[PATCH 0/5 v7] Keep rtsx_usb suspended when there's no card

[PATCH 0/5 v7] Keep rtsx_usb suspended when there's no card

[Kai-Heng Feng]

Hi,

This is based on Ulf's work [1] [2].

This patch series can keep rtsx_usb suspended, to save ~0.5W on Intel
platforms and ~1.5W on AMD platforms.

[1] https://patchwork.kernel.org/patch/10440583/
[2] https://patchwork.kernel.org/patch/10445725/

Kai-Heng Feng (5):
  memstick: rtsx_usb_ms: Add missing pm_runtime_disable() in probe
    function
  misc: rtsx_usb: Use USB remote wakeup signaling for card insertion
    detection
  memstick: Prevent memstick host from getting runtime suspended during
    card detection
  memstick: rtsx_usb_ms: Use ms_dev() helper
  memstick: rtsx_usb_ms: Support runtime power management

v7: Keep CONFIG_PM_SLEEP for .suspend and .resume callbacks.
    Use CONFIG_PM for .runtime_suspend and .runtime_resume callbacks.
    Reorder pm_runtime_get_noresume() before pm_runtime_enable().
    Add missing pm_runtime_disable().

v6: Move pm_runtime_get_noresume() to media_check(), to avoid
    potentially unblanced rpm count.

v5: Corretly use system suspend/resume and runtime suspend/resume callback.
    Prevent runtime callbacks get call during system suspend.

v4: Use pm_runtime_put() in memstick_check().

v3: Skip parent device check in rtsx_usb_resume_child().
    Remove dev_dbg() if it only prints function name.
    Use ms_dev() helper at more places.
    Remove const qualifier for UNIVERSAL_DEV_PM_OPS.

v2: Resend to linux-usb and LKML.

 drivers/memstick/core/memstick.c    |   3 +
 drivers/memstick/host/rtsx_usb_ms.c | 172 +++++++++++++++++-----------
 drivers/misc/cardreader/rtsx_usb.c  |   8 ++
 3 files changed, 117 insertions(+), 66 deletions(-)

-- 
2.19.1

[PATCH 1/5 v7] memstick: rtsx_usb_ms: Add missing pm_runtime_disable() in probe function

[Kai-Heng Feng]

If the probe fails, we should use pm_runtime_disable() to balance
pm_runtime_enable().

Add missing pm_runtime_disable() for rtsx_usb_ms.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index 4f64563df7de..e95e64974a91 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -770,6 +770,7 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
 	return 0;
 err_out:
 	memstick_free_host(msh);
+	pm_runtime_disable(ms_dev(host));
 	return err;
 }
 
-- 
2.19.1

[PATCH 2/5 v7] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Kai-Heng Feng]

Although rtsx_usb doesn't support card removal detection, card insertion
will resume rtsx_usb by USB remote wakeup signaling.

When rtsx_usb gets resumed, also resumes its child devices,
rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
slot.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/misc/cardreader/rtsx_usb.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index b97903ff1a72..f7a66f614085 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -723,8 +723,15 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
 	return 0;
 }
 
+static int rtsx_usb_resume_child(struct device *dev, void *data)
+{
+	pm_request_resume(dev);
+	return 0;
+}
+
 static int rtsx_usb_resume(struct usb_interface *intf)
 {
+	device_for_each_child(&intf->dev, NULL, rtsx_usb_resume_child);
 	return 0;
 }
 
@@ -734,6 +741,7 @@ static int rtsx_usb_reset_resume(struct usb_interface *intf)
 		(struct rtsx_ucr *)usb_get_intfdata(intf);
 
 	rtsx_usb_reset_chip(ucr);
+	device_for_each_child(&intf->dev, NULL, rtsx_usb_resume_child);
 	return 0;
 }
 
-- 
2.19.1

[PATCH 3/5 v7] memstick: Prevent memstick host from getting runtime suspended during card detection

[Kai-Heng Feng]

We can use MEMSTICK_POWER_{ON,OFF} along with pm_runtime_{get,put}
helpers to let memstick host support runtime pm.

The rpm count may go down to zero before the memstick host powers on, so
the host can be runtime suspended.

So before doing card detection, increment the rpm count to avoid the
host gets runtime suspended. Balance the rpm count after card detection
is done.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/core/memstick.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c
index 76382c858c35..1246d69ba187 100644
--- a/drivers/memstick/core/memstick.c
+++ b/drivers/memstick/core/memstick.c
@@ -18,6 +18,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 
 #define DRIVER_NAME "memstick"
 
@@ -436,6 +437,7 @@ static void memstick_check(struct work_struct *work)
 	struct memstick_dev *card;
 
 	dev_dbg(&host->dev, "memstick_check started\n");
+	pm_runtime_get_noresume(host->dev.parent);
 	mutex_lock(&host->lock);
 	if (!host->card) {
 		if (memstick_power_on(host))
@@ -479,6 +481,7 @@ static void memstick_check(struct work_struct *work)
 		host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_OFF);
 
 	mutex_unlock(&host->lock);
+	pm_runtime_put(host->dev.parent);
 	dev_dbg(&host->dev, "memstick_check finished\n");
 }
 
-- 
2.19.1

[PATCH 4/5 v7] memstick: rtsx_usb_ms: Use ms_dev() helper

[Kai-Heng Feng]

Use ms_dev() helper for consistency.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index e95e64974a91..24e9e6acf01a 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -786,7 +786,7 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 
 	mutex_lock(&host->host_mutex);
 	if (host->req) {
-		dev_dbg(&(pdev->dev),
+		dev_dbg(ms_dev(host),
 			"%s: Controller removed during transfer\n",
 			dev_name(&msh->dev));
 		host->req->error = -ENOMEDIUM;
@@ -808,10 +808,10 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	if (pm_runtime_active(ms_dev(host)))
 		pm_runtime_put(ms_dev(host));
 
-	pm_runtime_disable(&pdev->dev);
+	pm_runtime_disable(ms_dev(host));
 	platform_set_drvdata(pdev, NULL);
 
-	dev_dbg(&(pdev->dev),
+	dev_dbg(ms_dev(host),
 		": Realtek USB Memstick controller has been removed\n");
 
 	return 0;
-- 
2.19.1

[PATCH 5/5 v7] memstick: rtsx_usb_ms: Support runtime power management

[Kai-Heng Feng]

In order to let host's parent device, rtsx_usb, to use USB remote wake
up signaling to do card detection, it needs to be suspended. Hence it's
necessary to add runtime PM support for the memstick host.

To keep memstick host stays suspended when it's not in use, convert the
card detection function from kthread to delayed_work, which can be
scheduled when the host is resumed and can be canceled when the host is
suspended.

Put the device to suspend when there's no card and the power mode is
MEMSTICK_POWER_OFF.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 165 +++++++++++++++++-----------
 1 file changed, 102 insertions(+), 63 deletions(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index 24e9e6acf01a..5968c7701603 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -40,15 +40,14 @@ struct rtsx_usb_ms {
 
 	struct mutex		host_mutex;
 	struct work_struct	handle_req;
-
-	struct task_struct	*detect_ms;
-	struct completion	detect_ms_exit;
+	struct delayed_work	poll_card;
 
 	u8			ssc_depth;
 	unsigned int		clock;
 	int			power_mode;
 	unsigned char           ifmode;
 	bool			eject;
+	bool			system_suspending;
 };
 
 static inline struct device *ms_dev(struct rtsx_usb_ms *host)
@@ -545,7 +544,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 						host->req->error);
 			}
 		} while (!rc);
-		pm_runtime_put(ms_dev(host));
+		pm_runtime_put_sync(ms_dev(host));
 	}
 
 }
@@ -585,14 +584,14 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 			break;
 
 		if (value == MEMSTICK_POWER_ON) {
-			pm_runtime_get_sync(ms_dev(host));
+			pm_runtime_get_noresume(ms_dev(host));
 			err = ms_power_on(host);
+			if (err)
+				pm_runtime_put_noidle(ms_dev(host));
 		} else if (value == MEMSTICK_POWER_OFF) {
 			err = ms_power_off(host);
-			if (host->msh->card)
+			if (!err)
 				pm_runtime_put_noidle(ms_dev(host));
-			else
-				pm_runtime_put(ms_dev(host));
 		} else
 			err = -EINVAL;
 		if (!err)
@@ -638,12 +637,16 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	}
 out:
 	mutex_unlock(&ucr->dev_mutex);
-	pm_runtime_put(ms_dev(host));
+	pm_runtime_put_sync(ms_dev(host));
 
 	/* power-on delay */
-	if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON)
+	if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON) {
 		usleep_range(10000, 12000);
 
+		if (!host->eject)
+			schedule_delayed_work(&host->poll_card, 100);
+	}
+
 	dev_dbg(ms_dev(host), "%s: return = %d\n", __func__, err);
 	return err;
 }
@@ -654,9 +657,24 @@ static int rtsx_usb_ms_suspend(struct device *dev)
 	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
 	struct memstick_host *msh = host->msh;
 
-	dev_dbg(ms_dev(host), "--> %s\n", __func__);
+	/* Since we use rtsx_usb's resume callback to runtime resume its
+	 * children to implement remote wakeup signaling, this causes
+	 * rtsx_usb_ms' runtime resume callback runs after its suspend
+	 * callback:
+	 * rtsx_usb_ms_suspend()
+	 * rtsx_usb_resume()
+	 *   -> rtsx_usb_ms_runtime_resume()
+	 *     -> memstick_detect_change()
+	 *
+	 * rtsx_usb_suspend()
+	 *
+	 * To avoid this, skip runtime resume/suspend if system suspend is
+	 * underway.
+	 */
 
+	host->system_suspending = true;
 	memstick_suspend_host(msh);
+
 	return 0;
 }
 
@@ -665,58 +683,85 @@ static int rtsx_usb_ms_resume(struct device *dev)
 	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
 	struct memstick_host *msh = host->msh;
 
-	dev_dbg(ms_dev(host), "--> %s\n", __func__);
-
 	memstick_resume_host(msh);
+	host->system_suspending = false;
+
 	return 0;
 }
 #endif /* CONFIG_PM_SLEEP */
 
-/*
- * Thread function of ms card slot detection. The thread starts right after
- * successful host addition. It stops while the driver removal function sets
- * host->eject true.
- */
-static int rtsx_usb_detect_ms_card(void *__host)
+#ifdef CONFIG_PM
+static int rtsx_usb_ms_runtime_suspend(struct device *dev)
 {
-	struct rtsx_usb_ms *host = (struct rtsx_usb_ms *)__host;
+	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
+
+	if (host->system_suspending)
+		return 0;
+
+	if (host->msh->card || host->power_mode != MEMSTICK_POWER_OFF)
+		return -EAGAIN;
+
+	return 0;
+}
+
+static int rtsx_usb_ms_runtime_resume(struct device *dev)
+{
+	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
+
+
+	if (host->system_suspending)
+		return 0;
+
+	memstick_detect_change(host->msh);
+
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops rtsx_usb_ms_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(rtsx_usb_ms_suspend, rtsx_usb_ms_resume)
+	SET_RUNTIME_PM_OPS(rtsx_usb_ms_runtime_suspend, rtsx_usb_ms_runtime_resume, NULL)
+};
+
+
+static void rtsx_usb_ms_poll_card(struct work_struct *work)
+{
+	struct rtsx_usb_ms *host = container_of(work, struct rtsx_usb_ms,
+			poll_card.work);
 	struct rtsx_ucr *ucr = host->ucr;
-	u8 val = 0;
 	int err;
+	u8 val;
 
-	for (;;) {
-		pm_runtime_get_sync(ms_dev(host));
-		mutex_lock(&ucr->dev_mutex);
-
-		/* Check pending MS card changes */
-		err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
-		if (err) {
-			mutex_unlock(&ucr->dev_mutex);
-			goto poll_again;
-		}
+	if (host->eject || host->power_mode != MEMSTICK_POWER_ON)
+		return;
 
-		/* Clear the pending */
-		rtsx_usb_write_register(ucr, CARD_INT_PEND,
-				XD_INT | MS_INT | SD_INT,
-				XD_INT | MS_INT | SD_INT);
+	pm_runtime_get_sync(ms_dev(host));
+	mutex_lock(&ucr->dev_mutex);
 
+	/* Check pending MS card changes */
+	err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
+	if (err) {
 		mutex_unlock(&ucr->dev_mutex);
+		goto poll_again;
+	}
 
-		if (val & MS_INT) {
-			dev_dbg(ms_dev(host), "MS slot change detected\n");
-			memstick_detect_change(host->msh);
-		}
+	/* Clear the pending */
+	rtsx_usb_write_register(ucr, CARD_INT_PEND,
+			XD_INT | MS_INT | SD_INT,
+			XD_INT | MS_INT | SD_INT);
 
-poll_again:
-		pm_runtime_put(ms_dev(host));
-		if (host->eject)
-			break;
+	mutex_unlock(&ucr->dev_mutex);
 
-		schedule_timeout_idle(HZ);
+	if (val & MS_INT) {
+		dev_dbg(ms_dev(host), "MS slot change detected\n");
+		memstick_detect_change(host->msh);
 	}
 
-	complete(&host->detect_ms_exit);
-	return 0;
+poll_again:
+	pm_runtime_put_sync(ms_dev(host));
+
+	if (!host->eject && host->power_mode == MEMSTICK_POWER_ON)
+		schedule_delayed_work(&host->poll_card, 100);
 }
 
 static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
@@ -747,40 +792,36 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
 	mutex_init(&host->host_mutex);
 	INIT_WORK(&host->handle_req, rtsx_usb_ms_handle_req);
 
-	init_completion(&host->detect_ms_exit);
-	host->detect_ms = kthread_create(rtsx_usb_detect_ms_card, host,
-			"rtsx_usb_ms_%d", pdev->id);
-	if (IS_ERR(host->detect_ms)) {
-		dev_dbg(&(pdev->dev),
-				"Unable to create polling thread.\n");
-		err = PTR_ERR(host->detect_ms);
-		goto err_out;
-	}
+	INIT_DELAYED_WORK(&host->poll_card, rtsx_usb_ms_poll_card);
 
 	msh->request = rtsx_usb_ms_request;
 	msh->set_param = rtsx_usb_ms_set_param;
 	msh->caps = MEMSTICK_CAP_PAR4;
 
-	pm_runtime_enable(&pdev->dev);
+	pm_runtime_get_noresume(ms_dev(host));
+	pm_runtime_set_active(ms_dev(host));
+	pm_runtime_enable(ms_dev(host));
+
 	err = memstick_add_host(msh);
 	if (err)
 		goto err_out;
 
-	wake_up_process(host->detect_ms);
+	pm_runtime_put(ms_dev(host));
+
 	return 0;
 err_out:
 	memstick_free_host(msh);
 	pm_runtime_disable(ms_dev(host));
+	pm_runtime_put_noidle(ms_dev(host));
 	return err;
 }
 
 static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 {
 	struct rtsx_usb_ms *host = platform_get_drvdata(pdev);
-	struct memstick_host *msh;
+	struct memstick_host *msh = host->msh;
 	int err;
 
-	msh = host->msh;
 	host->eject = true;
 	cancel_work_sync(&host->handle_req);
 
@@ -798,7 +839,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	}
 	mutex_unlock(&host->host_mutex);
 
-	wait_for_completion(&host->detect_ms_exit);
 	memstick_remove_host(msh);
 	memstick_free_host(msh);
 
@@ -817,9 +857,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(rtsx_usb_ms_pm_ops,
-		rtsx_usb_ms_suspend, rtsx_usb_ms_resume);
-
 static struct platform_device_id rtsx_usb_ms_ids[] = {
 	{
 		.name = "rtsx_usb_ms",
@@ -835,7 +872,9 @@ static struct platform_driver rtsx_usb_ms_driver = {
 	.id_table       = rtsx_usb_ms_ids,
 	.driver		= {
 		.name	= "rtsx_usb_ms",
+#ifdef CONFIG_PM
 		.pm	= &rtsx_usb_ms_pm_ops,
+#endif
 	},
 };
 module_platform_driver(rtsx_usb_ms_driver);
-- 
2.19.1