[RFC,v14 3/5] PCI / PM: Add support for the PCIe WAKE# signal for OF

[Manikanta Maddireddy <mmaddireddy@nvidia.com>]

From: Jeffy Chen <jeffy.chen@rock-chips.com>

Add of_pci_setup_wake_irq() to parse the PCIe WAKE# interrupt from the
device tree and set the wake irq. Add of_pci_teardown_wake_irq() to clear
the wake irq.

Call of_pci_setup_wake_irq() in pci_device_probe() to setup PCIe WAKE#
interrupt during PCIe Endpoint enumeration.

Enable or disable PCIe WAKE# interrupt in platform_pci_set_wakeup().

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---

Changes in v14:
pci_platform_pm_ops structure is removed in latest kernel, so dropped
pci-of driver. Instead, enable wake in platform_pci_set_wakeup().

Changes in v13:
Fix compiler error reported by kbuild test robot <fengguang.wu@intel.com>

Changes in v12:
Enable the wake irq in noirq stage to avoid possible irq storm.

Changes in v11:
Only support 1-per-device PCIe WAKE# pin as suggested.

Changes in v10:
Use device_set_wakeup_capable() instead of device_set_wakeup_enable(),
since dedicated wakeirq will be lost in device_set_wakeup_enable(false).

Changes in v9:
Fix check error in .cleanup().
Move dedicated wakeirq setup to setup() callback and use
device_set_wakeup_enable() to enable/disable.

Changes in v8:
Add pci-of.c and use platform_pm_ops to handle the PCIe WAKE# signal.

Changes in v7:
Move PCIE_WAKE handling into pci core.

Changes in v6:
Fix device_init_wake error handling, and add some comments.

Changes in v5:
Rebase.

Changes in v3:
Fix error handling.

Changes in v2:
Use dev_pm_set_dedicated_wake_irq.

 drivers/pci/of.c         | 49 ++++++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-driver.c | 10 ++++++++
 drivers/pci/pci.c        |  7 ++++++
 drivers/pci/pci.h        |  8 +++++++
 4 files changed, 74 insertions(+)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index ff897c40ed71..1c348e63f175 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -13,6 +13,7 @@
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/pm_wakeirq.h>
 #include "pci.h"
 
 #ifdef CONFIG_PCI
@@ -705,3 +706,51 @@ u32 of_pci_get_slot_power_limit(struct device_node *node,
 	return slot_power_limit_mw;
 }
 EXPORT_SYMBOL_GPL(of_pci_get_slot_power_limit);
+
+int of_pci_setup_wake_irq(struct pci_dev *pdev)
+{
+	struct pci_dev *ppdev;
+	struct device_node *dn;
+	int ret, irq;
+
+	/* Get the pci_dev of our parent. Hopefully it's a port. */
+	ppdev = pdev->bus->self;
+	/* Nope, it's a host bridge. */
+	if (!ppdev)
+		return 0;
+
+	dn = pci_device_to_OF_node(ppdev);
+	if (!dn)
+		return 0;
+
+	irq = of_irq_get_byname(dn, "wakeup");
+	if (irq == -EPROBE_DEFER) {
+		return irq;
+	} else if (irq < 0) {
+		/* Ignore other errors, since a missing wakeup is non-fatal. */
+		dev_info(&pdev->dev, "cannot get wakeup interrupt: %d\n", irq);
+		return 0;
+	}
+
+	device_init_wakeup(&pdev->dev, true);
+
+	ret = dev_pm_set_dedicated_wake_irq(&pdev->dev, irq);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to set wake IRQ: %d\n", ret);
+		device_init_wakeup(&pdev->dev, false);
+		return ret;
+	}
+
+	/* Start out disabled to avoid irq storm */
+	dev_pm_disable_wake_irq(&pdev->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_pci_setup_wake_irq);
+
+void of_pci_teardown_wake_irq(struct pci_dev *pdev)
+{
+	dev_pm_clear_wake_irq(&pdev->dev);
+	device_init_wakeup(&pdev->dev, false);
+}
+EXPORT_SYMBOL_GPL(of_pci_teardown_wake_irq);
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index d934c27491c4..fca966137fac 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -14,6 +14,7 @@
 #include <linux/sched.h>
 #include <linux/sched/isolation.h>
 #include <linux/cpu.h>
+#include <linux/of_pci.h>
 #include <linux/pm_runtime.h>
 #include <linux/suspend.h>
 #include <linux/kexec.h>
@@ -456,10 +457,17 @@ static int pci_device_probe(struct device *dev)
 	if (error < 0)
 		return error;
 
+	error = of_pci_setup_wake_irq(pci_dev);
+	if (error < 0) {
+		pcibios_free_irq(pci_dev);
+		return error;
+	}
+
 	pci_dev_get(pci_dev);
 	error = __pci_device_probe(drv, pci_dev);
 	if (error) {
 		pcibios_free_irq(pci_dev);
+		of_pci_teardown_wake_irq(pci_dev);
 		pci_dev_put(pci_dev);
 	}
 
@@ -471,6 +479,8 @@ static void pci_device_remove(struct device *dev)
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct pci_driver *drv = pci_dev->driver;
 
+	of_pci_teardown_wake_irq(pci_dev);
+
 	if (drv->remove) {
 		pm_runtime_get_sync(dev);
 		drv->remove(pci_dev);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index fba95486caaf..332a0b98b6c3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -27,6 +27,7 @@
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/pci_hotplug.h>
 #include <linux/vmalloc.h>
 #include <asm/dma.h>
@@ -1052,6 +1053,12 @@ static inline int platform_pci_set_wakeup(struct pci_dev *dev, bool enable)
 	if (pci_use_mid_pm())
 		return PCI_POWER_ERROR;
 
+	/* Enable or disable wakeirq if set via device tree. */
+	if (enable)
+		dev_pm_enable_wake_irq(&dev->dev);
+	else
+		dev_pm_disable_wake_irq(&dev->dev);
+
 	return acpi_pci_wakeup(dev, enable);
 }
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9ed3b5550043..83a2af148631 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -631,6 +631,8 @@ int of_pci_get_max_link_speed(struct device_node *node);
 u32 of_pci_get_slot_power_limit(struct device_node *node,
 				u8 *slot_power_limit_value,
 				u8 *slot_power_limit_scale);
+int of_pci_setup_wake_irq(struct pci_dev *pdev);
+void of_pci_teardown_wake_irq(struct pci_dev *pdev);
 void pci_set_of_node(struct pci_dev *dev);
 void pci_release_of_node(struct pci_dev *dev);
 void pci_set_bus_of_node(struct pci_bus *bus);
@@ -669,6 +671,12 @@ of_pci_get_slot_power_limit(struct device_node *node,
 	return 0;
 }
 
+static inline int of_pci_setup_wake_irq(struct pci_dev *pdev)
+{
+	return 0;
+}
+
+static inline void of_pci_teardown_wake_irq(struct pci_dev *pdev) { }
 static inline void pci_set_of_node(struct pci_dev *dev) { }
 static inline void pci_release_of_node(struct pci_dev *dev) { }
 static inline void pci_set_bus_of_node(struct pci_bus *bus) { }
-- 
2.25.1