[+cc Vaibhav since my main question is about converting to generic PM]
On Thu, May 20, 2021 at 08:55:42PM +0530, Kashyap Desai wrote:
> Signed-off-by: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
> Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
> Reviewed-by: Tomas Henzl <thenzl@xxxxxxxxxx>
> Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
>
> Cc: sathya.prakash@xxxxxxxxxxxx
> ---
> drivers/scsi/mpi3mr/mpi3mr_os.c | 84 +++++++++++++++++++++++++++++++++
> 1 file changed, 84 insertions(+)
>
> diff --git a/drivers/scsi/mpi3mr/mpi3mr_os.c b/drivers/scsi/mpi3mr/mpi3mr_os.c
> index e63db7c..dd71cdc 100644
> --- a/drivers/scsi/mpi3mr/mpi3mr_os.c
> +++ b/drivers/scsi/mpi3mr/mpi3mr_os.c
> @@ -3389,6 +3389,86 @@ static void mpi3mr_shutdown(struct pci_dev *pdev)
> mpi3mr_cleanup_ioc(mrioc, 0);
> }
>
> +#ifdef CONFIG_PM
> +/**
> + * mpi3mr_suspend - PCI power management suspend callback
> + * @pdev: PCI device instance
> + * @state: New power state
> + *
> + * Change the power state to the given value and cleanup the IOC
> + * by issuing MUR and shutdown notification
> + *
> + * Return: 0 always.
> + */
> +static int mpi3mr_suspend(struct pci_dev *pdev, pm_message_t state)
> +{
> + struct Scsi_Host *shost = pci_get_drvdata(pdev);
> + struct mpi3mr_ioc *mrioc;
> + pci_power_t device_state;
> +
> + if (!shost)
> + return 0;
This test of "shost" is unnecessary. If you set the drvdata before
the .probe() method returns success, you will always get valid drvdata
here. And you do:
mpi3mr_probe
mpi3mr_init_ioc
mpi3mr_setup_resources
pci_set_drvdata(pdev, mrioc->shost)
Sure, it's *possible* that a random memory corruption will clear out
the drvdata pointer, but there's no point in testing for that.
> + mrioc = shost_priv(shost);
> + while (mrioc->reset_in_progress || mrioc->is_driver_loading)
> + ssleep(1);
> + mrioc->stop_drv_processing = 1;
> + mpi3mr_cleanup_fwevt_list(mrioc);
> + scsi_block_requests(shost);
> + mpi3mr_stop_watchdog(mrioc);
> + mpi3mr_cleanup_ioc(mrioc, 1);
This looks possibly wrong. mpi3mr_cleanup_ioc() takes a "reason",
which looks like it should be MPI3MR_COMPLETE_CLEANUP (0),
MPI3MR_REINIT_FAILURE (1), or MPI3MR_SUSPEND (2).
This should at least use the enum, and it looks like it should use
MPI3MR_SUSPEND instead of passing the MPI3MR_REINIT_FAILURE value.
> + device_state = pci_choose_state(pdev, state);
> + ioc_info(mrioc, "pdev=0x%p, slot=%s, entering operating state [D%d]\n",
> + pdev, pci_name(pdev), device_state);
> + pci_save_state(pdev);
> + pci_set_power_state(pdev, device_state);
> + mpi3mr_cleanup_resources(mrioc);
Why is mpi3mr_cleanup_resources() needed here? It frees IRQs,
iounmaps registers, calls pci_release_selected_regions(), etc.
Very few other drivers do this, and I don't think it's necessary for
suspend. And if you don't clean it up here, you won't need to
re-initialize it during resume.
I'm asking because I want to convert this from the legacy PCI power
management model to the generic PM model. The generic model works
like this:
suspend_devices_and_enter
dpm_suspend_start(PMSG_SUSPEND)
pci_pm_suspend # PCI bus .suspend() method
mpi3mr_suspend <-- device-specific stuff
suspend_enter
dpm_suspend_noirq(PMSG_SUSPEND)
pci_pm_suspend_noirq # PCI bus .suspend_noirq() method
pci_save_state <-- generic PCI
pci_prepare_to_sleep <-- generic PCI
pci_set_power_state
...
dpm_resume_end(PMSG_RESUME)
pci_pm_resume # PCI bus .resume() method
pci_restore_standard_config
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
mpi3mr_resume # dev->driver->pm->resume
Notice that in the generic model the PCI core takes care of
pci_save_state(), pci_set_power_state(), etc., and the device-specific
stuff is done before the generic PCI suspend, and after the generic
PCI resume.
mpi3mr_cleanup_resources() is problematic because the device-specific
stuff should be done *before* the generic PCI part, but you call it
*after* the generic PCI part. I think it would be *possible* to do it
after by making a mpi3mr_suspend_noirq() method, but there are hardly
any drivers that do that, and I think mpi3mr_cleanup_resources() is
unnecessary here anyway.
> + return 0;
> +}
> +
> +/**
> + * mpi3mr_resume - PCI power management resume callback
> + * @pdev: PCI device instance
> + *
> + * Restore the power state to D0 and reinitialize the controller
> + * and resume I/O operations to the target devices
> + *
> + * Return: 0 on success, non-zero on failure
> + */
> +static int mpi3mr_resume(struct pci_dev *pdev)
> +{
> + struct Scsi_Host *shost = pci_get_drvdata(pdev);
> + struct mpi3mr_ioc *mrioc;
> + pci_power_t device_state = pdev->current_state;
> + int r;
> +
> + mrioc = shost_priv(shost);
> +
> + ioc_info(mrioc, "pdev=0x%p, slot=%s, previous operating state [D%d]\n",
> + pdev, pci_name(pdev), device_state);
> + pci_set_power_state(pdev, PCI_D0);
> + pci_enable_wake(pdev, PCI_D0, 0);
> + pci_restore_state(pdev);
> + mrioc->pdev = pdev;
> + mrioc->cpu_count = num_online_cpus();
> + r = mpi3mr_setup_resources(mrioc);
> + if (r) {
> + ioc_info(mrioc, "%s: Setup resources failed[%d]\n",
> + __func__, r);
> + return r;
> + }
> +
> + mrioc->stop_drv_processing = 0;
> + mpi3mr_init_ioc(mrioc, 1);
> + scsi_unblock_requests(shost);
> + mpi3mr_start_watchdog(mrioc);
> +
> + return 0;
> +}
> +#endif
> +
> static const struct pci_device_id mpi3mr_pci_id_table[] = {
> {
> PCI_DEVICE_SUB(PCI_VENDOR_ID_LSI_LOGIC, 0x00A5,
> @@ -3404,6 +3484,10 @@ static struct pci_driver mpi3mr_pci_driver = {
> .probe = mpi3mr_probe,
> .remove = mpi3mr_remove,
> .shutdown = mpi3mr_shutdown,
> +#ifdef CONFIG_PM
> + .suspend = mpi3mr_suspend,
> + .resume = mpi3mr_resume,
> +#endif
> };
>
> static int __init mpi3mr_init(void)
> --
> 2.18.1
>
