[Linux-kernel-mentees] [PATCH v1 01/15] scsi: megaraid_sas: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

With legacy PM hooks, it was the responsibility of a driver to manage PCI
states and also the device's power state. The generic approach is to let
the PCI core handle the work.

PCI core passes "struct device*" as an argument to the .suspend() and
.resume() callbacks. As the .suspend() work with "struct instance*",
extract it from "struct device*" using dev_get_drv_data().

Driver was also using PCI helper functions like pci_save/restore_state(),
pci_disable/enable_device(), pci_set_power_state() and pci_enable_wake().
They should not be invoked by the driver.

Compile-tested only.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
---
 drivers/scsi/megaraid/megaraid_sas_base.c | 57 +++++++----------------
 1 file changed, 16 insertions(+), 41 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 00668335c2af..c1bf429d29db 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)
@@ -7579,7 +7577,7 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t state)
 
 	tasklet_kill(&instance->isr_tasklet);
 
-	pci_set_drvdata(instance->pdev, instance);
+	dev_set_drvdata(dev, instance);
 	instance->instancet->disable_intr(instance);
 
 	megasas_destroy_irqs(instance);
@@ -7587,48 +7585,30 @@ 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_enable_wake(pdev, PCI_D0, 0);
-	pci_restore_state(pdev);
+	device_wakeup_disable(dev);
 
-	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
@@ -7754,14 +7734,8 @@ 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)
@@ -7931,7 +7905,7 @@ static void megasas_detach_one(struct pci_dev *pdev)
 
 /**
  * megasas_shutdown -	Shutdown entry point
- * @device:		Generic device structure
+ * @pdev:		PCI device structure
  */
 static void megasas_shutdown(struct pci_dev *pdev)
 {
@@ -8508,6 +8482,8 @@ 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
  */
@@ -8517,8 +8493,7 @@ 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,
 };
 
-- 
2.27.0

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