint_irq(int irq, void *dev_id)
> +{
> +	struct msdc_host *host = dev_id;
> +	struct mmc_host *mmc = mmc_from_priv(host);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&host->lock, flags);
> +	if (likely(host->sdio_irq_cnt > 0)) {
> +		disable_irq_nosync(host->eint_irq);
> +		disable_irq_wake(host->eint_irq);
> +		host->sdio_irq_cnt--;
> +	}
> +	spin_unlock_irqrestore(&host->lock, flags);
> +
> +	sdio_signal_irq(mmc);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int msdc_request_dat1_eint_irq(struct msdc_host *host)
> +{
> +	struct gpio_desc *desc;
> +	int irq, ret;
> +
> +	desc = devm_gpiod_get(host->dev, "eint", GPIOD_IN);
> +	if (IS_ERR(desc))
> +		return PTR_ERR(desc);
> +
> +	ret = gpiod_to_irq(desc);
> +	if (ret < 0)
> +		return ret;
> +
> +	irq = ret;
> +	ret = devm_request_threaded_irq(host->dev, irq, NULL, msdc_sdio_eint_irq,
> +					IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_NO_AUTOEN,
> +					"sdio-eint", host);
> +	if (ret)
> +		return ret;
> +
> +	host->eint_irq = irq;
> +
> +	return 0;
> +}
> +
>   static const struct cqhci_host_ops msdc_cmdq_ops = {
>   	.enable         = msdc_cqe_enable,
>   	.disable        = msdc_cqe_disable,
> @@ -2631,6 +2683,23 @@ static int msdc_drv_probe(struct platform_device *pdev)
>   		goto host_free;
>   	}
>   
> +	if (!(mmc->caps2 & MMC_CAP2_NO_SDIO)) {

Please, also check for the async irq capability here:

if (!(mmc->caps2 & MMC_CAP2_NO_SDIO) && (mmc->caps2 & MMC_CAP2_SDIO_ASYNC_IRQ)) {

...because if we have "state_eint" specified in DT, but we didn't *also* specify
cap-sdio-async-irq, then clearly we don't want to use this functionality - hence
it becomes useless to register the interrupt handler for that because we're never
enabling the CCCR_INTERRUPT_EXT on the card (from drivers/mmc/core/host.c).

Regards,
Angelo

> +		/* Support for SDIO eint irq */
> +		host->pins_eint = pinctrl_lookup_state(host->pinctrl, "state_eint");
> +		if (IS_ERR(host->pins_eint)) {
> +			dev_dbg(&pdev->dev, "Cannot find pinctrl eint!\n");
> +		} else {
> +			host->pins_dat1 = pinctrl_lookup_state(host->pinctrl, "state_dat1");
> +			if (IS_ERR(host->pins_dat1)) {
> +				ret = dev_err_probe(&pdev->dev, PTR_ERR(host->pins_dat1),
> +						    "Cannot find pinctrl dat1!\n");
> +				goto host_free;
> +			}
> +
> +			host->sdio_eint_ready = true;
> +		}
> +	}
> +
>   	msdc_of_property_parse(pdev, host);
>   
>   	host->dev = &pdev->dev;
> @@ -2722,6 +2791,16 @@ static int msdc_drv_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto release;
>   
> +	if (host->sdio_eint_ready) {
> +		ret = msdc_request_dat1_eint_irq(host);
> +		if (ret) {
> +			dev_err(host->dev, "Failed to register data1 eint irq!\n");
> +			goto release;
> +		}
> +
> +		pinctrl_select_state(host->pinctrl, host->pins_dat1);
> +	}
> +
>   	pm_runtime_set_active(host->dev);
>   	pm_runtime_set_autosuspend_delay(host->dev, MTK_MMC_AUTOSUSPEND_DELAY);
>   	pm_runtime_use_autosuspend(host->dev);
> @@ -2841,16 +2920,31 @@ static void msdc_restore_reg(struct msdc_host *host)
>   
>   static int __maybe_unused msdc_runtime_suspend(struct device *dev)
>   {
> +	unsigned long flags;
>   	struct mmc_host *mmc = dev_get_drvdata(dev);
>   	struct msdc_host *host = mmc_priv(mmc);
>   
>   	msdc_save_reg(host);
> +
> +	if (host->sdio_eint_ready) {
> +		disable_irq(host->irq);
> +		pinctrl_select_state(host->pinctrl, host->pins_eint);
> +		spin_lock_irqsave(&host->lock, flags);
> +		if (host->sdio_irq_cnt == 0) {
> +			enable_irq(host->eint_irq);
> +			enable_irq_wake(host->eint_irq);
> +			host->sdio_irq_cnt++;
> +		}
> +		sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> +		spin_unlock_irqrestore(&host->lock, flags);
> +	}
>   	msdc_gate_clock(host);
>   	return 0;
>   }
>   
>   static int __maybe_unused msdc_runtime_resume(struct device *dev)
>   {
> +	unsigned long flags;
>   	struct mmc_host *mmc = dev_get_drvdata(dev);
>   	struct msdc_host *host = mmc_priv(mmc);
>   	int ret;
> @@ -2860,10 +2954,25 @@ static int __maybe_unused msdc_runtime_resume(struct device *dev)
>   		return ret;
>   
>   	msdc_restore_reg(host);
> +
> +	if (host->sdio_eint_ready) {
> +		spin_lock_irqsave(&host->lock, flags);
> +		if (host->sdio_irq_cnt > 0) {
> +			disable_irq_nosync(host->eint_irq);
> +			disable_irq_wake(host->eint_irq);
> +			host->sdio_irq_cnt--;
> +			sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> +		} else {
> +			sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
> +		}
> +		spin_unlock_irqrestore(&host->lock, flags);
> +		pinctrl_select_state(host->pinctrl, host->pins_uhs);
> +		enable_irq(host->irq);
> +	}
>   	return 0;
>   }
>   
> -static int __maybe_unused msdc_suspend(struct device *dev)
> +static int __maybe_unused msdc_suspend_noirq(struct device *dev)
>   {
>   	struct mmc_host *mmc = dev_get_drvdata(dev);
>   	int ret;
> @@ -2877,13 +2986,13 @@ static int __maybe_unused msdc_suspend(struct device *dev)
>   	return pm_runtime_force_suspend(dev);
>   }
>   
> -static int __maybe_unused msdc_resume(struct device *dev)
> +static int __maybe_unused msdc_resume_noirq(struct device *dev)
>   {
>   	return pm_runtime_force_resume(dev);
>   }
>   
>   static const struct dev_pm_ops msdc_dev_pm_ops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(msdc_suspend, msdc_resume)
> +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(msdc_suspend_noirq, msdc_resume_noirq)
>   	SET_RUNTIME_PM_OPS(msdc_runtime_suspend, msdc_runtime_resume, NULL)
>   };
>   
> 

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