Hi Mani,
On Fri, 5 Mar 2021 at 18:46, Manivannan Sadhasivam
<manivannan.sadhasivam@xxxxxxxxxx> wrote:
>
> On Fri, Mar 05, 2021 at 01:47:58PM +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>
> > ---
> > v2: replace force_runtime_suspend/resume via local function to ensure
> > device is always resumed during system resume whatever its runtime
> > pm state.
> >
> > 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..e36f5a9 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 +308,11 @@ 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_mark_last_busy(&pdev->dev);
>
> Do you really need to update the last_busy time here? You're already updating it
> before each runtime_put() call and those will overwrite this value.
Right, it is not strictly necessary.
>
> > + pm_runtime_allow(&pdev->dev);
> > break;
> > default:
> > break;
> > @@ -427,13 +434,19 @@ static int mhi_pci_get_irqs(struct mhi_controller *mhi_cntrl,
>
> [...]
>
> > -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);
>
> Remove the semicolon after "%d"
OK.
>
> > + 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 +786,13 @@ static int __maybe_unused mhi_pci_resume(struct device *dev)
> > pci_set_master(pdev);
> > pci_wake_from_d3(pdev, false);
> >
> > + /* It can be a remote wakeup (no mhi runtime_get), update access time */
> > + pm_runtime_mark_last_busy(dev);
>
> I think this should be moved after mhi_pm_resume().
you're right.
Loic
>
> Thanks,
> Mani
