Merge branch 'pci/pm'

- Cache the PTM capability offset instead of searching for it every time
  (Bjorn Helgaas)

- Separate PTM configuration from PTM enable (Bjorn Helgaas)

- Add pci_suspend_ptm() and pci_resume_ptm() to disable and re-enable PTM
  on suspend/resume so some Root Ports can safely enter a lower-power PM
  state (Bjorn Helgaas)

- Disable PTM for all devices during suspend; previously we only did this
  for Root Ports and even then only in certain cases (Bjorn Helgaas)

- Simplify pci_pm_suspend_noirq() (Rajvi Jingar)

- Reduce the delay after transitions to/from D3hot by using usleep_range()
  instead of msleep(), which reduces the typical delay from 19ms to 10ms
  (Sajid Dalvi, Will McVicker)

* pci/pm:
  PCI/PM: Reduce D3hot delay with usleep_range()
  PCI/PM: Simplify pci_pm_suspend_noirq()
  PCI/PM: Always disable PTM for all devices during suspend
  PCI/PTM: Consolidate PTM interface declarations
  PCI/PTM: Reorder functions in logical order
  PCI/PTM: Preserve RsvdP bits in PTM Control register
  PCI/PTM: Move pci_ptm_info() body into its only caller
  PCI/PTM: Add pci_suspend_ptm() and pci_resume_ptm()
  PCI/PTM: Separate configuration and enable
  PCI/PTM: Add pci_upstream_ptm() helper
  PCI/PTM: Cache PTM Capability offset

Author: bjorn-helgaas

drivers/pci/pci-driver.c

@@ -774,6 +774,12 @@ static int pci_pm_suspend(struct device *dev)
 
 	pci_dev->skip_bus_pm = false;
 
+	/*
+	 * Disabling PTM allows some systems, e.g., Intel mobile chips
+	 * since Coffee Lake, to enter a lower-power PM state.
+	 */
+	pci_suspend_ptm(pci_dev);
+
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_suspend(dev, PMSG_SUSPEND);
 
@@ -867,20 +873,15 @@ static int pci_pm_suspend_noirq(struct device *dev)
 		}
 	}
 
-	if (pci_dev->skip_bus_pm) {
+	if (!pci_dev->state_saved) {
+		pci_save_state(pci_dev);
+
 		/*
-		 * Either the device is a bridge with a child in D0 below it, or
-		 * the function is running for the second time in a row without
-		 * going through full resume, which is possible only during
-		 * suspend-to-idle in a spurious wakeup case.  The device should
-		 * be in D0 at this point, but if it is a bridge, it may be
-		 * necessary to save its state.
+		 * If the device is a bridge with a child in D0 below it,
+		 * it needs to stay in D0, so check skip_bus_pm to avoid
+		 * putting it into a low-power state in that case.
 		 */
-		if (!pci_dev->state_saved)
-			pci_save_state(pci_dev);
-	} else if (!pci_dev->state_saved) {
-		pci_save_state(pci_dev);
-		if (pci_power_manageable(pci_dev))
+		if (!pci_dev->skip_bus_pm && pci_power_manageable(pci_dev))
 			pci_prepare_to_sleep(pci_dev);
 	}
 
@@ -987,6 +988,8 @@ static int pci_pm_resume(struct device *dev)
 	if (pci_dev->state_saved)
 		pci_restore_standard_config(pci_dev);
 
+	pci_resume_ptm(pci_dev);
+
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_resume(dev);
 
@@ -1274,6 +1277,8 @@ static int pci_pm_runtime_suspend(struct device *dev)
 	pci_power_t prev = pci_dev->current_state;
 	int error;
 
+	pci_suspend_ptm(pci_dev);
+
 	/*
 	 * If pci_dev->driver is not set (unbound), we leave the device in D0,
 	 * but it may go to D3cold when the bridge above it runtime suspends.
@@ -1335,6 +1340,7 @@ static int pci_pm_runtime_resume(struct device *dev)
 	 * D3cold when the bridge above it runtime suspended.
 	 */
 	pci_pm_default_resume_early(pci_dev);
+	pci_resume_ptm(pci_dev);
 
 	if (!pci_dev->driver)
 		return 0;

drivers/pci/pci.c

@@ -66,13 +66,15 @@ struct pci_pme_device {
 
 static void pci_dev_d3_sleep(struct pci_dev *dev)
 {
-	unsigned int delay = dev->d3hot_delay;
-
-	if (delay < pci_pm_d3hot_delay)
-		delay = pci_pm_d3hot_delay;
-
-	if (delay)
-		msleep(delay);
+	unsigned int delay_ms = max(dev->d3hot_delay, pci_pm_d3hot_delay);
+	unsigned int upper;
+
+	if (delay_ms) {
+		/* Use a 20% upper bound, 1ms minimum */
+		upper = max(DIV_ROUND_CLOSEST(delay_ms, 5), 1U);
+		usleep_range(delay_ms * USEC_PER_MSEC,
+			     (delay_ms + upper) * USEC_PER_MSEC);
+	}
 }
 
 bool pci_reset_supported(struct pci_dev *dev)
@@ -2708,24 +2710,12 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
 	if (target_state == PCI_POWER_ERROR)
 		return -EIO;
 
-	/*
-	 * There are systems (for example, Intel mobile chips since Coffee
-	 * Lake) where the power drawn while suspended can be significantly
-	 * reduced by disabling PTM on PCIe root ports as this allows the
-	 * port to enter a lower-power PM state and the SoC to reach a
-	 * lower-power idle state as a whole.
-	 */
-	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
-		pci_disable_ptm(dev);
-
 	pci_enable_wake(dev, target_state, wakeup);
 
 	error = pci_set_power_state(dev, target_state);
 
-	if (error) {
+	if (error)
 		pci_enable_wake(dev, target_state, false);
-		pci_restore_ptm_state(dev);
-	}
 
 	return error;
 }
@@ -2766,24 +2756,12 @@ int pci_finish_runtime_suspend(struct pci_dev *dev)
 	if (target_state == PCI_POWER_ERROR)
 		return -EIO;
 
-	/*
-	 * There are systems (for example, Intel mobile chips since Coffee
-	 * Lake) where the power drawn while suspended can be significantly
-	 * reduced by disabling PTM on PCIe root ports as this allows the
-	 * port to enter a lower-power PM state and the SoC to reach a
-	 * lower-power idle state as a whole.
-	 */
-	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
-		pci_disable_ptm(dev);
-
 	__pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));
 
 	error = pci_set_power_state(dev, target_state);
 
-	if (error) {
+	if (error)
 		pci_enable_wake(dev, target_state, false);
-		pci_restore_ptm_state(dev);
-	}
 
 	return error;
 }

drivers/pci/pci.h

@@ -505,13 +505,17 @@ static inline int pci_iov_bus_range(struct pci_bus *bus)
 #endif /* CONFIG_PCI_IOV */
 
 #ifdef CONFIG_PCIE_PTM
+void pci_ptm_init(struct pci_dev *dev);
 void pci_save_ptm_state(struct pci_dev *dev);
 void pci_restore_ptm_state(struct pci_dev *dev);
-void pci_disable_ptm(struct pci_dev *dev);
+void pci_suspend_ptm(struct pci_dev *dev);
+void pci_resume_ptm(struct pci_dev *dev);
 #else
+static inline void pci_ptm_init(struct pci_dev *dev) { }
 static inline void pci_save_ptm_state(struct pci_dev *dev) { }
 static inline void pci_restore_ptm_state(struct pci_dev *dev) { }
-static inline void pci_disable_ptm(struct pci_dev *dev) { }
+static inline void pci_suspend_ptm(struct pci_dev *dev) { }
+static inline void pci_resume_ptm(struct pci_dev *dev) { }
 #endif
 
 unsigned long pci_cardbus_resource_alignment(struct resource *);
@@ -579,12 +583,6 @@ static inline void pcie_set_ecrc_checking(struct pci_dev *dev) { }
 static inline void pcie_ecrc_get_policy(char *str) { }
 #endif
 
-#ifdef CONFIG_PCIE_PTM
-void pci_ptm_init(struct pci_dev *dev);
-#else
-static inline void pci_ptm_init(struct pci_dev *dev) { }
-#endif
-
 struct pci_dev_reset_methods {
 	u16 vendor;
 	u16 device;