[Linux-kernel-mentees] [PATCH v4 1/3] mtip32xx: use generic power management

[Vaibhav Gupta]

Drivers using legacy power management .suspen()/.resume() callbacks
have to manage PCI states and device's PM states themselves. They also
need to take care of standard configuration registers.

Switch to generic power management framework using a single
"struct dev_pm_ops" variable to take the unnecessary load from the driver.
This also avoids the need for the driver to directly call most of the PCI
helper functions and device power state control functions, as through
the generic framework PCI Core takes care of the necessary operations,
and drivers are required to do only device-specific jobs.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40 at gmail.com>
---
 drivers/block/mtip32xx/mtip32xx.c | 54 +++++++------------------------
 1 file changed, 12 insertions(+), 42 deletions(-)

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 53ac59d19ae5..de1ac3366b97 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -4232,14 +4232,13 @@ static void mtip_pci_remove(struct pci_dev *pdev)
  *	0  Success
  *	<0 Error
  */
-static int mtip_pci_suspend(struct pci_dev *pdev, pm_message_t mesg)
+static int __maybe_unused mtip_pci_suspend(struct device *dev)
 {
 	int rv = 0;
-	struct driver_data *dd = pci_get_drvdata(pdev);
+	struct driver_data *dd = dev_get_drvdata(dev);
 
 	if (!dd) {
-		dev_err(&pdev->dev,
-			"Driver private datastructure is NULL\n");
+		dev_err(dev, "Driver private datastructure is NULL\n");
 		return -EFAULT;
 	}
 
@@ -4247,21 +4246,8 @@ static int mtip_pci_suspend(struct pci_dev *pdev, pm_message_t mesg)
 
 	/* Disable ports & interrupts then send standby immediate */
 	rv = mtip_block_suspend(dd);
-	if (rv < 0) {
-		dev_err(&pdev->dev,
-			"Failed to suspend controller\n");
-		return rv;
-	}
-
-	/*
-	 * Save the pci config space to pdev structure &
-	 * disable the device
-	 */
-	pci_save_state(pdev);
-	pci_disable_device(pdev);
-
-	/* Move to Low power state*/
-	pci_set_power_state(pdev, PCI_D3hot);
+	if (rv < 0)
+		dev_err(dev, "Failed to suspend controller\n");
 
 	return rv;
 }
@@ -4273,42 +4259,25 @@ static int mtip_pci_suspend(struct pci_dev *pdev, pm_message_t mesg)
  *      0  Success
  *      <0 Error
  */
-static int mtip_pci_resume(struct pci_dev *pdev)
+static int __maybe_unused mtip_pci_resume(struct device *dev)
 {
 	int rv = 0;
 	struct driver_data *dd;
 
-	dd = pci_get_drvdata(pdev);
+	dd = dev_get_drvdata(dev);
 	if (!dd) {
-		dev_err(&pdev->dev,
-			"Driver private datastructure is NULL\n");
+		dev_err(dev, "Driver private datastructure is NULL\n");
 		return -EFAULT;
 	}
 
-	/* Move the device to active State */
-	pci_set_power_state(pdev, PCI_D0);
-
-	/* Restore PCI configuration space */
-	pci_restore_state(pdev);
-
-	/* Enable the PCI device*/
-	rv = pcim_enable_device(pdev);
-	if (rv < 0) {
-		dev_err(&pdev->dev,
-			"Failed to enable card during resume\n");
-		goto err;
-	}
-	pci_set_master(pdev);
-
 	/*
 	 * Calls hbaReset, initPort, & startPort function
 	 * then enables interrupts
 	 */
 	rv = mtip_block_resume(dd);
 	if (rv < 0)
-		dev_err(&pdev->dev, "Unable to resume\n");
+		dev_err(dev, "Unable to resume\n");
 
-err:
 	clear_bit(MTIP_DDF_RESUME_BIT, &dd->dd_flag);
 
 	return rv;
@@ -4339,14 +4308,15 @@ static const struct pci_device_id mtip_pci_tbl[] = {
 	{ 0 }
 };
 
+static SIMPLE_DEV_PM_OPS(mtip_pci_pm_ops, mtip_pci_suspend, mtip_pci_resume);
+
 /* Structure that describes the PCI driver functions. */
 static struct pci_driver mtip_pci_driver = {
 	.name			= MTIP_DRV_NAME,
 	.id_table		= mtip_pci_tbl,
 	.probe			= mtip_pci_probe,
 	.remove			= mtip_pci_remove,
-	.suspend		= mtip_pci_suspend,
-	.resume			= mtip_pci_resume,
+	.driver.pm		= &mtip_pci_pm_ops,
 	.shutdown		= mtip_pci_shutdown,
 };
 
-- 
2.30.0