[Linux-kernel-mentees] [PATCH v4 29/29] scsi: pmcraid: use generic power management

[Vaibhav Gupta]

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 at gmail.com>
---
 drivers/scsi/pmcraid.c | 43 ++++++++++--------------------------------
 1 file changed, 10 insertions(+), 33 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 5c767cd8ffc3..834556ea21d2 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -5234,53 +5234,37 @@ static void pmcraid_remove(struct pci_dev *pdev)
 	return;
 }
 
-#ifdef CONFIG_PM
 /**
  * pmcraid_suspend - driver suspend entry point for power management
- * @pdev:   PCI device structure
- * @state:  PCI power state to suspend routine
+ * @dev:   Device structure
  *
  * Return Value - 0 always
  */
-static int pmcraid_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused pmcraid_suspend(struct device *dev)
 {
+	struct pci_dev *pdev = to_pci_dev(dev);
 	struct pmcraid_instance *pinstance = pci_get_drvdata(pdev);
 
 	pmcraid_shutdown(pdev);
 	pmcraid_disable_interrupts(pinstance, ~0);
 	pmcraid_kill_tasklets(pinstance);
-	pci_set_drvdata(pinstance->pdev, pinstance);
 	pmcraid_unregister_interrupt_handler(pinstance);
-	pci_save_state(pdev);
-	pci_disable_device(pdev);
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
 
 	return 0;
 }
 
 /**
  * pmcraid_resume - driver resume entry point PCI power management
- * @pdev: PCI device structure
+ * @dev: Device structure
  *
  * Return Value - 0 in case of success. Error code in case of any failure
  */
-static int pmcraid_resume(struct pci_dev *pdev)
+static int __maybe_unused pmcraid_resume(struct device *dev)
 {
+	struct pci_dev *pdev = to_pci_dev(dev);
 	struct pmcraid_instance *pinstance = pci_get_drvdata(pdev);
 	struct Scsi_Host *host = pinstance->host;
-	int rc;
-
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
-
-	rc = pci_enable_device(pdev);
-
-	if (rc) {
-		dev_err(&pdev->dev, "resume: Enable device failed\n");
-		return rc;
-	}
-
-	pci_set_master(pdev);
+	int rc = 0;
 
 	if (sizeof(dma_addr_t) == 4 ||
 	    dma_set_mask(&pdev->dev, DMA_BIT_MASK(64)))
@@ -5333,18 +5317,10 @@ static int pmcraid_resume(struct pci_dev *pdev)
 	scsi_host_put(host);
 
 disable_device:
-	pci_disable_device(pdev);
 
 	return rc;
 }
 
-#else
-
-#define pmcraid_suspend NULL
-#define pmcraid_resume  NULL
-
-#endif /* CONFIG_PM */
-
 /**
  * pmcraid_complete_ioa_reset - Called by either timer or tasklet during
  *				completion of the ioa reset
@@ -5832,6 +5808,8 @@ static int pmcraid_probe(struct pci_dev *pdev,
 	return -ENODEV;
 }
 
+static SIMPLE_DEV_PM_OPS(pmcraid_pm_ops, pmcraid_suspend, pmcraid_resume);
+
 /*
  * PCI driver structure of pmcraid driver
  */
@@ -5840,8 +5818,7 @@ static struct pci_driver pmcraid_driver = {
 	.id_table = pmcraid_pci_table,
 	.probe = pmcraid_probe,
 	.remove = pmcraid_remove,
-	.suspend = pmcraid_suspend,
-	.resume = pmcraid_resume,
+	.driver.pm = &pmcraid_pm_ops,
 	.shutdown = pmcraid_shutdown
 };
 
-- 
2.28.0