[PATCH v2] Bluetooth: btintel_pcie: Support suspend-resume

[ChandraShekar Devegowda <chandrashekar.devegowda@xxxxxxxxx>]

This patch contains the changes in driver for vendor specific handshake
during enter of D3 and D0 exit.
Command to test host initiated wake up after 60seconds
    sudo rtcwake -m mem-s 60
logs from testing:
    Bluetooth: hci0: BT device resumed to D0 in 1016 usecs

Signed-off-by: Kiran K <kiran.k@xxxxxxxxx>
Signed-off-by: ChandraShekar Devegowda <chandrashekar.devegowda@xxxxxxxxx>
---
 drivers/bluetooth/btintel_pcie.c | 58 ++++++++++++++++++++++++++++++++
 drivers/bluetooth/btintel_pcie.h |  4 +++
 2 files changed, 62 insertions(+)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 2b79952f3628..49b78d3ecdf9 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -273,6 +273,12 @@ static int btintel_pcie_reset_bt(struct btintel_pcie_data *data)
 	return reg == 0 ? 0 : -ENODEV;
 }
 
+static void btintel_pcie_set_persistence_mode(struct btintel_pcie_data *data)
+{
+	btintel_pcie_set_reg_bits(data, BTINTEL_PCIE_CSR_HW_BOOT_CONFIG,
+				  BTINTEL_PCIE_CSR_HW_BOOT_CONFIG_KEEP_ON);
+}
+
 /* This function enables BT function by setting BTINTEL_PCIE_CSR_FUNC_CTRL_MAC_INIT bit in
  * BTINTEL_PCIE_CSR_FUNC_CTRL_REG register and wait for MSI-X with
  * BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0.
@@ -297,6 +303,8 @@ static int btintel_pcie_enable_bt(struct btintel_pcie_data *data)
 	 */
 	data->boot_stage_cache = 0x0;
 
+	btintel_pcie_set_persistence_mode(data);
+
 	/* Set MAC_INIT bit to start primary bootloader */
 	reg = btintel_pcie_rd_reg32(data, BTINTEL_PCIE_CSR_FUNC_CTRL_REG);
 	reg &= ~(BTINTEL_PCIE_CSR_FUNC_CTRL_FUNC_INIT |
@@ -1647,11 +1655,61 @@ static void btintel_pcie_remove(struct pci_dev *pdev)
 	pci_set_drvdata(pdev, NULL);
 }
 
+static int btintel_pcie_suspend(struct device *dev)
+{
+	struct btintel_pcie_data *data;
+	int err;
+	struct  pci_dev *pdev = to_pci_dev(dev);
+
+	data = pci_get_drvdata(pdev);
+	data->gp0_received = false;
+	btintel_pcie_wr_sleep_cntrl(data, BTINTEL_PCIE_STATE_D3_HOT);
+	err = wait_event_timeout(data->gp0_wait_q, data->gp0_received,
+				 msecs_to_jiffies(BTINTEL_DEFAULT_INTR_TIMEOUT_MS));
+	if (!err) {
+		bt_dev_err(data->hdev, "failed to receive gp0 interrupt for suspend in %lu msecs",
+			   BTINTEL_DEFAULT_INTR_TIMEOUT_MS);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int btintel_pcie_resume(struct device *dev)
+{
+	struct btintel_pcie_data *data;
+	struct  pci_dev *pdev = to_pci_dev(dev);
+	ktime_t calltime, delta, rettime;
+	unsigned long long duration;
+	int err;
+
+	data = pci_get_drvdata(pdev);
+	data->gp0_received = false;
+	calltime = ktime_get();
+	btintel_pcie_wr_sleep_cntrl(data, BTINTEL_PCIE_STATE_D0);
+	err = wait_event_timeout(data->gp0_wait_q, data->gp0_received,
+				 msecs_to_jiffies(BTINTEL_DEFAULT_INTR_TIMEOUT_MS));
+	if (!err) {
+		bt_dev_err(data->hdev, "failed to receive gp0 interrupt for resume in %lu msecs",
+			   BTINTEL_DEFAULT_INTR_TIMEOUT_MS);
+		return -EBUSY;
+	}
+	rettime = ktime_get();
+	delta = ktime_sub(rettime, calltime);
+	duration = (unsigned long long)ktime_to_ns(delta) >> 10;
+	bt_dev_info(data->hdev, "BT device resumed to D0 in %llu usecs", duration);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(btintel_pcie_pm_ops, btintel_pcie_suspend,
+		btintel_pcie_resume);
+
 static struct pci_driver btintel_pcie_driver = {
 	.name = KBUILD_MODNAME,
 	.id_table = btintel_pcie_table,
 	.probe = btintel_pcie_probe,
 	.remove = btintel_pcie_remove,
+	.driver.pm = &btintel_pcie_pm_ops,
 };
 module_pci_driver(btintel_pcie_driver);
 
diff --git a/drivers/bluetooth/btintel_pcie.h b/drivers/bluetooth/btintel_pcie.h
index f9aada0543c4..38d0c8ea2b6f 100644
--- a/drivers/bluetooth/btintel_pcie.h
+++ b/drivers/bluetooth/btintel_pcie.h
@@ -8,6 +8,7 @@
 
 /* Control and Status Register(BTINTEL_PCIE_CSR) */
 #define BTINTEL_PCIE_CSR_BASE			(0x000)
+#define BTINTEL_PCIE_CSR_HW_BOOT_CONFIG		(BTINTEL_PCIE_CSR_BASE + 0x000)
 #define BTINTEL_PCIE_CSR_FUNC_CTRL_REG		(BTINTEL_PCIE_CSR_BASE + 0x024)
 #define BTINTEL_PCIE_CSR_HW_REV_REG		(BTINTEL_PCIE_CSR_BASE + 0x028)
 #define BTINTEL_PCIE_CSR_RF_ID_REG		(BTINTEL_PCIE_CSR_BASE + 0x09C)
@@ -48,6 +49,9 @@
 #define BTINTEL_PCIE_CSR_MSIX_IVAR_BASE		(BTINTEL_PCIE_CSR_MSIX_BASE + 0x0880)
 #define BTINTEL_PCIE_CSR_MSIX_IVAR(cause)	(BTINTEL_PCIE_CSR_MSIX_IVAR_BASE + (cause))
 
+/* CSR HW BOOT CONFIG Register */
+#define BTINTEL_PCIE_CSR_HW_BOOT_CONFIG_KEEP_ON		(BIT(31))
+
 /* Causes for the FH register interrupts */
 enum msix_fh_int_causes {
 	BTINTEL_PCIE_MSIX_FH_INT_CAUSES_0	= BIT(0),	/* cause 0 */
-- 
2.34.1