[PATCH 6.18 219/227] Bluetooth: btintel_pcie: Support for S4 (Hibernate)

Greg Kroah-Hartman
2026-01-28T16:02:22Z

From: Ravindra <ravindra@intel.com>

commit 1fb0d830dab89d0dc99bb84a7087b0ceca63d2d8 upstream.

During S4 (hibernate), the Bluetooth device loses power. Upon resume,
the driver performs the following actions:

1. Unregisters hdev
2. Calls function level reset
3. Registers hdev

Test case:
- run command sudo rtcwake -m disk -s 60

Signed-off-by: Ravindra <ravindra@intel.com>
Signed-off-by: Kiran K <kiran.k@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Cc: Mariappan Ramasamy <mail@nappairam.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/bluetooth/btintel_pcie.c | 41 +++++++++++++++++++++++++++++++++++++++
drivers/bluetooth/btintel_pcie.h | 2 +
2 files changed, 43 insertions(+)

--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -825,6 +825,11 @@ static inline bool btintel_pcie_in_d0(st
return !(data->boot_stage_cache & BTINTEL_PCIE_CSR_BOOT_STAGE_D3_STATE_READY);
}

+static inline bool btintel_pcie_in_device_halt(struct btintel_pcie_data *data)
+{
+ return data->boot_stage_cache & BTINTEL_PCIE_CSR_BOOT_STAGE_DEVICE_HALTED;
+}
+
static void btintel_pcie_wr_sleep_cntrl(struct btintel_pcie_data *data,
u32 dxstate)
{
@@ -2532,6 +2537,8 @@ static int btintel_pcie_suspend_late(str
dxstate = (mesg.event == PM_EVENT_SUSPEND ?
BTINTEL_PCIE_STATE_D3_HOT : BTINTEL_PCIE_STATE_D3_COLD);

+ data->pm_sx_event = mesg.event;
+
data->gp0_received = false;

start = ktime_get();
@@ -2581,6 +2588,20 @@ static int btintel_pcie_resume(struct de

start = ktime_get();

+ /* When the system enters S4 (hibernate) mode, bluetooth device loses
+ * power, which results in the erasure of its loaded firmware.
+ * Consequently, function level reset (flr) is required on system
+ * resume to bring the controller back into an operational state by
+ * initiating a new firmware download.
+ */
+
+ if (data->pm_sx_event == PM_EVENT_FREEZE ||
+ data->pm_sx_event == PM_EVENT_HIBERNATE) {
+ set_bit(BTINTEL_PCIE_CORE_HALTED, &data->flags);
+ btintel_pcie_reset(data->hdev);
+ return 0;
+ }
+
/* Refer: 6.4.11.7 -> Platform power management */
btintel_pcie_wr_sleep_cntrl(data, BTINTEL_PCIE_STATE_D0);
err = wait_event_timeout(data->gp0_wait_q, data->gp0_received,
@@ -2589,6 +2610,26 @@ static int btintel_pcie_resume(struct de
bt_dev_err(data->hdev,
"Timeout (%u ms) on alive interrupt for D0 entry",
BTINTEL_DEFAULT_INTR_TIMEOUT_MS);
+
+ /* Trigger function level reset if the controller is in error
+ * state during resume() to bring back the controller to
+ * operational mode
+ */
+
+ data->boot_stage_cache = btintel_pcie_rd_reg32(data,
+ BTINTEL_PCIE_CSR_BOOT_STAGE_REG);
+ if (btintel_pcie_in_error(data) ||
+ btintel_pcie_in_device_halt(data)) {
+ bt_dev_err(data->hdev, "Controller in error state for D0 entry");
+ if (!test_and_set_bit(BTINTEL_PCIE_COREDUMP_INPROGRESS,
+ &data->flags)) {
+ data->dmp_hdr.trigger_reason =
+ BTINTEL_PCIE_TRIGGER_REASON_FW_ASSERT;
+ queue_work(data->workqueue, &data->rx_work);
+ }
+ set_bit(BTINTEL_PCIE_CORE_HALTED, &data->flags);
+ btintel_pcie_reset(data->hdev);
+ }
return -EBUSY;
}

--- a/drivers/bluetooth/btintel_pcie.h
+++ b/drivers/bluetooth/btintel_pcie.h
@@ -464,6 +464,7 @@ struct btintel_pcie_dump_header {
* @txq: TX Queue struct
* @rxq: RX Queue struct
* @alive_intr_ctxt: Alive interrupt context
+ * @pm_sx_event: PM event on which system got suspended
*/
struct btintel_pcie_data {
struct pci_dev *pdev;
@@ -513,6 +514,7 @@ struct btintel_pcie_data {
u32 alive_intr_ctxt;
struct btintel_pcie_dbgc dbgc;
struct btintel_pcie_dump_header dmp_hdr;
+ u8 pm_sx_event;
};

static inline u32 btintel_pcie_rd_reg32(struct btintel_pcie_data *data,