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SubjectRe: [PATCH v2 1/3] firmware: arm_scpi: add support for device power state management
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On Thu, 2016-06-16 at 11:37 +0100, Sudeep Holla wrote:
> SCPI protocol supports device power state management. This deals with
> power states of various peripheral devices in the system other than the
> core compute subsystem.
>
> This patch adds support for the power state management of those
> peripheral devices.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

Reviewed-by: Jon Medhurst <tixy@linaro.org>
Tested-by: Jon Medhurst <tixy@linaro.org>

I've also tested this series on Juno r2 together with the coresight
changes [1], to the extent that enabling various kernel configs gets the
kernel log showing several lines like:

coresight-etm4x 22040000.etm: ETM 4.0 initialized

and if I omit the power domain entries from device-tree then boot hangs
as you indicated it would be expected due to coresight hardware being
powered off.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-June/433769.html


> ---
> drivers/firmware/arm_scpi.c | 30 ++++++++++++++++++++++++++++++
> include/linux/scpi_protocol.h | 2 ++
> 2 files changed, 32 insertions(+)
>
> diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
> index 51c6db0774cc..438893762076 100644
> --- a/drivers/firmware/arm_scpi.c
> +++ b/drivers/firmware/arm_scpi.c
> @@ -231,6 +231,11 @@ struct sensor_value {
> __le32 hi_val;
> } __packed;
>
> +struct dev_pstate_set {
> + u16 dev_id;
> + u8 pstate;
> +} __packed;
> +
> static struct scpi_drvinfo *scpi_info;
>
> static int scpi_linux_errmap[SCPI_ERR_MAX] = {
> @@ -537,6 +542,29 @@ static int scpi_sensor_get_value(u16 sensor, u64 *val)
> return ret;
> }
>
> +static int scpi_device_get_power_state(u16 dev_id)
> +{
> + int ret;
> + u8 pstate;
> + __le16 id = cpu_to_le16(dev_id);
> +
> + ret = scpi_send_message(SCPI_CMD_GET_DEVICE_PWR_STATE, &id,
> + sizeof(id), &pstate, sizeof(pstate));
> + return ret ? ret : pstate;
> +}
> +
> +static int scpi_device_set_power_state(u16 dev_id, u8 pstate)
> +{
> + int stat;
> + struct dev_pstate_set dev_set = {
> + .dev_id = cpu_to_le16(dev_id),
> + .pstate = pstate,
> + };
> +
> + return scpi_send_message(SCPI_CMD_SET_DEVICE_PWR_STATE, &dev_set,
> + sizeof(dev_set), &stat, sizeof(stat));
> +}
> +
> static struct scpi_ops scpi_ops = {
> .get_version = scpi_get_version,
> .clk_get_range = scpi_clk_get_range,
> @@ -548,6 +576,8 @@ static struct scpi_ops scpi_ops = {
> .sensor_get_capability = scpi_sensor_get_capability,
> .sensor_get_info = scpi_sensor_get_info,
> .sensor_get_value = scpi_sensor_get_value,
> + .device_get_power_state = scpi_device_get_power_state,
> + .device_set_power_state = scpi_device_set_power_state,
> };
>
> struct scpi_ops *get_scpi_ops(void)
> diff --git a/include/linux/scpi_protocol.h b/include/linux/scpi_protocol.h
> index 35de50a65665..dc5f989be226 100644
> --- a/include/linux/scpi_protocol.h
> +++ b/include/linux/scpi_protocol.h
> @@ -70,6 +70,8 @@ struct scpi_ops {
> int (*sensor_get_capability)(u16 *sensors);
> int (*sensor_get_info)(u16 sensor_id, struct scpi_sensor_info *);
> int (*sensor_get_value)(u16, u64 *);
> + int (*device_get_power_state)(u16);
> + int (*device_set_power_state)(u16, u8);
> };
>
> #if IS_REACHABLE(CONFIG_ARM_SCPI_PROTOCOL)
> --
> 2.7.4
>


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