[Linux-kernel-mentees] [PATCH v3 02/28] scsi: megaraid_sas: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

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.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
---
 drivers/scsi/megaraid/megaraid_sas_base.c | 51 ++++++-----------------
 1 file changed, 13 insertions(+), 38 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 93ade9915ec0..72aa7fabe051 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -7539,25 +7539,23 @@ static void megasas_shutdown_controller(struct megasas_instance *instance,
 	megasas_return_cmd(instance, cmd);
 }
 
-#ifdef CONFIG_PM
 /**
  * megasas_suspend -	driver suspend entry point
- * @pdev:		PCI device structure
- * @state:		PCI power state to suspend routine
+ * @dev:		Device structure
  */
-static int
-megasas_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused
+megasas_suspend(struct device *dev)
 {
 	struct megasas_instance *instance;
 
-	instance = pci_get_drvdata(pdev);
+	instance = dev_get_drvdata(dev);
 
 	if (!instance)
 		return 0;
 
 	instance->unload = 1;
 
-	dev_info(&pdev->dev, "%s is called\n", __func__);
+	dev_info(dev, "%s is called\n", __func__);
 
 	/* Shutdown SR-IOV heartbeat timer */
 	if (instance->requestorId && !instance->skip_heartbeat_timer_del)
@@ -7587,47 +7585,29 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t state)
 	if (instance->msix_vectors)
 		pci_free_irq_vectors(instance->pdev);
 
-	pci_save_state(pdev);
-	pci_disable_device(pdev);
-
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
-
 	return 0;
 }
 
 /**
  * megasas_resume-      driver resume entry point
- * @pdev:               PCI device structure
+ * @dev:		Device structure
  */
-static int
-megasas_resume(struct pci_dev *pdev)
+static int __maybe_unused
+megasas_resume(struct device *dev)
 {
 	int rval;
 	struct Scsi_Host *host;
 	struct megasas_instance *instance;
 	u32 status_reg;
 
-	instance = pci_get_drvdata(pdev);
+	instance = dev_get_drvdata(dev);
 
 	if (!instance)
 		return 0;
 
 	host = instance->host;
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
-
-	dev_info(&pdev->dev, "%s is called\n", __func__);
-	/*
-	 * PCI prepping: enable device set bus mastering and dma mask
-	 */
-	rval = pci_enable_device_mem(pdev);
 
-	if (rval) {
-		dev_err(&pdev->dev, "Enable device failed\n");
-		return rval;
-	}
-
-	pci_set_master(pdev);
+	dev_info(dev, "%s is called\n", __func__);
 
 	/*
 	 * We expect the FW state to be READY
@@ -7753,14 +7733,8 @@ megasas_resume(struct pci_dev *pdev)
 fail_set_dma_mask:
 fail_ready_state:
 
-	pci_disable_device(pdev);
-
 	return -ENODEV;
 }
-#else
-#define megasas_suspend	NULL
-#define megasas_resume	NULL
-#endif
 
 static inline int
 megasas_wait_for_adapter_operational(struct megasas_instance *instance)
@@ -8507,6 +8481,8 @@ static const struct file_operations megasas_mgmt_fops = {
 	.llseek = noop_llseek,
 };
 
+static SIMPLE_DEV_PM_OPS(megasas_pm_ops, megasas_suspend, megasas_resume);
+
 /*
  * PCI hotplug support registration structure
  */
@@ -8516,8 +8492,7 @@ static struct pci_driver megasas_pci_driver = {
 	.id_table = megasas_pci_table,
 	.probe = megasas_probe_one,
 	.remove = megasas_detach_one,
-	.suspend = megasas_suspend,
-	.resume = megasas_resume,
+	.driver.pm = &megasas_pm_ops,
 	.shutdown = megasas_shutdown,
 };
 
-- 
2.28.0

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