[PATCH v3 1/2] Bluetooth: btintel_pcie: Fix potential race condition in firmware download

[Kiran K <kiran.k@intel.com>]

During firmware download, if an error occurs, interrupts must be
disabled, synchronized, and re-enabled before retrying the download.
This change ensures proper interrupt handling to prevent race
conditions.

Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Signed-off-by: Kiran K <kiran.k@intel.com>
---
 drivers/bluetooth/btintel_pcie.c | 33 ++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 563165c5efae..e1c688dd2d45 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -2033,6 +2033,28 @@ static void btintel_pcie_release_hdev(struct btintel_pcie_data *data)
 	data->hdev = NULL;
 }
 
+static void btintel_pcie_disable_interrupts(struct btintel_pcie_data *data)
+{
+	spin_lock(&data->irq_lock);
+	btintel_pcie_wr_reg32(data, BTINTEL_PCIE_CSR_MSIX_FH_INT_MASK, data->fh_init_mask);
+	btintel_pcie_wr_reg32(data, BTINTEL_PCIE_CSR_MSIX_HW_INT_MASK, data->hw_init_mask);
+	spin_unlock(&data->irq_lock);
+}
+
+static void btintel_pcie_enable_interrupts(struct btintel_pcie_data *data)
+{
+	spin_lock(&data->irq_lock);
+	btintel_pcie_wr_reg32(data, BTINTEL_PCIE_CSR_MSIX_FH_INT_MASK, ~data->fh_init_mask);
+	btintel_pcie_wr_reg32(data, BTINTEL_PCIE_CSR_MSIX_HW_INT_MASK, ~data->hw_init_mask);
+	spin_unlock(&data->irq_lock);
+}
+
+static void btintel_pcie_synchronize_irqs(struct btintel_pcie_data *data)
+{
+	for (int i = 0; i < data->alloc_vecs; i++)
+		synchronize_irq(data->msix_entries[i].vector);
+}
+
 static int btintel_pcie_setup_internal(struct hci_dev *hdev)
 {
 	struct btintel_pcie_data *data = hci_get_drvdata(hdev);
@@ -2152,6 +2174,8 @@ static int btintel_pcie_setup(struct hci_dev *hdev)
 		bt_dev_err(hdev, "Firmware download retry count: %d",
 			   fw_dl_retry);
 		btintel_pcie_dump_debug_registers(hdev);
+		btintel_pcie_disable_interrupts(data);
+		btintel_pcie_synchronize_irqs(data);
 		err = btintel_pcie_reset_bt(data);
 		if (err) {
 			bt_dev_err(hdev, "Failed to do shr reset: %d", err);
@@ -2159,6 +2183,7 @@ static int btintel_pcie_setup(struct hci_dev *hdev)
 		}
 		usleep_range(10000, 12000);
 		btintel_pcie_reset_ia(data);
+		btintel_pcie_enable_interrupts(data);
 		btintel_pcie_config_msix(data);
 		err = btintel_pcie_enable_bt(data);
 		if (err) {
@@ -2291,6 +2316,12 @@ static void btintel_pcie_remove(struct pci_dev *pdev)
 
 	data = pci_get_drvdata(pdev);
 
+	btintel_pcie_disable_interrupts(data);
+
+	btintel_pcie_synchronize_irqs(data);
+
+	flush_work(&data->rx_work);
+
 	btintel_pcie_reset_bt(data);
 	for (int i = 0; i < data->alloc_vecs; i++) {
 		struct msix_entry *msix_entry;
@@ -2303,8 +2334,6 @@ static void btintel_pcie_remove(struct pci_dev *pdev)
 
 	btintel_pcie_release_hdev(data);
 
-	flush_work(&data->rx_work);
-
 	destroy_workqueue(data->workqueue);
 
 	btintel_pcie_free(data);
-- 
2.43.0