scsi: esas2r: 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/20201102164730.324035-12-vaibhavgupta40@gmail.comSigned-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/esas2r/esas2r.h

@@ -996,8 +996,9 @@ void esas2r_adapter_tasklet(unsigned long context);
 irqreturn_t esas2r_interrupt(int irq, void *dev_id);
 irqreturn_t esas2r_msi_interrupt(int irq, void *dev_id);
 void esas2r_kickoff_timer(struct esas2r_adapter *a);
-int esas2r_suspend(struct pci_dev *pcid, pm_message_t state);
-int esas2r_resume(struct pci_dev *pcid);
+
+extern const struct dev_pm_ops esas2r_pm_ops;
+
 void esas2r_fw_event_off(struct esas2r_adapter *a);
 void esas2r_fw_event_on(struct esas2r_adapter *a);
 bool esas2r_nvram_write(struct esas2r_adapter *a, struct esas2r_request *rq,

drivers/scsi/esas2r/esas2r_init.c

@@ -641,49 +641,27 @@ void esas2r_kill_adapter(int i)
 	}
 }
 
-int esas2r_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused esas2r_suspend(struct device *dev)
 {
-	struct Scsi_Host *host = pci_get_drvdata(pdev);
-	u32 device_state;
+	struct Scsi_Host *host = dev_get_drvdata(dev);
 	struct esas2r_adapter *a = (struct esas2r_adapter *)host->hostdata;
 
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev), "suspending adapter()");
+	esas2r_log_dev(ESAS2R_LOG_INFO, dev, "suspending adapter()");
 	if (!a)
 		return -ENODEV;
 
 	esas2r_adapter_power_down(a, 1);
-	device_state = pci_choose_state(pdev, state);
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev),
-		       "pci_save_state() called");
-	pci_save_state(pdev);
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev),
-		       "pci_disable_device() called");
-	pci_disable_device(pdev);
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev),
-		       "pci_set_power_state() called");
-	pci_set_power_state(pdev, device_state);
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev), "esas2r_suspend(): 0");
+	esas2r_log_dev(ESAS2R_LOG_INFO, dev, "esas2r_suspend(): 0");
 	return 0;
 }
 
-int esas2r_resume(struct pci_dev *pdev)
+static int __maybe_unused esas2r_resume(struct device *dev)
 {
-	struct Scsi_Host *host = pci_get_drvdata(pdev);
+	struct Scsi_Host *host = dev_get_drvdata(dev);
 	struct esas2r_adapter *a = (struct esas2r_adapter *)host->hostdata;
-	int rez;
-
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev), "resuming adapter()");
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev),
-		       "pci_set_power_state(PCI_D0) "
-		       "called");
-	pci_set_power_state(pdev, PCI_D0);
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev),
-		       "pci_restore_state() called");
-	pci_restore_state(pdev);
-	esas2r_log_dev(ESAS2R_LOG_INFO, &(pdev->dev),
-		       "pci_enable_device() called");
-	rez = pci_enable_device(pdev);
-	pci_set_master(pdev);
+	int rez = 0;
+
+	esas2r_log_dev(ESAS2R_LOG_INFO, dev, "resuming adapter()");
 
 	if (!a) {
 		rez = -ENODEV;
@@ -727,11 +705,13 @@ int esas2r_resume(struct pci_dev *pdev)
 	}
 
 error_exit:
-	esas2r_log_dev(ESAS2R_LOG_CRIT, &(pdev->dev), "esas2r_resume(): %d",
+	esas2r_log_dev(ESAS2R_LOG_CRIT, dev, "esas2r_resume(): %d",
 		       rez);
 	return rez;
 }
 
+SIMPLE_DEV_PM_OPS(esas2r_pm_ops, esas2r_suspend, esas2r_resume);
+
 bool esas2r_set_degraded_mode(struct esas2r_adapter *a, char *error_str)
 {
 	set_bit(AF_DEGRADED_MODE, &a->flags);

drivers/scsi/esas2r/esas2r_main.c

@@ -346,8 +346,7 @@ static struct pci_driver
 	.id_table	= esas2r_pci_table,
 	.probe		= esas2r_probe,
 	.remove		= esas2r_remove,
-	.suspend	= esas2r_suspend,
-	.resume		= esas2r_resume,
+	.driver.pm	= &esas2r_pm_ops,
 };
 
 static int esas2r_probe(struct pci_dev *pcid,