agp/ati: Convert to generic power management

Convert agpgart-ati from legacy PCI power management to the generic power
management framework.

Previously agpgart-ati used legacy PCI power management, and
agp_ati_suspend() and agp_ati_resume() were responsible for both
device-specific things and generic PCI things like saving and restoring
config space and managing power state:

  agp_ati_suspend
    pci_save_state                         <-- generic PCI
    pci_set_power_state(PCI_D3hot)         <-- generic PCI

  agp_ati_resume
    pci_set_power_state(PCI_D0)            <-- generic PCI
    pci_restore_state                      <-- generic PCI
    ati_configure                          <-- device-specific

With generic power management, the PCI bus PM methods do the generic PCI
things, and the driver needs only the device-specific part, i.e.,

  suspend_devices_and_enter
    dpm_suspend_start(PMSG_SUSPEND)
      pci_pm_suspend                       # PCI bus .suspend() method
        agp_ati_suspend                    <-- not needed at all; removed
    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
        agp_ati_resume                     # driver->pm->resume
          ati_configure                    <-- device-specific

Based on 0aeddbd0cb07 ("via-agp: convert to generic power management") by
Vaibhav Gupta <vaibhavgupta40@gmail.com>.

Link: https://lore.kernel.org/r/20221025203852.681822-5-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/char/agp/ati-agp.c b/drivers/char/agp/ati-agp.c
index 6f5530482d8332496fc48757f2d2a45ed26f96ea..3c1fce48aabe764d91b1381559d7a5c916c4fb53 100644 (file)
--- a/drivers/char/agp/ati-agp.c
+++ b/drivers/char/agp/ati-agp.c
@@ -238,23 +238,10 @@ static int ati_configure(void)
 }
 
 
-#ifdef CONFIG_PM
-static int agp_ati_suspend(struct pci_dev *dev, pm_message_t state)
+static int agp_ati_resume(struct device *dev)
 {
-       pci_save_state(dev);
-       pci_set_power_state(dev, PCI_D3hot);
-
-       return 0;
-}
-
-static int agp_ati_resume(struct pci_dev *dev)
-{
-       pci_set_power_state(dev, PCI_D0);
-       pci_restore_state(dev);
-
        return ati_configure();
 }
-#endif
 
 /*
  *Since we don't need contiguous memory we just try
@@ -559,15 +546,14 @@ static const struct pci_device_id agp_ati_pci_table[] = {
 
 MODULE_DEVICE_TABLE(pci, agp_ati_pci_table);
 
+static DEFINE_SIMPLE_DEV_PM_OPS(agp_ati_pm_ops, NULL, agp_ati_resume);
+
 static struct pci_driver agp_ati_pci_driver = {
        .name           = "agpgart-ati",
        .id_table       = agp_ati_pci_table,
        .probe          = agp_ati_probe,
        .remove         = agp_ati_remove,
-#ifdef CONFIG_PM
-       .suspend        = agp_ati_suspend,
-       .resume         = agp_ati_resume,
-#endif
+       .driver.pm      = &agp_ati_pm_ops,
 };
 
 static int __init agp_ati_init(void)