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Date:   Tue, 24 Nov 2020 14:49:15 -0600
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     ricky_wu@realtek.com
Cc:     arnd@arndb.de, gregkh@linuxfoundation.org, ulf.hansson@linaro.org,
        bhelgaas@google.com, vaibhavgupta40@gmail.com, kdlnx@doth.eu,
        dianders@chromium.org, rmfrfs@gmail.com, lee.jones@linaro.org,
        linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>, linux-pm@vger.kernel.org
Subject: Re: [PATCH] misc: rtsx: rts5249 support runtime PM
Message-ID: <20201124204915.GA585306@bjorn-Precision-5520>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20201124060202.776-1-ricky_wu@realtek.com>
Precedence: bulk

[+cc Rafael, linux-pm for runtime PM question below]

On Tue, Nov 24, 2020 at 02:02:02PM +0800, ricky_wu@realtek.com wrote:
> From: Ricky Wu <ricky_wu@realtek.com>
> 
> rtsx_pci_sdmmc: add to support autosuspend when the rtd3_en is set
> 
> rtsx_pcr: add callback functions about runtime PM
> add delay_work(rtd3_work) to decrease usage count to 0 when staying
> at idle over 10 sec
> 
> rts5249: add extra flow at init function to support wakeup from d3
> and set rtd3_en from register setting

This looks like several patches that should be split up.  The ASPM
changes should be unrelated to runtime PM.

> Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
> ---
>  drivers/misc/cardreader/rts5249.c  |  25 ++++--
>  drivers/misc/cardreader/rtsx_pcr.c | 122 +++++++++++++++++++++++++++--
>  drivers/misc/cardreader/rtsx_pcr.h |   1 +
>  drivers/mmc/host/rtsx_pci_sdmmc.c  |  18 ++++-
>  include/linux/rtsx_pci.h           |   1 +
>  5 files changed, 152 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/misc/cardreader/rts5249.c b/drivers/misc/cardreader/rts5249.c
> index b85279f1fc5e..1da3b1ca1121 100644
> --- a/drivers/misc/cardreader/rts5249.c
> +++ b/drivers/misc/cardreader/rts5249.c
> @@ -65,7 +65,6 @@ static void rtsx_base_fetch_vendor_settings(struct rtsx_pcr *pcr)
>  		pcr_dbg(pcr, "skip fetch vendor setting\n");
>  		return;
>  	}
> -

Doesn't look like an improvement to me.

>  	pcr->aspm_en = rtsx_reg_to_aspm(reg);
>  	pcr->sd30_drive_sel_1v8 = rtsx_reg_to_sd30_drive_sel_1v8(reg);
>  	pcr->card_drive_sel &= 0x3F;
> @@ -73,6 +72,8 @@ static void rtsx_base_fetch_vendor_settings(struct rtsx_pcr *pcr)
>  
>  	pci_read_config_dword(pdev, PCR_SETTING_REG2, &reg);
>  	pcr_dbg(pcr, "Cfg 0x%x: 0x%x\n", PCR_SETTING_REG2, reg);
> +
> +	pcr->rtd3_en = rtsx_reg_to_rtd3_uhsii(reg);
>  	if (rtsx_check_mmc_support(reg))
>  		pcr->extra_caps |= EXTRA_CAPS_NO_MMC;
>  	pcr->sd30_drive_sel_3v3 = rtsx_reg_to_sd30_drive_sel_3v3(reg);
> @@ -278,13 +279,25 @@ static int rts5249_extra_init_hw(struct rtsx_pcr *pcr)
>  
>  	rtsx_pci_send_cmd(pcr, CMD_TIMEOUT_DEF);
>  
> -	if (CHK_PCI_PID(pcr, PID_524A) || CHK_PCI_PID(pcr, PID_525A)) {
> +	if (CHK_PCI_PID(pcr, PID_524A) || CHK_PCI_PID(pcr, PID_525A))
>  		rtsx_pci_write_register(pcr, REG_VREF, PWD_SUSPND_EN, PWD_SUSPND_EN);
> -		rtsx_pci_write_register(pcr, RTS524A_PM_CTRL3, 0x01, 0x00);
> -		rtsx_pci_write_register(pcr, RTS524A_PME_FORCE_CTL, 0x30, 0x20);
> +
> +	if (pcr->rtd3_en) {
> +		if (CHK_PCI_PID(pcr, PID_524A) || CHK_PCI_PID(pcr, PID_525A)) {
> +			rtsx_pci_write_register(pcr, RTS524A_PM_CTRL3, 0x01, 0x01);
> +			rtsx_pci_write_register(pcr, RTS524A_PME_FORCE_CTL, 0x30, 0x30);
> +		} else {
> +			rtsx_pci_write_register(pcr, PM_CTRL3, 0x01, 0x01);
> +			rtsx_pci_write_register(pcr, PME_FORCE_CTL, 0xFF, 0x33);
> +		}
>  	} else {
> -		rtsx_pci_write_register(pcr, PME_FORCE_CTL, 0xFF, 0x30);
> -		rtsx_pci_write_register(pcr, PM_CTRL3, 0x01, 0x00);
> +		if (CHK_PCI_PID(pcr, PID_524A) || CHK_PCI_PID(pcr, PID_525A)) {
> +			rtsx_pci_write_register(pcr, RTS524A_PM_CTRL3, 0x01, 0x00);
> +			rtsx_pci_write_register(pcr, RTS524A_PME_FORCE_CTL, 0x30, 0x20);
> +		} else {
> +			rtsx_pci_write_register(pcr, PME_FORCE_CTL, 0xFF, 0x30);
> +			rtsx_pci_write_register(pcr, PM_CTRL3, 0x01, 0x00);
> +		}
>  	}
>  
>  	/*
> diff --git a/drivers/misc/cardreader/rtsx_pcr.c b/drivers/misc/cardreader/rtsx_pcr.c
> index 5d15607027e9..cb105563bde7 100644
> --- a/drivers/misc/cardreader/rtsx_pcr.c
> +++ b/drivers/misc/cardreader/rtsx_pcr.c
> @@ -20,6 +20,8 @@
>  #include <linux/rtsx_pci.h>
>  #include <linux/mmc/card.h>
>  #include <asm/unaligned.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
>  
>  #include "rtsx_pcr.h"
>  #include "rts5261.h"
> @@ -89,9 +91,16 @@ static void rtsx_comm_set_aspm(struct rtsx_pcr *pcr, bool enable)
>  	if (pcr->aspm_enabled == enable)
>  		return;
>  
> -	pcie_capability_clear_and_set_word(pcr->pci, PCI_EXP_LNKCTL,
> -					   PCI_EXP_LNKCTL_ASPMC,
> -					   enable ? pcr->aspm_en : 0);
> +	if (pcr->aspm_en & 0x02)
> +		rtsx_pci_write_register(pcr, ASPM_FORCE_CTL, FORCE_ASPM_CTL0 |
> +			FORCE_ASPM_CTL1, enable ? 0 : FORCE_ASPM_CTL0 | FORCE_ASPM_CTL1);
> +	else
> +		rtsx_pci_write_register(pcr, ASPM_FORCE_CTL, FORCE_ASPM_CTL0 |
> +			FORCE_ASPM_CTL1, FORCE_ASPM_CTL0 | FORCE_ASPM_CTL1);
> +
> +	if (!enable && (pcr->aspm_en & 0x02))
> +		mdelay(10);

This is a significant change that should be in its own patch and
explained.  Previously we did standard PCI config reads/writes to the
PCIe Link Control register.  After this change we'll use
rtsx_pci_write_register(), which looks like it writes to an MMIO
register in a BAR:

  rtsx_pci_probe
    pcr->remap_addr = ioremap(base, len)

  rtsx_pci_write_register
    rtsx_pci_writel(pcr, RTSX_HAIMR, val)
      iowrite32(val, pcr->remap_addr + reg)

It's not clear that the MMIO register in the BAR is the same as the
one in config space.  And we still write the Link Control register in
config space below and other places.  How are these supposed to be
coordinated?

Drivers should not change ASPM configuration directly.  Especially not
in obfuscated ways like this.

>  	pcr->aspm_enabled = enable;
>  }
> @@ -143,6 +152,9 @@ void rtsx_pci_start_run(struct rtsx_pcr *pcr)
>  	/* If pci device removed, don't queue idle work any more */
>  	if (pcr->remove_pci)
>  		return;
> +	if (pcr->rtd3_en)
> +		if (pcr->pci->dev.power.usage_count.counter == 0)
> +			pm_runtime_get(&(pcr->pci->dev));
>  
>  	if (pcr->state != PDEV_STAT_RUN) {
>  		pcr->state = PDEV_STAT_RUN;
> @@ -1075,6 +1087,19 @@ static void rtsx_pm_power_saving(struct rtsx_pcr *pcr)
>  	rtsx_comm_pm_power_saving(pcr);
>  }
>  
> +static void rtsx_pci_rtd3_work(struct work_struct *work)
> +{
> +	struct delayed_work *dwork = to_delayed_work(work);
> +	struct rtsx_pcr *pcr = container_of(dwork, struct rtsx_pcr, rtd3_work);
> +
> +	pcr_dbg(pcr, "--> %s\n", __func__);
> +
> +	while (pcr->pci->dev.power.usage_count.counter > 0) {
> +		if (pm_runtime_active(&(pcr->pci->dev)))
> +			pm_runtime_put(&(pcr->pci->dev));

I'm not a runtime PM expert, but this looks fishy.  AFAICT this is the
only driver in the tree that uses usage_count.counter this way, which
is a pretty big hint that this needs a closer look.  Cc'd Rafael.

> +	}
> +}
> +
>  static void rtsx_pci_idle_work(struct work_struct *work)
>  {
>  	struct delayed_work *dwork = to_delayed_work(work);
> @@ -1094,6 +1119,9 @@ static void rtsx_pci_idle_work(struct work_struct *work)
>  	rtsx_pm_power_saving(pcr);
>  
>  	mutex_unlock(&pcr->pcr_mutex);
> +
> +	if (pcr->rtd3_en)
> +		mod_delayed_work(system_wq, &pcr->rtd3_work, msecs_to_jiffies(10000));
>  }
>  
>  static void rtsx_base_force_power_down(struct rtsx_pcr *pcr, u8 pm_state)
> @@ -1283,7 +1311,7 @@ static int rtsx_pci_init_hw(struct rtsx_pcr *pcr)
>  	/* Wait SSC power stable */
>  	udelay(200);
>  
> -	rtsx_pci_disable_aspm(pcr);
> +	rtsx_disable_aspm(pcr);
>  	if (pcr->ops->optimize_phy) {
>  		err = pcr->ops->optimize_phy(pcr);
>  		if (err < 0)
> @@ -1357,8 +1385,7 @@ static int rtsx_pci_init_hw(struct rtsx_pcr *pcr)
>  	rtsx_pci_init_ocp(pcr);
>  
>  	/* Enable clk_request_n to enable clock power management */
> -	pcie_capability_write_word(pdev, PCI_EXP_LNKCTL,
> -				   PCI_EXP_LNKCTL_CLKREQ_EN);
> +	pci_write_config_byte(pdev, PCI_EXP_LNKCTL+1, 0x01);

Drivers should not write PCI_EXP_LNKCTL directly because that clobbers
things done by the PCI core, e.g., ASPM and common clock
configuration, Read Completion Boundary setting, etc.

But if you must, you should at least use this:

  pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL, 0,
                                     PCI_EXP_LNKCTL_CLKREQ_EN);

>  	/* Enter L1 when host tx idle */
>  	pci_write_config_byte(pdev, 0x70F, 0x5B);
>  
> @@ -1368,6 +1395,8 @@ static int rtsx_pci_init_hw(struct rtsx_pcr *pcr)
>  			return err;
>  	}
>  
> +	rtsx_pci_write_register(pcr, ASPM_FORCE_CTL, 0x30, 0x30);
> +
>  	/* No CD interrupt if probing driver with card inserted.
>  	 * So we need to initialize pcr->card_exist here.
>  	 */
> @@ -1571,6 +1600,12 @@ static int rtsx_pci_probe(struct pci_dev *pcidev,
>  		rtsx_pcr_cells[i].platform_data = handle;
>  		rtsx_pcr_cells[i].pdata_size = sizeof(*handle);
>  	}
> +
> +	if (pcr->rtd3_en) {
> +		INIT_DELAYED_WORK(&pcr->rtd3_work, rtsx_pci_rtd3_work);
> +		pm_runtime_enable(&pcidev->dev);
> +	}
> +
>  	ret = mfd_add_devices(&pcidev->dev, pcr->id, rtsx_pcr_cells,
>  			ARRAY_SIZE(rtsx_pcr_cells), NULL, 0, NULL);
>  	if (ret < 0)
> @@ -1610,6 +1645,9 @@ static void rtsx_pci_remove(struct pci_dev *pcidev)
>  
>  	pcr->remove_pci = true;
>  
> +	if (pcr->rtd3_en)
> +		pm_runtime_get_noresume(&pcr->pci->dev);
> +
>  	/* Disable interrupts at the pcr level */
>  	spin_lock_irq(&pcr->lock);
>  	rtsx_pci_writel(pcr, RTSX_BIER, 0);
> @@ -1619,6 +1657,9 @@ static void rtsx_pci_remove(struct pci_dev *pcidev)
>  	cancel_delayed_work_sync(&pcr->carddet_work);
>  	cancel_delayed_work_sync(&pcr->idle_work);
>  
> +	if (pcr->rtd3_en)
> +		cancel_delayed_work_sync(&pcr->rtd3_work);
> +
>  	mfd_remove_devices(&pcidev->dev);
>  
>  	dma_free_coherent(&(pcr->pci->dev), RTSX_RESV_BUF_LEN,
> @@ -1635,6 +1676,11 @@ static void rtsx_pci_remove(struct pci_dev *pcidev)
>  	idr_remove(&rtsx_pci_idr, pcr->id);
>  	spin_unlock(&rtsx_pci_lock);
>  
> +	if (pcr->rtd3_en) {
> +		pm_runtime_disable(&pcr->pci->dev);
> +		pm_runtime_put_noidle(&pcr->pci->dev);
> +	}
> +
>  	kfree(pcr->slots);
>  	kfree(pcr);
>  	kfree(handle);
> @@ -1716,13 +1762,75 @@ static void rtsx_pci_shutdown(struct pci_dev *pcidev)
>  		pci_disable_msi(pcr->pci);
>  }
>  
> +static int rtsx_pci_runtime_suspend(struct device *device)
> +{
> +	struct pci_dev *pcidev = to_pci_dev(device);
> +	struct pcr_handle *handle;
> +	struct rtsx_pcr *pcr;
> +
> +	handle = pci_get_drvdata(pcidev);
> +	pcr = handle->pcr;
> +	dev_dbg(&(pcidev->dev), "--> %s\n", __func__);
> +
> +	cancel_delayed_work(&pcr->carddet_work);
> +	cancel_delayed_work(&pcr->rtd3_work);
> +	cancel_delayed_work(&pcr->idle_work);
> +
> +	mutex_lock(&pcr->pcr_mutex);
> +	rtsx_pci_power_off(pcr, HOST_ENTER_S3);
> +
> +	free_irq(pcr->irq, (void *)pcr);
> +
> +	mutex_unlock(&pcr->pcr_mutex);
> +
> +	return 0;
> +}
> +
> +static int rtsx_pci_runtime_resume(struct device *device)
> +{
> +	struct pci_dev *pcidev = to_pci_dev(device);
> +	struct pcr_handle *handle;
> +	struct rtsx_pcr *pcr;
> +	int ret = 0;
> +
> +	handle = pci_get_drvdata(pcidev);
> +	pcr = handle->pcr;
> +	dev_dbg(&(pcidev->dev), "--> %s\n", __func__);
> +
> +	mutex_lock(&pcr->pcr_mutex);
> +
> +	rtsx_pci_write_register(pcr, HOST_SLEEP_STATE, 0x03, 0x00);
> +	rtsx_pci_acquire_irq(pcr);
> +	synchronize_irq(pcr->irq);
> +
> +	if (pcr->ops->fetch_vendor_settings)
> +		pcr->ops->fetch_vendor_settings(pcr);
> +
> +	rtsx_pci_init_hw(pcr);
> +
> +	if (pcr->slots[RTSX_SD_CARD].p_dev != NULL) {
> +		pcr->slots[RTSX_SD_CARD].card_event(
> +				pcr->slots[RTSX_SD_CARD].p_dev);
> +	}
> +
> +	schedule_delayed_work(&pcr->idle_work, msecs_to_jiffies(200));
> +
> +	mutex_unlock(&pcr->pcr_mutex);
> +	return ret;
> +}
> +
>  #else /* CONFIG_PM */
>  
>  #define rtsx_pci_shutdown NULL
> +#define rtsx_pci_runtime_suspend NULL
> +#define rtsx_pic_runtime_resume NULL
>  
>  #endif /* CONFIG_PM */
>  
> -static SIMPLE_DEV_PM_OPS(rtsx_pci_pm_ops, rtsx_pci_suspend, rtsx_pci_resume);
> +static const struct dev_pm_ops rtsx_pci_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(rtsx_pci_suspend, rtsx_pci_resume)
> +	SET_RUNTIME_PM_OPS(rtsx_pci_runtime_suspend, rtsx_pci_runtime_resume, NULL)
> +};
>  
>  static struct pci_driver rtsx_pci_driver = {
>  	.name = DRV_NAME_RTSX_PCI,
> diff --git a/drivers/misc/cardreader/rtsx_pcr.h b/drivers/misc/cardreader/rtsx_pcr.h
> index fe5f4ca0f937..daf057c4eea6 100644
> --- a/drivers/misc/cardreader/rtsx_pcr.h
> +++ b/drivers/misc/cardreader/rtsx_pcr.h
> @@ -90,6 +90,7 @@ static inline u8 map_sd_drive(int idx)
>  
>  #define rtsx_check_mmc_support(reg)		((reg) & 0x10)
>  #define rtsx_reg_to_rtd3(reg)				((reg) & 0x02)
> +#define rtsx_reg_to_rtd3_uhsii(reg)				((reg) & 0x04)
>  #define rtsx_reg_to_aspm(reg)			(((reg) >> 28) & 0x03)
>  #define rtsx_reg_to_sd30_drive_sel_1v8(reg)	(((reg) >> 26) & 0x03)
>  #define rtsx_reg_to_sd30_drive_sel_3v3(reg)	(((reg) >> 5) & 0x03)
> diff --git a/drivers/mmc/host/rtsx_pci_sdmmc.c b/drivers/mmc/host/rtsx_pci_sdmmc.c
> index eb395e144207..02f31f4d0944 100644
> --- a/drivers/mmc/host/rtsx_pci_sdmmc.c
> +++ b/drivers/mmc/host/rtsx_pci_sdmmc.c
> @@ -20,6 +20,7 @@
>  #include <linux/mmc/card.h>
>  #include <linux/rtsx_pci.h>
>  #include <asm/unaligned.h>
> +#include <linux/pm_runtime.h>
>  
>  struct realtek_pci_sdmmc {
>  	struct platform_device	*pdev;
> @@ -953,7 +954,6 @@ static int sd_set_power_mode(struct realtek_pci_sdmmc *host,
>  		unsigned char power_mode)
>  {
>  	int err;
> -

Not an improvement.  Looks like accidental whitespace change.  But if
you wanted to improve this function, you could (in a separate patch)
make it look like this:

  static int sd_set_power_mode(...)
  {
    if (power_mode == MMC_POWER_OFF)
      return sd_power_off(host);
    else
      return sd_power_on(host);
  }

>  	if (power_mode == MMC_POWER_OFF)
>  		err = sd_power_off(host);
>  	else
> @@ -1249,7 +1249,7 @@ static int sdmmc_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)
>  
>  out:
>  	/* Stop toggle SD clock in idle */
> -	err = rtsx_pci_write_register(pcr, SD_BUS_STAT,
> +	rtsx_pci_write_register(pcr, SD_BUS_STAT,
>  			SD_CLK_TOGGLE_EN | SD_CLK_FORCE_STOP, 0);
>  
>  	mutex_unlock(&pcr->pcr_mutex);
> @@ -1343,6 +1343,7 @@ static void init_extra_caps(struct realtek_pci_sdmmc *host)
>  static void realtek_init_host(struct realtek_pci_sdmmc *host)
>  {
>  	struct mmc_host *mmc = host->mmc;
> +	struct rtsx_pcr *pcr = host->pcr;
>  
>  	mmc->f_min = 250000;
>  	mmc->f_max = 208000000;
> @@ -1350,6 +1351,8 @@ static void realtek_init_host(struct realtek_pci_sdmmc *host)
>  	mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SD_HIGHSPEED |
>  		MMC_CAP_MMC_HIGHSPEED | MMC_CAP_BUS_WIDTH_TEST |
>  		MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
> +	if (pcr->rtd3_en)
> +		mmc->caps = mmc->caps | MMC_CAP_AGGRESSIVE_PM;
>  	mmc->caps2 = MMC_CAP2_NO_PRESCAN_POWERUP | MMC_CAP2_FULL_PWR_CYCLE;
>  	mmc->max_current_330 = 400;
>  	mmc->max_current_180 = 800;
> @@ -1407,6 +1410,12 @@ static int rtsx_pci_sdmmc_drv_probe(struct platform_device *pdev)
>  
>  	realtek_init_host(host);
>  
> +	if (pcr->rtd3_en) {
> +		pm_runtime_use_autosuspend(&pdev->dev);
> +		pm_runtime_set_autosuspend_delay(&pdev->dev, 5000);

I think you should swap the order of these so the delay is set first.
Maybe it doesn't matter because both are before pm_runtime_enable(),
but it's always good style to set parameters before enabling a
feature.

> +		pm_runtime_enable(&pdev->dev);
> +	}
> +
>  	mmc_add_host(mmc);
>  
>  	return 0;
> @@ -1426,6 +1435,11 @@ static int rtsx_pci_sdmmc_drv_remove(struct platform_device *pdev)
>  	pcr->slots[RTSX_SD_CARD].card_event = NULL;
>  	mmc = host->mmc;
>  
> +	if (pcr->rtd3_en) {
> +		pm_runtime_dont_use_autosuspend(&pdev->dev);
> +		pm_runtime_disable(&pdev->dev);
> +	}
> +
>  	cancel_work_sync(&host->work);
>  
>  	mutex_lock(&host->host_mutex);
> diff --git a/include/linux/rtsx_pci.h b/include/linux/rtsx_pci.h
> index 745f5e73f99a..689d955c2246 100644
> --- a/include/linux/rtsx_pci.h
> +++ b/include/linux/rtsx_pci.h
> @@ -1174,6 +1174,7 @@ struct rtsx_pcr {
>  
>  	struct delayed_work		carddet_work;
>  	struct delayed_work		idle_work;
> +	struct delayed_work		rtd3_work;
>  
>  	spinlock_t			lock;
>  	struct mutex			pcr_mutex;
> -- 
> 2.17.1
>