diff mbox series

[v2] Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test

Message ID 20231226113110.3923962-1-neeraj.sanjaykale@nxp.com
State New
Headers
Series [v2] Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test |

Commit Message

Neeraj Sanjay Kale Dec. 26, 2023, 11:31 a.m. UTC 
  This fixes the tx timeout issue seen while running a stress test on
btnxpuart for couple of hours, such that the interval between two HCI
commands coincide with the power save timeout value of 2 seconds.

Test procedure using bash script:
<load btnxpuart.ko>
hciconfig hci0 up
//Enable Power Save feature
hcitool -i hci0 cmd 3f 23 02 00 00
while (true)
do
    hciconfig hci0 leadv
    sleep 2
    hciconfig hci0 noleadv
    sleep 2
done

Error log, after adding few more debug prints:
Bluetooth: btnxpuart_queue_skb(): 01 0A 20 01 00
Bluetooth: hci0: Set UART break: on, status=0
Bluetooth: hci0: btnxpuart_tx_wakeup() tx_work scheduled
Bluetooth: hci0: btnxpuart_tx_work() dequeue: 01 0A 20 01 00
Can't set advertise mode on hci0: Connection timed out (110)
Bluetooth: hci0: command 0x200a tx timeout

When the power save mechanism turns on UART break, and btnxpuart_tx_work()
is scheduled simultaneously, psdata->ps_state is read as PS_STATE_AWAKE,
which prevents the psdata->work from being scheduled, which is responsible
to turn OFF UART break.

This issue is fixed by adding a ps_lock mutex around UART break on/off as
well as around ps_state read/write.
btnxpuart_tx_wakeup() will now read updated ps_state value. If ps_state is
PS_STATE_SLEEP, it will first schedule psdata->work, and then it will
reschedule itself once UART break has been turned off and ps_state is
PS_STATE_AWAKE.

Tested above script for 50,000 iterations and TX timeout error was not
observed anymore.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
---
v2: Add 2msec delay after enabling UART break, cancel ps_work when
ps_timer is restarted.
---
 drivers/bluetooth/btnxpuart.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

Comments

kernel test robot Dec. 27, 2023, 2:35 a.m. UTC | #1 
Hi Neeraj,

kernel test robot noticed the following build errors:

[auto build test ERROR on bluetooth/master]
[also build test ERROR on bluetooth-next/master linus/master v6.7-rc7 next-20231222]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Neeraj-Sanjay-Kale/Bluetooth-btnxpuart-Resolve-TX-timeout-error-in-power-save-stress-test/20231226-193718
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git master
patch link:    https://lore.kernel.org/r/20231226113110.3923962-1-neeraj.sanjaykale%40nxp.com
patch subject: [PATCH v2] Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test
config: arm-randconfig-003-20231227 (https://download.01.org/0day-ci/archive/20231227/202312271021.m0of6rmb-lkp@intel.com/config)
compiler: clang version 18.0.0git (https://github.com/llvm/llvm-project d3ef86708241a3bee902615c190dead1638c4e09)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231227/202312271021.m0of6rmb-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312271021.m0of6rmb-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/bluetooth/btnxpuart.c:356:4: error: call to undeclared function 'usleep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     356 |                         usleep(2000); /* Allow chip to detect UART-break and enter sleep */
         |                         ^
   1 error generated.


vim +/usleep +356 drivers/bluetooth/btnxpuart.c

   333	
   334	static void ps_control(struct hci_dev *hdev, u8 ps_state)
   335	{
   336		struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
   337		struct ps_data *psdata = &nxpdev->psdata;
   338		int status;
   339	
   340		if (psdata->ps_state == ps_state ||
   341		    !test_bit(BTNXPUART_SERDEV_OPEN, &nxpdev->tx_state))
   342			return;
   343	
   344		mutex_lock(&psdata->ps_lock);
   345		switch (psdata->cur_h2c_wakeupmode) {
   346		case WAKEUP_METHOD_DTR:
   347			if (ps_state == PS_STATE_AWAKE)
   348				status = serdev_device_set_tiocm(nxpdev->serdev, TIOCM_DTR, 0);
   349			else
   350				status = serdev_device_set_tiocm(nxpdev->serdev, 0, TIOCM_DTR);
   351			break;
   352		case WAKEUP_METHOD_BREAK:
   353		default:
   354			if (ps_state == PS_STATE_AWAKE) {
   355				status = serdev_device_break_ctl(nxpdev->serdev, 0);
 > 356				usleep(2000); /* Allow chip to detect UART-break and enter sleep */
   357			} else {
   358				status = serdev_device_break_ctl(nxpdev->serdev, -1);
   359			}
   360			bt_dev_dbg(hdev, "Set UART break: %s, status=%d",
   361				   str_on_off(ps_state == PS_STATE_SLEEP), status);
   362			break;
   363		}
   364		if (!status)
   365			psdata->ps_state = ps_state;
   366		mutex_unlock(&psdata->ps_lock);
   367	
   368		if (ps_state == PS_STATE_AWAKE)
   369			btnxpuart_tx_wakeup(nxpdev);
   370	}
   371
kernel test robot Dec. 27, 2023, 11:41 a.m. UTC | #2 
Hi Neeraj,

kernel test robot noticed the following build errors:

[auto build test ERROR on bluetooth/master]
[also build test ERROR on bluetooth-next/master linus/master v6.7-rc7 next-20231222]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Neeraj-Sanjay-Kale/Bluetooth-btnxpuart-Resolve-TX-timeout-error-in-power-save-stress-test/20231226-193718
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth.git master
patch link:    https://lore.kernel.org/r/20231226113110.3923962-1-neeraj.sanjaykale%40nxp.com
patch subject: [PATCH v2] Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20231227/202312271920.D4X4fO6I-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231227/202312271920.D4X4fO6I-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312271920.D4X4fO6I-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/bluetooth/btnxpuart.c: In function 'ps_control':
>> drivers/bluetooth/btnxpuart.c:356:25: error: implicit declaration of function 'usleep'; did you mean 'fsleep'? [-Werror=implicit-function-declaration]
     356 |                         usleep(2000); /* Allow chip to detect UART-break and enter sleep */
         |                         ^~~~~~
         |                         fsleep
   cc1: some warnings being treated as errors


vim +356 drivers/bluetooth/btnxpuart.c

   333	
   334	static void ps_control(struct hci_dev *hdev, u8 ps_state)
   335	{
   336		struct btnxpuart_dev *nxpdev = hci_get_drvdata(hdev);
   337		struct ps_data *psdata = &nxpdev->psdata;
   338		int status;
   339	
   340		if (psdata->ps_state == ps_state ||
   341		    !test_bit(BTNXPUART_SERDEV_OPEN, &nxpdev->tx_state))
   342			return;
   343	
   344		mutex_lock(&psdata->ps_lock);
   345		switch (psdata->cur_h2c_wakeupmode) {
   346		case WAKEUP_METHOD_DTR:
   347			if (ps_state == PS_STATE_AWAKE)
   348				status = serdev_device_set_tiocm(nxpdev->serdev, TIOCM_DTR, 0);
   349			else
   350				status = serdev_device_set_tiocm(nxpdev->serdev, 0, TIOCM_DTR);
   351			break;
   352		case WAKEUP_METHOD_BREAK:
   353		default:
   354			if (ps_state == PS_STATE_AWAKE) {
   355				status = serdev_device_break_ctl(nxpdev->serdev, 0);
 > 356				usleep(2000); /* Allow chip to detect UART-break and enter sleep */
   357			} else {
   358				status = serdev_device_break_ctl(nxpdev->serdev, -1);
   359			}
   360			bt_dev_dbg(hdev, "Set UART break: %s, status=%d",
   361				   str_on_off(ps_state == PS_STATE_SLEEP), status);
   362			break;
   363		}
   364		if (!status)
   365			psdata->ps_state = ps_state;
   366		mutex_unlock(&psdata->ps_lock);
   367	
   368		if (ps_state == PS_STATE_AWAKE)
   369			btnxpuart_tx_wakeup(nxpdev);
   370	}
   371
diff mbox series

Patch

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index b7e66b7ac570..c6ef5878abe5 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -126,6 +126,7 @@  struct ps_data {
 	struct hci_dev *hdev;
 	struct work_struct work;
 	struct timer_list ps_timer;
+	struct mutex ps_lock;
 };
 
 struct wakeup_cmd_payload {
@@ -317,6 +318,9 @@  static void ps_start_timer(struct btnxpuart_dev *nxpdev)
 
 	if (psdata->cur_psmode == PS_MODE_ENABLE)
 		mod_timer(&psdata->ps_timer, jiffies + msecs_to_jiffies(psdata->h2c_ps_interval));
+
+	if (psdata->ps_state == PS_STATE_AWAKE && psdata->ps_cmd == PS_CMD_ENTER_PS)
+		cancel_work_sync(&psdata->work);
 }
 
 static void ps_cancel_timer(struct btnxpuart_dev *nxpdev)
@@ -337,6 +341,7 @@  static void ps_control(struct hci_dev *hdev, u8 ps_state)
 	    !test_bit(BTNXPUART_SERDEV_OPEN, &nxpdev->tx_state))
 		return;
 
+	mutex_lock(&psdata->ps_lock);
 	switch (psdata->cur_h2c_wakeupmode) {
 	case WAKEUP_METHOD_DTR:
 		if (ps_state == PS_STATE_AWAKE)
@@ -346,16 +351,20 @@  static void ps_control(struct hci_dev *hdev, u8 ps_state)
 		break;
 	case WAKEUP_METHOD_BREAK:
 	default:
-		if (ps_state == PS_STATE_AWAKE)
+		if (ps_state == PS_STATE_AWAKE) {
 			status = serdev_device_break_ctl(nxpdev->serdev, 0);
-		else
+			usleep(2000); /* Allow chip to detect UART-break and enter sleep */
+		} else {
 			status = serdev_device_break_ctl(nxpdev->serdev, -1);
+		}
 		bt_dev_dbg(hdev, "Set UART break: %s, status=%d",
 			   str_on_off(ps_state == PS_STATE_SLEEP), status);
 		break;
 	}
 	if (!status)
 		psdata->ps_state = ps_state;
+	mutex_unlock(&psdata->ps_lock);
+
 	if (ps_state == PS_STATE_AWAKE)
 		btnxpuart_tx_wakeup(nxpdev);
 }
@@ -391,17 +400,25 @@  static void ps_setup(struct hci_dev *hdev)
 
 	psdata->hdev = hdev;
 	INIT_WORK(&psdata->work, ps_work_func);
+	mutex_init(&psdata->ps_lock);
 	timer_setup(&psdata->ps_timer, ps_timeout_func, 0);
 }
 
-static void ps_wakeup(struct btnxpuart_dev *nxpdev)
+static bool ps_wakeup(struct btnxpuart_dev *nxpdev)
 {
 	struct ps_data *psdata = &nxpdev->psdata;
+	u8 ps_state;
+
+	mutex_lock(&psdata->ps_lock);
+	ps_state = psdata->ps_state;
+	mutex_unlock(&psdata->ps_lock);
 
-	if (psdata->ps_state != PS_STATE_AWAKE) {
+	if (ps_state != PS_STATE_AWAKE) {
 		psdata->ps_cmd = PS_CMD_EXIT_PS;
 		schedule_work(&psdata->work);
+		return true;
 	}
+	return false;
 }
 
 static int send_ps_cmd(struct hci_dev *hdev, void *data)
@@ -1171,7 +1188,6 @@  static struct sk_buff *nxp_dequeue(void *data)
 {
 	struct btnxpuart_dev *nxpdev = (struct btnxpuart_dev *)data;
 
-	ps_wakeup(nxpdev);
 	ps_start_timer(nxpdev);
 	return skb_dequeue(&nxpdev->txq);
 }
@@ -1186,6 +1202,11 @@  static void btnxpuart_tx_work(struct work_struct *work)
 	struct sk_buff *skb;
 	int len;
 
+	if (ps_wakeup(nxpdev)) {
+		schedule_work(&nxpdev->tx_work);
+		return;
+	}
+
 	while ((skb = nxp_dequeue(nxpdev))) {
 		len = serdev_device_write_buf(serdev, skb->data, skb->len);
 		hdev->stat.byte_tx += len;