On Fri, Mar 05, 2021 at 08:16:48PM +0100, Loic Poulain wrote:
> When the device is idle it is possible to move it into the lowest MHI
> PM state (M3). In that mode, all MHI operations are suspended and the
> PCI device can be safely put into PCI D3 state.
>
> The device is then resumed from D3/M3 either because of host initiated
> MHI operation (e.g. buffer TX) or because the device (modem) has
> triggered wake-up via PME feature (e.g. on incoming data).
>
> Same procedures can be used for system wide or runtime suspend/resume.
>
> Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
Applied to mhi-next!
Thanks,
Mani
> ---
> v2: replace force_runtime_suspend/resume via local function to ensure
> device is always resumed during system resume whatever its runtime
> pm state.
> v3: - remove extra mark_last_busy
> - move mark_last_busy after mhi_pm_suspend
> - remove terminal semicolon from print
>
> drivers/bus/mhi/pci_generic.c | 95 +++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 86 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c
> index 4ab0aa8..92ab9bb 100644
> --- a/drivers/bus/mhi/pci_generic.c
> +++ b/drivers/bus/mhi/pci_generic.c
> @@ -14,6 +14,7 @@
> #include <linux/mhi.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> +#include <linux/pm_runtime.h>
> #include <linux/timer.h>
> #include <linux/workqueue.h>
>
> @@ -274,6 +275,7 @@ MODULE_DEVICE_TABLE(pci, mhi_pci_id_table);
>
> enum mhi_pci_device_status {
> MHI_PCI_DEV_STARTED,
> + MHI_PCI_DEV_SUSPENDED,
> };
>
> struct mhi_pci_device {
> @@ -306,6 +308,10 @@ static void mhi_pci_status_cb(struct mhi_controller *mhi_cntrl,
> case MHI_CB_FATAL_ERROR:
> case MHI_CB_SYS_ERROR:
> dev_warn(&pdev->dev, "firmware crashed (%u)\n", cb);
> + pm_runtime_forbid(&pdev->dev);
> + break;
> + case MHI_CB_EE_MISSION_MODE:
> + pm_runtime_allow(&pdev->dev);
> break;
> default:
> break;
> @@ -427,13 +433,19 @@ static int mhi_pci_get_irqs(struct mhi_controller *mhi_cntrl,
>
> static int mhi_pci_runtime_get(struct mhi_controller *mhi_cntrl)
> {
> - /* no PM for now */
> - return 0;
> + /* The runtime_get() MHI callback means:
> + * Do whatever is requested to leave M3.
> + */
> + return pm_runtime_get(mhi_cntrl->cntrl_dev);
> }
>
> static void mhi_pci_runtime_put(struct mhi_controller *mhi_cntrl)
> {
> - /* no PM for now */
> + /* The runtime_put() MHI callback means:
> + * Device can be moved in M3 state.
> + */
> + pm_runtime_mark_last_busy(mhi_cntrl->cntrl_dev);
> + pm_runtime_put(mhi_cntrl->cntrl_dev);
> }
>
> static void mhi_pci_recovery_work(struct work_struct *work)
> @@ -447,6 +459,7 @@ static void mhi_pci_recovery_work(struct work_struct *work)
> dev_warn(&pdev->dev, "device recovery started\n");
>
> del_timer(&mhi_pdev->health_check_timer);
> + pm_runtime_forbid(&pdev->dev);
>
> /* Clean up MHI state */
> if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) {
> @@ -454,7 +467,6 @@ static void mhi_pci_recovery_work(struct work_struct *work)
> 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);
> @@ -488,6 +500,10 @@ static void health_check(struct timer_list *t)
> struct mhi_pci_device *mhi_pdev = from_timer(mhi_pdev, t, health_check_timer);
> struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl;
>
> + if (!test_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status) ||
> + test_bit(MHI_PCI_DEV_SUSPENDED, &mhi_pdev->status))
> + return;
> +
> if (!mhi_pci_is_alive(mhi_cntrl)) {
> dev_err(mhi_cntrl->cntrl_dev, "Device died\n");
> queue_work(system_long_wq, &mhi_pdev->recovery_work);
> @@ -575,6 +591,14 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> /* start health check */
> mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);
>
> + /* Only allow runtime-suspend if PME capable (for wakeup) */
> + if (pci_pme_capable(pdev, PCI_D3hot)) {
> + pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
> + pm_runtime_use_autosuspend(&pdev->dev);
> + pm_runtime_mark_last_busy(&pdev->dev);
> + pm_runtime_put_noidle(&pdev->dev);
> + }
> +
> return 0;
>
> err_unprepare:
> @@ -598,6 +622,10 @@ static void mhi_pci_remove(struct pci_dev *pdev)
> mhi_unprepare_after_power_down(mhi_cntrl);
> }
>
> + /* balancing probe put_noidle */
> + if (pci_pme_capable(pdev, PCI_D3hot))
> + pm_runtime_get_noresume(&pdev->dev);
> +
> mhi_unregister_controller(mhi_cntrl);
> }
>
> @@ -708,31 +736,48 @@ 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)
> +static int __maybe_unused mhi_pci_runtime_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;
> + int err;
> +
> + if (test_and_set_bit(MHI_PCI_DEV_SUSPENDED, &mhi_pdev->status))
> + return 0;
>
> del_timer(&mhi_pdev->health_check_timer);
> cancel_work_sync(&mhi_pdev->recovery_work);
>
> + if (!test_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status) ||
> + mhi_cntrl->ee != MHI_EE_AMSS)
> + goto pci_suspend; /* Nothing to do at MHI level */
> +
> /* Transition to M3 state */
> - mhi_pm_suspend(mhi_cntrl);
> + err = mhi_pm_suspend(mhi_cntrl);
> + if (err) {
> + dev_err(&pdev->dev, "failed to suspend device: %d\n", err);
> + clear_bit(MHI_PCI_DEV_SUSPENDED, &mhi_pdev->status);
> + return -EBUSY;
> + }
>
> +pci_suspend:
> pci_disable_device(pdev);
> pci_wake_from_d3(pdev, true);
>
> return 0;
> }
>
> -static int __maybe_unused mhi_pci_resume(struct device *dev)
> +static int __maybe_unused mhi_pci_runtime_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;
>
> + if (!test_and_clear_bit(MHI_PCI_DEV_SUSPENDED, &mhi_pdev->status))
> + return 0;
> +
> err = pci_enable_device(pdev);
> if (err)
> goto err_recovery;
> @@ -740,6 +785,10 @@ static int __maybe_unused mhi_pci_resume(struct device *dev)
> pci_set_master(pdev);
> pci_wake_from_d3(pdev, false);
>
> + if (!test_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status) ||
> + mhi_cntrl->ee != MHI_EE_AMSS)
> + return 0; /* Nothing to do at MHI level */
> +
> /* Exit M3, transition to M0 state */
> err = mhi_pm_resume(mhi_cntrl);
> if (err) {
> @@ -750,16 +799,44 @@ static int __maybe_unused mhi_pci_resume(struct device *dev)
> /* Resume health check */
> mod_timer(&mhi_pdev->health_check_timer, jiffies + HEALTH_CHECK_PERIOD);
>
> + /* It can be a remote wakeup (no mhi runtime_get), update access time */
> + pm_runtime_mark_last_busy(dev);
> +
> return 0;
>
> err_recovery:
> - /* The device may have loose power or crashed, try recovering it */
> + /* Do not fail to not mess up our PCI device state, the device likely
> + * lost power (d3cold) and we simply need to reset it from the recovery
> + * procedure, trigger the recovery asynchronously to prevent system
> + * suspend exit delaying.
> + */
> queue_work(system_long_wq, &mhi_pdev->recovery_work);
> + pm_runtime_mark_last_busy(dev);
>
> - return err;
> + return 0;
> +}
> +
> +static int __maybe_unused mhi_pci_suspend(struct device *dev)
> +{
> + pm_runtime_disable(dev);
> + return mhi_pci_runtime_suspend(dev);
> +}
> +
> +static int __maybe_unused mhi_pci_resume(struct device *dev)
> +{
> + int ret;
> +
> + /* Depending the platform, device may have lost power (d3cold), we need
> + * to resume it now to check its state and recover when necessary.
> + */
> + ret = mhi_pci_runtime_resume(dev);
> + pm_runtime_enable(dev);
> +
> + return ret;
> }
>
> 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)
> };
>
> --
> 2.7.4
>
