[PATCH v2] firewire: ohci: Convert to generic power management

[Bjorn Helgaas]

From: Vaibhav Gupta <vaibhavgupta40@xxxxxxxxx>

Convert firewire-ohci from legacy PCI power management to the generic power
management framework.

Previously firewire-ohci used legacy PCI power management, and
pci_suspend() and pci_resume() were responsible for both device-specific
things and generic PCI things like saving and restoring config space and
managing power state:

  pci_suspend
    software_reset                         <-- device-specific
    pci_save_state                         <-- generic PCI
    pci_set_power_state                    <-- generic PCI
    pmac_ohci_off                          <-- device-specific

  pci_resume
    pmac_ohci_on                           <-- device-specific
    pci_set_power_state(PCI_D0)            <-- generic PCI
    pci_restore_state                      <-- generic PCI
    pci_enable_device                      <-- generic PCI
    ohci_enable                            <-- device-specific

Convert to generic power management where 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
        pci_suspend                        # driver->pm->suspend
          software_reset                   <-- device-specific
          pmac_ohci_off                    <-- device-specific
    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
        pci_resume                         # driver->pm->resume
          pmac_ohci_on                     <-- device-specific
          ohci_enable                      <-- device-specific

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20200720150715.624520-1-vaibhavgupta40@xxxxxxxxx
Signed-off-by: Vaibhav Gupta <vaibhavgupta40@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
 drivers/firewire/ohci.c | 35 ++++++++---------------------------
 1 file changed, 8 insertions(+), 27 deletions(-)

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 17c9d825188b..aee705132330 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -3165,8 +3165,7 @@ static int ohci_set_iso_channels(struct fw_iso_context *base, u64 *channels)
 	return ret;
 }
 
-#ifdef CONFIG_PM
-static void ohci_resume_iso_dma(struct fw_ohci *ohci)
+static void __maybe_unused ohci_resume_iso_dma(struct fw_ohci *ohci)
 {
 	int i;
 	struct iso_context *ctx;
@@ -3183,7 +3182,6 @@ static void ohci_resume_iso_dma(struct fw_ohci *ohci)
 			ohci_start_iso(&ctx->base, 0, ctx->sync, ctx->tags);
 	}
 }
-#endif
 
 static int queue_iso_transmit(struct iso_context *ctx,
 			      struct fw_iso_packet *packet,
@@ -3789,39 +3787,24 @@ static void pci_remove(struct pci_dev *dev)
 	dev_notice(&dev->dev, "removed fw-ohci device\n");
 }
 
-#ifdef CONFIG_PM
-static int pci_suspend(struct pci_dev *dev, pm_message_t state)
+static int __maybe_unused pci_suspend(struct device *devp)
 {
+	struct pci_dev *dev = to_pci_dev(devp);
 	struct fw_ohci *ohci = pci_get_drvdata(dev);
-	int err;
 
 	software_reset(ohci);
-	err = pci_save_state(dev);
-	if (err) {
-		ohci_err(ohci, "pci_save_state failed\n");
-		return err;
-	}
-	err = pci_set_power_state(dev, pci_choose_state(dev, state));
-	if (err)
-		ohci_err(ohci, "pci_set_power_state failed with %d\n", err);
 	pmac_ohci_off(dev);
 
 	return 0;
 }
 
-static int pci_resume(struct pci_dev *dev)
+static int __maybe_unused pci_resume(struct device *devp)
 {
+	struct pci_dev *dev = to_pci_dev(devp);
 	struct fw_ohci *ohci = pci_get_drvdata(dev);
 	int err;
 
 	pmac_ohci_on(dev);
-	pci_set_power_state(dev, PCI_D0);
-	pci_restore_state(dev);
-	err = pci_enable_device(dev);
-	if (err) {
-		ohci_err(ohci, "pci_enable_device failed\n");
-		return err;
-	}
 
 	/* Some systems don't setup GUID register on resume from ram  */
 	if (!reg_read(ohci, OHCI1394_GUIDLo) &&
@@ -3838,7 +3821,6 @@ static int pci_resume(struct pci_dev *dev)
 
 	return 0;
 }
-#endif
 
 static const struct pci_device_id pci_table[] = {
 	{ PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_FIREWIRE_OHCI, ~0) },
@@ -3847,15 +3829,14 @@ static const struct pci_device_id pci_table[] = {
 
 MODULE_DEVICE_TABLE(pci, pci_table);
 
+static SIMPLE_DEV_PM_OPS(pci_pm_ops, pci_suspend, pci_resume);
+
 static struct pci_driver fw_ohci_pci_driver = {
 	.name		= ohci_driver_name,
 	.id_table	= pci_table,
 	.probe		= pci_probe,
 	.remove		= pci_remove,
-#ifdef CONFIG_PM
-	.resume		= pci_resume,
-	.suspend	= pci_suspend,
-#endif
+	.driver.pm	= &pci_pm_ops,
 };
 
 static int __init fw_ohci_init(void)
-- 
2.25.1