[PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Hari Kanigeri]

Resending correcting the subject format based on Benoit's comment and
fixing the over-indentation pointed out by Sergei.
 
Thanks to Rene Sapiens and Omar Ramirez for their inputs on initial patch
set.
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37278.html

The patch set addresses the following review comments from Rene and Omar.
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37626.html
https://patchwork.kernel.org/patch/255091/
https://patchwork.kernel.org/patch/255081/

Following patches are changed because of above review comments:
omap:mailbox-send message in process context
omap:mailbox-add notification support for multiple readers

Following patch is dropped from initial patch set
omap:mailbox-resolve multiple receiver problem

The patch set is tested on omap4 SDP board.

Fernando Guzman Lugo (1):
  OMAP: mailbox: change full flag per mailbox queue instead of global

Hari Kanigeri (5):
  OMAP: mailbox: fix rx interrupt disable in omap4
  OMAP: mailbox: fix checkpatch warnings
  OMAP: mailbox: send message in process context
  OMAP: mailbox: add notification support for multiple readers
  OMAP4: clocks: add dummy clock for mailbox

 arch/arm/mach-omap2/clock44xx_data.c      |    1 +
 arch/arm/mach-omap2/mailbox.c             |    5 +-
 arch/arm/plat-omap/include/plat/mailbox.h |    8 +-
 arch/arm/plat-omap/mailbox.c              |  127 +++++++++++++++++------------
 4 files changed, 83 insertions(+), 58 deletions(-)

[PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Hari Kanigeri]

Resending correcting the subject format based on Benoit's comment and
fixing the over-indentation pointed out by Sergei.
 
Thanks to Rene Sapiens and Omar Ramirez for their inputs on initial patch
set.
http://www.mail-archive.com/linux-omap at vger.kernel.org/msg37278.html

The patch set addresses the following review comments from Rene and Omar.
http://www.mail-archive.com/linux-omap at vger.kernel.org/msg37626.html
https://patchwork.kernel.org/patch/255091/
https://patchwork.kernel.org/patch/255081/

Following patches are changed because of above review comments:
omap:mailbox-send message in process context
omap:mailbox-add notification support for multiple readers

Following patch is dropped from initial patch set
omap:mailbox-resolve multiple receiver problem

The patch set is tested on omap4 SDP board.

Fernando Guzman Lugo (1):
  OMAP: mailbox: change full flag per mailbox queue instead of global

Hari Kanigeri (5):
  OMAP: mailbox: fix rx interrupt disable in omap4
  OMAP: mailbox: fix checkpatch warnings
  OMAP: mailbox: send message in process context
  OMAP: mailbox: add notification support for multiple readers
  OMAP4: clocks: add dummy clock for mailbox

 arch/arm/mach-omap2/clock44xx_data.c      |    1 +
 arch/arm/mach-omap2/mailbox.c             |    5 +-
 arch/arm/plat-omap/include/plat/mailbox.h |    8 +-
 arch/arm/plat-omap/mailbox.c              |  127 +++++++++++++++++------------
 4 files changed, 83 insertions(+), 58 deletions(-)

[PATCH v2 1/6] OMAP: mailbox: change full flag per mailbox queue instead of global

[Hari Kanigeri]

From: Fernando Guzman Lugo <x0095840@ti.com>

As pointed by Ohad Ben-Cohen, the variable rq_full flag is a
global variable, so if there are multiple mailbox users
there will be conflics. Now there is a full flag per
mailbox queue.

Version 2:
- Rebase to the latest.
Version 3:
- Remove spin_lock protection. When the full flag is
true the interrupt for that mailbox is disabled. So there
is no race condition if full flag is modified before
calling omap_mbox_enable_irq.

Reported-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/plat-omap/include/plat/mailbox.h |    1 +
 arch/arm/plat-omap/mailbox.c              |    7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h
index 9976565..13f2ef3 100644
--- a/arch/arm/plat-omap/include/plat/mailbox.h
+++ b/arch/arm/plat-omap/include/plat/mailbox.h
@@ -48,6 +48,7 @@ struct omap_mbox_queue {
 	struct tasklet_struct	tasklet;
 	int	(*callback)(void *);
 	struct omap_mbox	*mbox;
+	bool full;
 };
 
 struct omap_mbox {
diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index d2fafb8..9ce3570 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -33,7 +33,6 @@
 
 static struct workqueue_struct *mboxd;
 static struct omap_mbox **mboxes;
-static bool rq_full;
 
 static int mbox_configured;
 static DEFINE_MUTEX(mbox_configured_lock);
@@ -148,6 +147,10 @@ static void mbox_rx_work(struct work_struct *work)
 
 		if (mq->callback)
 			mq->callback((void *)msg);
+		if (mq->full) {
+			mq->full = false;
+			omap_mbox_enable_irq(mq->mbox, IRQ_RX);
+		}
 	}
 }
 
@@ -170,7 +173,7 @@ static void __mbox_rx_interrupt(struct omap_mbox *mbox)
 	while (!mbox_fifo_empty(mbox)) {
 		if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
 			omap_mbox_disable_irq(mbox, IRQ_RX);
-			rq_full = true;
+			mq->full = true;
 			goto nomem;
 		}
 
-- 
1.7.0

[PATCH v2 1/6] OMAP: mailbox: change full flag per mailbox queue instead of global

[Hari Kanigeri]

From: Fernando Guzman Lugo <x0095840@ti.com>

As pointed by Ohad Ben-Cohen, the variable rq_full flag is a
global variable, so if there are multiple mailbox users
there will be conflics. Now there is a full flag per
mailbox queue.

Version 2:
- Rebase to the latest.
Version 3:
- Remove spin_lock protection. When the full flag is
true the interrupt for that mailbox is disabled. So there
is no race condition if full flag is modified before
calling omap_mbox_enable_irq.

Reported-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/plat-omap/include/plat/mailbox.h |    1 +
 arch/arm/plat-omap/mailbox.c              |    7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h
index 9976565..13f2ef3 100644
--- a/arch/arm/plat-omap/include/plat/mailbox.h
+++ b/arch/arm/plat-omap/include/plat/mailbox.h
@@ -48,6 +48,7 @@ struct omap_mbox_queue {
 	struct tasklet_struct	tasklet;
 	int	(*callback)(void *);
 	struct omap_mbox	*mbox;
+	bool full;
 };
 
 struct omap_mbox {
diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index d2fafb8..9ce3570 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -33,7 +33,6 @@
 
 static struct workqueue_struct *mboxd;
 static struct omap_mbox **mboxes;
-static bool rq_full;
 
 static int mbox_configured;
 static DEFINE_MUTEX(mbox_configured_lock);
@@ -148,6 +147,10 @@ static void mbox_rx_work(struct work_struct *work)
 
 		if (mq->callback)
 			mq->callback((void *)msg);
+		if (mq->full) {
+			mq->full = false;
+			omap_mbox_enable_irq(mq->mbox, IRQ_RX);
+		}
 	}
 }
 
@@ -170,7 +173,7 @@ static void __mbox_rx_interrupt(struct omap_mbox *mbox)
 	while (!mbox_fifo_empty(mbox)) {
 		if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
 			omap_mbox_disable_irq(mbox, IRQ_RX);
-			rq_full = true;
+			mq->full = true;
 			goto nomem;
 		}
 
-- 
1.7.0

[PATCH v2 2/6] OMAP: mailbox: fix rx interrupt disable in omap4

[Hari Kanigeri]

disabling rx interrupt on omap4 is different than its pre-decessors.
The bit in OMAP4_MAILBOX_IRQENABLE_CLR should be set to disable the
interrupts instead of clearing the bit.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/mach-omap2/mailbox.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/mailbox.c b/arch/arm/mach-omap2/mailbox.c
index 42dbfa4..82b5ced 100644
--- a/arch/arm/mach-omap2/mailbox.c
+++ b/arch/arm/mach-omap2/mailbox.c
@@ -195,7 +195,10 @@ static void omap2_mbox_disable_irq(struct omap_mbox *mbox,
 	struct omap_mbox2_priv *p = (struct omap_mbox2_priv *)mbox->priv;
 	u32 l, bit = (irq == IRQ_TX) ? p->notfull_bit : p->newmsg_bit;
 	l = mbox_read_reg(p->irqdisable);
-	l &= ~bit;
+	if (cpu_is_omap44xx())
+		l |= bit;
+	else
+		l &= ~bit;
 	mbox_write_reg(l, p->irqdisable);
 }
 
-- 
1.7.0

[PATCH v2 2/6] OMAP: mailbox: fix rx interrupt disable in omap4

[Hari Kanigeri]

disabling rx interrupt on omap4 is different than its pre-decessors.
The bit in OMAP4_MAILBOX_IRQENABLE_CLR should be set to disable the
interrupts instead of clearing the bit.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/mach-omap2/mailbox.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/mailbox.c b/arch/arm/mach-omap2/mailbox.c
index 42dbfa4..82b5ced 100644
--- a/arch/arm/mach-omap2/mailbox.c
+++ b/arch/arm/mach-omap2/mailbox.c
@@ -195,7 +195,10 @@ static void omap2_mbox_disable_irq(struct omap_mbox *mbox,
 	struct omap_mbox2_priv *p = (struct omap_mbox2_priv *)mbox->priv;
 	u32 l, bit = (irq == IRQ_TX) ? p->notfull_bit : p->newmsg_bit;
 	l = mbox_read_reg(p->irqdisable);
-	l &= ~bit;
+	if (cpu_is_omap44xx())
+		l |= bit;
+	else
+		l &= ~bit;
 	mbox_write_reg(l, p->irqdisable);
 }
 
-- 
1.7.0

[PATCH v2 3/6] OMAP: mailbox: fix checkpatch warnings

[Hari Kanigeri]

Fix the checkpatch warnings observed in mailbox module

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/plat-omap/mailbox.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 9ce3570..abfc495 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -279,11 +279,11 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 
 	return 0;
 
- fail_alloc_rxq:
+fail_alloc_rxq:
 	mbox_queue_free(mbox->txq);
- fail_alloc_txq:
+fail_alloc_txq:
 	free_irq(mbox->irq, mbox);
- fail_request_irq:
+fail_request_irq:
 	if (mbox->ops->shutdown)
 		mbox->ops->shutdown(mbox);
 
@@ -394,7 +394,8 @@ static int __init omap_mbox_init(void)
 
 	/* kfifo size sanity check: alignment and minimal size */
 	mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
-	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size, sizeof(mbox_msg_t));
+	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
+							sizeof(mbox_msg_t));
 
 	return 0;
 }
-- 
1.7.0

[PATCH v2 3/6] OMAP: mailbox: fix checkpatch warnings

[Hari Kanigeri]

Fix the checkpatch warnings observed in mailbox module

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/plat-omap/mailbox.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 9ce3570..abfc495 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -279,11 +279,11 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 
 	return 0;
 
- fail_alloc_rxq:
+fail_alloc_rxq:
 	mbox_queue_free(mbox->txq);
- fail_alloc_txq:
+fail_alloc_txq:
 	free_irq(mbox->irq, mbox);
- fail_request_irq:
+fail_request_irq:
 	if (mbox->ops->shutdown)
 		mbox->ops->shutdown(mbox);
 
@@ -394,7 +394,8 @@ static int __init omap_mbox_init(void)
 
 	/* kfifo size sanity check: alignment and minimal size */
 	mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
-	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size, sizeof(mbox_msg_t));
+	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
+							sizeof(mbox_msg_t));
 
 	return 0;
 }
-- 
1.7.0

[PATCH v2 4/6] OMAP: mailbox: send message in process context

[Hari Kanigeri]

Schedule the Tasklet to send only when mailbox fifo is full and there are
pending messages in kifo, else send the message directly in the Process
context. This would avoid needless scheduling of Tasklet for every message
transfer

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/plat-omap/mailbox.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index abfc495..b14bc34 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -92,20 +92,25 @@ int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg)
 	struct omap_mbox_queue *mq = mbox->txq;
 	int ret = 0, len;
 
-	spin_lock(&mq->lock);
+	spin_lock_bh(&mq->lock);
 
 	if (kfifo_avail(&mq->fifo) < sizeof(msg)) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	if (kfifo_is_empty(&mq->fifo) && !__mbox_poll_for_space(mbox)) {
+		mbox_fifo_write(mbox, msg);
+		goto out;
+	}
+
 	len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 	WARN_ON(len != sizeof(msg));
 
 	tasklet_schedule(&mbox->txq->tasklet);
 
 out:
-	spin_unlock(&mq->lock);
+	spin_unlock_bh(&mq->lock);
 	return ret;
 }
 EXPORT_SYMBOL(omap_mbox_msg_send);
-- 
1.7.0

[PATCH v2 4/6] OMAP: mailbox: send message in process context

[Hari Kanigeri]

Schedule the Tasklet to send only when mailbox fifo is full and there are
pending messages in kifo, else send the message directly in the Process
context. This would avoid needless scheduling of Tasklet for every message
transfer

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/plat-omap/mailbox.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index abfc495..b14bc34 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -92,20 +92,25 @@ int omap_mbox_msg_send(struct omap_mbox *mbox, mbox_msg_t msg)
 	struct omap_mbox_queue *mq = mbox->txq;
 	int ret = 0, len;
 
-	spin_lock(&mq->lock);
+	spin_lock_bh(&mq->lock);
 
 	if (kfifo_avail(&mq->fifo) < sizeof(msg)) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	if (kfifo_is_empty(&mq->fifo) && !__mbox_poll_for_space(mbox)) {
+		mbox_fifo_write(mbox, msg);
+		goto out;
+	}
+
 	len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 	WARN_ON(len != sizeof(msg));
 
 	tasklet_schedule(&mbox->txq->tasklet);
 
 out:
-	spin_unlock(&mq->lock);
+	spin_unlock_bh(&mq->lock);
 	return ret;
 }
 EXPORT_SYMBOL(omap_mbox_msg_send);
-- 
1.7.0

[PATCH v2 5/6] OMAP: mailbox: add notification support for multiple readers

[Hari Kanigeri]

In the current mailbox driver, the mailbox internal pointer for
callback can be directly manipulated by the Users, so a second
User can easily corrupt the first user's callback pointer.
The initial effort to correct this issue can be referred here:
https://patchwork.kernel.org/patch/107520/

Along with fixing the above stated issue, this patch  adds the
flexibility option to register notifications from
multiple readers to the events received on a mailbox instance.
The discussion regarding this can be referred here.
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg30671.html

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
---
 arch/arm/plat-omap/include/plat/mailbox.h |    7 +-
 arch/arm/plat-omap/mailbox.c              |  102 ++++++++++++++++-------------
 2 files changed, 60 insertions(+), 49 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h
index 13f2ef3..cc3921e 100644
--- a/arch/arm/plat-omap/include/plat/mailbox.h
+++ b/arch/arm/plat-omap/include/plat/mailbox.h
@@ -46,7 +46,6 @@ struct omap_mbox_queue {
 	struct kfifo		fifo;
 	struct work_struct	work;
 	struct tasklet_struct	tasklet;
-	int	(*callback)(void *);
 	struct omap_mbox	*mbox;
 	bool full;
 };
@@ -58,13 +57,15 @@ struct omap_mbox {
 	struct omap_mbox_ops	*ops;
 	struct device		*dev;
 	void			*priv;
+	int			use_count;
+	struct blocking_notifier_head   notifier;
 };
 
 int omap_mbox_msg_send(struct omap_mbox *, mbox_msg_t msg);
 void omap_mbox_init_seq(struct omap_mbox *);
 
-struct omap_mbox *omap_mbox_get(const char *);
-void omap_mbox_put(struct omap_mbox *);
+struct omap_mbox *omap_mbox_get(const char *, struct notifier_block *nb);
+void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb);
 
 int omap_mbox_register(struct device *parent, struct omap_mbox **);
 int omap_mbox_unregister(void);
diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index b14bc34..b1f8f2c 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -28,6 +28,7 @@
 #include <linux/slab.h>
 #include <linux/kfifo.h>
 #include <linux/err.h>
+#include <linux/notifier.h>
 
 #include <plat/mailbox.h>
 
@@ -150,8 +151,8 @@ static void mbox_rx_work(struct work_struct *work)
 		len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 		WARN_ON(len != sizeof(msg));
 
-		if (mq->callback)
-			mq->callback((void *)msg);
+		blocking_notifier_call_chain(&mq->mbox->notifier, len,
+							(void *)msg);
 		if (mq->full) {
 			mq->full = false;
 			omap_mbox_enable_irq(mq->mbox, IRQ_RX);
@@ -247,41 +248,40 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 	int ret = 0;
 	struct omap_mbox_queue *mq;
 
-	if (mbox->ops->startup) {
-		mutex_lock(&mbox_configured_lock);
-		if (!mbox_configured)
+	mutex_lock(&mbox_configured_lock);
+	if (!mbox_configured++) {
+		if (likely(mbox->ops->startup)) {
 			ret = mbox->ops->startup(mbox);
-
-		if (ret) {
-			mutex_unlock(&mbox_configured_lock);
-			return ret;
-		}
-		mbox_configured++;
-		mutex_unlock(&mbox_configured_lock);
+			if (unlikely(ret))
+				goto fail_startup;
+		} else
+			goto fail_startup;
 	}
 
-	ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
-				mbox->name, mbox);
-	if (ret) {
-		printk(KERN_ERR
-			"failed to register mailbox interrupt:%d\n", ret);
-		goto fail_request_irq;
-	}
-
-	mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
-	if (!mq) {
-		ret = -ENOMEM;
-		goto fail_alloc_txq;
-	}
-	mbox->txq = mq;
+	if (!mbox->use_count++) {
+		ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
+							mbox->name, mbox);
+		if (unlikely(ret)) {
+			pr_err("failed to register mailbox interrupt:%d\n",
+									ret);
+			goto fail_request_irq;
+		}
+		mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
+		if (!mq) {
+			ret = -ENOMEM;
+			goto fail_alloc_txq;
+		}
+		mbox->txq = mq;
 
-	mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
-	if (!mq) {
-		ret = -ENOMEM;
-		goto fail_alloc_rxq;
+		mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
+		if (!mq) {
+			ret = -ENOMEM;
+			goto fail_alloc_rxq;
+		}
+		mbox->rxq = mq;
+		mq->mbox = mbox;
 	}
-	mbox->rxq = mq;
-
+	mutex_unlock(&mbox_configured_lock);
 	return 0;
 
 fail_alloc_rxq:
@@ -291,29 +291,34 @@ fail_alloc_txq:
 fail_request_irq:
 	if (mbox->ops->shutdown)
 		mbox->ops->shutdown(mbox);
-
+	mbox->use_count--;
+fail_startup:
+	mbox_configured--;
+	mutex_unlock(&mbox_configured_lock);
 	return ret;
 }
 
 static void omap_mbox_fini(struct omap_mbox *mbox)
 {
-	free_irq(mbox->irq, mbox);
-	tasklet_kill(&mbox->txq->tasklet);
-	flush_work(&mbox->rxq->work);
-	mbox_queue_free(mbox->txq);
-	mbox_queue_free(mbox->rxq);
+	mutex_lock(&mbox_configured_lock);
+
+	if (!--mbox->use_count) {
+		free_irq(mbox->irq, mbox);
+		tasklet_kill(&mbox->txq->tasklet);
+		flush_work(&mbox->rxq->work);
+		mbox_queue_free(mbox->txq);
+		mbox_queue_free(mbox->rxq);
+	}
 
-	if (mbox->ops->shutdown) {
-		mutex_lock(&mbox_configured_lock);
-		if (mbox_configured > 0)
-			mbox_configured--;
-		if (!mbox_configured)
+	if (likely(mbox->ops->shutdown)) {
+		if (!--mbox_configured)
 			mbox->ops->shutdown(mbox);
-		mutex_unlock(&mbox_configured_lock);
 	}
+
+	mutex_unlock(&mbox_configured_lock);
 }
 
-struct omap_mbox *omap_mbox_get(const char *name)
+struct omap_mbox *omap_mbox_get(const char *name, struct notifier_block *nb)
 {
 	struct omap_mbox *mbox;
 	int ret;
@@ -332,12 +337,16 @@ struct omap_mbox *omap_mbox_get(const char *name)
 	if (ret)
 		return ERR_PTR(-ENODEV);
 
+	if (nb)
+		blocking_notifier_chain_register(&mbox->notifier, nb);
+
 	return mbox;
 }
 EXPORT_SYMBOL(omap_mbox_get);
 
-void omap_mbox_put(struct omap_mbox *mbox)
+void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb)
 {
+	blocking_notifier_chain_unregister(&mbox->notifier, nb);
 	omap_mbox_fini(mbox);
 }
 EXPORT_SYMBOL(omap_mbox_put);
@@ -361,6 +370,7 @@ int omap_mbox_register(struct device *parent, struct omap_mbox **list)
 			ret = PTR_ERR(mbox->dev);
 			goto err_out;
 		}
+		BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
 	}
 	return 0;
 
-- 
1.7.0

[PATCH v2 5/6] OMAP: mailbox: add notification support for multiple readers

[Hari Kanigeri]

In the current mailbox driver, the mailbox internal pointer for
callback can be directly manipulated by the Users, so a second
User can easily corrupt the first user's callback pointer.
The initial effort to correct this issue can be referred here:
https://patchwork.kernel.org/patch/107520/

Along with fixing the above stated issue, this patch  adds the
flexibility option to register notifications from
multiple readers to the events received on a mailbox instance.
The discussion regarding this can be referred here.
http://www.mail-archive.com/linux-omap at vger.kernel.org/msg30671.html

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
---
 arch/arm/plat-omap/include/plat/mailbox.h |    7 +-
 arch/arm/plat-omap/mailbox.c              |  102 ++++++++++++++++-------------
 2 files changed, 60 insertions(+), 49 deletions(-)

diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h
index 13f2ef3..cc3921e 100644
--- a/arch/arm/plat-omap/include/plat/mailbox.h
+++ b/arch/arm/plat-omap/include/plat/mailbox.h
@@ -46,7 +46,6 @@ struct omap_mbox_queue {
 	struct kfifo		fifo;
 	struct work_struct	work;
 	struct tasklet_struct	tasklet;
-	int	(*callback)(void *);
 	struct omap_mbox	*mbox;
 	bool full;
 };
@@ -58,13 +57,15 @@ struct omap_mbox {
 	struct omap_mbox_ops	*ops;
 	struct device		*dev;
 	void			*priv;
+	int			use_count;
+	struct blocking_notifier_head   notifier;
 };
 
 int omap_mbox_msg_send(struct omap_mbox *, mbox_msg_t msg);
 void omap_mbox_init_seq(struct omap_mbox *);
 
-struct omap_mbox *omap_mbox_get(const char *);
-void omap_mbox_put(struct omap_mbox *);
+struct omap_mbox *omap_mbox_get(const char *, struct notifier_block *nb);
+void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb);
 
 int omap_mbox_register(struct device *parent, struct omap_mbox **);
 int omap_mbox_unregister(void);
diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index b14bc34..b1f8f2c 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -28,6 +28,7 @@
 #include <linux/slab.h>
 #include <linux/kfifo.h>
 #include <linux/err.h>
+#include <linux/notifier.h>
 
 #include <plat/mailbox.h>
 
@@ -150,8 +151,8 @@ static void mbox_rx_work(struct work_struct *work)
 		len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 		WARN_ON(len != sizeof(msg));
 
-		if (mq->callback)
-			mq->callback((void *)msg);
+		blocking_notifier_call_chain(&mq->mbox->notifier, len,
+							(void *)msg);
 		if (mq->full) {
 			mq->full = false;
 			omap_mbox_enable_irq(mq->mbox, IRQ_RX);
@@ -247,41 +248,40 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 	int ret = 0;
 	struct omap_mbox_queue *mq;
 
-	if (mbox->ops->startup) {
-		mutex_lock(&mbox_configured_lock);
-		if (!mbox_configured)
+	mutex_lock(&mbox_configured_lock);
+	if (!mbox_configured++) {
+		if (likely(mbox->ops->startup)) {
 			ret = mbox->ops->startup(mbox);
-
-		if (ret) {
-			mutex_unlock(&mbox_configured_lock);
-			return ret;
-		}
-		mbox_configured++;
-		mutex_unlock(&mbox_configured_lock);
+			if (unlikely(ret))
+				goto fail_startup;
+		} else
+			goto fail_startup;
 	}
 
-	ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
-				mbox->name, mbox);
-	if (ret) {
-		printk(KERN_ERR
-			"failed to register mailbox interrupt:%d\n", ret);
-		goto fail_request_irq;
-	}
-
-	mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
-	if (!mq) {
-		ret = -ENOMEM;
-		goto fail_alloc_txq;
-	}
-	mbox->txq = mq;
+	if (!mbox->use_count++) {
+		ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
+							mbox->name, mbox);
+		if (unlikely(ret)) {
+			pr_err("failed to register mailbox interrupt:%d\n",
+									ret);
+			goto fail_request_irq;
+		}
+		mq = mbox_queue_alloc(mbox, NULL, mbox_tx_tasklet);
+		if (!mq) {
+			ret = -ENOMEM;
+			goto fail_alloc_txq;
+		}
+		mbox->txq = mq;
 
-	mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
-	if (!mq) {
-		ret = -ENOMEM;
-		goto fail_alloc_rxq;
+		mq = mbox_queue_alloc(mbox, mbox_rx_work, NULL);
+		if (!mq) {
+			ret = -ENOMEM;
+			goto fail_alloc_rxq;
+		}
+		mbox->rxq = mq;
+		mq->mbox = mbox;
 	}
-	mbox->rxq = mq;
-
+	mutex_unlock(&mbox_configured_lock);
 	return 0;
 
 fail_alloc_rxq:
@@ -291,29 +291,34 @@ fail_alloc_txq:
 fail_request_irq:
 	if (mbox->ops->shutdown)
 		mbox->ops->shutdown(mbox);
-
+	mbox->use_count--;
+fail_startup:
+	mbox_configured--;
+	mutex_unlock(&mbox_configured_lock);
 	return ret;
 }
 
 static void omap_mbox_fini(struct omap_mbox *mbox)
 {
-	free_irq(mbox->irq, mbox);
-	tasklet_kill(&mbox->txq->tasklet);
-	flush_work(&mbox->rxq->work);
-	mbox_queue_free(mbox->txq);
-	mbox_queue_free(mbox->rxq);
+	mutex_lock(&mbox_configured_lock);
+
+	if (!--mbox->use_count) {
+		free_irq(mbox->irq, mbox);
+		tasklet_kill(&mbox->txq->tasklet);
+		flush_work(&mbox->rxq->work);
+		mbox_queue_free(mbox->txq);
+		mbox_queue_free(mbox->rxq);
+	}
 
-	if (mbox->ops->shutdown) {
-		mutex_lock(&mbox_configured_lock);
-		if (mbox_configured > 0)
-			mbox_configured--;
-		if (!mbox_configured)
+	if (likely(mbox->ops->shutdown)) {
+		if (!--mbox_configured)
 			mbox->ops->shutdown(mbox);
-		mutex_unlock(&mbox_configured_lock);
 	}
+
+	mutex_unlock(&mbox_configured_lock);
 }
 
-struct omap_mbox *omap_mbox_get(const char *name)
+struct omap_mbox *omap_mbox_get(const char *name, struct notifier_block *nb)
 {
 	struct omap_mbox *mbox;
 	int ret;
@@ -332,12 +337,16 @@ struct omap_mbox *omap_mbox_get(const char *name)
 	if (ret)
 		return ERR_PTR(-ENODEV);
 
+	if (nb)
+		blocking_notifier_chain_register(&mbox->notifier, nb);
+
 	return mbox;
 }
 EXPORT_SYMBOL(omap_mbox_get);
 
-void omap_mbox_put(struct omap_mbox *mbox)
+void omap_mbox_put(struct omap_mbox *mbox, struct notifier_block *nb)
 {
+	blocking_notifier_chain_unregister(&mbox->notifier, nb);
 	omap_mbox_fini(mbox);
 }
 EXPORT_SYMBOL(omap_mbox_put);
@@ -361,6 +370,7 @@ int omap_mbox_register(struct device *parent, struct omap_mbox **list)
 			ret = PTR_ERR(mbox->dev);
 			goto err_out;
 		}
+		BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
 	}
 	return 0;
 
-- 
1.7.0

[PATCH v2 6/6] OMAP4: clocks: add dummy clock for mailbox

[Hari Kanigeri]

In omap4, there is no explicit configuration register to enable mailbox clocks.
Defining dummy clock for mailbox clock module to keep the mailbox driver
backward compatible with previous omaps.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/mach-omap2/clock44xx_data.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/clock44xx_data.c b/arch/arm/mach-omap2/clock44xx_data.c
index e10db7a..bdd9b85 100644
--- a/arch/arm/mach-omap2/clock44xx_data.c
+++ b/arch/arm/mach-omap2/clock44xx_data.c
@@ -2687,6 +2687,7 @@ static struct omap_clk omap44xx_clks[] = {
 	CLK(NULL,	"uart3_ick",			&dummy_ck,	CK_443X),
 	CLK(NULL,	"uart4_ick",			&dummy_ck,	CK_443X),
 	CLK("omap_wdt",	"ick",				&dummy_ck,	CK_443X),
+	CLK(NULL,	"mailboxes_ick",	&dummy_ck,	CK_443X),
 };
 
 int __init omap4xxx_clk_init(void)
-- 
1.7.0

[PATCH v2 6/6] OMAP4: clocks: add dummy clock for mailbox

[Hari Kanigeri]

In omap4, there is no explicit configuration register to enable mailbox clocks.
Defining dummy clock for mailbox clock module to keep the mailbox driver
backward compatible with previous omaps.

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
---
 arch/arm/mach-omap2/clock44xx_data.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/clock44xx_data.c b/arch/arm/mach-omap2/clock44xx_data.c
index e10db7a..bdd9b85 100644
--- a/arch/arm/mach-omap2/clock44xx_data.c
+++ b/arch/arm/mach-omap2/clock44xx_data.c
@@ -2687,6 +2687,7 @@ static struct omap_clk omap44xx_clks[] = {
 	CLK(NULL,	"uart3_ick",			&dummy_ck,	CK_443X),
 	CLK(NULL,	"uart4_ick",			&dummy_ck,	CK_443X),
 	CLK("omap_wdt",	"ick",				&dummy_ck,	CK_443X),
+	CLK(NULL,	"mailboxes_ick",	&dummy_ck,	CK_443X),
 };
 
 int __init omap4xxx_clk_init(void)
-- 
1.7.0

Re: [PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Cousson, Benoit]

On 11/10/2010 7:00 PM, Hari Kanigeri wrote:
> Resending correcting the subject format based on Benoit's comment and
> fixing the over-indentation pointed out by Sergei.

Pure nitpicking:
That's a pretty fast update... but then it should be a v3 :-)

Why does the cover letter not use the same format?
[PATCH 0/6] [v2] instead of  [PATCH v2 0/6]

Thanks,
Benoit

>
> Thanks to Rene Sapiens and Omar Ramirez for their inputs on initial patch
> set.
> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37278.html
>
> The patch set addresses the following review comments from Rene and Omar.
> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg37626.html
> https://patchwork.kernel.org/patch/255091/
> https://patchwork.kernel.org/patch/255081/
>
> Following patches are changed because of above review comments:
> omap:mailbox-send message in process context
> omap:mailbox-add notification support for multiple readers
>
> Following patch is dropped from initial patch set
> omap:mailbox-resolve multiple receiver problem
>
> The patch set is tested on omap4 SDP board.
>
> Fernando Guzman Lugo (1):
>    OMAP: mailbox: change full flag per mailbox queue instead of global
>
> Hari Kanigeri (5):
>    OMAP: mailbox: fix rx interrupt disable in omap4
>    OMAP: mailbox: fix checkpatch warnings
>    OMAP: mailbox: send message in process context
>    OMAP: mailbox: add notification support for multiple readers
>    OMAP4: clocks: add dummy clock for mailbox
>
>   arch/arm/mach-omap2/clock44xx_data.c      |    1 +
>   arch/arm/mach-omap2/mailbox.c             |    5 +-
>   arch/arm/plat-omap/include/plat/mailbox.h |    8 +-
>   arch/arm/plat-omap/mailbox.c              |  127 +++++++++++++++++------------
>   4 files changed, 83 insertions(+), 58 deletions(-)
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Cousson, Benoit]

On 11/10/2010 7:00 PM, Hari Kanigeri wrote:
> Resending correcting the subject format based on Benoit's comment and
> fixing the over-indentation pointed out by Sergei.

Pure nitpicking:
That's a pretty fast update... but then it should be a v3 :-)

Why does the cover letter not use the same format?
[PATCH 0/6] [v2] instead of  [PATCH v2 0/6]

Thanks,
Benoit

>
> Thanks to Rene Sapiens and Omar Ramirez for their inputs on initial patch
> set.
> http://www.mail-archive.com/linux-omap at vger.kernel.org/msg37278.html
>
> The patch set addresses the following review comments from Rene and Omar.
> http://www.mail-archive.com/linux-omap at vger.kernel.org/msg37626.html
> https://patchwork.kernel.org/patch/255091/
> https://patchwork.kernel.org/patch/255081/
>
> Following patches are changed because of above review comments:
> omap:mailbox-send message in process context
> omap:mailbox-add notification support for multiple readers
>
> Following patch is dropped from initial patch set
> omap:mailbox-resolve multiple receiver problem
>
> The patch set is tested on omap4 SDP board.
>
> Fernando Guzman Lugo (1):
>    OMAP: mailbox: change full flag per mailbox queue instead of global
>
> Hari Kanigeri (5):
>    OMAP: mailbox: fix rx interrupt disable in omap4
>    OMAP: mailbox: fix checkpatch warnings
>    OMAP: mailbox: send message in process context
>    OMAP: mailbox: add notification support for multiple readers
>    OMAP4: clocks: add dummy clock for mailbox
>
>   arch/arm/mach-omap2/clock44xx_data.c      |    1 +
>   arch/arm/mach-omap2/mailbox.c             |    5 +-
>   arch/arm/plat-omap/include/plat/mailbox.h |    8 +-
>   arch/arm/plat-omap/mailbox.c              |  127 +++++++++++++++++------------
>   4 files changed, 83 insertions(+), 58 deletions(-)
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Hari Kanigeri]

Benoit,

>> Resending correcting the subject format based on Benoit's comment and
>> fixing the over-indentation pointed out by Sergei.
>
> Pure nitpicking:
> That's a pretty fast update... but then it should be a v3 :-)

Have to do it fast to keep your attention :). Since you are saying it
is pure nitpicking I will leave it at v2 unless you insist.

>
> Why does the cover letter not use the same format?
> [PATCH 0/6] [v2] instead of  [PATCH v2 0/6]
>
Will take care of in this next revisions.

Thank you,
Best regards,
Hari
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Hari Kanigeri]

Benoit,

>> Resending correcting the subject format based on Benoit's comment and
>> fixing the over-indentation pointed out by Sergei.
>
> Pure nitpicking:
> That's a pretty fast update... but then it should be a v3 :-)

Have to do it fast to keep your attention :). Since you are saying it
is pure nitpicking I will leave it at v2 unless you insist.

>
> Why does the cover letter not use the same format?
> [PATCH 0/6] [v2] instead of ?[PATCH v2 0/6]
>
Will take care of in this next revisions.

Thank you,
Best regards,
Hari

Re: [PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Cousson, Benoit]

On 11/10/2010 9:16 PM, Hari Kanigeri wrote:
> Benoit,
>
>>> Resending correcting the subject format based on Benoit's comment and
>>> fixing the over-indentation pointed out by Sergei.
>>
>> Pure nitpicking:
>> That's a pretty fast update... but then it should be a v3 :-)
>
> Have to do it fast to keep your attention :). Since you are saying it
> is pure nitpicking I will leave it at v2 unless you insist.

Yeah, that's fine for me.

Benoit

[PATCH 0/6] [v2] OMAP: mailbox: enhancements and fixes

[Cousson, Benoit]

On 11/10/2010 9:16 PM, Hari Kanigeri wrote:
> Benoit,
>
>>> Resending correcting the subject format based on Benoit's comment and
>>> fixing the over-indentation pointed out by Sergei.
>>
>> Pure nitpicking:
>> That's a pretty fast update... but then it should be a v3 :-)
>
> Have to do it fast to keep your attention :). Since you are saying it
> is pure nitpicking I will leave it at v2 unless you insist.

Yeah, that's fine for me.

Benoit