On Tue, Sep 08, 2020 at 12:32:09PM -0500, Bjorn Helgaas wrote:
> On Mon, Jul 20, 2020 at 07:04:14PM +0530, Vaibhav Gupta wrote:
> > With legacy PM hooks, it was the responsibility of a driver to manage PCI
> > states and also the device's power state. The generic approach is to let
> > the PCI core handle the work.
> >
> > PCI core passes "struct device*" as an argument to the .suspend() and
> > .resume() callbacks. As the .suspend() work with "struct instance*",
> > extract it from "struct device*" using dev_get_drv_data().
> >
> > Driver was also using PCI helper functions like pci_save/restore_state(),
> > pci_disable/enable_device(), pci_set_power_state() and pci_enable_wake().
> > They should not be invoked by the driver.
> >
> > Compile-tested only.
> >
> > Signed-off-by: Vaibhav Gupta <vaibhavgupt...@gmail.com>
> > ---
> > drivers/scsi/megaraid/megaraid_sas_base.c | 61 ++++++-----------------
> > 1 file changed, 16 insertions(+), 45 deletions(-)
> >
> > diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c
> > b/drivers/scsi/megaraid/megaraid_sas_base.c
> > index 00668335c2af..4a6ee7778977 100644
> > --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> > +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> > @@ -7539,25 +7539,21 @@ static void megasas_shutdown_controller(struct
> > megasas_instance *instance,
> > megasas_return_cmd(instance, cmd);
> > }
> >
> > -#ifdef CONFIG_PM
> > /**
> > * megasas_suspend - driver suspend entry point
> > - * @pdev: PCI device structure
> > - * @state: PCI power state to suspend routine
> > + * @dev: Device structure
> > */
> > -static int
> > -megasas_suspend(struct pci_dev *pdev, pm_message_t state)
> > +static int __maybe_unused
> > +megasas_suspend(struct device *dev)
> > {
> > - struct megasas_instance *instance;
> > -
> > - instance = pci_get_drvdata(pdev);
> > + struct megasas_instance *instance = dev_get_drvdata(dev);
> >
> > if (!instance)
> > return 0;
> >
> > instance->unload = 1;
> >
> > - dev_info(&pdev->dev, "%s is called\n", __func__);
> > + dev_info(dev, "%s is called\n", __func__);
> >
> > /* Shutdown SR-IOV heartbeat timer */
> > if (instance->requestorId && !instance->skip_heartbeat_timer_del)
> > @@ -7579,7 +7575,7 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t
> > state)
> >
> > tasklet_kill(&instance->isr_tasklet);
> >
> > - pci_set_drvdata(instance->pdev, instance);
> > + dev_set_drvdata(dev, instance);
>
> It *might* be correct to replace "instance->pdev" with "dev", but it's
> not obvious and deserves some explanation. It's true that you can
> replace &pdev->dev with dev, but I don't know anything about
> instance->dev.
>
> I don't think this change is actually necessary, is it?
> "instance->pdev" is still a pci_dev pointer, so pci_set_drvdata()
> should work fine.
>
> It looks goofy to use pci_set_drvdata() or dev_set_drvdata() in a
> suspend routine, but I didn't bother trying to figure out what's going
> on here.
>
There is no instance->dev . The 'dev' passed dev_set_drvdata() is same
&pdev->dev. The dev pointer used here, points to same value.
pci_get_drvdata() and pci_set_drvdata() invoke dev_get_drvdata() and
dev_set_drvdata() respectively. And they do nothing else. Seems like additional
unnecessary function calls and operations.
We can get rid of these PCI helper functions too.
> > instance->instancet->disable_intr(instance);
> >
> > megasas_destroy_irqs(instance);
> > @@ -7587,48 +7583,28 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t
> > state)
> > if (instance->msix_vectors)
> > pci_free_irq_vectors(instance->pdev);
> >
> > - pci_save_state(pdev);
> > - pci_disable_device(pdev);
> > -
> > - pci_set_power_state(pdev, pci_choose_state(pdev, state));
> > -
> > return 0;
> > }
> >
> > /**
> > * megasas_resume- driver resume entry point
> > - * @pdev: PCI device structure
> > + * @dev: Device structure
> > */
> > -static int
> > -megasas_resume(struct pci_dev *pdev)
> > +static int __maybe_unused
> > +megasas_resume(struct device *dev)
> > {
> > int rval;
> > struct Scsi_Host *host;
> > - struct megasas_instance *instance;
> > + struct megasas_instance *instance = dev_get_drvdata(dev);
> > u32 status_reg;
> >
> > - instance = pci_get_drvdata(pdev);
> > -
> > if (!instance)
> > return 0;
> >
> > host = instance->host;
> > - pci_set_power_state(pdev, PCI_D0);
> > - pci_enable_wake(pdev, PCI_D0, 0);
> > - pci_restore_state(pdev);
> > + device_wakeup_disable(dev);
>
> Shouldn't there be a corresponding device_wakeup_enable() or similar
> elsewhere?
>
> Maybe the fact that megasas disables wakeup but never enables it is a
> latent bug?
>
Yeah, I guess I sent this patch a lot earlier than we figured this out and
didn't notice it later. I will send v3 for it.
> > - dev_info(&pdev->dev, "%s is called\n", __func__);
> > - /*
> > - * PCI prepping: enable device set bus mastering and dma mask
> > - */
> > - rval = pci_enable_device_mem(pdev);
> > -
> > - if (rval) {
> > - dev_err(&pdev->dev, "Enable device failed\n");
> > - return rval;
> > - }
> > -
> > - pci_set_master(pdev);
> > + dev_info(dev, "%s is called\n", __func__);
> >
> > /*
> > * We expect the FW state to be READY
> > @@ -7754,14 +7730,8 @@ megasas_resume(struct pci_dev *pdev)
> > fail_set_dma_mask:
> > fail_ready_state:
> >
> > - pci_disable_device(pdev);
> > -
> > return -ENODEV;
> > }
> > -#else
> > -#define megasas_suspend NULL
> > -#define megasas_resume NULL
> > -#endif
> >
> > static inline int
> > megasas_wait_for_adapter_operational(struct megasas_instance *instance)
> > @@ -7931,7 +7901,7 @@ static void megasas_detach_one(struct pci_dev *pdev)
> >
> > /**
> > * megasas_shutdown - Shutdown entry point
> > - * @device: Generic device structure
> > + * @pdev: PCI device structure
>
> Looks like an unrelated typo fix? I would put this in a separate
> patch.
>
Okay.
> > */
> > static void megasas_shutdown(struct pci_dev *pdev)
> > {
> > @@ -8508,6 +8478,8 @@ static const struct file_operations megasas_mgmt_fops
> > = {
> > .llseek = noop_llseek,
> > };
> >
> > +static SIMPLE_DEV_PM_OPS(megasas_pm_ops, megasas_suspend, megasas_resume);
> > +
> > /*
> > * PCI hotplug support registration structure
> > */
> > @@ -8517,8 +8489,7 @@ static struct pci_driver megasas_pci_driver = {
> > .id_table = megasas_pci_table,
> > .probe = megasas_probe_one,
> > .remove = megasas_detach_one,
> > - .suspend = megasas_suspend,
> > - .resume = megasas_resume,
> > + .driver.pm = &megasas_pm_ops,
> > .shutdown = megasas_shutdown,
> > };
> >
> > --
> > 2.27.0
> >
