[PATCH v2 00/13] OMAP mailbox FIFO removal

[PATCH v2 00/13] OMAP mailbox FIFO removal

[Andrew Davis]

Hello all,

Core of this series is the last patch removing the message FIFO
from OMAP mailbox. This hurts our real-time performance. It was a
legacy leftover from before the common mailbox framework anyway.

The rest of the patches are cleanups found along the way.

Thanks,
Andrew

Changes for v2:
 - Use threaded irq as suggested by Hari and to
     fix possible "scheduling while atomic" issue
 - Use oneshot irq as we do not want to enable the
     irq again until we clear our the messages
 - Rebase on v6.9-rc3

Andrew Davis (13):
  mailbox: omap: Remove unused omap_mbox_{enable,disable}_irq()
    functions
  mailbox: omap: Remove unused omap_mbox_request_channel() function
  mailbox: omap: Move omap_mbox_irq_t into driver
  mailbox: omap: Move fifo size check to point of use
  mailbox: omap: Remove unneeded header omap-mailbox.h
  mailbox: omap: Remove device class
  mailbox: omap: Use devm_pm_runtime_enable() helper
  mailbox: omap: Merge mailbox child node setup loops
  mailbox: omap: Use function local struct mbox_controller
  mailbox: omap: Use mbox_controller channel list directly
  mailbox: omap: Remove mbox_chan_to_omap_mbox()
  mailbox: omap: Reverse FIFO busy check logic
  mailbox: omap: Remove kernel FIFO message queuing

 drivers/mailbox/Kconfig        |   9 -
 drivers/mailbox/omap-mailbox.c | 519 +++++++--------------------------
 include/linux/omap-mailbox.h   |  13 -
 3 files changed, 108 insertions(+), 433 deletions(-)

-- 
2.39.2

[PATCH v2 01/13] mailbox: omap: Remove unused omap_mbox_{enable,disable}_irq() functions

[Andrew Davis]

These function are not used, remove these here.

While here, remove the leading _ from the driver internal functions that
do the same thing as the functions removed.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 42 ++++++++--------------------------
 include/linux/omap-mailbox.h   |  3 ---
 2 files changed, 10 insertions(+), 35 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index c961706fe61d5..624a7ccc27285 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -197,7 +197,7 @@ static int is_mbox_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 	return (int)(enable & status & bit);
 }
 
-static void _omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
+static void omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 {
 	u32 l;
 	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
@@ -210,7 +210,7 @@ static void _omap_mbox_enable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 	mbox_write_reg(mbox->parent, l, irqenable);
 }
 
-static void _omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
+static void omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 {
 	struct omap_mbox_fifo *fifo = (irq == IRQ_TX) ?
 				&mbox->tx_fifo : &mbox->rx_fifo;
@@ -227,28 +227,6 @@ static void _omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 	mbox_write_reg(mbox->parent, bit, irqdisable);
 }
 
-void omap_mbox_enable_irq(struct mbox_chan *chan, omap_mbox_irq_t irq)
-{
-	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
-
-	if (WARN_ON(!mbox))
-		return;
-
-	_omap_mbox_enable_irq(mbox, irq);
-}
-EXPORT_SYMBOL(omap_mbox_enable_irq);
-
-void omap_mbox_disable_irq(struct mbox_chan *chan, omap_mbox_irq_t irq)
-{
-	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
-
-	if (WARN_ON(!mbox))
-		return;
-
-	_omap_mbox_disable_irq(mbox, irq);
-}
-EXPORT_SYMBOL(omap_mbox_disable_irq);
-
 /*
  * Message receiver(workqueue)
  */
@@ -269,7 +247,7 @@ static void mbox_rx_work(struct work_struct *work)
 		spin_lock_irq(&mq->lock);
 		if (mq->full) {
 			mq->full = false;
-			_omap_mbox_enable_irq(mq->mbox, IRQ_RX);
+			omap_mbox_enable_irq(mq->mbox, IRQ_RX);
 		}
 		spin_unlock_irq(&mq->lock);
 	}
@@ -280,7 +258,7 @@ static void mbox_rx_work(struct work_struct *work)
  */
 static void __mbox_tx_interrupt(struct omap_mbox *mbox)
 {
-	_omap_mbox_disable_irq(mbox, IRQ_TX);
+	omap_mbox_disable_irq(mbox, IRQ_TX);
 	ack_mbox_irq(mbox, IRQ_TX);
 	mbox_chan_txdone(mbox->chan, 0);
 }
@@ -293,7 +271,7 @@ 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);
+			omap_mbox_disable_irq(mbox, IRQ_RX);
 			mq->full = true;
 			goto nomem;
 		}
@@ -375,7 +353,7 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 	if (mbox->send_no_irq)
 		mbox->chan->txdone_method = TXDONE_BY_ACK;
 
-	_omap_mbox_enable_irq(mbox, IRQ_RX);
+	omap_mbox_enable_irq(mbox, IRQ_RX);
 
 	return 0;
 
@@ -386,7 +364,7 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 
 static void omap_mbox_fini(struct omap_mbox *mbox)
 {
-	_omap_mbox_disable_irq(mbox, IRQ_RX);
+	omap_mbox_disable_irq(mbox, IRQ_RX);
 	free_irq(mbox->irq, mbox);
 	flush_work(&mbox->rxq->work);
 	mbox_queue_free(mbox->rxq);
@@ -533,10 +511,10 @@ static int omap_mbox_chan_send_noirq(struct omap_mbox *mbox, u32 msg)
 	int ret = -EBUSY;
 
 	if (!mbox_fifo_full(mbox)) {
-		_omap_mbox_enable_irq(mbox, IRQ_RX);
+		omap_mbox_enable_irq(mbox, IRQ_RX);
 		mbox_fifo_write(mbox, msg);
 		ret = 0;
-		_omap_mbox_disable_irq(mbox, IRQ_RX);
+		omap_mbox_disable_irq(mbox, IRQ_RX);
 
 		/* we must read and ack the interrupt directly from here */
 		mbox_fifo_read(mbox);
@@ -556,7 +534,7 @@ static int omap_mbox_chan_send(struct omap_mbox *mbox, u32 msg)
 	}
 
 	/* always enable the interrupt */
-	_omap_mbox_enable_irq(mbox, IRQ_TX);
+	omap_mbox_enable_irq(mbox, IRQ_TX);
 	return ret;
 }
 
diff --git a/include/linux/omap-mailbox.h b/include/linux/omap-mailbox.h
index 8aa984ec1f38b..426a80fb32b5c 100644
--- a/include/linux/omap-mailbox.h
+++ b/include/linux/omap-mailbox.h
@@ -20,7 +20,4 @@ struct mbox_client;
 struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl,
 					    const char *chan_name);
 
-void omap_mbox_enable_irq(struct mbox_chan *chan, omap_mbox_irq_t irq);
-void omap_mbox_disable_irq(struct mbox_chan *chan, omap_mbox_irq_t irq);
-
 #endif /* OMAP_MAILBOX_H */
-- 
2.39.2

[PATCH v2 02/13] mailbox: omap: Remove unused omap_mbox_request_channel() function

[Andrew Davis]

This function is not used, remove this function.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 36 ----------------------------------
 include/linux/omap-mailbox.h   |  6 ------
 2 files changed, 42 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 624a7ccc27285..8151722eef383 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -389,42 +389,6 @@ static struct omap_mbox *omap_mbox_device_find(struct omap_mbox_device *mdev,
 	return mbox;
 }
 
-struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl,
-					    const char *chan_name)
-{
-	struct device *dev = cl->dev;
-	struct omap_mbox *mbox = NULL;
-	struct omap_mbox_device *mdev;
-	int ret;
-
-	if (!dev)
-		return ERR_PTR(-ENODEV);
-
-	if (dev->of_node) {
-		pr_err("%s: please use mbox_request_channel(), this API is supported only for OMAP non-DT usage\n",
-		       __func__);
-		return ERR_PTR(-ENODEV);
-	}
-
-	mutex_lock(&omap_mbox_devices_lock);
-	list_for_each_entry(mdev, &omap_mbox_devices, elem) {
-		mbox = omap_mbox_device_find(mdev, chan_name);
-		if (mbox)
-			break;
-	}
-	mutex_unlock(&omap_mbox_devices_lock);
-
-	if (!mbox || !mbox->chan)
-		return ERR_PTR(-ENOENT);
-
-	ret = mbox_bind_client(mbox->chan, cl);
-	if (ret)
-		return ERR_PTR(ret);
-
-	return mbox->chan;
-}
-EXPORT_SYMBOL(omap_mbox_request_channel);
-
 static struct class omap_mbox_class = { .name = "mbox", };
 
 static int omap_mbox_register(struct omap_mbox_device *mdev)
diff --git a/include/linux/omap-mailbox.h b/include/linux/omap-mailbox.h
index 426a80fb32b5c..f8ddf8e814167 100644
--- a/include/linux/omap-mailbox.h
+++ b/include/linux/omap-mailbox.h
@@ -14,10 +14,4 @@ typedef int __bitwise omap_mbox_irq_t;
 #define IRQ_TX ((__force omap_mbox_irq_t) 1)
 #define IRQ_RX ((__force omap_mbox_irq_t) 2)
 
-struct mbox_chan;
-struct mbox_client;
-
-struct mbox_chan *omap_mbox_request_channel(struct mbox_client *cl,
-					    const char *chan_name);
-
 #endif /* OMAP_MAILBOX_H */
-- 
2.39.2

[PATCH v2 03/13] mailbox: omap: Move omap_mbox_irq_t into driver

[Andrew Davis]

This is only used internal to the driver, move it out of the
public header and into the driver file. While we are here,
this is not used as a bitwise, so drop that and make it a
simple enum type.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 5 +++++
 include/linux/omap-mailbox.h   | 4 ----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 8151722eef383..c083734b6954c 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -51,6 +51,11 @@
 #define MBOX_INTR_CFG_TYPE1		0
 #define MBOX_INTR_CFG_TYPE2		1
 
+typedef enum {
+	IRQ_TX = 1,
+	IRQ_RX = 2,
+} omap_mbox_irq_t;
+
 struct omap_mbox_fifo {
 	unsigned long msg;
 	unsigned long fifo_stat;
diff --git a/include/linux/omap-mailbox.h b/include/linux/omap-mailbox.h
index f8ddf8e814167..3cc5c4ed7f5a6 100644
--- a/include/linux/omap-mailbox.h
+++ b/include/linux/omap-mailbox.h
@@ -10,8 +10,4 @@ typedef uintptr_t mbox_msg_t;
 
 #define omap_mbox_message(data) (u32)(mbox_msg_t)(data)
 
-typedef int __bitwise omap_mbox_irq_t;
-#define IRQ_TX ((__force omap_mbox_irq_t) 1)
-#define IRQ_RX ((__force omap_mbox_irq_t) 2)
-
 #endif /* OMAP_MAILBOX_H */
-- 
2.39.2

[PATCH v2 04/13] mailbox: omap: Move fifo size check to point of use

[Andrew Davis]

The mbox_kfifo_size can be changed at runtime, the sanity
check on it's value should be done when it is used, not
only once at init time.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index c083734b6954c..167348fb1b33b 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -310,6 +310,7 @@ static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
 					void (*work)(struct work_struct *))
 {
 	struct omap_mbox_queue *mq;
+	unsigned int size;
 
 	if (!work)
 		return NULL;
@@ -320,7 +321,10 @@ static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
 
 	spin_lock_init(&mq->lock);
 
-	if (kfifo_alloc(&mq->fifo, mbox_kfifo_size, GFP_KERNEL))
+	/* kfifo size sanity check: alignment and minimal size */
+	size = ALIGN(mbox_kfifo_size, sizeof(u32));
+	size = max_t(unsigned int, size, sizeof(u32));
+	if (kfifo_alloc(&mq->fifo, size, GFP_KERNEL))
 		goto error;
 
 	INIT_WORK(&mq->work, work);
@@ -838,10 +842,6 @@ static int __init omap_mbox_init(void)
 	if (err)
 		return err;
 
-	/* kfifo size sanity check: alignment and minimal size */
-	mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(u32));
-	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size, sizeof(u32));
-
 	err = platform_driver_register(&omap_mbox_driver);
 	if (err)
 		class_unregister(&omap_mbox_class);
-- 
2.39.2

[PATCH v2 05/13] mailbox: omap: Remove unneeded header omap-mailbox.h

[Andrew Davis]

The type of message sent using omap-mailbox is always u32. The definition
of mbox_msg_t is uintptr_t which is wrong as that type changes based on
the architecture (32bit vs 64bit). This type should have been defined as
u32. Instead of making that change here, simply remove the header usage
and fix the last couple users of the same in this driver.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 167348fb1b33b..4c673cb732ed1 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -19,7 +19,6 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
-#include <linux/omap-mailbox.h>
 #include <linux/mailbox_controller.h>
 #include <linux/mailbox_client.h>
 
@@ -239,16 +238,14 @@ static void mbox_rx_work(struct work_struct *work)
 {
 	struct omap_mbox_queue *mq =
 			container_of(work, struct omap_mbox_queue, work);
-	mbox_msg_t data;
 	u32 msg;
 	int len;
 
 	while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
 		len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
 		WARN_ON(len != sizeof(msg));
-		data = msg;
 
-		mbox_chan_received_data(mq->mbox->chan, (void *)data);
+		mbox_chan_received_data(mq->mbox->chan, (void *)(uintptr_t)msg);
 		spin_lock_irq(&mq->lock);
 		if (mq->full) {
 			mq->full = false;
@@ -515,7 +512,7 @@ static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
 {
 	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
 	int ret;
-	u32 msg = omap_mbox_message(data);
+	u32 msg = (u32)(uintptr_t)(data);
 
 	if (!mbox)
 		return -EINVAL;
-- 
2.39.2

[PATCH v2 06/13] mailbox: omap: Remove device class

[Andrew Davis]

The driver currently creates a new device class "mbox". Then for each
mailbox adds a device to that class. This class provides no file
operations provided for any userspace users of this device class.
It may have been extended to be functional in our vendor tree at
some point, but that is not the case anymore, nor does it matter
for the upstream tree.

Remove this device class and related functions and variables.
This also allows us to switch to module_platform_driver() as
there is nothing left to do in module_init().

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 89 +---------------------------------
 1 file changed, 2 insertions(+), 87 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 4c673cb732ed1..ea467931faf46 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -87,7 +87,6 @@ struct omap_mbox_device {
 	u32 intr_type;
 	struct omap_mbox **mboxes;
 	struct mbox_controller controller;
-	struct list_head elem;
 };
 
 struct omap_mbox_fifo_info {
@@ -107,7 +106,6 @@ struct omap_mbox {
 	const char		*name;
 	int			irq;
 	struct omap_mbox_queue	*rxq;
-	struct device		*dev;
 	struct omap_mbox_device *parent;
 	struct omap_mbox_fifo	tx_fifo;
 	struct omap_mbox_fifo	rx_fifo;
@@ -116,10 +114,6 @@ struct omap_mbox {
 	bool			send_no_irq;
 };
 
-/* global variables for the mailbox devices */
-static DEFINE_MUTEX(omap_mbox_devices_lock);
-static LIST_HEAD(omap_mbox_devices);
-
 static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
 module_param(mbox_kfifo_size, uint, S_IRUGO);
 MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)");
@@ -395,61 +389,6 @@ static struct omap_mbox *omap_mbox_device_find(struct omap_mbox_device *mdev,
 	return mbox;
 }
 
-static struct class omap_mbox_class = { .name = "mbox", };
-
-static int omap_mbox_register(struct omap_mbox_device *mdev)
-{
-	int ret;
-	int i;
-	struct omap_mbox **mboxes;
-
-	if (!mdev || !mdev->mboxes)
-		return -EINVAL;
-
-	mboxes = mdev->mboxes;
-	for (i = 0; mboxes[i]; i++) {
-		struct omap_mbox *mbox = mboxes[i];
-
-		mbox->dev = device_create(&omap_mbox_class, mdev->dev,
-					0, mbox, "%s", mbox->name);
-		if (IS_ERR(mbox->dev)) {
-			ret = PTR_ERR(mbox->dev);
-			goto err_out;
-		}
-	}
-
-	mutex_lock(&omap_mbox_devices_lock);
-	list_add(&mdev->elem, &omap_mbox_devices);
-	mutex_unlock(&omap_mbox_devices_lock);
-
-	ret = devm_mbox_controller_register(mdev->dev, &mdev->controller);
-
-err_out:
-	if (ret) {
-		while (i--)
-			device_unregister(mboxes[i]->dev);
-	}
-	return ret;
-}
-
-static int omap_mbox_unregister(struct omap_mbox_device *mdev)
-{
-	int i;
-	struct omap_mbox **mboxes;
-
-	if (!mdev || !mdev->mboxes)
-		return -EINVAL;
-
-	mutex_lock(&omap_mbox_devices_lock);
-	list_del(&mdev->elem);
-	mutex_unlock(&omap_mbox_devices_lock);
-
-	mboxes = mdev->mboxes;
-	for (i = 0; mboxes[i]; i++)
-		device_unregister(mboxes[i]->dev);
-	return 0;
-}
-
 static int omap_mbox_chan_startup(struct mbox_chan *chan)
 {
 	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
@@ -782,7 +721,7 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	mdev->controller.chans = chnls;
 	mdev->controller.num_chans = info_count;
 	mdev->controller.of_xlate = omap_mbox_of_xlate;
-	ret = omap_mbox_register(mdev);
+	ret = devm_mbox_controller_register(mdev->dev, &mdev->controller);
 	if (ret)
 		return ret;
 
@@ -809,7 +748,6 @@ static int omap_mbox_probe(struct platform_device *pdev)
 
 unregister:
 	pm_runtime_disable(mdev->dev);
-	omap_mbox_unregister(mdev);
 	return ret;
 }
 
@@ -818,7 +756,6 @@ static void omap_mbox_remove(struct platform_device *pdev)
 	struct omap_mbox_device *mdev = platform_get_drvdata(pdev);
 
 	pm_runtime_disable(mdev->dev);
-	omap_mbox_unregister(mdev);
 }
 
 static struct platform_driver omap_mbox_driver = {
@@ -830,29 +767,7 @@ static struct platform_driver omap_mbox_driver = {
 		.of_match_table = of_match_ptr(omap_mailbox_of_match),
 	},
 };
-
-static int __init omap_mbox_init(void)
-{
-	int err;
-
-	err = class_register(&omap_mbox_class);
-	if (err)
-		return err;
-
-	err = platform_driver_register(&omap_mbox_driver);
-	if (err)
-		class_unregister(&omap_mbox_class);
-
-	return err;
-}
-subsys_initcall(omap_mbox_init);
-
-static void __exit omap_mbox_exit(void)
-{
-	platform_driver_unregister(&omap_mbox_driver);
-	class_unregister(&omap_mbox_class);
-}
-module_exit(omap_mbox_exit);
+module_platform_driver(omap_mbox_driver);
 
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("omap mailbox: interrupt driven messaging");
-- 
2.39.2

[PATCH v2 07/13] mailbox: omap: Use devm_pm_runtime_enable() helper

[Andrew Davis]

Use device life-cycle managed runtime enable function to simplify probe
and exit paths.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index ea467931faf46..4f956c7b4072c 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -726,11 +726,11 @@ static int omap_mbox_probe(struct platform_device *pdev)
 		return ret;
 
 	platform_set_drvdata(pdev, mdev);
-	pm_runtime_enable(mdev->dev);
+	devm_pm_runtime_enable(mdev->dev);
 
 	ret = pm_runtime_resume_and_get(mdev->dev);
 	if (ret < 0)
-		goto unregister;
+		return ret;
 
 	/*
 	 * just print the raw revision register, the format is not
@@ -741,26 +741,14 @@ static int omap_mbox_probe(struct platform_device *pdev)
 
 	ret = pm_runtime_put_sync(mdev->dev);
 	if (ret < 0 && ret != -ENOSYS)
-		goto unregister;
+		return ret;
 
 	devm_kfree(&pdev->dev, finfoblk);
 	return 0;
-
-unregister:
-	pm_runtime_disable(mdev->dev);
-	return ret;
-}
-
-static void omap_mbox_remove(struct platform_device *pdev)
-{
-	struct omap_mbox_device *mdev = platform_get_drvdata(pdev);
-
-	pm_runtime_disable(mdev->dev);
 }
 
 static struct platform_driver omap_mbox_driver = {
 	.probe	= omap_mbox_probe,
-	.remove_new = omap_mbox_remove,
 	.driver	= {
 		.name = "omap-mailbox",
 		.pm = &omap_mbox_pm_ops,
-- 
2.39.2

[PATCH v2 08/13] mailbox: omap: Merge mailbox child node setup loops

[Andrew Davis]

Currently the driver loops through all mailbox child nodes twice, once
to read in data from each node, and again to make use of this data.
Instead read the data and make use of it in one pass. This removes
the need for several temporary data structures and reduces the
complexity of this main loop in probe.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 119 +++++++++++++--------------------
 1 file changed, 46 insertions(+), 73 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 4f956c7b4072c..17c9b9df78b1d 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -89,19 +89,6 @@ struct omap_mbox_device {
 	struct mbox_controller controller;
 };
 
-struct omap_mbox_fifo_info {
-	int tx_id;
-	int tx_usr;
-	int tx_irq;
-
-	int rx_id;
-	int rx_usr;
-	int rx_irq;
-
-	const char *name;
-	bool send_no_irq;
-};
-
 struct omap_mbox {
 	const char		*name;
 	int			irq;
@@ -574,8 +561,7 @@ static int omap_mbox_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct mbox_chan *chnls;
-	struct omap_mbox **list, *mbox, *mboxblk;
-	struct omap_mbox_fifo_info *finfo, *finfoblk;
+	struct omap_mbox **list, *mbox;
 	struct omap_mbox_device *mdev;
 	struct omap_mbox_fifo *fifo;
 	struct device_node *node = pdev->dev.of_node;
@@ -609,40 +595,6 @@ static int omap_mbox_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	finfoblk = devm_kcalloc(&pdev->dev, info_count, sizeof(*finfoblk),
-				GFP_KERNEL);
-	if (!finfoblk)
-		return -ENOMEM;
-
-	finfo = finfoblk;
-	child = NULL;
-	for (i = 0; i < info_count; i++, finfo++) {
-		child = of_get_next_available_child(node, child);
-		ret = of_property_read_u32_array(child, "ti,mbox-tx", tmp,
-						 ARRAY_SIZE(tmp));
-		if (ret)
-			return ret;
-		finfo->tx_id = tmp[0];
-		finfo->tx_irq = tmp[1];
-		finfo->tx_usr = tmp[2];
-
-		ret = of_property_read_u32_array(child, "ti,mbox-rx", tmp,
-						 ARRAY_SIZE(tmp));
-		if (ret)
-			return ret;
-		finfo->rx_id = tmp[0];
-		finfo->rx_irq = tmp[1];
-		finfo->rx_usr = tmp[2];
-
-		finfo->name = child->name;
-
-		finfo->send_no_irq = of_property_read_bool(child, "ti,mbox-send-noirq");
-
-		if (finfo->tx_id >= num_fifos || finfo->rx_id >= num_fifos ||
-		    finfo->tx_usr >= num_users || finfo->rx_usr >= num_users)
-			return -EINVAL;
-	}
-
 	mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_KERNEL);
 	if (!mdev)
 		return -ENOMEM;
@@ -667,36 +619,58 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	if (!chnls)
 		return -ENOMEM;
 
-	mboxblk = devm_kcalloc(&pdev->dev, info_count, sizeof(*mbox),
-			       GFP_KERNEL);
-	if (!mboxblk)
-		return -ENOMEM;
+	child = NULL;
+	for (i = 0; i < info_count; i++) {
+		int tx_id, tx_irq, tx_usr;
+		int rx_id,         rx_usr;
+
+		mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+		if (!mbox)
+			return -ENOMEM;
+
+		child = of_get_next_available_child(node, child);
+		ret = of_property_read_u32_array(child, "ti,mbox-tx", tmp,
+						 ARRAY_SIZE(tmp));
+		if (ret)
+			return ret;
+		tx_id = tmp[0];
+		tx_irq = tmp[1];
+		tx_usr = tmp[2];
+
+		ret = of_property_read_u32_array(child, "ti,mbox-rx", tmp,
+						 ARRAY_SIZE(tmp));
+		if (ret)
+			return ret;
+		rx_id = tmp[0];
+		/* rx_irq = tmp[1]; */
+		rx_usr = tmp[2];
+
+		if (tx_id >= num_fifos || rx_id >= num_fifos ||
+		    tx_usr >= num_users || rx_usr >= num_users)
+			return -EINVAL;
 
-	mbox = mboxblk;
-	finfo = finfoblk;
-	for (i = 0; i < info_count; i++, finfo++) {
 		fifo = &mbox->tx_fifo;
-		fifo->msg = MAILBOX_MESSAGE(finfo->tx_id);
-		fifo->fifo_stat = MAILBOX_FIFOSTATUS(finfo->tx_id);
-		fifo->intr_bit = MAILBOX_IRQ_NOTFULL(finfo->tx_id);
-		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, finfo->tx_usr);
-		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, finfo->tx_usr);
-		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, finfo->tx_usr);
+		fifo->msg = MAILBOX_MESSAGE(tx_id);
+		fifo->fifo_stat = MAILBOX_FIFOSTATUS(tx_id);
+		fifo->intr_bit = MAILBOX_IRQ_NOTFULL(tx_id);
+		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, tx_usr);
+		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, tx_usr);
+		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, tx_usr);
 
 		fifo = &mbox->rx_fifo;
-		fifo->msg = MAILBOX_MESSAGE(finfo->rx_id);
-		fifo->msg_stat =  MAILBOX_MSGSTATUS(finfo->rx_id);
-		fifo->intr_bit = MAILBOX_IRQ_NEWMSG(finfo->rx_id);
-		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, finfo->rx_usr);
-		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, finfo->rx_usr);
-		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, finfo->rx_usr);
-
-		mbox->send_no_irq = finfo->send_no_irq;
+		fifo->msg = MAILBOX_MESSAGE(rx_id);
+		fifo->msg_stat =  MAILBOX_MSGSTATUS(rx_id);
+		fifo->intr_bit = MAILBOX_IRQ_NEWMSG(rx_id);
+		fifo->irqenable = MAILBOX_IRQENABLE(intr_type, rx_usr);
+		fifo->irqstatus = MAILBOX_IRQSTATUS(intr_type, rx_usr);
+		fifo->irqdisable = MAILBOX_IRQDISABLE(intr_type, rx_usr);
+
+		mbox->send_no_irq = of_property_read_bool(child, "ti,mbox-send-noirq");
 		mbox->intr_type = intr_type;
 
 		mbox->parent = mdev;
-		mbox->name = finfo->name;
-		mbox->irq = platform_get_irq(pdev, finfo->tx_irq);
+		mbox->name = child->name;
+		mbox->irq = platform_get_irq(pdev, tx_irq);
 		if (mbox->irq < 0)
 			return mbox->irq;
 		mbox->chan = &chnls[i];
@@ -743,7 +717,6 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	if (ret < 0 && ret != -ENOSYS)
 		return ret;
 
-	devm_kfree(&pdev->dev, finfoblk);
 	return 0;
 }
 
-- 
2.39.2

[PATCH v2 09/13] mailbox: omap: Use function local struct mbox_controller

[Andrew Davis]

The mbox_controller struct is only needed in the probe function. Make
it a local variable instead of storing a copy in omap_mbox_device
to simplify that struct.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 17c9b9df78b1d..97f59d9f9f319 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -86,7 +86,6 @@ struct omap_mbox_device {
 	u32 num_fifos;
 	u32 intr_type;
 	struct omap_mbox **mboxes;
-	struct mbox_controller controller;
 };
 
 struct omap_mbox {
@@ -541,7 +540,7 @@ static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
 	struct omap_mbox_device *mdev;
 	struct omap_mbox *mbox;
 
-	mdev = container_of(controller, struct omap_mbox_device, controller);
+	mdev = dev_get_drvdata(controller->dev);
 	if (WARN_ON(!mdev))
 		return ERR_PTR(-EINVAL);
 
@@ -567,6 +566,7 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	struct device_node *node = pdev->dev.of_node;
 	struct device_node *child;
 	const struct omap_mbox_match_data *match_data;
+	struct mbox_controller *controller;
 	u32 intr_type, info_count;
 	u32 num_users, num_fifos;
 	u32 tmp[3];
@@ -685,17 +685,20 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	mdev->intr_type = intr_type;
 	mdev->mboxes = list;
 
+	controller = devm_kzalloc(&pdev->dev, sizeof(*controller), GFP_KERNEL);
+	if (!controller)
+		return -ENOMEM;
 	/*
 	 * OMAP/K3 Mailbox IP does not have a Tx-Done IRQ, but rather a Tx-Ready
 	 * IRQ and is needed to run the Tx state machine
 	 */
-	mdev->controller.txdone_irq = true;
-	mdev->controller.dev = mdev->dev;
-	mdev->controller.ops = &omap_mbox_chan_ops;
-	mdev->controller.chans = chnls;
-	mdev->controller.num_chans = info_count;
-	mdev->controller.of_xlate = omap_mbox_of_xlate;
-	ret = devm_mbox_controller_register(mdev->dev, &mdev->controller);
+	controller->txdone_irq = true;
+	controller->dev = mdev->dev;
+	controller->ops = &omap_mbox_chan_ops;
+	controller->chans = chnls;
+	controller->num_chans = info_count;
+	controller->of_xlate = omap_mbox_of_xlate;
+	ret = devm_mbox_controller_register(mdev->dev, controller);
 	if (ret)
 		return ret;
 
-- 
2.39.2

[PATCH v2 10/13] mailbox: omap: Use mbox_controller channel list directly

[Andrew Davis]

The driver stores a list of omap_mbox structs so it can later use it to
lookup the mailbox names in of_xlate. This same information is already
available in the mbox_controller passed into of_xlate. Simply use that
data and remove the extra allocation and storage of the omap_mbox list.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 42 +++++++++-------------------------
 1 file changed, 11 insertions(+), 31 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 97f59d9f9f319..8e42266cb31a5 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -85,7 +85,6 @@ struct omap_mbox_device {
 	u32 num_users;
 	u32 num_fifos;
 	u32 intr_type;
-	struct omap_mbox **mboxes;
 };
 
 struct omap_mbox {
@@ -356,25 +355,6 @@ static void omap_mbox_fini(struct omap_mbox *mbox)
 	mbox_queue_free(mbox->rxq);
 }
 
-static struct omap_mbox *omap_mbox_device_find(struct omap_mbox_device *mdev,
-					       const char *mbox_name)
-{
-	struct omap_mbox *_mbox, *mbox = NULL;
-	struct omap_mbox **mboxes = mdev->mboxes;
-	int i;
-
-	if (!mboxes)
-		return NULL;
-
-	for (i = 0; (_mbox = mboxes[i]); i++) {
-		if (!strcmp(_mbox->name, mbox_name)) {
-			mbox = _mbox;
-			break;
-		}
-	}
-	return mbox;
-}
-
 static int omap_mbox_chan_startup(struct mbox_chan *chan)
 {
 	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
@@ -539,6 +519,7 @@ static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
 	struct device_node *node;
 	struct omap_mbox_device *mdev;
 	struct omap_mbox *mbox;
+	int i;
 
 	mdev = dev_get_drvdata(controller->dev);
 	if (WARN_ON(!mdev))
@@ -551,16 +532,23 @@ static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,
 		return ERR_PTR(-ENODEV);
 	}
 
-	mbox = omap_mbox_device_find(mdev, node->name);
+	for (i = 0; i < controller->num_chans; i++) {
+		mbox = controller->chans[i].con_priv;
+		if (!strcmp(mbox->name, node->name)) {
+			of_node_put(node);
+			return &controller->chans[i];
+		}
+	}
+
 	of_node_put(node);
-	return mbox ? mbox->chan : ERR_PTR(-ENOENT);
+	return ERR_PTR(-ENOENT);
 }
 
 static int omap_mbox_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct mbox_chan *chnls;
-	struct omap_mbox **list, *mbox;
+	struct omap_mbox *mbox;
 	struct omap_mbox_device *mdev;
 	struct omap_mbox_fifo *fifo;
 	struct device_node *node = pdev->dev.of_node;
@@ -608,12 +596,6 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	if (!mdev->irq_ctx)
 		return -ENOMEM;
 
-	/* allocate one extra for marking end of list */
-	list = devm_kcalloc(&pdev->dev, info_count + 1, sizeof(*list),
-			    GFP_KERNEL);
-	if (!list)
-		return -ENOMEM;
-
 	chnls = devm_kcalloc(&pdev->dev, info_count + 1, sizeof(*chnls),
 			     GFP_KERNEL);
 	if (!chnls)
@@ -675,7 +657,6 @@ static int omap_mbox_probe(struct platform_device *pdev)
 			return mbox->irq;
 		mbox->chan = &chnls[i];
 		chnls[i].con_priv = mbox;
-		list[i] = mbox++;
 	}
 
 	mutex_init(&mdev->cfg_lock);
@@ -683,7 +664,6 @@ static int omap_mbox_probe(struct platform_device *pdev)
 	mdev->num_users = num_users;
 	mdev->num_fifos = num_fifos;
 	mdev->intr_type = intr_type;
-	mdev->mboxes = list;
 
 	controller = devm_kzalloc(&pdev->dev, sizeof(*controller), GFP_KERNEL);
 	if (!controller)
-- 
2.39.2

[PATCH v2 11/13] mailbox: omap: Remove mbox_chan_to_omap_mbox()

[Andrew Davis]

This function only checks if mbox_chan *chan is not NULL, but that cannot
be the case and if it was returning NULL which is not later checked
doesn't save us from this. The second check for chan->con_priv is
completely redundant as if it was NULL we would return NULL just the
same. Simply dereference con_priv directly and remove this function.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 8e42266cb31a5..8e2760d2c5b0c 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -103,14 +103,6 @@ static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
 module_param(mbox_kfifo_size, uint, S_IRUGO);
 MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)");
 
-static struct omap_mbox *mbox_chan_to_omap_mbox(struct mbox_chan *chan)
-{
-	if (!chan || !chan->con_priv)
-		return NULL;
-
-	return (struct omap_mbox *)chan->con_priv;
-}
-
 static inline
 unsigned int mbox_read_reg(struct omap_mbox_device *mdev, size_t ofs)
 {
@@ -357,7 +349,7 @@ static void omap_mbox_fini(struct omap_mbox *mbox)
 
 static int omap_mbox_chan_startup(struct mbox_chan *chan)
 {
-	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
+	struct omap_mbox *mbox = chan->con_priv;
 	struct omap_mbox_device *mdev = mbox->parent;
 	int ret = 0;
 
@@ -372,7 +364,7 @@ static int omap_mbox_chan_startup(struct mbox_chan *chan)
 
 static void omap_mbox_chan_shutdown(struct mbox_chan *chan)
 {
-	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
+	struct omap_mbox *mbox = chan->con_priv;
 	struct omap_mbox_device *mdev = mbox->parent;
 
 	mutex_lock(&mdev->cfg_lock);
@@ -415,7 +407,7 @@ static int omap_mbox_chan_send(struct omap_mbox *mbox, u32 msg)
 
 static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
 {
-	struct omap_mbox *mbox = mbox_chan_to_omap_mbox(chan);
+	struct omap_mbox *mbox = chan->con_priv;
 	int ret;
 	u32 msg = (u32)(uintptr_t)(data);
 
-- 
2.39.2

[PATCH v2 12/13] mailbox: omap: Reverse FIFO busy check logic

[Andrew Davis]

It is much more clear to check if the hardware FIFO is full and return
EBUSY if true. This allows us to also remove one level of indention
from the core of this function. It also makes the similarities between
omap_mbox_chan_send_noirq() and omap_mbox_chan_send() more obvious.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/omap-mailbox.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 8e2760d2c5b0c..c5d4083125856 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -375,34 +375,33 @@ static void omap_mbox_chan_shutdown(struct mbox_chan *chan)
 
 static int omap_mbox_chan_send_noirq(struct omap_mbox *mbox, u32 msg)
 {
-	int ret = -EBUSY;
+	if (mbox_fifo_full(mbox))
+		return -EBUSY;
 
-	if (!mbox_fifo_full(mbox)) {
-		omap_mbox_enable_irq(mbox, IRQ_RX);
-		mbox_fifo_write(mbox, msg);
-		ret = 0;
-		omap_mbox_disable_irq(mbox, IRQ_RX);
+	omap_mbox_enable_irq(mbox, IRQ_RX);
+	mbox_fifo_write(mbox, msg);
+	omap_mbox_disable_irq(mbox, IRQ_RX);
 
-		/* we must read and ack the interrupt directly from here */
-		mbox_fifo_read(mbox);
-		ack_mbox_irq(mbox, IRQ_RX);
-	}
+	/* we must read and ack the interrupt directly from here */
+	mbox_fifo_read(mbox);
+	ack_mbox_irq(mbox, IRQ_RX);
 
-	return ret;
+	return 0;
 }
 
 static int omap_mbox_chan_send(struct omap_mbox *mbox, u32 msg)
 {
-	int ret = -EBUSY;
-
-	if (!mbox_fifo_full(mbox)) {
-		mbox_fifo_write(mbox, msg);
-		ret = 0;
+	if (mbox_fifo_full(mbox)) {
+		/* always enable the interrupt */
+		omap_mbox_enable_irq(mbox, IRQ_TX);
+		return -EBUSY;
 	}
 
+	mbox_fifo_write(mbox, msg);
+
 	/* always enable the interrupt */
 	omap_mbox_enable_irq(mbox, IRQ_TX);
-	return ret;
+	return 0;
 }
 
 static int omap_mbox_chan_send_data(struct mbox_chan *chan, void *data)
-- 
2.39.2

[PATCH v2 13/13] mailbox: omap: Remove kernel FIFO message queuing

[Andrew Davis]

The kernel FIFO queue has a couple issues. The biggest issue is that
it causes extra latency in a path that can be used in real-time tasks,
such as communication with real-time remote processors.

The whole FIFO idea itself looks to be a leftover from before the
unified mailbox framework. The current mailbox framework expects
mbox_chan_received_data() to be called with data immediately as it
arrives. Remove the FIFO and pass the messages to the mailbox
framework directly as part of a threaded IRQ handler.

Signed-off-by: Andrew Davis <afd@ti.com>
---
 drivers/mailbox/Kconfig        |   9 ---
 drivers/mailbox/omap-mailbox.c | 107 ++-------------------------------
 2 files changed, 5 insertions(+), 111 deletions(-)

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 42940108a1874..78e4c74fbe5c2 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -68,15 +68,6 @@ config OMAP2PLUS_MBOX
 	  OMAP2/3; or IPU, IVA HD and DSP in OMAP4/5. Say Y here if you
 	  want to use OMAP2+ Mailbox framework support.
 
-config OMAP_MBOX_KFIFO_SIZE
-	int "Mailbox kfifo default buffer size (bytes)"
-	depends on OMAP2PLUS_MBOX
-	default 256
-	help
-	  Specify the default size of mailbox's kfifo buffers (bytes).
-	  This can also be changed at runtime (via the mbox_kfifo_size
-	  module parameter).
-
 config ROCKCHIP_MBOX
 	bool "Rockchip Soc Integrated Mailbox Support"
 	depends on ARCH_ROCKCHIP || COMPILE_TEST
diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index c5d4083125856..46747559b438f 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -65,14 +65,6 @@ struct omap_mbox_fifo {
 	u32 intr_bit;
 };
 
-struct omap_mbox_queue {
-	spinlock_t		lock;
-	struct kfifo		fifo;
-	struct work_struct	work;
-	struct omap_mbox	*mbox;
-	bool full;
-};
-
 struct omap_mbox_match_data {
 	u32 intr_type;
 };
@@ -90,7 +82,6 @@ struct omap_mbox_device {
 struct omap_mbox {
 	const char		*name;
 	int			irq;
-	struct omap_mbox_queue	*rxq;
 	struct omap_mbox_device *parent;
 	struct omap_mbox_fifo	tx_fifo;
 	struct omap_mbox_fifo	rx_fifo;
@@ -99,10 +90,6 @@ struct omap_mbox {
 	bool			send_no_irq;
 };
 
-static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
-module_param(mbox_kfifo_size, uint, S_IRUGO);
-MODULE_PARM_DESC(mbox_kfifo_size, "Size of omap's mailbox kfifo (bytes)");
-
 static inline
 unsigned int mbox_read_reg(struct omap_mbox_device *mdev, size_t ofs)
 {
@@ -202,30 +189,6 @@ static void omap_mbox_disable_irq(struct omap_mbox *mbox, omap_mbox_irq_t irq)
 	mbox_write_reg(mbox->parent, bit, irqdisable);
 }
 
-/*
- * Message receiver(workqueue)
- */
-static void mbox_rx_work(struct work_struct *work)
-{
-	struct omap_mbox_queue *mq =
-			container_of(work, struct omap_mbox_queue, work);
-	u32 msg;
-	int len;
-
-	while (kfifo_len(&mq->fifo) >= sizeof(msg)) {
-		len = kfifo_out(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
-		WARN_ON(len != sizeof(msg));
-
-		mbox_chan_received_data(mq->mbox->chan, (void *)(uintptr_t)msg);
-		spin_lock_irq(&mq->lock);
-		if (mq->full) {
-			mq->full = false;
-			omap_mbox_enable_irq(mq->mbox, IRQ_RX);
-		}
-		spin_unlock_irq(&mq->lock);
-	}
-}
-
 /*
  * Mailbox interrupt handler
  */
@@ -238,27 +201,15 @@ static void __mbox_tx_interrupt(struct omap_mbox *mbox)
 
 static void __mbox_rx_interrupt(struct omap_mbox *mbox)
 {
-	struct omap_mbox_queue *mq = mbox->rxq;
 	u32 msg;
-	int len;
 
 	while (!mbox_fifo_empty(mbox)) {
-		if (unlikely(kfifo_avail(&mq->fifo) < sizeof(msg))) {
-			omap_mbox_disable_irq(mbox, IRQ_RX);
-			mq->full = true;
-			goto nomem;
-		}
-
 		msg = mbox_fifo_read(mbox);
-
-		len = kfifo_in(&mq->fifo, (unsigned char *)&msg, sizeof(msg));
-		WARN_ON(len != sizeof(msg));
+		mbox_chan_received_data(mbox->chan, (void *)(uintptr_t)msg);
 	}
 
-	/* no more messages in the fifo. clear IRQ source. */
+	/* clear IRQ source. */
 	ack_mbox_irq(mbox, IRQ_RX);
-nomem:
-	schedule_work(&mbox->rxq->work);
 }
 
 static irqreturn_t mbox_interrupt(int irq, void *p)
@@ -274,57 +225,15 @@ static irqreturn_t mbox_interrupt(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
-static struct omap_mbox_queue *mbox_queue_alloc(struct omap_mbox *mbox,
-					void (*work)(struct work_struct *))
-{
-	struct omap_mbox_queue *mq;
-	unsigned int size;
-
-	if (!work)
-		return NULL;
-
-	mq = kzalloc(sizeof(*mq), GFP_KERNEL);
-	if (!mq)
-		return NULL;
-
-	spin_lock_init(&mq->lock);
-
-	/* kfifo size sanity check: alignment and minimal size */
-	size = ALIGN(mbox_kfifo_size, sizeof(u32));
-	size = max_t(unsigned int, size, sizeof(u32));
-	if (kfifo_alloc(&mq->fifo, size, GFP_KERNEL))
-		goto error;
-
-	INIT_WORK(&mq->work, work);
-	return mq;
-
-error:
-	kfree(mq);
-	return NULL;
-}
-
-static void mbox_queue_free(struct omap_mbox_queue *q)
-{
-	kfifo_free(&q->fifo);
-	kfree(q);
-}
-
 static int omap_mbox_startup(struct omap_mbox *mbox)
 {
 	int ret = 0;
-	struct omap_mbox_queue *mq;
-
-	mq = mbox_queue_alloc(mbox, mbox_rx_work);
-	if (!mq)
-		return -ENOMEM;
-	mbox->rxq = mq;
-	mq->mbox = mbox;
 
-	ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
-			  mbox->name, mbox);
+	ret = request_threaded_irq(mbox->irq, NULL, mbox_interrupt,
+				   IRQF_ONESHOT, mbox->name, mbox);
 	if (unlikely(ret)) {
 		pr_err("failed to register mailbox interrupt:%d\n", ret);
-		goto fail_request_irq;
+		return ret;
 	}
 
 	if (mbox->send_no_irq)
@@ -333,18 +242,12 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 	omap_mbox_enable_irq(mbox, IRQ_RX);
 
 	return 0;
-
-fail_request_irq:
-	mbox_queue_free(mbox->rxq);
-	return ret;
 }
 
 static void omap_mbox_fini(struct omap_mbox *mbox)
 {
 	omap_mbox_disable_irq(mbox, IRQ_RX);
 	free_irq(mbox->irq, mbox);
-	flush_work(&mbox->rxq->work);
-	mbox_queue_free(mbox->rxq);
 }
 
 static int omap_mbox_chan_startup(struct mbox_chan *chan)
-- 
2.39.2

Re: [PATCH v2 00/13] OMAP mailbox FIFO removal

[Dominic Rath]

Hello Andrew,

On 10.04.2024 15:59, Andrew Davis wrote:
> Changes for v2:
>   - Use threaded irq as suggested by Hari and to
>       fix possible "scheduling while atomic" issue

sorry for beeing late, I noticed this already got merged.

I was wondering what the reason was for ending up with the
threaded irq.

In your v1 thread your final conclusion appeared to be

> So for now I just kept this using the regular IRQ context as before.

We looked into this some time ago, and noticed that the IRQ approach 
caused problems in the virtio/rpmsg code. I'd like to understand if your 
change was for the same reason, or something else we missed before.

Regards,

Dominic

Re: [PATCH v2 00/13] OMAP mailbox FIFO removal

[Andrew Davis]

On 6/13/24 2:58 AM, Dominic Rath wrote:
> Hello Andrew,
> 
> On 10.04.2024 15:59, Andrew Davis wrote:
>> Changes for v2:
>>   - Use threaded irq as suggested by Hari and to
>>       fix possible "scheduling while atomic" issue
> 
> sorry for beeing late, I noticed this already got merged.
> 
> I was wondering what the reason was for ending up with the
> threaded irq.
> 
> In your v1 thread your final conclusion appeared to be
> 
>> So for now I just kept this using the regular IRQ context as before.
> 
> We looked into this some time ago, and noticed that the IRQ approach caused problems in the virtio/rpmsg code. I'd like to understand if your change was for the same reason, or something else we missed before.
> 

It is most likely the same reason. Seems despite its name, rproc_vq_interrupt() cannot
be called from an IRQ/atomic context. As the following backtrace shows, that function
calls down into functions which are not IRQ safe. So we needed to keep it threaded:

[    5.389374] BUG: scheduling while atomic: (udev-worker)/232/0x00010002
[    5.395917] Modules linked in: videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 phy_j721e_wiz display_connector omap_mailbox(+) videodev tps6594_i2c(+) videobuf2_common phy_can_transceiver at24 cd6
[    5.433562] CPU: 0 PID: 232 Comm: (udev-worker) Not tainted 6.10.0-rc1-next-20240528-dirty #10
[    5.442158] Hardware name: Texas Instruments AM69 SK (DT)
[    5.447540] Call trace:
[    5.449976]  dump_backtrace+0x94/0xec
[    5.453640]  show_stack+0x18/0x24
[    5.456944]  dump_stack_lvl+0x78/0x90
[    5.460598]  dump_stack+0x18/0x24
[    5.463900]  __schedule_bug+0x50/0x68
[    5.467552]  __schedule+0x80c/0xb0c
[    5.471029]  schedule+0x34/0x104
[    5.474243]  schedule_preempt_disabled+0x24/0x40
[    5.478845]  rwsem_down_write_slowpath+0x31c/0x56c
[    5.483622]  down_write+0x90/0x94
[    5.486924]  kernfs_add_one+0x3c/0x148
[    5.490661]  kernfs_create_dir_ns+0x50/0x94
[    5.494830]  sysfs_create_dir_ns+0x70/0x10c
[    5.498999]  kobject_add_internal+0x98/0x26c
[    5.503254]  kobject_add+0x9c/0x10c
[    5.506729]  device_add+0xc0/0x790
[    5.510120]  rpmsg_register_device_override+0x10c/0x1c0
[    5.515333]  rpmsg_register_device+0x14/0x20
[    5.519590]  virtio_rpmsg_create_channel+0xb0/0x104
[    5.524452]  rpmsg_create_channel+0x28/0x60
[    5.528622]  rpmsg_ns_cb+0x100/0x1dc
[    5.532185]  rpmsg_recv_done+0x114/0x2e4
[    5.536094]  vring_interrupt+0x68/0xa4
[    5.539833]  rproc_vq_interrupt+0x2c/0x48
[    5.543830]  k3_r5_rproc_mbox_callback+0x84/0x90 [ti_k3_r5_remoteproc]
[    5.550348]  mbox_chan_received_data+0x1c/0x2c
[    5.554779]  mbox_interrupt+0xa0/0x17c [omap_mailbox]
[    5.559820]  __handle_irq_event_percpu+0x48/0x13c
[    5.564511]  handle_irq_event+0x4c/0xac

Andrew

> Regards,
> 
> Dominic

Re: [PATCH v2 00/13] OMAP mailbox FIFO removal

[Dominic Rath]

On 13.06.2024 14:22, Andrew Davis wrote:
>> We looked into this some time ago, and noticed that the IRQ approach 
>> caused problems in the virtio/rpmsg code. I'd like to understand if 
>> your change was for the same reason, or something else we missed before.
>>
> 
> It is most likely the same reason. Seems despite its name, 
> rproc_vq_interrupt() cannot
> be called from an IRQ/atomic context. As the following backtrace shows, 
> that function
> calls down into functions which are not IRQ safe. So we needed to keep 
> it threaded:

Thanks for confirming. This is exactly what we've been seeing.

Regards,

Dominic

Re: [PATCH v2 00/13] OMAP mailbox FIFO removal

[Dominic Rath]

On 13.06.2024 14:22, Andrew Davis wrote:
>> We looked into this some time ago, and noticed that the IRQ approach 
>> caused problems in the virtio/rpmsg code. I'd like to understand if 
>> your change was for the same reason, or something else we missed before.
>>
> 
> It is most likely the same reason. Seems despite its name, 
> rproc_vq_interrupt() cannot
> be called from an IRQ/atomic context. As the following backtrace shows, 
> that function
> calls down into functions which are not IRQ safe. So we needed to keep 
> it threaded:
> 
> [    5.389374] BUG: scheduling while atomic: (udev-worker)/232/0x00010002
> [    5.395917] Modules linked in: videobuf2_dma_contig videobuf2_memops 
> videobuf2_v4l2 phy_j721e_wiz display_connector omap_mailbox(+) videodev 
> tps6594_i2c(+) videobuf2_common phy_can_transceiver at24 cd6
> [    5.433562] CPU: 0 PID: 232 Comm: (udev-worker) Not tainted 
> 6.10.0-rc1-next-20240528-dirty #10
> [    5.442158] Hardware name: Texas Instruments AM69 SK (DT)
> [    5.447540] Call trace:
> [    5.449976]  dump_backtrace+0x94/0xec
> [    5.453640]  show_stack+0x18/0x24
> [    5.456944]  dump_stack_lvl+0x78/0x90
> [    5.460598]  dump_stack+0x18/0x24
> [    5.463900]  __schedule_bug+0x50/0x68
> [    5.467552]  __schedule+0x80c/0xb0c
> [    5.471029]  schedule+0x34/0x104
> [    5.474243]  schedule_preempt_disabled+0x24/0x40
> [    5.478845]  rwsem_down_write_slowpath+0x31c/0x56c
> [    5.483622]  down_write+0x90/0x94
> [    5.486924]  kernfs_add_one+0x3c/0x148
> [    5.490661]  kernfs_create_dir_ns+0x50/0x94
> [    5.494830]  sysfs_create_dir_ns+0x70/0x10c
> [    5.498999]  kobject_add_internal+0x98/0x26c
> [    5.503254]  kobject_add+0x9c/0x10c
> [    5.506729]  device_add+0xc0/0x790
> [    5.510120]  rpmsg_register_device_override+0x10c/0x1c0
> [    5.515333]  rpmsg_register_device+0x14/0x20
> [    5.519590]  virtio_rpmsg_create_channel+0xb0/0x104
> [    5.524452]  rpmsg_create_channel+0x28/0x60
> [    5.528622]  rpmsg_ns_cb+0x100/0x1dc
> [    5.532185]  rpmsg_recv_done+0x114/0x2e4
> [    5.536094]  vring_interrupt+0x68/0xa4
> [    5.539833]  rproc_vq_interrupt+0x2c/0x48
> [    5.543830]  k3_r5_rproc_mbox_callback+0x84/0x90 [ti_k3_r5_remoteproc]
> [    5.550348]  mbox_chan_received_data+0x1c/0x2c
> [    5.554779]  mbox_interrupt+0xa0/0x17c [omap_mailbox]
> [    5.559820]  __handle_irq_event_percpu+0x48/0x13c
> [    5.564511]  handle_irq_event+0x4c/0xac
> 

I looked into this a bit more closely, together with the colleague who 
implemented our internal workaround, and we came up with one more concern:

Have you considered that this synchronous path from the (threaded) IRQ 
draining the mailbox down to the (potentially blocking) rpmsg_* calls 
might let the hardware mailbox grow full?

 From what I remember the vring (?) has room for 512 messages, but the 
hardware mailbox on e.g. the AM64x can only handle four messages. At 
least with the current implementation on TI's MCU+ SDK running on the 
R5f that could cause the R5f to block, waiting for room in the hardware 
mailbox, while there are plenty of vring buffers available.

Best Regards,

Dominic

Re: [PATCH v2 00/13] OMAP mailbox FIFO removal

[Andrew Davis]

On 6/26/24 9:39 AM, Dominic Rath wrote:
> On 13.06.2024 14:22, Andrew Davis wrote:
>>> We looked into this some time ago, and noticed that the IRQ approach caused problems in the virtio/rpmsg code. I'd like to understand if your change was for the same reason, or something else we missed before.
>>>
>>
>> It is most likely the same reason. Seems despite its name, rproc_vq_interrupt() cannot
>> be called from an IRQ/atomic context. As the following backtrace shows, that function
>> calls down into functions which are not IRQ safe. So we needed to keep it threaded:
>>
>> [    5.389374] BUG: scheduling while atomic: (udev-worker)/232/0x00010002
>> [    5.395917] Modules linked in: videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 phy_j721e_wiz display_connector omap_mailbox(+) videodev tps6594_i2c(+) videobuf2_common phy_can_transceiver at24 cd6
>> [    5.433562] CPU: 0 PID: 232 Comm: (udev-worker) Not tainted 6.10.0-rc1-next-20240528-dirty #10
>> [    5.442158] Hardware name: Texas Instruments AM69 SK (DT)
>> [    5.447540] Call trace:
>> [    5.449976]  dump_backtrace+0x94/0xec
>> [    5.453640]  show_stack+0x18/0x24
>> [    5.456944]  dump_stack_lvl+0x78/0x90
>> [    5.460598]  dump_stack+0x18/0x24
>> [    5.463900]  __schedule_bug+0x50/0x68
>> [    5.467552]  __schedule+0x80c/0xb0c
>> [    5.471029]  schedule+0x34/0x104
>> [    5.474243]  schedule_preempt_disabled+0x24/0x40
>> [    5.478845]  rwsem_down_write_slowpath+0x31c/0x56c
>> [    5.483622]  down_write+0x90/0x94
>> [    5.486924]  kernfs_add_one+0x3c/0x148
>> [    5.490661]  kernfs_create_dir_ns+0x50/0x94
>> [    5.494830]  sysfs_create_dir_ns+0x70/0x10c
>> [    5.498999]  kobject_add_internal+0x98/0x26c
>> [    5.503254]  kobject_add+0x9c/0x10c
>> [    5.506729]  device_add+0xc0/0x790
>> [    5.510120]  rpmsg_register_device_override+0x10c/0x1c0
>> [    5.515333]  rpmsg_register_device+0x14/0x20
>> [    5.519590]  virtio_rpmsg_create_channel+0xb0/0x104
>> [    5.524452]  rpmsg_create_channel+0x28/0x60
>> [    5.528622]  rpmsg_ns_cb+0x100/0x1dc
>> [    5.532185]  rpmsg_recv_done+0x114/0x2e4
>> [    5.536094]  vring_interrupt+0x68/0xa4
>> [    5.539833]  rproc_vq_interrupt+0x2c/0x48
>> [    5.543830]  k3_r5_rproc_mbox_callback+0x84/0x90 [ti_k3_r5_remoteproc]
>> [    5.550348]  mbox_chan_received_data+0x1c/0x2c
>> [    5.554779]  mbox_interrupt+0xa0/0x17c [omap_mailbox]
>> [    5.559820]  __handle_irq_event_percpu+0x48/0x13c
>> [    5.564511]  handle_irq_event+0x4c/0xac
>>
> 
> I looked into this a bit more closely, together with the colleague who implemented our internal workaround, and we came up with one more concern:
> 
> Have you considered that this synchronous path from the (threaded) IRQ draining the mailbox down to the (potentially blocking) rpmsg_* calls might let the hardware mailbox grow full?
> 
>  From what I remember the vring (?) has room for 512 messages, but the hardware mailbox on e.g. the AM64x can only handle four messages. At least with the current implementation on TI's MCU+ SDK running on the R5f that could cause the R5f to block, waiting for room in the hardware mailbox, while there are plenty of vring buffers available.
> 

We would like to switch back to the non-threaded handler at some point. As you mention doing this
in a threaded way increase the risk of the hardware message queue filling and blocking the remote side.
(Plus the threaded handling can add latency to the message handling which should be avoided for real-time
reasons)

The fix might be to have rpmsg_recv_done() callback simply queue the message and then schedule another
worker to actually do the next stage processing. That way complex actions on messages do not block
vring_interrupt() which should be treated like an atomic context call.

Anyway for now, I'd expect the much faster host core (2xA53 @ 1GHZ in AM64) to be able to outpace the
R5s and keep the mailbox drained. Are you actually running into this issue or is the concern based on
ensuring RT performance(not blocking on mailbox queue filled) on the R5 side?

Andrew

> Best Regards,
> 
> Dominic