[PATCH v4 2/3] HID: Intel-thc-hid: Intel-quicki2c: Refine recover callback

[Even Xu <even.xu@intel.com>]

Refine recover flow:
1. Use workqueue to handle recover flow instead of processing in irq
   handler.
2. Call thc_rxdma_reset() API to simplify the recover operation.
3. Disable interrupt during whole recover flow.
4. If recover fails, disable interrupt to avoid interrupt storm.

Signed-off-by: Even Xu <even.xu@intel.com>
---
 .../intel-quicki2c/pci-quicki2c.c             | 66 ++++++++++++-------
 .../intel-quicki2c/quicki2c-dev.h             |  5 ++
 2 files changed, 48 insertions(+), 23 deletions(-)

diff --git a/drivers/hid/intel-thc-hid/intel-quicki2c/pci-quicki2c.c b/drivers/hid/intel-thc-hid/intel-quicki2c/pci-quicki2c.c
index 46d3e9a01999..3ccbddfe8e5e 100644
--- a/drivers/hid/intel-thc-hid/intel-quicki2c/pci-quicki2c.c
+++ b/drivers/hid/intel-thc-hid/intel-quicki2c/pci-quicki2c.c
@@ -245,28 +245,31 @@ static irqreturn_t quicki2c_irq_quick_handler(int irq, void *dev_id)
 }
 
 /**
- * try_recover - Try to recovery THC and Device
- * @qcdev: Pointer to quicki2c_device structure
+ * try_recover - Recover callback to recover THC
+ * @work: pointer to work_struct
  *
  * This function is an error handler, called when fatal error happens.
- * It try to reset touch device and re-configure THC to recovery
- * communication between touch device and THC.
- *
- * Return: 0 if successful or error code on failure
+ * It try to reset Touch Device and re-configure THC to recover
+ * transferring between Device and THC.
  */
-static int try_recover(struct quicki2c_device *qcdev)
+static void try_recover(struct work_struct *work)
 {
-	int ret;
+	struct quicki2c_device *qcdev = container_of(work, struct quicki2c_device, recover_work);
 
-	thc_dma_unconfigure(qcdev->thc_hw);
+	if (READ_ONCE(qcdev->recovery_disabled))
+		return;
 
-	ret = thc_dma_configure(qcdev->thc_hw);
-	if (ret) {
-		dev_err(qcdev->dev, "Reconfig DMA failed\n");
-		return ret;
-	}
+	if (pm_runtime_resume_and_get(qcdev->dev))
+		return;
 
-	return 0;
+	thc_interrupt_enable(qcdev->thc_hw, false);
+
+	if (thc_rxdma_reset(qcdev->thc_hw))
+		qcdev->state = QUICKI2C_DISABLED;
+	else
+		thc_interrupt_enable(qcdev->thc_hw, true);
+
+	pm_runtime_put_autosuspend(qcdev->dev);
 }
 
 static int handle_input_report(struct quicki2c_device *qcdev)
@@ -343,11 +346,10 @@ static irqreturn_t quicki2c_irq_thread_handler(int irq, void *dev_id)
 	}
 
 exit:
-	thc_interrupt_enable(qcdev->thc_hw, true);
-
 	if (err_recover)
-		if (try_recover(qcdev))
-			qcdev->state = QUICKI2C_DISABLED;
+		schedule_work(&qcdev->recover_work);
+	else
+		thc_interrupt_enable(qcdev->thc_hw, true);
 
 	pm_runtime_put_autosuspend(qcdev->dev);
 
@@ -386,6 +388,8 @@ static struct quicki2c_device *quicki2c_dev_init(struct pci_dev *pdev, void __io
 	qcdev->ddata = ddata;
 
 	init_waitqueue_head(&qcdev->reset_ack_wq);
+	WRITE_ONCE(qcdev->recovery_disabled, false);
+	INIT_WORK(&qcdev->recover_work, try_recover);
 
 	/* THC hardware init */
 	qcdev->thc_hw = thc_dev_init(qcdev->dev, qcdev->mem_addr);
@@ -439,6 +443,9 @@ static struct quicki2c_device *quicki2c_dev_init(struct pci_dev *pdev, void __io
  */
 static void quicki2c_dev_deinit(struct quicki2c_device *qcdev)
 {
+	WRITE_ONCE(qcdev->recovery_disabled, true);
+	cancel_work_sync(&qcdev->recover_work);
+
 	thc_interrupt_quiesce(qcdev->thc_hw, true);
 	thc_interrupt_enable(qcdev->thc_hw, false);
 	thc_ltr_unconfig(qcdev->thc_hw);
@@ -772,12 +779,13 @@ static void quicki2c_remove(struct pci_dev *pdev)
 		return;
 
 	quicki2c_hid_remove(qcdev);
+
+	quicki2c_dev_deinit(qcdev);
+
 	quicki2c_dma_deinit(qcdev);
 
 	pm_runtime_get_noresume(qcdev->dev);
 
-	quicki2c_dev_deinit(qcdev);
-
 	pci_clear_master(pdev);
 }
 
@@ -796,10 +804,10 @@ static void quicki2c_shutdown(struct pci_dev *pdev)
 	if (!qcdev)
 		return;
 
+	quicki2c_dev_deinit(qcdev);
+
 	/* Must stop DMA before reboot to avoid DMA entering into unknown state */
 	quicki2c_dma_deinit(qcdev);
-
-	quicki2c_dev_deinit(qcdev);
 }
 
 static int quicki2c_suspend(struct device *device)
@@ -826,6 +834,9 @@ static int quicki2c_suspend(struct device *device)
 	if (ret)
 		return ret;
 
+	WRITE_ONCE(qcdev->recovery_disabled, true);
+	cancel_work_sync(&qcdev->recover_work);
+
 	ret = thc_interrupt_quiesce(qcdev->thc_hw, true);
 	if (ret)
 		return ret;
@@ -867,6 +878,8 @@ static int quicki2c_resume(struct device *device)
 	if (ret)
 		return ret;
 
+	WRITE_ONCE(qcdev->recovery_disabled, false);
+
 	if (!device_may_wakeup(qcdev->dev))
 		return quicki2c_set_power(qcdev, HIDI2C_ON);
 
@@ -883,6 +896,9 @@ static int quicki2c_freeze(struct device *device)
 	if (!qcdev)
 		return -ENODEV;
 
+	WRITE_ONCE(qcdev->recovery_disabled, true);
+	cancel_work_sync(&qcdev->recover_work);
+
 	ret = thc_interrupt_quiesce(qcdev->thc_hw, true);
 	if (ret)
 		return ret;
@@ -914,6 +930,8 @@ static int quicki2c_thaw(struct device *device)
 	if (ret)
 		return ret;
 
+	WRITE_ONCE(qcdev->recovery_disabled, false);
+
 	return 0;
 }
 
@@ -938,6 +956,8 @@ static int quicki2c_poweroff(struct device *device)
 
 	thc_ltr_unconfig(qcdev->thc_hw);
 
+	quicki2c_dev_deinit(qcdev);
+
 	quicki2c_dma_deinit(qcdev);
 
 	return 0;
diff --git a/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h
index 61dbdece59a1..d72565de67b9 100644
--- a/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h
+++ b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h
@@ -191,6 +191,8 @@ struct acpi_device;
  * @i2c_max_frame_size: Max RX frame size (unit in Bytes)
  * @i2c_int_delay_enable: Indicate interrupt delay feature enabled or not
  * @i2c_int_delay: Interrupt detection delay value (unit in 10 us)
+ * @recover_work: Work structure for recovery
+ * @recovery_disabled: Whether recovery work is blocked during teardown
  */
 struct quicki2c_device {
 	struct device *dev;
@@ -226,6 +228,9 @@ struct quicki2c_device {
 	u32 i2c_max_frame_size;
 	u32 i2c_int_delay_enable;
 	u32 i2c_int_delay;
+
+	struct work_struct recover_work;
+	bool recovery_disabled;
 };
 
 #endif /* _QUICKI2C_DEV_H_ */
-- 
2.43.0