[ACPI] PCI can now get suspend state from firmware
pci_choose_state() can now call
platform_pci_choose_state()
and ACPI can answer
http://bugzilla.kernel.org/show_bug.cgi?id=4277
Signed-off-by: David Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index f94c86f..8eb5997 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1,6 +1,6 @@
/*
* File: pci-acpi.c
- * Purpose: Provide PCI support in ACPI
+ * Purpose: Provde PCI support in ACPI
*
* Copyright (C) 2005 David Shaohua Li <shaohua.li@intel.com>
* Copyright (C) 2004 Tom Long Nguyen <tom.l.nguyen@intel.com>
@@ -17,6 +17,7 @@
#include <acpi/acpi_bus.h>
#include <linux/pci-acpi.h>
+#include "pci.h"
static u32 ctrlset_buf[3] = {0, 0, 0};
static u32 global_ctrlsets = 0;
@@ -209,6 +210,49 @@
}
EXPORT_SYMBOL(pci_osc_control_set);
+/*
+ * _SxD returns the D-state with the highest power
+ * (lowest D-state number) supported in the S-state "x".
+ *
+ * If the devices does not have a _PRW
+ * (Power Resources for Wake) supporting system wakeup from "x"
+ * then the OS is free to choose a lower power (higher number
+ * D-state) than the return value from _SxD.
+ *
+ * But if _PRW is enabled at S-state "x", the OS
+ * must not choose a power lower than _SxD --
+ * unless the device has an _SxW method specifying
+ * the lowest power (highest D-state number) the device
+ * may enter while still able to wake the system.
+ *
+ * ie. depending on global OS policy:
+ *
+ * if (_PRW at S-state x)
+ * choose from highest power _SxD to lowest power _SxW
+ * else // no _PRW at S-state x
+ * choose highest power _SxD or any lower power
+ *
+ * currently we simply return _SxD, if present.
+ */
+
+static int acpi_pci_choose_state(struct pci_dev *pdev, pm_message_t state)
+{
+ char dstate_str[] = "_S0D";
+ acpi_status status;
+ unsigned long val;
+ struct device *dev = &pdev->dev;
+
+ /* Fixme: the check is wrong after pm_message_t is a struct */
+ if ((state >= PM_SUSPEND_MAX) || !DEVICE_ACPI_HANDLE(dev))
+ return -EINVAL;
+ dstate_str[2] += state; /* _S1D, _S2D, _S3D, _S4D */
+ status = acpi_evaluate_integer(DEVICE_ACPI_HANDLE(dev), dstate_str,
+ NULL, &val);
+ if (ACPI_SUCCESS(status))
+ return val;
+ return -ENODEV;
+}
+
/* ACPI bus type */
static int pci_acpi_find_device(struct device *dev, acpi_handle *handle)
{
@@ -255,6 +299,7 @@
ret = register_acpi_bus_type(&pci_acpi_bus);
if (ret)
return 0;
+ platform_pci_choose_state = acpi_pci_choose_state;
return 0;
}
arch_initcall(pci_acpi_init);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f04b9ff..5af9418 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -304,6 +304,8 @@
return 0;
}
+int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state) = NULL;
+
/**
* pci_choose_state - Choose the power state of a PCI device
* @dev: PCI device to be suspended
@@ -316,10 +318,17 @@
pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state)
{
+ int ret;
+
if (!pci_find_capability(dev, PCI_CAP_ID_PM))
return PCI_D0;
- switch (state) {
+ if (platform_pci_choose_state) {
+ ret = platform_pci_choose_state(dev, state);
+ if (ret >= 0)
+ state = ret;
+ }
+ switch (state) {
case 0: return PCI_D0;
case 3: return PCI_D3hot;
default:
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 744da0d..25c4492 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -11,6 +11,9 @@
void (*alignf)(void *, struct resource *,
unsigned long, unsigned long),
void *alignf_data);
+/* Firmware callbacks */
+extern int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
+
/* PCI /proc functions */
#ifdef CONFIG_PROC_FS
extern int pci_proc_attach_device(struct pci_dev *dev);