[PATCH v2 6/8] mhi: pci_generic: Add PCI error handlers

[Loic Poulain <loic.poulain@xxxxxxxxxx>]

In AER capable root complex, errors are reported to the host which
can then act accordingly and perform PCI recovering procedure.

This patch enables error reporting and implements error_detected,
slot_reset and resume callbacks.

Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
 drivers/bus/mhi/pci_generic.c | 50 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index 3eefef3..b01b279 100644
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2020 Linaro Ltd <loic.poulain@xxxxxxxxxx>
  */
 
+#include <linux/aer.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/mhi.h>
@@ -407,6 +408,8 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	pci_save_state(pdev);
 	mhi_pdev->pci_state = pci_store_saved_state(pdev);
 
+	pci_enable_pcie_error_reporting(pdev);
+
 	err = mhi_register_controller(mhi_cntrl, mhi_cntrl_config);
 	if (err)
 		return err;
@@ -506,7 +509,54 @@ void mhi_pci_reset_done(struct pci_dev *pdev)
 	set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);
 }
 
+static pci_ers_result_t mhi_pci_error_detected(struct pci_dev *pdev,
+					       pci_channel_state_t state)
+{
+	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+	struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+	dev_err(&pdev->dev, "PCI error detected, state = %u\n", state);
+
+	if (state == pci_channel_io_perm_failure)
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	/* Clean up MHI state */
+	if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
+		mhi_power_down(mhi_cntrl, false);
+		mhi_unprepare_after_power_down(mhi_cntrl);
+	} else {
+		/* Nothing to do */
+		return PCI_ERS_RESULT_RECOVERED;
+	}
+
+	pci_disable_device(pdev);
+
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
+static pci_ers_result_t mhi_pci_slot_reset(struct pci_dev *pdev)
+{
+	if (pci_enable_device(pdev)) {
+		dev_err(&pdev->dev, "Cannot re-enable PCI device after reset.\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void mhi_pci_io_resume(struct pci_dev *pdev)
+{
+	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
+
+	dev_err(&pdev->dev, "PCI slot reset done\n");
+
+	queue_work(system_long_wq, &mhi_pdev->recovery_work);
+}
+
 static const struct pci_error_handlers mhi_pci_err_handler = {
+	.error_detected = mhi_pci_error_detected,
+	.slot_reset = mhi_pci_slot_reset,
+	.resume = mhi_pci_io_resume,
 	.reset_prepare = mhi_pci_reset_prepare,
 	.reset_done = mhi_pci_reset_done,
 };
-- 
2.7.4