[RFC PATCH v12 4/5] PCI / PM: Add support for the PCIe WAKE# signal for OF

Jeffy Chen
2017-12-26T02:09:17Z

Add of_pci_setup_wake_irq() and of_pci_teardown_wake_irq() to handle
the PCIe WAKE# interrupt.

Also use the dedicated wakeirq infrastructure to simplify it.

And add pci-of.c to enable/disable the wakeup irq in noirq stage to
avoid possible irq storm.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.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/of/of_pci_irq.c | 52 +++++++++++++++++++++++++++++++++
drivers/pci/Makefile | 1 +
drivers/pci/pci-driver.c | 10 +++++++
drivers/pci/pci-of.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_pci.h | 9 ++++++
5 files changed, 147 insertions(+)
create mode 100644 drivers/pci/pci-of.c

diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c
index d39565d5477b..af7afe6cbce2 100644
--- a/drivers/of/of_pci_irq.c
+++ b/drivers/of/of_pci_irq.c
@@ -1,8 +1,60 @@
#include <linux/kernel.h>
#include <linux/of_pci.h>
#include <linux/of_irq.h>
+#include <linux/pm_wakeirq.h>
#include <linux/export.h>

+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)
+{
+ if (!pdev->dev.power.wakeirq)
+ return;
+
+ dev_pm_clear_wake_irq(&pdev->dev);
+ device_init_wakeup(&pdev->dev, false);
+}
+EXPORT_SYMBOL_GPL(of_pci_teardown_wake_irq);
+
/**
* of_irq_parse_pci - Resolve the interrupt for a PCI device
* @pdev: the device whose interrupt is to be resolved
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index c7819b973df7..d0182c82162a 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_PCI_IOV) += iov.o
# ACPI _DSM provided firmware instance and string name
#
obj-$(CONFIG_ACPI) += pci-acpi.o
+obj-$(CONFIG_OF) += pci-of.o

# SMBIOS provided firmware instance and labels
obj-$(CONFIG_PCI_LABEL) += pci-label.o
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index d79dbc377b9c..b4475ff35d97 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -17,6 +17,7 @@
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/cpu.h>
+#include <linux/of_pci.h>
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
#include <linux/kexec.h>
@@ -421,10 +422,17 @@ 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);
if (pci_device_can_probe(pci_dev)) {
error = __pci_device_probe(drv, pci_dev);
if (error) {
+ of_pci_teardown_wake_irq(pci_dev);
pcibios_free_irq(pci_dev);
pci_dev_put(pci_dev);
}
@@ -438,6 +446,8 @@ static int 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) {
if (drv->remove) {
pm_runtime_get_sync(dev);
diff --git a/drivers/pci/pci-of.c b/drivers/pci/pci-of.c
new file mode 100644
index 000000000000..ad413b2de508
--- /dev/null
+++ b/drivers/pci/pci-of.c
@@ -0,0 +1,75 @@
+/*
+ * File: pci-of.c
+ * Purpose: Provide PCI PM/wakeup support in OF systems
+ *
+ * Copyright (C) 2017 Google, Inc.
+ * Brian Norris <briannorris@chromium.org>
+ *
+ * Copyright (C) 2017 Rockchip Electronics Co., Ltd.
+ * Jeffy Chen <jeffy.chen@rock-chips.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pm_wakeirq.h>
+#include "pci.h"
+
+static bool of_pci_power_manageable(struct pci_dev *dev)
+{
+ return false;
+}
+
+static int of_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
+{
+ return -ENOSYS;
+}
+
+static pci_power_t of_pci_get_power_state(struct pci_dev *dev)
+{
+ return PCI_UNKNOWN;
+}
+
+static pci_power_t of_pci_choose_state(struct pci_dev *pdev)
+{
+ return PCI_POWER_ERROR;
+}
+
+static int of_pci_wakeup(struct pci_dev *dev, bool enable)
+{
+ if (enable)
+ dev_pm_enable_wake_irq(&dev->dev);
+ else
+ dev_pm_disable_wake_irq(&dev->dev);
+ return 0;
+}
+
+static bool of_pci_need_resume(struct pci_dev *dev)
+{
+ return false;
+}
+
+static const struct pci_platform_pm_ops of_pci_platform_pm = {
+ .is_manageable = of_pci_power_manageable,
+ .set_state = of_pci_set_power_state,
+ .get_state = of_pci_get_power_state,
+ .choose_state = of_pci_choose_state,
+ .set_wakeup = of_pci_wakeup,
+ .need_resume = of_pci_need_resume,
+};
+
+static int __init of_pci_init(void)
+{
+ if (!acpi_disabled)
+ return 0;
+
+ pci_set_platform_pm(&of_pci_platform_pm);
+
+ return 0;
+}
+arch_initcall(of_pci_init);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index bf588a05d0d0..80fe8ae3393e 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -10,6 +10,8 @@ struct of_phandle_args;
struct device_node;

#ifdef CONFIG_OF_PCI
+int of_pci_setup_wake_irq(struct pci_dev *pdev);
+void of_pci_teardown_wake_irq(struct pci_dev *pdev);
int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq);
struct device_node *of_pci_find_child_device(struct device_node *parent,
unsigned int devfn);
@@ -23,6 +25,13 @@ int of_pci_map_rid(struct device_node *np, u32 rid,
const char *map_name, const char *map_mask_name,
struct device_node **target, u32 *id_out);
#else
+static inline int of_pci_setup_wake_irq(struct pci_dev *pdev)
+{
+ return 0;
+}
+
+static void of_pci_teardown_wake_irq(struct pci_dev *pdev) { };
+
static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
{
return 0;
--
2.11.0