[Intel-gfx] [PATCH 2/9] drm/i915/gt: Add media freq factor to per-gt sysfs
Rodrigo Vivi
rodrigo.vivi at intel.com
Thu Apr 21 20:57:03 UTC 2022
On Tue, Apr 19, 2022 at 10:21:26PM -0700, Ashutosh Dixit wrote:
> Expose new sysfs to program and retrieve media freq factor. Factor values
> of 0 (dynamic), 0.5 and 1.0 are supported via a u8.8 fixed point
> representation (corresponding to integer values of 0, 128 and 256
> respectively).
>
> Media freq factor is converted to media_ratio_mode for GuC. It is
> programmed into GuC using H2G SLPC interface. It is retrieved from GuC
> through a register read. A cached media_ratio_mode is maintained to
> preserve set values across GuC resets.
>
> This patch adds the following sysfs files to gt/gtN sysfs:
> * media_freq_factor
> * media_freq_factor.scale
>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Signed-off-by: Dale B Stimson <dale.b.stimson at intel.com>
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
> ---
> drivers/gpu/drm/i915/gt/intel_gt_regs.h | 1 +
> drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c | 130 ++++++++++++++++++
> .../drm/i915/gt/uc/abi/guc_actions_slpc_abi.h | 6 +
> drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 20 +++
> drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h | 1 +
> .../gpu/drm/i915/gt/uc/intel_guc_slpc_types.h | 3 +
> 6 files changed, 161 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> index 12d892851684..b06ba95f8cd2 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
> @@ -732,6 +732,7 @@
> #define GEN6_AGGRESSIVE_TURBO (0 << 15)
> #define GEN9_SW_REQ_UNSLICE_RATIO_SHIFT 23
> #define GEN9_IGNORE_SLICE_RATIO (0 << 0)
> +#define GEN12_MEDIA_FREQ_RATIO REG_BIT(13)
>
> #define GEN6_RC_VIDEO_FREQ _MMIO(0xa00c)
> #define GEN6_RC_CTL_RC6pp_ENABLE (1 << 16)
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> index 26cbfa6477d1..2b1cd6a01724 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> @@ -557,6 +557,128 @@ static const struct attribute *freq_attrs[] = {
> NULL
> };
>
> +/*
> + * Scaling for multipliers (aka frequency factors).
> + * The format of the value in the register is u8.8.
> + *
> + * The presentation to userspace is inspired by the perf event framework.
> + * See:
> + * Documentation/ABI/testing/sysfs-bus-event_source-devices-events
> + * for description of:
> + * /sys/bus/event_source/devices/<pmu>/events/<event>.scale
> + *
> + * Summary: Expose two sysfs files for each multiplier.
> + *
> + * 1. File <attr> contains a raw hardware value.
> + * 2. File <attr>.scale contains the multiplicative scale factor to be
> + * used by userspace to compute the actual value.
> + *
> + * So userspace knows that to get the frequency_factor it multiplies the
> + * provided value by the specified scale factor and vice-versa.
> + *
> + * That way there is no precision loss in the kernel interface and API
> + * is future proof should one day the hardware register change to u16.u16,
> + * on some platform. (Or any other fixed point representation.)
> + *
> + * Example:
> + * File <attr> contains the value 2.5, represented as u8.8 0x0280, which
> + * is comprised of:
> + * - an integer part of 2
> + * - a fractional part of 0x80 (representing 0x80 / 2^8 == 0x80 / 256).
> + * File <attr>.scale contains a string representation of floating point
> + * value 0.00390625 (which is (1 / 256)).
> + * Userspace computes the actual value:
> + * 0x0280 * 0.00390625 -> 2.5
> + * or converts an actual value to the value to be written into <attr>:
> + * 2.5 / 0.00390625 -> 0x0280
> + */
> +
> +#define U8_8_VAL_MASK 0xffff
> +#define U8_8_SCALE_TO_VALUE "0.00390625"
I really like this style because it gets future proof...
Well, honestly I don't believe that for Media multipliers we will be ever
move away from the GuC API. Nevertheless we have other cases in the pipeline
like balancing the gt and basedie that benefits of this abstraction and
it is good to have a standard api and in sync.
For this reason I'm in favor of this one here and code looks correct to me,
so:
Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Should we split this series with only this 2 first patches so we don't
get blocked on the intel_pcode refactor?
> +
> +static ssize_t freq_factor_scale_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buff)
> +{
> + return sysfs_emit(buff, "%s\n", U8_8_SCALE_TO_VALUE);
> +}
> +
> +static u32 media_ratio_mode_to_factor(u32 mode)
> +{
> + /* 0 -> 0, 1 -> 256, 2 -> 128 */
> + return !mode ? mode : 256 / mode;
> +}
> +
> +static ssize_t media_freq_factor_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buff)
> +{
> + struct intel_gt *gt = intel_gt_sysfs_get_drvdata(dev, attr->attr.name);
> + struct intel_guc_slpc *slpc = >->uc.guc.slpc;
> + intel_wakeref_t wakeref;
> + u32 mode;
> +
> + /*
> + * Retrieve media_ratio_mode from GEN6_RPNSWREQ bit 13 set by
> + * GuC. GEN6_RPNSWREQ:13 value 0 represents 1:2 and 1 represents 1:1
> + */
> + if (IS_XEHPSDV(gt->i915) &&
> + slpc->media_ratio_mode == SLPC_MEDIA_RATIO_MODE_DYNAMIC_CONTROL) {
> + /*
> + * For XEHPSDV dynamic mode GEN6_RPNSWREQ:13 does not contain
> + * the media_ratio_mode, just return the cached media ratio
> + */
> + mode = slpc->media_ratio_mode;
> + } else {
> + with_intel_runtime_pm(gt->uncore->rpm, wakeref)
> + mode = intel_uncore_read(gt->uncore, GEN6_RPNSWREQ);
> + mode = REG_FIELD_GET(GEN12_MEDIA_FREQ_RATIO, mode) ?
> + SLPC_MEDIA_RATIO_MODE_FIXED_ONE_TO_ONE :
> + SLPC_MEDIA_RATIO_MODE_FIXED_ONE_TO_TWO;
> + }
> +
> + return sysfs_emit(buff, "%u\n", media_ratio_mode_to_factor(mode));
> +}
> +
> +static ssize_t media_freq_factor_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buff, size_t count)
> +{
> + struct intel_gt *gt = intel_gt_sysfs_get_drvdata(dev, attr->attr.name);
> + struct intel_guc_slpc *slpc = >->uc.guc.slpc;
> + u32 factor, mode;
> + int err;
> +
> + err = kstrtou32(buff, 0, &factor);
> + if (err)
> + return err;
> +
> + for (mode = SLPC_MEDIA_RATIO_MODE_DYNAMIC_CONTROL;
> + mode <= SLPC_MEDIA_RATIO_MODE_FIXED_ONE_TO_TWO; mode++)
> + if (factor == media_ratio_mode_to_factor(mode))
> + break;
> +
> + if (mode > SLPC_MEDIA_RATIO_MODE_FIXED_ONE_TO_TWO)
> + return -EINVAL;
> +
> + err = intel_guc_slpc_set_media_ratio_mode(slpc, mode);
> + if (!err) {
> + slpc->media_ratio_mode = mode;
> + DRM_DEBUG("Set slpc->media_ratio_mode to %d", mode);
> + }
> + return err ?: count;
> +}
> +
> +static DEVICE_ATTR_RW(media_freq_factor);
> +static struct device_attribute dev_attr_media_freq_factor_scale =
> + __ATTR(media_freq_factor.scale, 0444, freq_factor_scale_show, NULL);
> +
> +static const struct attribute *media_perf_power_attrs[] = {
> + &dev_attr_media_freq_factor.attr,
> + &dev_attr_media_freq_factor_scale.attr,
> + NULL
> +};
> +
> static int intel_sysfs_rps_init(struct intel_gt *gt, struct kobject *kobj,
> const struct attribute * const *attrs)
> {
> @@ -598,4 +720,12 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj)
> drm_warn(>->i915->drm,
> "failed to create gt%u throttle sysfs files (%pe)",
> gt->info.id, ERR_PTR(ret));
> +
> + if (HAS_MEDIA_RATIO_MODE(gt->i915) && intel_uc_uses_guc_slpc(>->uc)) {
> + ret = sysfs_create_files(kobj, media_perf_power_attrs);
> + if (ret)
> + drm_warn(>->i915->drm,
> + "failed to create add gt%u media_perf_power_attrs sysfs (%pe)\n",
> + gt->info.id, ERR_PTR(ret));
> + }
> }
> diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h
> index 62cb4254a77a..4c840a2639dc 100644
> --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h
> +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_actions_slpc_abi.h
> @@ -122,6 +122,12 @@ enum slpc_param_id {
> SLPC_MAX_PARAM = 32,
> };
>
> +enum slpc_media_ratio_mode {
> + SLPC_MEDIA_RATIO_MODE_DYNAMIC_CONTROL = 0,
> + SLPC_MEDIA_RATIO_MODE_FIXED_ONE_TO_ONE = 1,
> + SLPC_MEDIA_RATIO_MODE_FIXED_ONE_TO_TWO = 2,
> +};
> +
> enum slpc_event_id {
> SLPC_EVENT_RESET = 0,
> SLPC_EVENT_SHUTDOWN = 1,
> 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 1db833da42df..2df31af70d63 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> @@ -260,6 +260,7 @@ int intel_guc_slpc_init(struct intel_guc_slpc *slpc)
> slpc->boost_freq = 0;
> atomic_set(&slpc->num_waiters, 0);
> slpc->num_boosts = 0;
> + slpc->media_ratio_mode = SLPC_MEDIA_RATIO_MODE_DYNAMIC_CONTROL;
>
> mutex_init(&slpc->lock);
> INIT_WORK(&slpc->boost_work, slpc_boost_work);
> @@ -506,6 +507,22 @@ int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val)
> return ret;
> }
>
> +int intel_guc_slpc_set_media_ratio_mode(struct intel_guc_slpc *slpc, u32 val)
> +{
> + struct drm_i915_private *i915 = slpc_to_i915(slpc);
> + intel_wakeref_t wakeref;
> + int ret = 0;
> +
> + if (!HAS_MEDIA_RATIO_MODE(i915))
> + return -ENODEV;
> +
> + with_intel_runtime_pm(&i915->runtime_pm, wakeref)
> + ret = slpc_set_param(slpc,
> + SLPC_PARAM_MEDIA_FF_RATIO_MODE,
> + val);
> + return ret;
> +}
> +
> void intel_guc_pm_intrmsk_enable(struct intel_gt *gt)
> {
> u32 pm_intrmsk_mbz = 0;
> @@ -654,6 +671,9 @@ int intel_guc_slpc_enable(struct intel_guc_slpc *slpc)
> return ret;
> }
>
> + /* Set cached media freq ratio mode */
> + intel_guc_slpc_set_media_ratio_mode(slpc, slpc->media_ratio_mode);
> +
> return 0;
> }
>
> 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 0caa8fee3c04..82a98f78f96c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
> @@ -38,6 +38,7 @@ int intel_guc_slpc_set_boost_freq(struct intel_guc_slpc *slpc, u32 val);
> int intel_guc_slpc_get_max_freq(struct intel_guc_slpc *slpc, u32 *val);
> int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val);
> int intel_guc_slpc_print_info(struct intel_guc_slpc *slpc, struct drm_printer *p);
> +int intel_guc_slpc_set_media_ratio_mode(struct intel_guc_slpc *slpc, u32 val);
> void intel_guc_pm_intrmsk_enable(struct intel_gt *gt);
> void intel_guc_slpc_boost(struct intel_guc_slpc *slpc);
> void intel_guc_slpc_dec_waiters(struct intel_guc_slpc *slpc);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> index bf5b9a563c09..73d208123528 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> @@ -29,6 +29,9 @@ struct intel_guc_slpc {
> u32 min_freq_softlimit;
> u32 max_freq_softlimit;
>
> + /* cached media ratio mode */
> + u32 media_ratio_mode;
> +
> /* Protects set/reset of boost freq
> * and value of num_waiters
> */
> --
> 2.34.1
>
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