[PATCH 14/18] MMC: OMAP: Use tasklet instead of workqueue for cover switch notification

[PATCH 14/18] MMC: OMAP: Use tasklet instead of workqueue for cover switch notification

[Carlos Aguiar]

From: Jarkko Lavinen <jarkko.lavinen@nokia.com>

The cover waitqueue is occasionally scheduled twice from timer
and the interrupt and oops follows. It would have been possible
to fix this problem with spinlocks but using tasklet was a dropin
solution with no need for locking.

This path also adds some cleanups.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
---
 drivers/mmc/host/omap.c |   67 ++++++++++++++++++++++++++++-------------------
 1 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index a90b276..c26ad3b 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -94,7 +94,7 @@
 
 /* Specifies how often in millisecs to poll for card status changes
  * when the cover switch is open */
-#define OMAP_MMC_SWITCH_POLL_DELAY	500
+#define OMAP_MMC_COVER_POLL_DELAY	500
 
 struct mmc_omap_host;
 
@@ -106,8 +106,8 @@ struct mmc_omap_slot {
 	unsigned int		fclk_freq;
 	unsigned		powered:1;
 
-	struct work_struct      switch_work;
-	struct timer_list       switch_timer;
+	struct tasklet_struct	cover_tasklet;
+	struct timer_list       cover_timer;
 	unsigned		cover_open;
 
 	struct mmc_request      *mrq;
@@ -740,40 +740,51 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-void omap_mmc_notify_cover_event(struct device *dev, int slot, int is_closed)
+void omap_mmc_notify_cover_event(struct device *dev, int num, int is_closed)
 {
+	int cover_open;
 	struct mmc_omap_host *host = dev_get_drvdata(dev);
+	struct mmc_omap_slot *slot = host->slots[num];
 
-	BUG_ON(slot >= host->nr_slots);
+	BUG_ON(num >= host->nr_slots);
 
 	/* Other subsystems can call in here before we're initialised. */
-	if (host->nr_slots == 0 || !host->slots[slot])
+	if (host->nr_slots == 0 || !host->slots[num])
 		return;
 
-	schedule_work(&host->slots[slot]->switch_work);
+	cover_open = mmc_omap_cover_is_open(slot);
+	if (cover_open != slot->cover_open) {
+		slot->cover_open = cover_open;
+		sysfs_notify(&slot->mmc->class_dev.kobj, NULL, "cover_switch");
+	}
+
+	tasklet_hi_schedule(&slot->cover_tasklet);
 }
 
-static void mmc_omap_switch_timer(unsigned long arg)
+static void mmc_omap_cover_timer(unsigned long arg)
 {
 	struct mmc_omap_slot *slot = (struct mmc_omap_slot *) arg;
-
-	schedule_work(&slot->switch_work);
+	tasklet_schedule(&slot->cover_tasklet);
 }
 
-static void mmc_omap_cover_handler(struct work_struct *work)
+static void mmc_omap_cover_handler(unsigned long param)
 {
-	struct mmc_omap_slot *slot = container_of(work, struct mmc_omap_slot,
-						  switch_work);
-	int cover_open;
+	struct mmc_omap_slot *slot = (struct mmc_omap_slot *)param;
+	int cover_open = mmc_omap_cover_is_open(slot);
 
-	cover_open = mmc_omap_cover_is_open(slot);
-	if (cover_open != slot->cover_open) {
-		sysfs_notify(&slot->mmc->class_dev.kobj, NULL, "cover_switch");
-		slot->cover_open = cover_open;
-		dev_info(mmc_dev(slot->mmc), "cover is now %s\n",
-			 cover_open ? "open" : "closed");
-	}
-	mmc_detect_change(slot->mmc, slot->id);
+	mmc_detect_change(slot->mmc, 0);
+	if (!cover_open)
+		return;
+
+	/*
+	 * If no card is inserted, we postpone polling until
+	 * the cover has been closed.
+	 */
+	if (slot->mmc->card == NULL || !mmc_card_present(slot->mmc->card))
+		return;
+
+	mod_timer(&slot->cover_timer,
+		  jiffies + msecs_to_jiffies(OMAP_MMC_COVER_POLL_DELAY));
 }
 
 /* Prepare to transfer the next segment of a scatterlist */
@@ -1247,10 +1258,11 @@ static int __init mmc_omap_new_slot(struct mmc_omap_host *host, int id)
 		if (r < 0)
 			goto err_remove_slot_name;
 
-		INIT_WORK(&slot->switch_work, mmc_omap_cover_handler);
-		setup_timer(&slot->switch_timer, mmc_omap_switch_timer,
-			    (unsigned long) slot);
-		schedule_work(&slot->switch_work);
+		setup_timer(&slot->cover_timer, mmc_omap_cover_timer,
+			    (unsigned long)slot);
+		tasklet_init(&slot->cover_tasklet, mmc_omap_cover_handler,
+			     (unsigned long)slot);
+		tasklet_schedule(&slot->cover_tasklet);
 	}
 
 	if (slot->pdata->get_ro != NULL) {
@@ -1285,7 +1297,8 @@ static void mmc_omap_remove_slot(struct mmc_omap_slot *slot)
 	if (slot->pdata->get_ro != NULL)
 		device_remove_file(&mmc->class_dev, &dev_attr_ro);
 
-	del_timer_sync(&slot->switch_timer);
+	tasklet_kill(&slot->cover_tasklet);
+	del_timer_sync(&slot->cover_timer);
 	flush_scheduled_work();
 
 	mmc_remove_host(mmc);
-- 1.5.3.GIT

[PATCH 00/18] MMC: OMAP: Sync MMC OMAP driver with mainline tree

[Carlos Aguiar]

Hi Pierre, Tony and folks,

The new version of the patch series that follows is a synchronization
of MMC OMAP driver from Linux-OMAP tree into mainline tree.

Improvements and corrections are based on comments from Pierre Ossman and 
Roel Kluin, from LKML.

Just to remind you, basically it brings MMC multislot support for OMAP boards 
with one slot (like H2 1611, H3 1710) or two slots (like H4 2420 and N800).
Others boards supported by such feature are: N770, Siemens SX1 and Apollon.

BR,

Carlos.

-- 
Carlos Eduardo Aguiar
Nokia Institute of Technology - INdT
Open Source Mobile Research Center - OSMRC - Manaus
Core Team
Phone: +55 92 2126-1079
Mobile: +55 92 8127-1797
E-mail: carlos.aguiar@indt.org.br

Re: [PATCH 00/18] MMC: OMAP: Sync MMC OMAP driver with mainline tree

[Pierre Ossman]

On Fri, 14 Mar 2008 15:35:56 -0400
Carlos Aguiar <carlos.aguiar@indt.org.br> wrote:

Except for the issue with the device attributes, the patch set looks fine. Send me a fix for that patch (and affected subsequent) and I'll queue it up.

-- 
     -- Pierre Ossman

  Linux kernel, MMC maintainer        http://www.kernel.org
  PulseAudio, core developer          http://pulseaudio.org
  rdesktop, core developer          http://www.rdesktop.org

[PATCH 14/18] MMC: OMAP: Use tasklet instead of workqueue for cover switch notification

[Carlos Aguiar]

From: Jarkko Lavinen <jarkko.lavinen@nokia.com>

The cover waitqueue is occasionally scheduled twice from timer
and the interrupt and oops follows. It would have been possible
to fix this problem with spinlocks but using tasklet was a dropin
solution with no need for locking.

This path also adds some cleanups.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
---
 drivers/mmc/host/omap.c |   67 ++++++++++++++++++++++++++++-------------------
 1 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index 0e7ceb0..f97f390 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -94,7 +94,7 @@
 
 /* Specifies how often in millisecs to poll for card status changes
  * when the cover switch is open */
-#define OMAP_MMC_SWITCH_POLL_DELAY	500
+#define OMAP_MMC_COVER_POLL_DELAY	500
 
 struct mmc_omap_host;
 
@@ -106,8 +106,8 @@ struct mmc_omap_slot {
 	unsigned int		fclk_freq;
 	unsigned		powered:1;
 
-	struct work_struct      switch_work;
-	struct timer_list       switch_timer;
+	struct tasklet_struct	cover_tasklet;
+	struct timer_list       cover_timer;
 	unsigned		cover_open;
 
 	struct mmc_request      *mrq;
@@ -740,40 +740,51 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-void omap_mmc_notify_cover_event(struct device *dev, int slot, int is_closed)
+void omap_mmc_notify_cover_event(struct device *dev, int num, int is_closed)
 {
+	int cover_open;
 	struct mmc_omap_host *host = dev_get_drvdata(dev);
+	struct mmc_omap_slot *slot = host->slots[num];
 
-	BUG_ON(slot >= host->nr_slots);
+	BUG_ON(num >= host->nr_slots);
 
 	/* Other subsystems can call in here before we're initialised. */
-	if (host->nr_slots == 0 || !host->slots[slot])
+	if (host->nr_slots == 0 || !host->slots[num])
 		return;
 
-	schedule_work(&host->slots[slot]->switch_work);
+	cover_open = mmc_omap_cover_is_open(slot);
+	if (cover_open != slot->cover_open) {
+		slot->cover_open = cover_open;
+		sysfs_notify(&slot->mmc->class_dev.kobj, NULL, "cover_switch");
+	}
+
+	tasklet_hi_schedule(&slot->cover_tasklet);
 }
 
-static void mmc_omap_switch_timer(unsigned long arg)
+static void mmc_omap_cover_timer(unsigned long arg)
 {
 	struct mmc_omap_slot *slot = (struct mmc_omap_slot *) arg;
-
-	schedule_work(&slot->switch_work);
+	tasklet_schedule(&slot->cover_tasklet);
 }
 
-static void mmc_omap_cover_handler(struct work_struct *work)
+static void mmc_omap_cover_handler(unsigned long param)
 {
-	struct mmc_omap_slot *slot = container_of(work, struct mmc_omap_slot,
-						  switch_work);
-	int cover_open;
+	struct mmc_omap_slot *slot = (struct mmc_omap_slot *)param;
+	int cover_open = mmc_omap_cover_is_open(slot);
 
-	cover_open = mmc_omap_cover_is_open(slot);
-	if (cover_open != slot->cover_open) {
-		sysfs_notify(&slot->mmc->class_dev.kobj, NULL, "cover_switch");
-		slot->cover_open = cover_open;
-		dev_info(mmc_dev(slot->mmc), "cover is now %s\n",
-			 cover_open ? "open" : "closed");
-	}
-	mmc_detect_change(slot->mmc, slot->id);
+	mmc_detect_change(slot->mmc, 0);
+	if (!cover_open)
+		return;
+
+	/*
+	 * If no card is inserted, we postpone polling until
+	 * the cover has been closed.
+	 */
+	if (slot->mmc->card == NULL || !mmc_card_present(slot->mmc->card))
+		return;
+
+	mod_timer(&slot->cover_timer,
+		  jiffies + msecs_to_jiffies(OMAP_MMC_COVER_POLL_DELAY));
 }
 
 /* Prepare to transfer the next segment of a scatterlist */
@@ -1237,10 +1248,11 @@ static int __init mmc_omap_new_slot(struct mmc_omap_host *host, int id)
 		if (r < 0)
 			goto err_remove_slot_name;
 
-		INIT_WORK(&slot->switch_work, mmc_omap_cover_handler);
-		setup_timer(&slot->switch_timer, mmc_omap_switch_timer,
-			    (unsigned long) slot);
-		schedule_work(&slot->switch_work);
+		setup_timer(&slot->cover_timer, mmc_omap_cover_timer,
+			    (unsigned long)slot);
+		tasklet_init(&slot->cover_tasklet, mmc_omap_cover_handler,
+			     (unsigned long)slot);
+		tasklet_schedule(&slot->cover_tasklet);
 	}
 
 	return 0;
@@ -1263,7 +1275,8 @@ static void mmc_omap_remove_slot(struct mmc_omap_slot *slot)
 	if (slot->pdata->get_cover_state != NULL)
 		device_remove_file(&mmc->class_dev, &dev_attr_cover_switch);
 
-	del_timer_sync(&slot->switch_timer);
+	tasklet_kill(&slot->cover_tasklet);
+	del_timer_sync(&slot->cover_timer);
 	flush_scheduled_work();
 
 	mmc_remove_host(mmc);
-- 1.5.3.GIT

[PATCH 14/18] MMC: OMAP: Use tasklet instead of workqueue for cover switch notification

[Carlos Aguiar]

From: Jarkko Lavinen <jarkko.lavinen@nokia.com>

The cover waitqueue is occasionally scheduled twice from timer
and the interrupt and oops follows. It would have been possible
to fix this problem with spinlocks but using tasklet was a dropin
sloution with no need for locking.

This path also adds some cleanups.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
---
 drivers/mmc/host/omap.c |   67 ++++++++++++++++++++++++++++-------------------
 1 files changed, 40 insertions(+), 27 deletions(-)

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index 61d2293..276ccf4 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -95,7 +95,7 @@
 
 /* Specifies how often in millisecs to poll for card status changes
  * when the cover switch is open */
-#define OMAP_MMC_SWITCH_POLL_DELAY	500
+#define OMAP_MMC_COVER_POLL_DELAY	500
 
 struct mmc_omap_host;
 
@@ -107,8 +107,8 @@ struct mmc_omap_slot {
 	unsigned int		fclk_freq;
 	unsigned		powered:1;
 
-	struct work_struct      switch_work;
-	struct timer_list       switch_timer;
+	struct tasklet_struct	cover_tasklet;
+	struct timer_list       cover_timer;
 	unsigned		cover_open;
 
 	struct mmc_request      *mrq;
@@ -758,40 +758,51 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-void omap_mmc_notify_cover_event(struct device *dev, int slot, int is_closed)
+void omap_mmc_notify_cover_event(struct device *dev, int num, int is_closed)
 {
+	int cover_open;
 	struct mmc_omap_host *host = dev_get_drvdata(dev);
+	struct mmc_omap_slot *slot = host->slots[num];
 
-	BUG_ON(slot >= host->nr_slots);
+	BUG_ON(num >= host->nr_slots);
 
 	/* Other subsystems can call in here before we're initialised. */
-	if (host->nr_slots == 0 || !host->slots[slot])
+	if (host->nr_slots == 0 || !host->slots[num])
 		return;
 
-	schedule_work(&host->slots[slot]->switch_work);
+	cover_open = mmc_omap_cover_is_open(slot);
+	if (cover_open != slot->cover_open) {
+		slot->cover_open = cover_open;
+		sysfs_notify(&slot->mmc->class_dev.kobj, NULL, "cover_switch");
+	}
+
+	tasklet_hi_schedule(&slot->cover_tasklet);
 }
 
-static void mmc_omap_switch_timer(unsigned long arg)
+static void mmc_omap_cover_timer(unsigned long arg)
 {
 	struct mmc_omap_slot *slot = (struct mmc_omap_slot *) arg;
-
-	schedule_work(&slot->switch_work);
+	tasklet_schedule(&slot->cover_tasklet);
 }
 
-static void mmc_omap_cover_handler(struct work_struct *work)
+static void mmc_omap_cover_handler(unsigned long param)
 {
-	struct mmc_omap_slot *slot = container_of(work, struct mmc_omap_slot,
-						  switch_work);
-	int cover_open;
+	struct mmc_omap_slot *slot = (struct mmc_omap_slot *)param;
+	int cover_open = mmc_omap_cover_is_open(slot);
 
-	cover_open = mmc_omap_cover_is_open(slot);
-	if (cover_open != slot->cover_open) {
-		sysfs_notify(&slot->mmc->class_dev.kobj, NULL, "cover_switch");
-		slot->cover_open = cover_open;
-		dev_info(mmc_dev(slot->mmc), "cover is now %s\n",
-			 cover_open ? "open" : "closed");
-	}
-	mmc_detect_change(slot->mmc, slot->id);
+	mmc_detect_change(slot->mmc, 0);
+	if (!cover_open)
+		return;
+
+	/*
+	 * If no card is inserted, we postpone polling until
+	 * the cover has been closed.
+	 */
+	if (slot->mmc->card == NULL || !mmc_card_present(slot->mmc->card))
+		return;
+
+	mod_timer(&slot->cover_timer,
+		  jiffies + msecs_to_jiffies(OMAP_MMC_COVER_POLL_DELAY));
 }
 
 /* Prepare to transfer the next segment of a scatterlist */
@@ -1266,10 +1277,11 @@ static int __init mmc_omap_new_slot(struct mmc_omap_host *host, int id)
 		if (r < 0)
 			goto err_remove_slot_name;
 
-		INIT_WORK(&slot->switch_work, mmc_omap_cover_handler);
-		setup_timer(&slot->switch_timer, mmc_omap_switch_timer,
-			    (unsigned long) slot);
-		schedule_work(&slot->switch_work);
+		setup_timer(&slot->cover_timer, mmc_omap_cover_timer,
+			    (unsigned long)slot);
+		tasklet_init(&slot->cover_tasklet, mmc_omap_cover_handler,
+			     (unsigned long)slot);
+		tasklet_schedule(&slot->cover_tasklet);
 	}
 
 	if (slot->pdata->get_ro != NULL) {
@@ -1303,7 +1315,8 @@ static void mmc_omap_remove_slot(struct mmc_omap_slot *slot)
 	if (slot->pdata->get_ro != NULL)
 		device_remove_file(&mmc->class_dev, &dev_attr_ro);
 
-	del_timer_sync(&slot->switch_timer);
+	tasklet_kill(&slot->cover_tasklet);
+	del_timer_sync(&slot->cover_timer);
 	flush_scheduled_work();
 
 	mmc_remove_host(mmc);
-- 1.5.3.GIT