Re: [PATCH v9 3/3] mmc: mediatek: add support for SDIO eint wakup IRQ

From: Ulf Hansson
Date: Mon Apr 04 2022 - 11:02:02 EST

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On Tue, 29 Mar 2022 at 05:29, 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 "state_eint" is mandatory. Since
> this feature depends on asynchronous interrupts, "wakeup-source",
> "keep-power-in-suspend" and "cap-sdio-irq" flags are necessary, and
> the interrupts list should be extended:
> &mmcX {
> ...
> interrupts-extended = <...>,
> <&pio xxx IRQ_TYPE_LEVEL_LOW>;
> ...
> pinctrl-names = "default", "state_uhs", "state_eint";
> ...
> pinctrl-2 = <&mmc2_pins_eint>;
> ...
> cap-sdio-irq;
> keep-power-in-suspend;
> wakeup-source;
> ...
> };
>
> 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 | 94 +++++++++++++++++++++++++++++++++++----
> 1 file changed, 86 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 65037e1d7723..2905d7134243 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>
> */
>
> @@ -20,6 +20,7 @@
> #include <linux/platform_device.h>
> #include <linux/pm.h>
> #include <linux/pm_runtime.h>
> +#include <linux/pm_wakeirq.h>
> #include <linux/regulator/consumer.h>
> #include <linux/slab.h>
> #include <linux/spinlock.h>
> @@ -440,8 +441,11 @@ struct msdc_host {
> struct pinctrl *pinctrl;
> struct pinctrl_state *pins_default;
> struct pinctrl_state *pins_uhs;
> + struct pinctrl_state *pins_eint;
> struct delayed_work req_timeout;
> int irq; /* host interrupt */
> + int eint_irq; /* interrupt from sdio device for waking up system */
> + int sdio_wake_irq_depth;
> struct reset_control *reset;
>
> struct clk *src_clk; /* msdc source clock */
> @@ -465,6 +469,7 @@ 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 +1532,12 @@ 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_enable_async_irq(mmc->card)) {

It might not be obvious, but in fact mmc->card always exists in this
case, hence there is no need to check the pointer before using it.

> + 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)
> @@ -2631,6 +2638,18 @@ static int msdc_drv_probe(struct platform_device *pdev)
> goto host_free;
> }
>
> + /* Support for SDIO eint irq ? */
> + if (mmc->pm_caps & MMC_PM_WAKE_SDIO_IRQ) {
> + host->pins_eint = pinctrl_lookup_state(host->pinctrl, "state_eint");
> + if (IS_ERR(host->pins_eint)) {
> + ret = dev_err_probe(&pdev->dev, PTR_ERR(host->pins_eint),
> + "Cannot find pinctrl eint!\n");
> + goto host_free;
> + }
> +
> + host->sdio_eint_ready = true;

Rather than using a separate variable, couldn't we just check "if
(host->pins_eint)" to know whether wakeup settings shall be managed?

> + }
> +
> msdc_of_property_parse(pdev, host);
>
> host->dev = &pdev->dev;
> @@ -2722,6 +2741,21 @@ static int msdc_drv_probe(struct platform_device *pdev)
> if (ret)
> goto release;
>
> + if (host->sdio_eint_ready) {
> + host->eint_irq = irq_of_parse_and_map(host->dev->of_node, 1);
> + ret = host->eint_irq ? dev_pm_set_dedicated_wake_irq(host->dev, host->eint_irq) :
> + -ENODEV;

I think it would make better sense to call
dev_pm_set_dedicated_wake_irq() from msdc_enable_sdio_irq(). In this
way, you can still support SDIO irqs, even if there are no GPIO irq
for available for re-routing.

In other words, if the GPIO irq is available, then that's the best
option and we should use that - otherwise we need to keep preventing
runtime-suspend by bumping the runtime PM usage count.

> +
> + if (ret) {
> + dev_err(host->dev, "Failed to register data1 eint irq!\n");
> + goto release;
> + }
> +
> + dev_pm_disable_wake_irq(host->dev);
> + pinctrl_select_state(host->pinctrl, host->pins_uhs);
> + }
> +
> + device_init_wakeup(host->dev, true);

I think this better belongs under the condition of whether
MMC_PM_WAKE_SDIO_IRQ and MMC_PM_KEEP_POWER caps are set.

> pm_runtime_set_active(host->dev);
> pm_runtime_set_autosuspend_delay(host->dev, MTK_MMC_AUTOSUSPEND_DELAY);
> pm_runtime_use_autosuspend(host->dev);
> @@ -2734,6 +2768,7 @@ static int msdc_drv_probe(struct platform_device *pdev)
> return 0;
> end:
> pm_runtime_disable(host->dev);
> + dev_pm_clear_wake_irq(host->dev);
> release:
> platform_set_drvdata(pdev, NULL);
> msdc_deinit_hw(host);
> @@ -2845,6 +2880,16 @@ static int __maybe_unused msdc_runtime_suspend(struct device *dev)
> struct msdc_host *host = mmc_priv(mmc);
>
> msdc_save_reg(host);
> +
> + if (host->sdio_eint_ready) {

The core provides a helper function, sdio_irq_claimed(), that can be
used to know whether there is an SDIO irq registered. It looks like
that certainly can be useful here.

> + disable_irq(host->irq);
> + pinctrl_select_state(host->pinctrl, host->pins_eint);
> + if (host->sdio_wake_irq_depth == 0) {
> + dev_pm_enable_wake_irq(dev);

This should be managed from the runtime PM core. See rpm_suspend().

Or perhaps there is a reason that doesn't work for you?

> + host->sdio_wake_irq_depth++;

Again, sdio_irq_claimed() is probably better to use.

> + }
> + sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> + }
> msdc_gate_clock(host);
> return 0;
> }
> @@ -2860,12 +2905,25 @@ static int __maybe_unused msdc_runtime_resume(struct device *dev)
> return ret;
>
> msdc_restore_reg(host);
> +
> + if (host->sdio_eint_ready) {
> + if (host->sdio_wake_irq_depth > 0) {
> + dev_pm_disable_wake_irq(dev);
> + host->sdio_wake_irq_depth--;
> + sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> + } else {
> + sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
> + }
> + 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);
> + struct msdc_host *host = mmc_priv(mmc);
> int ret;
>
> if (mmc->caps2 & MMC_CAP2_CQE) {
> @@ -2874,16 +2932,36 @@ static int __maybe_unused msdc_suspend(struct device *dev)
> return ret;
> }
>
> + if (host->sdio_eint_ready)
> + enable_irq_wake(host->eint_irq);

The PM core should manage this for us through dpm_suspend_noirq(), I
think. We just need to make sure that the runtime PM status of the
device has been set to RPM_SUSPENDED before dpm_suspend_noirq() gets
called. Have a look at dpm_suspend_noirq() ->
device_wakeup_arm_wake_irqs() -> dev_pm_arm_wake_irq().

In other words (and unless I am missing something), if we continue to
call pm_runtime_force_suspend() from a ->suspend() callback this
should work just fine.

> +
> 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)
> {
> + struct mmc_host *mmc = dev_get_drvdata(dev);
> + struct msdc_host *host = mmc_priv(mmc);
> +
> + if (host->sdio_eint_ready) {
> + disable_irq_wake(host->eint_irq);
> +
> + /*
> + * In noirq resume stage, msdc_runtime_resume()
> + * won't be called, so disalbe wake irq here
> + * to block dedicated wake irq handler callback.
> + */
> + if (likely(host->sdio_wake_irq_depth > 0)) {
> + dev_pm_disable_wake_irq(dev);
> + host->sdio_wake_irq_depth--;
> + }

Similar comment as from the system suspend case. I don't think we need
to move to the noirq phase.

Or maybe I am missing something here?

> + }
> +
> 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)
> };
>
> --
> 2.25.1
>

Kind regards
Uffe

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