Re: [Intel-gfx] [PATCH 07/14] drm/i915/guc/slpc: Add methods to set min/max frequency

Michal Wajdeczko
2021-07-21T17:42:36Z

On 21.07.2021 18:11, Vinay Belgaumkar wrote:
> Add param set h2g helpers to set the min and max frequencies
> for use by SLPC.
>
> v2: Address review comments (Michal W)
>
> Signed-off-by: Sundaresan Sujaritha <sujaritha.sundaresan@intel.com>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
> ---
> drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 84 +++++++++++++++++++++
> drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h | 2 +
> 2 files changed, 86 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> index 48db2a8f67d1..b40c39ba4049 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> @@ -109,6 +109,18 @@ static u32 slpc_get_state(struct intel_guc_slpc *slpc)
> return data->header.global_state;
> }
>
> +static int guc_action_slpc_set_param(struct intel_guc *guc, u8 id, u32 value)
> +{
> + u32 request[] = {
> + INTEL_GUC_ACTION_SLPC_REQUEST,
> + SLPC_EVENT(SLPC_EVENT_PARAMETER_SET, 2),
> + id,
> + value,
> + };
> +
> + return intel_guc_send(guc, request, ARRAY_SIZE(request));

beware of possible non-zero data0 returned by guc_send()

> +}
> +
> static bool slpc_is_running(struct intel_guc_slpc *slpc)
> {
> return (slpc_get_state(slpc) == SLPC_GLOBAL_STATE_RUNNING);
> @@ -143,6 +155,15 @@ static int slpc_query_task_state(struct intel_guc_slpc *slpc)
> return ret;
> }
>
> +static int slpc_set_param(struct intel_guc_slpc *slpc, u8 id, u32 value)
> +{
> + struct intel_guc *guc = slpc_to_guc(slpc);
> +
> + GEM_BUG_ON(id >= SLPC_MAX_PARAM);
> +
> + return guc_action_slpc_set_param(guc, id, value);
> +}
> +
> static const char *slpc_state_string(struct intel_guc_slpc *slpc)
> {
> const char *str = NULL;
> @@ -238,6 +259,69 @@ u32 slpc_decode_max_freq(struct intel_guc_slpc *slpc)
> GT_FREQUENCY_MULTIPLIER, GEN9_FREQ_SCALER);
> }
>
> +/**
> + * intel_guc_slpc_set_max_freq() - Set max frequency limit for SLPC.
> + * @slpc: pointer to intel_guc_slpc.
> + * @val: frequency (MHz)
> + *
> + * This function will invoke GuC SLPC action to update the max frequency
> + * limit for unslice.
> + *
> + * Return: 0 on success, non-zero error code on failure.
> + */
> +int intel_guc_slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 val)
> +{
> + int ret;
> + struct drm_i915_private *i915 = slpc_to_i915(slpc);
> + intel_wakeref_t wakeref;

nit: move "ret" as last

> +
> + with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
> + ret = slpc_set_param(slpc,
> + SLPC_PARAM_GLOBAL_MAX_GT_UNSLICE_FREQ_MHZ,
> + val);
> + if (ret) {
> + drm_err(&i915->drm,
> + "Set max frequency unslice returned (%pe)\n", ERR_PTR(ret));
> + /* Return standardized err code for sysfs */
> + ret = -EIO;

maybe caller (hook in sysfs) can sanitize this error ?

Michal

> + }
> + }
> +
> + return ret;
> +}
> +
> +/**
> + * intel_guc_slpc_set_min_freq() - Set min frequency limit for SLPC.
> + * @slpc: pointer to intel_guc_slpc.
> + * @val: frequency (MHz)
> + *
> + * This function will invoke GuC SLPC action to update the min unslice
> + * frequency.
> + *
> + * Return: 0 on success, non-zero error code on failure.
> + */
> +int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val)
> +{
> + int ret;
> + struct intel_guc *guc = slpc_to_guc(slpc);
> + struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
> + intel_wakeref_t wakeref;
> +
> + with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
> + ret = slpc_set_param(slpc,
> + SLPC_PARAM_GLOBAL_MIN_GT_UNSLICE_FREQ_MHZ,
> + val);
> + if (ret) {
> + drm_err(&i915->drm,
> + "Set min frequency for unslice returned (%pe)\n", ERR_PTR(ret));
> + /* Return standardized err code for sysfs */
> + ret = -EIO;
> + }
> + }
> +
> + return ret;
> +}
> +
> /*
> * intel_guc_slpc_enable() - Start SLPC
> * @slpc: pointer to intel_guc_slpc.
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> index f02249ff5f1b..3a1a7eaafc12 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> @@ -30,5 +30,7 @@ void intel_guc_slpc_init_early(struct intel_guc_slpc *slpc);
> int intel_guc_slpc_init(struct intel_guc_slpc *slpc);
> int intel_guc_slpc_enable(struct intel_guc_slpc *slpc);
> void intel_guc_slpc_fini(struct intel_guc_slpc *slpc);
> +int intel_guc_slpc_set_max_freq(struct intel_guc_slpc *slpc, u32 val);
> +int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val);
>
> #endif
>