bus: mhi: pci-generic: Fix hibernation

This patch fixes crash after resuming from hibernation. The issue
occurs when mhi stack is builtin and so part of the 'restore-kernel',
causing the device to be resumed from 'restored kernel' with a no
more valid context (memory mappings etc...) and leading to spurious
crashes.

This patch fixes the issue by implementing proper freeze/restore
callbacks.

Link: https://lore.kernel.org/r/1622571445-4505-1-git-send-email-loic.poulain@linaro.org
Reported-by: Shujun Wang <wsj20369@163.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210606153741.20725-4-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index 0a6619a..b3357a8 100644 (file)
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -935,9 +935,43 @@ static int __maybe_unused mhi_pci_resume(struct device *dev)
        return ret;
 }
 
+static int __maybe_unused mhi_pci_freeze(struct device *dev)
+{
+       struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);
+       struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+       /* We want to stop all operations, hibernation does not guarantee that
+        * device will be in the same state as before freezing, especially if
+        * the intermediate restore kernel reinitializes MHI device with new
+        * context.
+        */
+       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);
+       }
+
+       return 0;
+}
+
+static int __maybe_unused mhi_pci_restore(struct device *dev)
+{
+       struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);
+
+       /* Reinitialize the device */
+       queue_work(system_long_wq, &mhi_pdev->recovery_work);
+
+       return 0;
+}
+
 static const struct dev_pm_ops mhi_pci_pm_ops = {
        SET_RUNTIME_PM_OPS(mhi_pci_runtime_suspend, mhi_pci_runtime_resume, NULL)
-       SET_SYSTEM_SLEEP_PM_OPS(mhi_pci_suspend, mhi_pci_resume)
+#ifdef CONFIG_PM_SLEEP
+       .suspend = mhi_pci_suspend,
+       .resume = mhi_pci_resume,
+       .freeze = mhi_pci_freeze,
+       .thaw = mhi_pci_restore,
+       .restore = mhi_pci_restore,
+#endif
 };
 
 static struct pci_driver mhi_pci_driver = {