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.
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
drivers/bus/mhi/pci_generic.c | 100 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 100 insertions(+)
diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
index b48c382..75f565b 100644
--- 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
@@ -187,6 +188,7 @@ 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;
};
@@ -319,6 +321,48 @@ 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;
+
+ 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;
@@ -333,6 +377,8 @@ 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;
mhi_cntrl->cntrl_dev = &pdev->dev;
@@ -395,6 +441,8 @@ 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);
@@ -463,12 +511,64 @@ static const struct pci_error_handlers mhi_pci_err_handler = {
.reset_done = mhi_pci_reset_done,
};
+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;
+
+ /* 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 0;
+}
+
+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);
--
2.7.4
