On Sunday, September 18, 2016 05:39:20 AM Lukas Wunner wrote:
> Usually the most accurate way to determine a PCI device's power state is
> to read its PM Control & Status Register. There are two cases however
> when this is not an option: If the device doesn't have the PM
> capability at all, or if it is in D3cold (in which case its config space
> is inaccessible).
>
> In both cases, we can alternatively query the platform firmware for its
> opinion on the device's power state. To facilitate this, augment struct
> pci_platform_pm_ops with a ->get_power callback and implement it for
> acpi_pci_platform_pm (the only pci_platform_pm_ops existing so far).
>
> It is used by a forthcoming commit to let pci_update_current_state()
> recognize D3cold.
>
> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
> Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
>
> Changes since v1:
> * In acpi_pci_get_power_state(), only check for ACPI_STATE_UNKNOWN
> instead of ACPI_STATE_D0 and ACPI_STATE_D3_COLD.
> * Move the change to pci_update_current_state() to new patch [3/5].
>
> drivers/pci/pci-acpi.c | 22 ++++++++++++++++++++++
> drivers/pci/pci.c | 10 ++++++++--
> drivers/pci/pci.h | 3 +++
> 3 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> index 9a033e8..d966d47 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -452,6 +452,27 @@ static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
> return error;
> }
>
> +static pci_power_t acpi_pci_get_power_state(struct pci_dev *dev)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
> + static const pci_power_t state_conv[] = {
> + [ACPI_STATE_D0] = PCI_D0,
> + [ACPI_STATE_D1] = PCI_D1,
> + [ACPI_STATE_D2] = PCI_D2,
> + [ACPI_STATE_D3_HOT] = PCI_D3hot,
> + [ACPI_STATE_D3_COLD] = PCI_D3cold,
> + };
> + int state;
> +
> + if (!adev || !acpi_device_power_manageable(adev))
> + return PCI_UNKNOWN;
> +
> + if (acpi_device_get_power(adev, &state) || state == ACPI_STATE_UNKNOWN)
> + return PCI_UNKNOWN;
> +
> + return state_conv[state];
> +}
> +
> static bool acpi_pci_can_wakeup(struct pci_dev *dev)
> {
> struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
> @@ -534,6 +555,7 @@ static bool acpi_pci_need_resume(struct pci_dev *dev)
> static const struct pci_platform_pm_ops acpi_pci_platform_pm = {
> .is_manageable = acpi_pci_power_manageable,
> .set_state = acpi_pci_set_power_state,
> + .get_state = acpi_pci_get_power_state,
> .choose_state = acpi_pci_choose_state,
> .sleep_wake = acpi_pci_sleep_wake,
> .run_wake = acpi_pci_run_wake,
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 72a9d3a..6ea0d2d 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -552,8 +552,9 @@ static const struct pci_platform_pm_ops *pci_platform_pm;
>
> int pci_set_platform_pm(const struct pci_platform_pm_ops *ops)
> {
> - if (!ops->is_manageable || !ops->set_state || !ops->choose_state ||
> - !ops->sleep_wake || !ops->run_wake || !ops->need_resume)
> + if (!ops->is_manageable || !ops->set_state || !ops->get_state ||
> + !ops->choose_state || !ops->sleep_wake || !ops->run_wake ||
> + !ops->need_resume)
> return -EINVAL;
> pci_platform_pm = ops;
> return 0;
> @@ -570,6 +571,11 @@ static inline int platform_pci_set_power_state(struct pci_dev *dev,
> return pci_platform_pm ? pci_platform_pm->set_state(dev, t) : -ENOSYS;
> }
>
> +static inline pci_power_t platform_pci_get_power_state(struct pci_dev *dev)
> +{
> + return pci_platform_pm ? pci_platform_pm->get_state(dev) : PCI_UNKNOWN;
> +}
> +
> static inline pci_power_t platform_pci_choose_state(struct pci_dev *dev)
> {
> return pci_platform_pm ?
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 194521b..4518562 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -42,6 +42,8 @@ int pci_probe_reset_function(struct pci_dev *dev);
> *
> * @set_state: invokes the platform firmware to set the device's power state
> *
> + * @get_state: queries the platform firmware for a device's current power state
> + *
> * @choose_state: returns PCI power state of given device preferred by the
> * platform; to be used during system-wide transitions from a
> * sleeping state to the working state and vice versa
> @@ -62,6 +64,7 @@ int pci_probe_reset_function(struct pci_dev *dev);
> struct pci_platform_pm_ops {
> bool (*is_manageable)(struct pci_dev *dev);
> int (*set_state)(struct pci_dev *dev, pci_power_t state);
> + pci_power_t (*get_state)(struct pci_dev *dev);
> pci_power_t (*choose_state)(struct pci_dev *dev);
> int (*sleep_wake)(struct pci_dev *dev, bool enable);
> int (*run_wake)(struct pci_dev *dev, bool enable);
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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