Fw: [linux-pm] [patch 2.6.21-rc5-git 1/3] new platform_enable_wake() hook; use it in PCI
Jordan Crouse
jordan.crouse at amd.com
Sun Apr 8 12:54:46 EDT 2007
Of interest to devel@
----- Forwarded message from David Brownell <david-b at pacbell.net> -----
From: David Brownell <david-b at pacbell.net>
Date: Thu, 5 Apr 2007 12:48:56 -0700
To: linux-acpi at vger.kernel.org, linux-pm at lists.linux-foundation.org
Subject: [linux-pm] [patch 2.6.21-rc5-git 1/3] new
platform_enable_wake() hook; use it in PCI
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#.)
Signed-off-by: David Brownell <dbrownell at users.sourceforge.net>
---
drivers/base/power/main.c | 3 ++
drivers/pci/pci.c | 61 ++++++++++++++++++++++++++++++++--------------
include/linux/pm.h | 5 +++
3 files changed, 51 insertions(+), 18 deletions(-)
--- g26.orig/include/linux/pm.h 2007-04-04 12:26:00.000000000 -0700
+++ g26/include/linux/pm.h 2007-04-04 13:03:34.000000000 -0700
@@ -273,6 +273,11 @@ extern void __suspend_report_result(cons
__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
+ */
+extern int (*platform_enable_wakeup)(struct device *dev, int is_on);
+
#else /* !CONFIG_PM */
static inline int device_suspend(pm_message_t state)
--- g26.orig/drivers/base/power/main.c 2007-04-04 13:03:33.000000000 -0700
+++ g26/drivers/base/power/main.c 2007-04-04 13:03:34.000000000 -0700
@@ -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) = NULL;
+
+
/**
* device_pm_set_parent - Specify power dependency.
* @dev: Device who needs power.
--- g26.orig/drivers/pci/pci.c 2007-04-04 12:26:06.000000000 -0700
+++ g26/drivers/pci/pci.c 2007-04-04 13:31:37.000000000 -0700
@@ -891,31 +891,53 @@ 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.
- *
- * -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.
- *
+ * 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
+ *
+ * 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.
+ */
+
+ if (platform_enable_wakeup) {
+ status = platform_enable_wakeup(&dev->dev, enable);
+ if (status)
+ return status;
+ } else
+ status = -EIO;
+
/* 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 +946,11 @@ int pci_enable_wake(struct pci_dev *dev,
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 (enable && platform_enable_wakeup)
+ (void) platform_enable_wakeup(&dev->dev, 0);
return enable ? -EINVAL : 0;
+ }
pci_read_config_word(dev, pm + PCI_PM_CTRL, &value);
@@ -936,7 +961,7 @@ int pci_enable_wake(struct pci_dev *dev,
value &= ~PCI_PM_CTRL_PME_ENABLE;
pci_write_config_word(dev, pm + PCI_PM_CTRL, value);
-
+
return 0;
}
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----- End forwarded message -----
--
Jordan Crouse
Senior Linux Engineer
Advanced Micro Devices, Inc.
<www.amd.com/embeddedprocessors>
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