PCI/PM: Relocate pci_set_low_power_state()

Because pci_set_power_state() is the only caller of
pci_set_low_power_state(), put the latter next to the former.

No functional impact.

Link: https://lore.kernel.org/r/3202976.44csPzL39Z@kreacherSigned-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -1067,85 +1067,6 @@ static inline bool platform_pci_bridge_d3(struct pci_dev *dev)
 	return acpi_pci_bridge_d3(dev);
 }
 
-/**
- * pci_set_low_power_state - Put a PCI device into a low-power state.
- * @dev: PCI device to handle.
- * @state: PCI power state (D1, D2, D3hot) to put the device into.
- *
- * Use the device's PCI_PM_CTRL register to put it into a low-power state.
- *
- * RETURN VALUE:
- * -EINVAL if the requested state is invalid.
- * -EIO if device does not support PCI PM or its PM capabilities register has a
- * wrong version, or device doesn't support the requested state.
- * 0 if device already is in the requested state.
- * 0 if device's power state has been successfully changed.
- */
-static int pci_set_low_power_state(struct pci_dev *dev, pci_power_t state)
-{
-	u16 pmcsr;
-
-	/* Check if we're already there */
-	if (dev->current_state == state)
-		return 0;
-
-	if (!dev->pm_cap)
-		return -EIO;
-
-	if (state < PCI_D1 || state > PCI_D3hot)
-		return -EINVAL;
-
-	/*
-	 * Validate transition: We can enter D0 from any state, but if
-	 * we're already in a low-power state, we can only go deeper.  E.g.,
-	 * we can go from D1 to D3, but we can't go directly from D3 to D1;
-	 * we'd have to go from D3 to D0, then to D1.
-	 */
-	if (dev->current_state <= PCI_D3cold && dev->current_state > state) {
-		pci_err(dev, "invalid power transition (from %s to %s)\n",
-			pci_power_name(dev->current_state),
-			pci_power_name(state));
-		return -EINVAL;
-	}
-
-	/* Check if this device supports the desired state */
-	if ((state == PCI_D1 && !dev->d1_support)
-	   || (state == PCI_D2 && !dev->d2_support))
-		return -EIO;
-
-	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
-	if (PCI_POSSIBLE_ERROR(pmcsr)) {
-		pci_err(dev, "Unable to change power state from %s to %s, device inaccessible\n",
-			pci_power_name(dev->current_state),
-			pci_power_name(state));
-		return -EIO;
-	}
-
-	pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
-	pmcsr |= state;
-
-	/* Enter specified state */
-	pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);
-
-	/* Mandatory power management transition delays; see PCI PM 1.2. */
-	if (state == PCI_D3hot)
-		pci_dev_d3_sleep(dev);
-	else if (state == PCI_D2)
-		udelay(PCI_PM_D2_DELAY);
-
-	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
-	dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK;
-	if (dev->current_state != state)
-		pci_info_ratelimited(dev, "Refused to change power state from %s to %s\n",
-				     pci_power_name(dev->current_state),
-				     pci_power_name(state));
-
-	if (dev->bus->self)
-		pcie_aspm_pm_state_change(dev->bus->self);
-
-	return 0;
-}
-
 /**
  * pci_update_current_state - Read power state of given device and cache it
  * @dev: PCI device to handle.
@@ -1363,6 +1284,85 @@ void pci_bus_set_current_state(struct pci_bus *bus, pci_power_t state)
 		pci_walk_bus(bus, __pci_dev_set_current_state, &state);
 }
 
+/**
+ * pci_set_low_power_state - Put a PCI device into a low-power state.
+ * @dev: PCI device to handle.
+ * @state: PCI power state (D1, D2, D3hot) to put the device into.
+ *
+ * Use the device's PCI_PM_CTRL register to put it into a low-power state.
+ *
+ * RETURN VALUE:
+ * -EINVAL if the requested state is invalid.
+ * -EIO if device does not support PCI PM or its PM capabilities register has a
+ * wrong version, or device doesn't support the requested state.
+ * 0 if device already is in the requested state.
+ * 0 if device's power state has been successfully changed.
+ */
+static int pci_set_low_power_state(struct pci_dev *dev, pci_power_t state)
+{
+	u16 pmcsr;
+
+	/* Check if we're already there */
+	if (dev->current_state == state)
+		return 0;
+
+	if (!dev->pm_cap)
+		return -EIO;
+
+	if (state < PCI_D1 || state > PCI_D3hot)
+		return -EINVAL;
+
+	/*
+	 * Validate transition: We can enter D0 from any state, but if
+	 * we're already in a low-power state, we can only go deeper.  E.g.,
+	 * we can go from D1 to D3, but we can't go directly from D3 to D1;
+	 * we'd have to go from D3 to D0, then to D1.
+	 */
+	if (dev->current_state <= PCI_D3cold && dev->current_state > state) {
+		pci_err(dev, "invalid power transition (from %s to %s)\n",
+			pci_power_name(dev->current_state),
+			pci_power_name(state));
+		return -EINVAL;
+	}
+
+	/* Check if this device supports the desired state */
+	if ((state == PCI_D1 && !dev->d1_support)
+	   || (state == PCI_D2 && !dev->d2_support))
+		return -EIO;
+
+	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
+	if (PCI_POSSIBLE_ERROR(pmcsr)) {
+		pci_err(dev, "Unable to change power state from %s to %s, device inaccessible\n",
+			pci_power_name(dev->current_state),
+			pci_power_name(state));
+		return -EIO;
+	}
+
+	pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
+	pmcsr |= state;
+
+	/* Enter specified state */
+	pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);
+
+	/* Mandatory power management transition delays; see PCI PM 1.2. */
+	if (state == PCI_D3hot)
+		pci_dev_d3_sleep(dev);
+	else if (state == PCI_D2)
+		udelay(PCI_PM_D2_DELAY);
+
+	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
+	dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK;
+	if (dev->current_state != state)
+		pci_info_ratelimited(dev, "Refused to change power state from %s to %s\n",
+				     pci_power_name(dev->current_state),
+				     pci_power_name(state));
+
+	if (dev->bus->self)
+		pcie_aspm_pm_state_change(dev->bus->self);
+
+	return 0;
+}
+
 /**
  * pci_set_power_state - Set the power state of a PCI device
  * @dev: PCI device to handle.