mhi: pci_generic: Add suspend/resume/recovery procedure

Add support for system wide suspend/resume. During suspend, MHI
device controller must be put in M3 state and PCI bus in D3 state.

Add a recovery procedure allowing to reinitialize the device in case
of error during resume steps, which can happen if device loses power
(and so its context) while system suspend.

Reviewed-by Hemant Kumar <hemantk@codeaurora.org>

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index f0dfa625db1695b852326371b0d898d7e230eac6..2552c2ea75e87ee8f683cfe1dde2b944f457597d 100644 (file)
--- a/drivers/bus/mhi/pci_generic.c
+++ b/drivers/bus/mhi/pci_generic.c
@@ -13,6 +13,7 @@
 #include <linux/mhi.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/workqueue.h>
 
 #define MHI_PCI_DEFAULT_BAR_NUM 0
 
@@ -186,6 +187,7 @@ enum mhi_pci_device_status {
 struct mhi_pci_device {
        struct mhi_controller mhi_cntrl;
        struct pci_saved_state *pci_state;
+       struct work_struct recovery_work;
        unsigned long status;
 };
 
@@ -313,6 +315,50 @@ static void mhi_pci_runtime_put(struct mhi_controller *mhi_cntrl)
        /* no PM for now */
 }
 
+static void mhi_pci_recovery_work(struct work_struct *work)
+{
+       struct mhi_pci_device *mhi_pdev = container_of(work, struct mhi_pci_device,
+                                                      recovery_work);
+       struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+       struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev);
+       int err;
+
+       dev_warn(&pdev->dev, "device recovery started\n");
+
+       /* 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);
+       }
+
+       /* Check if we can recover without full reset */
+       pci_set_power_state(pdev, PCI_D0);
+       pci_load_saved_state(pdev, mhi_pdev->pci_state);
+       pci_restore_state(pdev);
+
+       if (!mhi_pci_is_alive(mhi_cntrl))
+               goto err_try_reset;
+
+       err = mhi_prepare_for_power_up(mhi_cntrl);
+       if (err)
+               goto err_try_reset;
+
+       err = mhi_sync_power_up(mhi_cntrl);
+       if (err)
+               goto err_unprepare;
+
+       dev_dbg(&pdev->dev, "Recovery completed\n");
+
+       set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status);
+       return;
+
+err_unprepare:
+       mhi_unprepare_after_power_down(mhi_cntrl);
+err_try_reset:
+       if (pci_reset_function(pdev))
+               dev_err(&pdev->dev, "Recovery failed\n");
+}
+
 static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
        const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data;
@@ -328,6 +374,8 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (!mhi_pdev)
                return -ENOMEM;
 
+       INIT_WORK(&mhi_pdev->recovery_work, mhi_pci_recovery_work);
+
        mhi_cntrl_config = info->config;
        mhi_cntrl = &mhi_pdev->mhi_cntrl;
 
@@ -391,6 +439,8 @@ static void mhi_pci_remove(struct pci_dev *pdev)
        struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
        struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
 
+       cancel_work_sync(&mhi_pdev->recovery_work);
+
        if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
                mhi_power_down(mhi_cntrl, true);
                mhi_unprepare_after_power_down(mhi_cntrl);
@@ -456,12 +506,67 @@ static const struct pci_error_handlers mhi_pci_err_handler = {
        .reset_done = mhi_pci_reset_done,
 };
 
+static int  __maybe_unused mhi_pci_suspend(struct device *dev)
+{
+       struct pci_dev *pdev = to_pci_dev(dev);
+       struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);
+       struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+
+       cancel_work_sync(&mhi_pdev->recovery_work);
+
+       /* Transition to M3 state */
+       mhi_pm_suspend(mhi_cntrl);
+
+       pci_save_state(pdev);
+       pci_disable_device(pdev);
+       pci_wake_from_d3(pdev, true);
+       pci_set_power_state(pdev, PCI_D3hot);
+
+       return 0;
+}
+
+static int __maybe_unused mhi_pci_resume(struct device *dev)
+{
+       struct pci_dev *pdev = to_pci_dev(dev);
+       struct mhi_pci_device *mhi_pdev = dev_get_drvdata(dev);
+       struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
+       int err;
+
+       pci_set_power_state(pdev, PCI_D0);
+       pci_restore_state(pdev);
+       pci_set_master(pdev);
+
+       err = pci_enable_device(pdev);
+       if (err)
+               goto err_recovery;
+
+       /* Exit M3, transition to M0 state */
+       err = mhi_pm_resume(mhi_cntrl);
+       if (err) {
+               dev_err(&pdev->dev, "failed to resume device: %d\n", err);
+               goto err_recovery;
+       }
+
+       return 0;
+
+err_recovery:
+       /* The device may have loose power or crashed, try recovering it */
+       queue_work(system_long_wq, &mhi_pdev->recovery_work);
+
+       return err;
+}
+
+static const struct dev_pm_ops mhi_pci_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(mhi_pci_suspend, mhi_pci_resume)
+};
+
 static struct pci_driver mhi_pci_driver = {
        .name           = "mhi-pci-generic",
        .id_table       = mhi_pci_id_table,
        .probe          = mhi_pci_probe,
        .remove         = mhi_pci_remove,
        .err_handler    = &mhi_pci_err_handler,
+       .driver.pm      = &mhi_pci_pm_ops
 };
 module_pci_driver(mhi_pci_driver);