+ linux-pci@xxxxxxxxxxxxxxx, bhelgaas@xxxxxxxxxx
>-----Original Message-----
>From: K, Kiran <kiran.k@xxxxxxxxx>
>Sent: Sunday, May 25, 2025 3:46 PM
>To: linux-bluetooth@xxxxxxxxxxxxxxx
>Cc: Srivatsa, Ravishankar <ravishankar.srivatsa@xxxxxxxxx>; Tumkur Narayan,
>Chethan <chethan.tumkur.narayan@xxxxxxxxx>; Devegowda, Chandrashekar
><chandrashekar.devegowda@xxxxxxxxx>; Satija, Vijay <vijay.satija@xxxxxxxxx>;
>K, Kiran <kiran.k@xxxxxxxxx>
>Subject: [PATCH v2 2/2] Bluetooth: btintel_pcie: Support Function level reset
>
>From: Chandrashekar Devegowda <chandrashekar.devegowda@xxxxxxxxx>
>
>Support function level reset (flr) on hardware exception to recover controller.
>Driver also implements the back-off time of 5 seconds and the maximum
>number of retries are limited to 5 before giving up.
>
>Signed-off-by: Chandrashekar Devegowda
><chandrashekar.devegowda@xxxxxxxxx>
>Signed-off-by: Kiran K <kiran.k@xxxxxxxxx>
>---
> drivers/bluetooth/btintel_pcie.c | 234 ++++++++++++++++++++++++++++++-
> drivers/bluetooth/btintel_pcie.h | 4 +-
> 2 files changed, 235 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
>index 74a957784525..6779a2cfa75d 100644
>--- a/drivers/bluetooth/btintel_pcie.c
>+++ b/drivers/bluetooth/btintel_pcie.c
>@@ -41,6 +41,13 @@ static const struct pci_device_id btintel_pcie_table[] = {
>}; MODULE_DEVICE_TABLE(pci, btintel_pcie_table);
>
>+struct btintel_pcie_dev_restart_data {
>+ struct list_head list;
>+ u8 restart_count;
>+ time64_t last_error;
>+ char name[];
>+};
>+
> /* Intel PCIe uses 4 bytes of HCI type instead of 1 byte BT SIG HCI type */
> #define BTINTEL_PCIE_HCI_TYPE_LEN 4
> #define BTINTEL_PCIE_HCI_CMD_PKT 0x00000001
>@@ -62,6 +69,9 @@ MODULE_DEVICE_TABLE(pci, btintel_pcie_table);
> #define BTINTEL_PCIE_TRIGGER_REASON_USER_TRIGGER 0x17A2
> #define BTINTEL_PCIE_TRIGGER_REASON_FW_ASSERT 0x1E61
>
>+#define BTINTEL_PCIE_RESET_OK_TIME_SECS 5
>+#define BTINTEL_PCIE_FLR_RESET_MAX_RETRY 5
>+
> /* Alive interrupt context */
> enum {
> BTINTEL_PCIE_ROM,
>@@ -99,6 +109,14 @@ struct btintel_pcie_dbgc_ctxt {
> struct btintel_pcie_dbgc_ctxt_buf
>bufs[BTINTEL_PCIE_DBGC_BUFFER_COUNT];
> };
>
>+struct btintel_pcie_removal {
>+ struct pci_dev *pdev;
>+ struct work_struct work;
>+};
>+
>+static LIST_HEAD(btintel_pcie_restart_data_list);
>+static DEFINE_SPINLOCK(btintel_pcie_restart_data_lock);
>+
> /* This function initializes the memory for DBGC buffers and formats the
> * DBGC fragment which consists header info and DBGC buffer's LSB, MSB and
> * size as the payload
>@@ -1927,6 +1945,9 @@ static int btintel_pcie_send_frame(struct hci_dev
>*hdev,
> u32 type;
> u32 old_ctxt;
>
>+ if (test_bit(BTINTEL_PCIE_CORE_HALTED, &data->flags))
>+ return -ENODEV;
>+
> /* Due to the fw limitation, the type header of the packet should be
> * 4 bytes unlike 1 byte for UART. In UART, the firmware can read
> * the first byte to get the packet type and redirect the rest of data @@
>-2187,9 +2208,204 @@ static int btintel_pcie_setup(struct hci_dev *hdev)
> }
> btintel_pcie_start_rx(data);
> }
>+
>+ if (!err)
>+ set_bit(BTINTEL_PCIE_SETUP_DONE, &data->flags);
> return err;
> }
>
>+static struct btintel_pcie_dev_restart_data
>*btintel_pcie_get_restart_data(struct pci_dev *pdev,
>+ struct
>device *dev)
>+{
>+ struct btintel_pcie_dev_restart_data *tmp, *data = NULL;
>+ const char *name = pci_name(pdev);
>+ struct hci_dev *hdev = to_hci_dev(dev);
>+
>+ spin_lock(&btintel_pcie_restart_data_lock);
>+ list_for_each_entry(tmp, &btintel_pcie_restart_data_list, list) {
>+ if (strcmp(tmp->name, name))
>+ continue;
>+ data = tmp;
>+ break;
>+ }
>+ spin_unlock(&btintel_pcie_restart_data_lock);
>+
>+ if (data) {
>+ bt_dev_dbg(hdev, "Found restart data for BDF:%s", data-
>>name);
>+ return data;
>+ }
>+
>+ /* First time allocate */
>+ data = kzalloc(struct_size(data, name, strlen(name) + 1), GFP_ATOMIC);
>+ if (!data)
>+ return NULL;
>+
>+ strscpy_pad(data->name, name, strlen(name) + 1);
>+ spin_lock(&btintel_pcie_restart_data_lock);
>+ list_add_tail(&data->list, &btintel_pcie_restart_data_list);
>+ spin_unlock(&btintel_pcie_restart_data_lock);
>+
>+ return data;
>+}
>+
>+static void btintel_pcie_free_restart_list(void)
>+{
>+ struct btintel_pcie_dev_restart_data *tmp;
>+
>+ while ((tmp = list_first_entry_or_null(&btintel_pcie_restart_data_list,
>+ typeof(*tmp), list))) {
>+ list_del(&tmp->list);
>+ kfree(tmp);
>+ }
>+}
>+
>+static void btintel_pcie_inc_restart_count(struct pci_dev *pdev,
>+ struct device *dev)
>+{
>+ struct btintel_pcie_dev_restart_data *data;
>+ struct hci_dev *hdev = to_hci_dev(dev);
>+ time64_t retry_window;
>+
>+ data = btintel_pcie_get_restart_data(pdev, dev);
>+ if (!data)
>+ return;
>+
>+ retry_window = ktime_get_boottime_seconds() - data->last_error;
>+ if (data->restart_count == 0) {
>+ /* First iteration initialise the time and counter */
>+ data->last_error = ktime_get_boottime_seconds();
>+ data->restart_count++;
>+ bt_dev_dbg(hdev, "First iteration initialise. last_error:%lld
>seconds restart_count:%d",
>+ data->last_error, data->restart_count);
>+ } else if (retry_window < BTINTEL_PCIE_RESET_OK_TIME_SECS &&
>+ data->restart_count <=
>BTINTEL_PCIE_FLR_RESET_MAX_RETRY) {
>+ /* FLR triggered still within the Max retry time so
>+ * increment the counter
>+ */
>+ data->restart_count++;
>+ bt_dev_dbg(hdev, "flr triggered still within the max retry time
>so increment the restart_count:%d",
>+ data->restart_count);
>+ } else if (retry_window > BTINTEL_PCIE_RESET_OK_TIME_SECS) {
>+ /* FLR triggered out of the retry window so reset */
>+ bt_dev_dbg(hdev, "flr triggered out of retry window.
>last_error:%lld seconds restart_count:%d",
>+ data->last_error, data->restart_count);
>+ data->last_error = 0;
>+ data->restart_count = 0;
>+ }
>+}
>+
>+static int btintel_pcie_setup_hdev(struct btintel_pcie_data *data);
>+
>+static void btintel_pcie_removal_work(struct work_struct *wk) {
>+ struct btintel_pcie_removal *removal =
>+ container_of(wk, struct btintel_pcie_removal, work);
>+ struct pci_dev *pdev = removal->pdev;
>+ struct btintel_pcie_data *data;
>+ int err;
>+
>+ pci_lock_rescan_remove();
>+
>+ if (!pdev->bus)
>+ goto error;
>+
>+ data = pci_get_drvdata(pdev);
>+
>+ btintel_pcie_disable_interrupts(data);
>+ btintel_pcie_synchronize_irqs(data);
>+ flush_workqueue(data->workqueue);
>+
>+ bt_dev_dbg(data->hdev, "Release bluetooth interface");
>+ btintel_pcie_release_hdev(data);
>+
>+ err = pci_reset_function(pdev);
>+ if (err) {
>+ BT_ERR("Failed resetting the pcie device (%d)", err);
>+ goto error;
>+ }
>+
>+ btintel_pcie_enable_interrupts(data);
>+ btintel_pcie_config_msix(data);
>+
>+ err = btintel_pcie_enable_bt(data);
>+ if (err) {
>+ BT_ERR("Failed to enable bluetooth hardware after reset
>(%d)",
>+ err);
>+ goto error;
>+ }
>+
>+ btintel_pcie_reset_ia(data);
>+ btintel_pcie_start_rx(data);
>+ data->flags = 0;
>+
>+ err = btintel_pcie_setup_hdev(data);
>+ if (err) {
>+ BT_ERR("Failed registering hdev (%d)", err);
>+ goto error;
>+ }
>+error:
>+ pci_dev_put(pdev);
>+ pci_unlock_rescan_remove();
>+ kfree(removal);
>+}
>+
>+static void btintel_pcie_reset(struct hci_dev *hdev) {
>+ struct btintel_pcie_removal *removal;
>+ struct btintel_pcie_data *data;
>+
>+ data = hci_get_drvdata(hdev);
>+
>+ if (!test_bit(BTINTEL_PCIE_SETUP_DONE, &data->flags))
>+ return;
>+
>+ removal = kzalloc(sizeof(*removal), GFP_ATOMIC);
>+ if (!removal)
>+ return;
>+
>+ flush_work(&data->rx_work);
>+ flush_work(&hdev->dump.dump_rx);
>+
>+ removal->pdev = data->pdev;
>+ INIT_WORK(&removal->work, btintel_pcie_removal_work);
>+ pci_dev_get(removal->pdev);
>+ schedule_work(&removal->work);
>+}
>+
>+static void btintel_pcie_hw_error(struct hci_dev *hdev, u8 code) {
>+ struct btintel_pcie_dev_restart_data *data;
>+ struct btintel_pcie_data *dev_data = hci_get_drvdata(hdev);
>+ struct pci_dev *pdev = dev_data->pdev;
>+ time64_t retry_window;
>+
>+ if (code == 0x13) {
>+ bt_dev_err(hdev, "Encountered top exception");
>+ return;
>+ }
>+
>+ data = btintel_pcie_get_restart_data(pdev, &hdev->dev);
>+ if (!data)
>+ return;
>+
>+ retry_window = ktime_get_boottime_seconds() - data->last_error;
>+
>+ /* If within 5 seconds max 5 attempts have already been made
>+ * then stop any more retry and indicate to user for cold boot
>+ */
>+ if (retry_window < BTINTEL_PCIE_RESET_OK_TIME_SECS &&
>+ data->restart_count >= BTINTEL_PCIE_FLR_RESET_MAX_RETRY) {
>+ bt_dev_err(hdev, "Max recovery retries(%d) exhausted.",
>+ BTINTEL_PCIE_FLR_RESET_MAX_RETRY);
>+ bt_dev_dbg(hdev, "Boot time:%lld seconds first_flr at:%lld
>seconds restart_count:%d",
>+ ktime_get_boottime_seconds(), data->last_error,
>+ data->restart_count);
>+ return;
>+ }
>+ btintel_pcie_inc_restart_count(pdev, &hdev->dev);
>+ btintel_pcie_reset(hdev);
>+}
>+
> static int btintel_pcie_setup_hdev(struct btintel_pcie_data *data) {
> int err;
>@@ -2211,9 +2427,10 @@ static int btintel_pcie_setup_hdev(struct
>btintel_pcie_data *data)
> hdev->send = btintel_pcie_send_frame;
> hdev->setup = btintel_pcie_setup;
> hdev->shutdown = btintel_shutdown_combined;
>- hdev->hw_error = btintel_hw_error;
>+ hdev->hw_error = btintel_pcie_hw_error;
> hdev->set_diag = btintel_set_diag;
> hdev->set_bdaddr = btintel_set_bdaddr;
>+ hdev->reset = btintel_pcie_reset;
>
> err = hci_register_dev(hdev);
> if (err < 0) {
>@@ -2361,7 +2578,20 @@ static struct pci_driver btintel_pcie_driver = {
> .driver.coredump = btintel_pcie_coredump #endif }; -
>module_pci_driver(btintel_pcie_driver);
>+
>+static int __init btintel_pcie_init(void) {
>+ return pci_register_driver(&btintel_pcie_driver);
>+}
>+
>+static void __exit btintel_pcie_exit(void) {
>+ pci_unregister_driver(&btintel_pcie_driver);
>+ btintel_pcie_free_restart_list();
>+}
>+
>+module_init(btintel_pcie_init);
>+module_exit(btintel_pcie_exit);
>
> MODULE_AUTHOR("Tedd Ho-Jeong An <tedd.an@xxxxxxxxx>");
>MODULE_DESCRIPTION("Intel Bluetooth PCIe transport driver ver " VERSION);
>diff --git a/drivers/bluetooth/btintel_pcie.h b/drivers/bluetooth/btintel_pcie.h
>index 21b964b15c1c..62b6bcdaf10f 100644
>--- a/drivers/bluetooth/btintel_pcie.h
>+++ b/drivers/bluetooth/btintel_pcie.h
>@@ -117,7 +117,9 @@ enum {
> enum {
> BTINTEL_PCIE_CORE_HALTED,
> BTINTEL_PCIE_HWEXP_INPROGRESS,
>- BTINTEL_PCIE_COREDUMP_INPROGRESS
>+ BTINTEL_PCIE_COREDUMP_INPROGRESS,
>+ BTINTEL_PCIE_RECOVERY_IN_PROGRESS,
>+ BTINTEL_PCIE_SETUP_DONE
> };
>
> enum btintel_pcie_tlv_type {
>--
>2.43.0
