ACPI / PM: Move device power management functions to device_pm.c

Move ACPI device power management functions from drivers/acpi/bus.c
to drivers/acpi/device_pm.c.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 288 insertions, 0 deletions

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 8be4b29e38aa..8bca7465c78d 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -30,6 +30,12 @@
 
 #include <acpi/acpi.h>
 #include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+
+#include "internal.h"
+
+#define _COMPONENT      ACPI_POWER_COMPONENT
+ACPI_MODULE_NAME("device_pm");
 
 static DEFINE_MUTEX(acpi_pm_notifier_lock);
 
@@ -94,6 +100,288 @@ acpi_status acpi_remove_pm_notifier(struct acpi_device *adev,
 }
 
 /**
+ * acpi_power_state_string - String representation of ACPI device power state.
+ * @state: ACPI device power state to return the string representation of.
+ */
+const char *acpi_power_state_string(int state)
+{
+        switch (state) {
+        case ACPI_STATE_D0:
+                return "D0";
+        case ACPI_STATE_D1:
+                return "D1";
+        case ACPI_STATE_D2:
+                return "D2";
+        case ACPI_STATE_D3_HOT:
+                return "D3hot";
+        case ACPI_STATE_D3_COLD:
+                return "D3";
+        default:
+                return "(unknown)";
+        }
+}
+
+/**
+ * acpi_device_get_power - Get power state of an ACPI device.
+ * @device: Device to get the power state of.
+ * @state: Place to store the power state of the device.
+ *
+ * This function does not update the device's power.state field, but it may
+ * update its parent's power.state field (when the parent's power state is
+ * unknown and the device's power state turns out to be D0).
+ */
+int acpi_device_get_power(struct acpi_device *device, int *state)
+{
+        int result = ACPI_STATE_UNKNOWN;
+
+        if (!device || !state)
+                return -EINVAL;
+
+        if (!device->flags.power_manageable) {
+                /* TBD: Non-recursive algorithm for walking up hierarchy. */
+                *state = device->parent ?
+                        device->parent->power.state : ACPI_STATE_D0;
+                goto out;
+        }
+
+        /*
+         * Get the device's power state either directly (via _PSC) or
+         * indirectly (via power resources).
+         */
+        if (device->power.flags.explicit_get) {
+                unsigned long long psc;
+                acpi_status status = acpi_evaluate_integer(device->handle,
+                                                           "_PSC", NULL, &psc);
+                if (ACPI_FAILURE(status))
+                        return -ENODEV;
+
+                result = psc;
+        }
+        /* The test below covers ACPI_STATE_UNKNOWN too. */
+        if (result <= ACPI_STATE_D2) {
+          ; /* Do nothing. */
+        } else if (device->power.flags.power_resources) {
+                int error = acpi_power_get_inferred_state(device, &result);
+                if (error)
+                        return error;
+        } else if (result == ACPI_STATE_D3_HOT) {
+                result = ACPI_STATE_D3;
+        }
+
+        /*
+         * If we were unsure about the device parent's power state up to this
+         * point, the fact that the device is in D0 implies that the parent has
+         * to be in D0 too.
+         */
+        if (device->parent && device->parent->power.state == ACPI_STATE_UNKNOWN
+            && result == ACPI_STATE_D0)
+                device->parent->power.state = ACPI_STATE_D0;
+
+        *state = result;
+
+ out:
+        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",
+                          device->pnp.bus_id, acpi_power_state_string(*state)));
+
+        return 0;
+}
+
+/**
+ * acpi_device_set_power - Set power state of an ACPI device.
+ * @device: Device to set the power state of.
+ * @state: New power state to set.
+ *
+ * Callers must ensure that the device is power manageable before using this
+ * function.
+ */
+int acpi_device_set_power(struct acpi_device *device, int state)
+{
+        int result = 0;
+        acpi_status status = AE_OK;
+        char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
+        bool cut_power = false;
+
+        if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
+                return -EINVAL;
+
+        /* Make sure this is a valid target state */
+
+        if (state == device->power.state) {
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at %s\n",
+                                  acpi_power_state_string(state)));
+                return 0;
+        }
+
+        if (!device->power.states[state].flags.valid) {
+                printk(KERN_WARNING PREFIX "Device does not support %s\n",
+                       acpi_power_state_string(state));
+                return -ENODEV;
+        }
+        if (device->parent && (state < device->parent->power.state)) {
+                printk(KERN_WARNING PREFIX
+                              "Cannot set device to a higher-powered"
+                              " state than parent\n");
+                return -ENODEV;
+        }
+
+        /* For D3cold we should first transition into D3hot. */
+        if (state == ACPI_STATE_D3_COLD
+            && device->power.states[ACPI_STATE_D3_COLD].flags.os_accessible) {
+                state = ACPI_STATE_D3_HOT;
+                object_name[3] = '3';
+                cut_power = true;
+        }
+
+        /*
+         * Transition Power
+         * ----------------
+         * On transitions to a high-powered state we first apply power (via
+         * power resources) then evalute _PSx.  Conversly for transitions to
+         * a lower-powered state.
+         */
+        if (state < device->power.state) {
+                if (device->power.state >= ACPI_STATE_D3_HOT &&
+                    state != ACPI_STATE_D0) {
+                        printk(KERN_WARNING PREFIX
+                              "Cannot transition to non-D0 state from D3\n");
+                        return -ENODEV;
+                }
+                if (device->power.flags.power_resources) {
+                        result = acpi_power_transition(device, state);
+                        if (result)
+                                goto end;
+                }
+                if (device->power.states[state].flags.explicit_set) {
+                        status = acpi_evaluate_object(device->handle,
+                                                      object_name, NULL, NULL);
+                        if (ACPI_FAILURE(status)) {
+                                result = -ENODEV;
+                                goto end;
+                        }
+                }
+        } else {
+                if (device->power.states[state].flags.explicit_set) {
+                        status = acpi_evaluate_object(device->handle,
+                                                      object_name, NULL, NULL);
+                        if (ACPI_FAILURE(status)) {
+                                result = -ENODEV;
+                                goto end;
+                        }
+                }
+                if (device->power.flags.power_resources) {
+                        result = acpi_power_transition(device, state);
+                        if (result)
+                                goto end;
+                }
+        }
+
+        if (cut_power)
+                result = acpi_power_transition(device, ACPI_STATE_D3_COLD);
+
+      end:
+        if (result)
+                printk(KERN_WARNING PREFIX
+                              "Device [%s] failed to transition to %s\n",
+                              device->pnp.bus_id,
+                              acpi_power_state_string(state));
+        else {
+                device->power.state = state;
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                  "Device [%s] transitioned to %s\n",
+                                  device->pnp.bus_id,
+                                  acpi_power_state_string(state)));
+        }
+
+        return result;
+}
+EXPORT_SYMBOL(acpi_device_set_power);
+
+int acpi_bus_set_power(acpi_handle handle, int state)
+{
+        struct acpi_device *device;
+        int result;
+
+        result = acpi_bus_get_device(handle, &device);
+        if (result)
+                return result;
+
+        if (!device->flags.power_manageable) {
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                "Device [%s] is not power manageable\n",
+                                dev_name(&device->dev)));
+                return -ENODEV;
+        }
+
+        return acpi_device_set_power(device, state);
+}
+EXPORT_SYMBOL(acpi_bus_set_power);
+
+int acpi_bus_init_power(struct acpi_device *device)
+{
+        int state;
+        int result;
+
+        if (!device)
+                return -EINVAL;
+
+        device->power.state = ACPI_STATE_UNKNOWN;
+
+        result = acpi_device_get_power(device, &state);
+        if (result)
+                return result;
+
+        if (device->power.flags.power_resources)
+                result = acpi_power_on_resources(device, state);
+
+        if (!result)
+                device->power.state = state;
+
+        return result;
+}
+
+int acpi_bus_update_power(acpi_handle handle, int *state_p)
+{
+        struct acpi_device *device;
+        int state;
+        int result;
+
+        result = acpi_bus_get_device(handle, &device);
+        if (result)
+                return result;
+
+        result = acpi_device_get_power(device, &state);
+        if (result)
+                return result;
+
+        result = acpi_device_set_power(device, state);
+        if (!result && state_p)
+                *state_p = state;
+
+        return result;
+}
+EXPORT_SYMBOL_GPL(acpi_bus_update_power);
+
+bool acpi_bus_power_manageable(acpi_handle handle)
+{
+        struct acpi_device *device;
+        int result;
+
+        result = acpi_bus_get_device(handle, &device);
+        return result ? false : device->flags.power_manageable;
+}
+EXPORT_SYMBOL(acpi_bus_power_manageable);
+
+bool acpi_bus_can_wakeup(acpi_handle handle)
+{
+        struct acpi_device *device;
+        int result;
+
+        result = acpi_bus_get_device(handle, &device);
+        return result ? false : device->wakeup.flags.valid;
+}
+EXPORT_SYMBOL(acpi_bus_can_wakeup);
+
+/**
  * acpi_device_power_state - Get preferred power state of ACPI device.
  * @dev: Device whose preferred target power state to return.
  * @adev: ACPI device node corresponding to @dev.