6.6-stable review patch. If anyone has any objections, please let me know.
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From: Neeraj Sanjay Kale neeraj.sanjaykale@nxp.com
[ Upstream commit e4db90e4eb8d5487098712ffb1048f3fa6d25e98 ]
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 Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Stable-dep-of: 35237475384a ("Bluetooth: btnxpuart: Fix random crash seen while removing driver") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bluetooth/btnxpuart.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-)
diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c index b5d40e0e05f31..2e18f89a931b8 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 { @@ -333,6 +334,9 @@ 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) @@ -353,6 +357,7 @@ 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) @@ -366,12 +371,15 @@ static void ps_control(struct hci_dev *hdev, u8 ps_state) status = serdev_device_break_ctl(nxpdev->serdev, 0); else status = serdev_device_break_ctl(nxpdev->serdev, -1); + msleep(20); /* Allow chip to detect UART-break and enter sleep */ 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); } @@ -407,17 +415,25 @@ 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;
- if (psdata->ps_state != PS_STATE_AWAKE) { + mutex_lock(&psdata->ps_lock); + ps_state = psdata->ps_state; + mutex_unlock(&psdata->ps_lock); + + 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) @@ -1215,7 +1231,6 @@ 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); } @@ -1230,6 +1245,9 @@ static void btnxpuart_tx_work(struct work_struct *work) struct sk_buff *skb; int len;
+ if (ps_wakeup(nxpdev)) + return; + while ((skb = nxp_dequeue(nxpdev))) { len = serdev_device_write_buf(serdev, skb->data, skb->len); hdev->stat.byte_tx += len;