PCI/PM: Remove unused pci_driver.resume_early() hook

The struct pci_driver.resume_early() hook is one of the legacy PCI power
management callbacks, and there are no remaining users of it.  Remove it.

Link: https://lore.kernel.org/r/20191101204558.210235-6-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/power/pci.rst

@@ -692,7 +692,7 @@ controlling the runtime power management of their devices.
 At the time of this writing there are two ways to define power management
 callbacks for a PCI device driver, the recommended one, based on using a
 dev_pm_ops structure described in Documentation/driver-api/pm/devices.rst, and
-the "legacy" one, in which the .suspend(), .suspend_late(), .resume_early(), and
+the "legacy" one, in which the .suspend(), .suspend_late(), and
 .resume() callbacks from struct pci_driver are used.  The legacy approach,
 however, doesn't allow one to define runtime power management callbacks and is
 not really suitable for any new drivers.  Therefore it is not covered by this

drivers/pci/pci-driver.c

@@ -630,15 +630,6 @@ Fixup:
 	return 0;
 }
 
-static int pci_legacy_resume_early(struct device *dev)
-{
-	struct pci_dev *pci_dev = to_pci_dev(dev);
-	struct pci_driver *drv = pci_dev->driver;
-
-	return drv && drv->resume_early ?
-			drv->resume_early(pci_dev) : 0;
-}
-
 static int pci_legacy_resume(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
@@ -662,8 +653,7 @@ static void pci_pm_default_suspend(struct pci_dev *pci_dev)
 static bool pci_has_legacy_pm_support(struct pci_dev *pci_dev)
 {
 	struct pci_driver *drv = pci_dev->driver;
-	bool ret = drv && (drv->suspend || drv->suspend_late || drv->resume
-		|| drv->resume_early);
+	bool ret = drv && (drv->suspend || drv->suspend_late || drv->resume);
 
 	/*
 	 * Legacy PM support is used by default, so warn if the new framework is
@@ -944,7 +934,7 @@ static int pci_pm_resume_noirq(struct device *dev)
 	pcie_pme_root_status_cleanup(pci_dev);
 
 	if (pci_has_legacy_pm_support(pci_dev))
-		return pci_legacy_resume_early(dev);
+		return 0;
 
 	if (pm && pm->resume_noirq)
 		return pm->resume_noirq(dev);
@@ -1074,9 +1064,8 @@ static int pci_pm_thaw_noirq(struct device *dev)
 	}
 
 	/*
-	 * Both the legacy ->resume_early() and the new pm->thaw_noirq()
-	 * callbacks assume the device has been returned to D0 and its
-	 * config state has been restored.
+	 * The pm->thaw_noirq() callback assumes the device has been
+	 * returned to D0 and its config state has been restored.
 	 *
 	 * In addition, pci_restore_state() restores MSI-X state in MMIO
 	 * space, which requires the device to be in D0, so return it to D0
@@ -1087,7 +1076,7 @@ static int pci_pm_thaw_noirq(struct device *dev)
 	pci_restore_state(pci_dev);
 
 	if (pci_has_legacy_pm_support(pci_dev))
-		return pci_legacy_resume_early(dev);
+		return 0;
 
 	if (pm && pm->thaw_noirq)
 		return pm->thaw_noirq(dev);
@@ -1219,7 +1208,7 @@ static int pci_pm_restore_noirq(struct device *dev)
 	pci_fixup_device(pci_fixup_resume_early, pci_dev);
 
 	if (pci_has_legacy_pm_support(pci_dev))
-		return pci_legacy_resume_early(dev);
+		return 0;
 
 	if (pm && pm->restore_noirq)
 		return pm->restore_noirq(dev);

include/linux/pci.h

@@ -806,7 +806,6 @@ struct module;
  *		context, so it can sleep.
  * @suspend:	Put device into low power state.
  * @suspend_late: Put device into low power state.
- * @resume_early: Wake device from low power state.
  * @resume:	Wake device from low power state.
  *		(Please see Documentation/power/pci.rst for descriptions
  *		of PCI Power Management and the related functions.)
@@ -830,7 +829,6 @@ struct pci_driver {
 	void (*remove)(struct pci_dev *dev);	/* Device removed (NULL if not a hot-plug capable driver) */
 	int  (*suspend)(struct pci_dev *dev, pm_message_t state);	/* Device suspended */
 	int  (*suspend_late)(struct pci_dev *dev, pm_message_t state);
-	int  (*resume_early)(struct pci_dev *dev);
 	int  (*resume)(struct pci_dev *dev);	/* Device woken up */
 	void (*shutdown)(struct pci_dev *dev);
 	int  (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */