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Bluetooth: hci_qca: Fix SSR (SubSystem Restart) fail when BT_EN is pulled up by hw

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On QCS9075 and QCA8275 platforms, the BT_EN pin is always pulled up by hw
and cannot be controlled by the host. As a result, in case of a firmware
crash, the host cannot trigger a cold reset. Instead, the BT controller
performs a warm restart on its own, without reloading the firmware.

This leads to the controller remaining in IBS_WAKE state, while the host
expects it to be in sleep mode. The mismatch causes HCI reset commands
to time out. Additionally, the driver does not clear internal flags
QCA_SSR_TRIGGERED and QCA_IBS_DISABLED, which blocks the reset sequence.
If the SSR duration exceeds 2 seconds, the host may enter TX sleep mode
due to tx_idle_timeout, further preventing recovery. Also, memcoredump_flag
is not cleared, so only the first SSR generates a coredump.

Tell the driver that the BT controller has undergone a proper restart sequence:

- Clear QCA_SSR_TRIGGERED and QCA_IBS_DISABLED flags after SSR.
- Add a 50ms delay to allow the controller to complete its warm reset.
- Reset tx_idle_timer to prevent the host from entering TX sleep mode.
- Clear memcoredump_flag to allow multiple coredump captures.

Apply these steps only when HCI_QUIRK_NON_PERSISTENT_SETUP is not set,
which indicates that BT_EN is defined in DTS and cannot be toggled.

Refer to the comment in include/net/bluetooth/hci.h for details on
HCI_QUIRK_NON_PERSISTENT_SETUP.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Shuai Zhang <shuai.zhang@oss.qualcomm.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Shuai Zhang 2025-12-03 11:37:12 +08:00 committed by Luiz Augusto von Dentz
parent e75e408dc5
commit fce1a9244a
1 changed files with 33 additions and 0 deletions
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33
drivers/bluetooth/hci_qca.c
View File

@ -1653,6 +1653,39 @@ static void qca_hw_error(struct hci_dev *hdev, u8 code)
skb_queue_purge(&qca->rx_memdump_q);
}
/*
* If the BT chip's bt_en pin is connected to a 3.3V power supply via
* hardware and always stays high, driver cannot control the bt_en pin.
* As a result, during SSR (SubSystem Restart), QCA_SSR_TRIGGERED and
* QCA_IBS_DISABLED flags cannot be cleared, which leads to a reset
* command timeout.
* Add an msleep delay to ensure controller completes the SSR process.
*
* Host will not download the firmware after SSR, controller to remain
* in the IBS_WAKE state, and the host needs to synchronize with it
*
* Since the bluetooth chip has been reset, clear the memdump state.
*/
if (!hci_test_quirk(hu->hdev, HCI_QUIRK_NON_PERSISTENT_SETUP)) {
/*
* When the SSR (SubSystem Restart) duration exceeds 2 seconds,
* it triggers host tx_idle_delay, which sets host TX state
* to sleep. Reset tx_idle_timer after SSR to prevent
* host enter TX IBS_Sleep mode.
*/
mod_timer(&qca->tx_idle_timer, jiffies +
msecs_to_jiffies(qca->tx_idle_delay));
/* Controller reset completion time is 50ms */
msleep(50);
clear_bit(QCA_SSR_TRIGGERED, &qca->flags);
clear_bit(QCA_IBS_DISABLED, &qca->flags);
qca->tx_ibs_state = HCI_IBS_TX_AWAKE;
qca->memdump_state = QCA_MEMDUMP_IDLE;
}
clear_bit(QCA_HW_ERROR_EVENT, &qca->flags);
}