scsi: aic7xxx: Use generic power management

Drivers should do only device-specific jobs. But in general, drivers using
legacy PCI PM framework for .suspend()/.resume() have to manage many PCI
PM-related tasks themselves which can be done by PCI Core itself. This
brings extra load on the driver and it directly calls PCI helper functions
to handle them.

Switch to the new generic framework by updating function signatures and
define a "struct dev_pm_ops" variable to bind PM callbacks. Also, remove
unnecessary calls to the PCI Helper functions along with the legacy
.suspend & .resume bindings.

Link: https://lore.kernel.org/r/20201102164730.324035-7-vaibhavgupta40@gmail.comSigned-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aic7xxx/aic7xxx.h

@@ -1134,9 +1134,7 @@ const struct ahc_pci_identity	*ahc_find_pci_device(ahc_dev_softc_t);
 int			 ahc_pci_config(struct ahc_softc *,
 					const struct ahc_pci_identity *);
 int			 ahc_pci_test_register_access(struct ahc_softc *);
-#ifdef CONFIG_PM
-void			 ahc_pci_resume(struct ahc_softc *ahc);
-#endif
+void __maybe_unused	 ahc_pci_resume(struct ahc_softc *ahc);
 
 /*************************** EISA/VL Front End ********************************/
 struct aic7770_identity *aic7770_find_device(uint32_t);
@@ -1160,10 +1158,8 @@ int			 ahc_chip_init(struct ahc_softc *ahc);
 int			 ahc_init(struct ahc_softc *ahc);
 void			 ahc_intr_enable(struct ahc_softc *ahc, int enable);
 void			 ahc_pause_and_flushwork(struct ahc_softc *ahc);
-#ifdef CONFIG_PM
-int			 ahc_suspend(struct ahc_softc *ahc); 
-int			 ahc_resume(struct ahc_softc *ahc);
-#endif
+int __maybe_unused	 ahc_suspend(struct ahc_softc *ahc);
+int __maybe_unused	 ahc_resume(struct ahc_softc *ahc);
 void			 ahc_set_unit(struct ahc_softc *, int);
 void			 ahc_set_name(struct ahc_softc *, char *);
 void			 ahc_free(struct ahc_softc *ahc);

drivers/scsi/aic7xxx/aic7xxx_core.c

@@ -5590,8 +5590,7 @@ ahc_pause_and_flushwork(struct ahc_softc *ahc)
 	ahc->flags &= ~AHC_ALL_INTERRUPTS;
 }
 
-#ifdef CONFIG_PM
-int
+int __maybe_unused
 ahc_suspend(struct ahc_softc *ahc)
 {
 
@@ -5617,7 +5616,7 @@ ahc_suspend(struct ahc_softc *ahc)
 	return (0);
 }
 
-int
+int __maybe_unused
 ahc_resume(struct ahc_softc *ahc)
 {
 
@@ -5626,7 +5625,6 @@ ahc_resume(struct ahc_softc *ahc)
 	ahc_restart(ahc);
 	return (0);
 }
-#endif
 /************************** Busy Target Table *********************************/
 /*
  * Return the untagged transaction id for a given target/channel lun.

drivers/scsi/aic7xxx/aic7xxx_osm_pci.c

@@ -121,47 +121,23 @@ static const struct pci_device_id ahc_linux_pci_id_table[] = {
 
 MODULE_DEVICE_TABLE(pci, ahc_linux_pci_id_table);
 
-#ifdef CONFIG_PM
-static int
-ahc_linux_pci_dev_suspend(struct pci_dev *pdev, pm_message_t mesg)
+static int __maybe_unused
+ahc_linux_pci_dev_suspend(struct device *dev)
 {
-	struct ahc_softc *ahc = pci_get_drvdata(pdev);
-	int rc;
-
-	if ((rc = ahc_suspend(ahc)))
-		return rc;
+	struct ahc_softc *ahc = dev_get_drvdata(dev);
 
-	pci_save_state(pdev);
-	pci_disable_device(pdev);
-
-	if (mesg.event & PM_EVENT_SLEEP)
-		pci_set_power_state(pdev, PCI_D3hot);
-
-	return rc;
+	return ahc_suspend(ahc);
 }
 
-static int
-ahc_linux_pci_dev_resume(struct pci_dev *pdev)
+static int __maybe_unused
+ahc_linux_pci_dev_resume(struct device *dev)
 {
-	struct ahc_softc *ahc = pci_get_drvdata(pdev);
-	int rc;
-
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
-
-	if ((rc = pci_enable_device(pdev))) {
-		dev_printk(KERN_ERR, &pdev->dev,
-			   "failed to enable device after resume (%d)\n", rc);
-		return rc;
-	}
-
-	pci_set_master(pdev);
+	struct ahc_softc *ahc = dev_get_drvdata(dev);
 
 	ahc_pci_resume(ahc);
 
 	return (ahc_resume(ahc));
 }
-#endif
 
 static void
 ahc_linux_pci_dev_remove(struct pci_dev *pdev)
@@ -319,14 +295,14 @@ ahc_pci_write_config(ahc_dev_softc_t pci, int reg, uint32_t value, int width)
 	}
 }
 
+static SIMPLE_DEV_PM_OPS(ahc_linux_pci_dev_pm_ops,
+			 ahc_linux_pci_dev_suspend,
+			 ahc_linux_pci_dev_resume);
 
 static struct pci_driver aic7xxx_pci_driver = {
 	.name		= "aic7xxx",
 	.probe		= ahc_linux_pci_dev_probe,
-#ifdef CONFIG_PM
-	.suspend	= ahc_linux_pci_dev_suspend,
-	.resume		= ahc_linux_pci_dev_resume,
-#endif
+	.driver.pm	= &ahc_linux_pci_dev_pm_ops,
 	.remove		= ahc_linux_pci_dev_remove,
 	.id_table	= ahc_linux_pci_id_table
 };

drivers/scsi/aic7xxx/aic7xxx_pci.c

@@ -2008,8 +2008,7 @@ ahc_pci_chip_init(struct ahc_softc *ahc)
 	return (ahc_chip_init(ahc));
 }
 
-#ifdef CONFIG_PM
-void
+void __maybe_unused
 ahc_pci_resume(struct ahc_softc *ahc)
 {
 	/*
@@ -2040,7 +2039,6 @@ ahc_pci_resume(struct ahc_softc *ahc)
 		ahc_release_seeprom(&sd);
 	}
 }
-#endif
 
 static int
 ahc_aic785X_setup(struct ahc_softc *ahc)