[PATCH 42/46] define platform wakeup hook, use in pci_enable_wake()

Greg Kroah-Hartman
2007-04-27T19:00:09Z

From: David Brownell <david-b@pacbell.net>

This defines a platform hook to enable/disable a device as a wakeup event
source. It's initially for use with ACPI, but more generally it could be used
whenever enable_irq_wake()/disable_irq_wake() don't suffice.

The hook is called -- if available -- inside pci_enable_wake(); and the
semantics of that call are enhanced so that support for PCI PME# is no longer
needed. It can now work for devices with "legacy PCI PM", when platform
support allows it. (That support would use some board-specific signal for for
the same purpose as PME#.)

[akpm@linux-foundation.org: Make it compile with CONFIG_PM=n]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/power/main.c | 3 ++
drivers/pci/pci.c | 58 +++++++++++++++++++++++++++++++-------------
include/linux/pm.h | 19 ++++++++++++++
3 files changed, 63 insertions(+), 17 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index bbbb973..05dc876 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -29,6 +29,9 @@ LIST_HEAD(dpm_off_irq);
DECLARE_MUTEX(dpm_sem);
DECLARE_MUTEX(dpm_list_sem);

+int (*platform_enable_wakeup)(struct device *dev, int is_on);
+
+
/**
* device_pm_set_parent - Specify power dependency.
* @dev: Device who needs power.
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d3eab05..2a45827 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -13,6 +13,7 @@
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>
+#include <linux/pm.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/string.h>
@@ -891,31 +892,48 @@ pci_disable_device(struct pci_dev *dev)
}

/**
- * pci_enable_wake - enable device to generate PME# when suspended
- * @dev: - PCI device to operate on
- * @state: - Current state of device.
- * @enable: - Flag to enable or disable generation
- *
- * Set the bits in the device's PM Capabilities to generate PME# when
- * the system is suspended.
+ * pci_enable_wake - enable PCI device as wakeup event source
+ * @dev: PCI device affected
+ * @state: PCI state from which device will issue wakeup events
+ * @enable: True to enable event generation; false to disable
*
- * -EIO is returned if device doesn't have PM Capabilities.
- * -EINVAL is returned if device supports it, but can't generate wake events.
- * 0 if operation is successful.
- *
+ * This enables the device as a wakeup event source, or disables it.
+ * When such events involves platform-specific hooks, those hooks are
+ * called automatically by this routine.
+ *
+ * Devices with legacy power management (no standard PCI PM capabilities)
+ * always require such platform hooks. Depending on the platform, devices
+ * supporting the standard PCI PME# signal may require such platform hooks;
+ * they always update bits in config space to allow PME# generation.
+ *
+ * -EIO is returned if the device can't ever be a wakeup event source.
+ * -EINVAL is returned if the device can't generate wakeup events from
+ * the specified PCI state. Returns zero if the operation is successful.
*/
int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
{
int pm;
+ int status;
u16 value;

+ /* Note that drivers should verify device_may_wakeup(&dev->dev)
+ * before calling this function. Platform code should report
+ * errors when drivers try to enable wakeup on devices that
+ * can't issue wakeups, or on which wakeups were disabled by
+ * userspace updating the /sys/devices.../power/wakeup file.
+ */
+
+ status = call_platform_enable_wakeup(&dev->dev, enable);
+
/* find PCI PM capability in list */
pm = pci_find_capability(dev, PCI_CAP_ID_PM);

- /* If device doesn't support PM Capabilities, but request is to disable
- * wake events, it's a nop; otherwise fail */
- if (!pm)
- return enable ? -EIO : 0;
+ /* If device doesn't support PM Capabilities, but caller wants to
+ * disable wake events, it's a NOP. Otherwise fail unless the
+ * platform hooks handled this legacy device already.
+ */
+ if (!pm)
+ return enable ? status : 0;

/* Check device's ability to generate PME# */
pci_read_config_word(dev,pm+PCI_PM_PMC,&value);
@@ -924,8 +942,14 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
value >>= ffs(PCI_PM_CAP_PME_MASK) - 1; /* First bit of mask */

/* Check if it can generate PME# from requested state. */
- if (!value || !(value & (1 << state)))
+ if (!value || !(value & (1 << state))) {
+ /* if it can't, revert what the platform hook changed,
+ * always reporting the base "EINVAL, can't PME#" error
+ */
+ if (enable)
+ call_platform_enable_wakeup(&dev->dev, 0);
return enable ? -EINVAL : 0;
+ }

pci_read_config_word(dev, pm + PCI_PM_CTRL, &value);

@@ -936,7 +960,7 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
value &= ~PCI_PM_CTRL_PME_ENABLE;

pci_write_config_word(dev, pm + PCI_PM_CTRL, value);
-
+
return 0;
}

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 21db05a..b0ab623 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -273,6 +273,20 @@ extern void __suspend_report_result(const char *function, void *fn, int ret);
__suspend_report_result(__FUNCTION__, fn, ret); \
} while (0)

+/*
+ * Platform hook to activate device wakeup capability, if that's not already
+ * handled by enable_irq_wake() etc.
+ * Returns zero on success, else negative errno
+ */
+extern int (*platform_enable_wakeup)(struct device *dev, int is_on);
+
+static inline int call_platform_enable_wakeup(struct device *dev, int is_on)
+{
+ if (platform_enable_wakeup)
+ return (*platform_enable_wakeup)(dev, is_on);
+ return 0;
+}
+
#else /* !CONFIG_PM */

static inline int device_suspend(pm_message_t state)
@@ -294,6 +308,11 @@ static inline void dpm_runtime_resume(struct device * dev)

#define suspend_report_result(fn, ret) do { } while (0)

+static inline int call_platform_enable_wakeup(struct device *dev, int is_on)
+{
+ return -EIO;
+}
+
#endif

/* changes to device_may_wakeup take effect on the next pm state change.
--
1.5.1.2