On Fri, 21 Jan 2022 at 08:19, Axe Yang <axe.yang@xxxxxxxxxxxx> wrote:
>
> 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";
Looks like you need to update the DT docs too to describe these new
things, right?
> ...
> pinctrl-2 = <&mmc2_pins_eint>;
> pinctrl-3 = <&mmc2_pins_dat1>;
> ...
> cap-sdio-async-irq;
> ...
> };
>
> Co-developed-by: Yong Mao <yong.mao@xxxxxxxxxxxx>
> Signed-off-by: Yong Mao <yong.mao@xxxxxxxxxxxx>
> Signed-off-by: Axe Yang <axe.yang@xxxxxxxxxxxx>
> ---
> drivers/mmc/host/mtk-sd.c | 123 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 115 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 65037e1d7723..f8e38228d810 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) 2014-2015, 2022 MediaTek Inc.
> * Author: Chaotian.Jing <chaotian.jing@xxxxxxxxxxxx>
> */
>
> @@ -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 +2469,48 @@ 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);
> +
> + spin_lock(&host->lock);
> + 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(&host->lock);
> +
> + 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);
> +
> + irq = gpiod_to_irq(desc);
> + if (irq < 0)
> + return irq;
> +
> + ret = devm_request_threaded_irq(host->dev, irq, NULL, msdc_sdio_eint_irq,
> + IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_NO_AUTOEN,
> + "sdio-eint", host);
Again, I think you need to update the DT doc to describe these new
IRQ/GPIO things.
> + 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 +2681,23 @@ static int msdc_drv_probe(struct platform_device *pdev)
> goto host_free;
> }
>
> + if (!(mmc->caps2 & MMC_CAP2_NO_SDIO) && (mmc->caps2 & MMC_CAP2_SDIO_ASYNC_IRQ)) {
> + /* 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 +2789,16 @@ 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);
> @@ -2843,8 +2920,22 @@ static int __maybe_unused msdc_runtime_suspend(struct device *dev)
> {
> struct mmc_host *mmc = dev_get_drvdata(dev);
> struct msdc_host *host = mmc_priv(mmc);
> + unsigned long flags;
>
> 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;
> }
> @@ -2853,6 +2944,7 @@ static int __maybe_unused msdc_runtime_resume(struct device *dev)
> {
> struct mmc_host *mmc = dev_get_drvdata(dev);
> struct msdc_host *host = mmc_priv(mmc);
> + unsigned long flags;
> int ret;
>
> ret = msdc_ungate_clock(host);
> @@ -2860,10 +2952,25 @@ 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 +2984,13 @@ 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)
> };
>
Overall the approach makes perfect sense to me!
However, I think the code can be simplified and made more robust by
using the wakeirq interface instead. Please have a look at
dev_pm_set_dedicated_wake_irq() and friends. Using them, will let the
runtime PM core deal with disabling/enabling the IRQ, rather than
having to do that manually by the driver, for example.
If you want to get inspired by an existing implementation, please have
a look at the sdhci-omap driver.
Kind regards
Uffe
