Re: [Intel-gfx] [PATCH 1/1] RFC : drm/i915: Adding new sysfs frequency attributes

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 08 Oct 2021, Sujaritha Sundaresan <sujaritha.sundaresan@intel.com> wrote:
> This patch adds the following new sysfs frequency attributes;

Why?

Sysfs is uapi. What's the userspace consumer for these?

More comments inline.

> 	- punit_req_freq_mhz
> 	- throttle_reason_status
> 	- throttle_reason_pl1
> 	- throttle_reason_pl2
> 	- throttle_reason_pl4
> 	- throttle_reason_thermal
> 	- throttle_reason_prochot
> 	- throttle_reason_ratl
> 	- throttle_reason_vr_thermalert
> 	- throttle_reason_vr_tdc
>
> Signed-off-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
> Cc: Dale B Stimson <dale.b.stimson@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_rps.c |  83 +++++++++++++++++
>  drivers/gpu/drm/i915/gt/intel_rps.h |  10 +++
>  drivers/gpu/drm/i915/i915_reg.h     |  11 +++
>  drivers/gpu/drm/i915/i915_sysfs.c   | 135 ++++++++++++++++++++++++++++
>  4 files changed, 239 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
> index 172de6c9f949..c03d99f2608c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
> @@ -2153,6 +2153,89 @@ u32 intel_rps_read_state_cap(struct intel_rps *rps)
>  		return intel_uncore_read(uncore, GEN6_RP_STATE_CAP);
>  }
>  
> +static u32 __rps_read_mmio(struct intel_gt *gt, i915_reg_t reg32)
> +{
> +	intel_wakeref_t wakeref;
> +	u32 val;
> +
> +	with_intel_runtime_pm(gt->uncore->rpm, wakeref)
> +		val = intel_uncore_read(gt->uncore, reg32);
> +
> +	return val;
> +}
> +
> +u32 intel_rps_read_throttle_reason_status(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 status = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & GT0_PERF_LIMIT_REASONS_MASK;
> +
> +	return status;
> +}
> +
> +u32 intel_rps_read_throttle_reason_pl1(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 pl1 = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & POWER_LIMIT_1_MASK;
> +
> +	return pl1;
> +}
> +
> +u32 intel_rps_read_throttle_reason_pl2(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 pl2 = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & POWER_LIMIT_2_MASK;
> +
> +	return pl2;
> +}
> +
> +u32 intel_rps_read_throttle_reason_pl4(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 pl4 = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & POWER_LIMIT_4_MASK;
> +
> +	return pl4;
> +}
> +
> +u32 intel_rps_read_throttle_reason_thermal(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 thermal = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & THERMAL_LIMIT_MASK;
> +
> +	return thermal;
> +}
> +
> +u32 intel_rps_read_throttle_reason_prochot(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 prochot = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & PROCHOT_MASK;
> +
> +	return prochot;
> +}
> +
> +u32 intel_rps_read_throttle_reason_ratl(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 ratl = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & RATL_MASK;
> +
> +	return ratl;
> +}
> +
> +u32 intel_rps_read_throttle_reason_vr_thermalert(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 thermalert = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & VR_THERMALERT_MASK;
> +
> +	return thermalert;
> +}
> +
> +u32 intel_rps_read_throttle_reason_vr_tdc(struct intel_rps *rps)
> +{
> +	struct intel_gt *gt = rps_to_gt(rps);
> +	u32 tdc = __rps_read_mmio(gt, GT0_PERF_LIMIT_REASONS) & VR_TDC_MASK;
> +
> +	return tdc;
> +}
> +
>  /* External interface for intel_ips.ko */
>  
>  static struct drm_i915_private __rcu *ips_mchdev;
> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.h b/drivers/gpu/drm/i915/gt/intel_rps.h
> index 11960d64ca82..d6ac97f1facd 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rps.h
> +++ b/drivers/gpu/drm/i915/gt/intel_rps.h
> @@ -42,6 +42,16 @@ u32 intel_rps_get_rpn_frequency(struct intel_rps *rps);
>  u32 intel_rps_read_punit_req(struct intel_rps *rps);
>  u32 intel_rps_read_punit_req_frequency(struct intel_rps *rps);
>  u32 intel_rps_read_state_cap(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_status(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_pl1(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_pl2(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_pl4(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_thermal(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_prochot(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_ratl(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_vr_thermalert(struct intel_rps *rps);
> +u32 intel_rps_read_throttle_reason_vr_tdc(struct intel_rps *rps);
>  
>  void gen5_rps_irq_handler(struct intel_rps *rps);
>  void gen6_rps_irq_handler(struct intel_rps *rps, u32 pm_iir);
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index a897f4abea0c..9ac322269d49 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4152,6 +4152,17 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
>  #define GEN9_RP_STATE_LIMITS	_MMIO(0x138148)
>  #define XEHPSDV_RP_STATE_CAP	_MMIO(0x250014)
>  
> +#define GT0_PERF_LIMIT_REASONS	_MMIO(0x1381A8)
> +#define GT0_PERF_LIMIT_REASONS_MASK    0x00000de3
> +#define POWER_LIMIT_1_MASK     0x00000400
> +#define POWER_LIMIT_2_MASK     0x00000800
> +#define POWER_LIMIT_4_MASK     0x00000100
> +#define THERMAL_LIMIT_MASK     0x00000002
> +#define PROCHOT_MASK   0x00000001
> +#define RATL_MASK      0x00000020
> +#define VR_THERMALERT_MASK     0x00000040
> +#define VR_TDC_MASK    0x00000080

Please read the big comment near the top of the file you're changing.

> +
>  /*
>   * Logical Context regs
>   */
> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
> index cdf0e9c6fd73..b2938029eed6 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -435,6 +435,141 @@ static const struct attribute * const vlv_attrs[] = {
>  	NULL,
>  };
>  
> +static ssize_t punit_req_freq_mhz_show(struct device *kdev,
> +				       struct device_attribute *attr,
> +				       char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	u32 preq = intel_rps_read_punit_req_frequency(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%d\n", preq);
> +}
> +
> +static ssize_t throttle_reason_status_show(struct device *kdev,
> +					   struct device_attribute *attr,
> +					   char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool status = !!intel_rps_read_throttle_reason_status(rps);

!! is unnecessary for standard bools. Ditto everywhere here.

> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", status);
> +}
> +
> +static ssize_t throttle_reason_pl1_show(struct device *kdev,
> +					struct device_attribute *attr,
> +					char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool pl1 = !!intel_rps_read_throttle_reason_pl1(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", pl1);
> +}
> +
> +static ssize_t throttle_reason_pl2_show(struct device *kdev,
> +					struct device_attribute *attr,
> +					char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool pl2 = !!intel_rps_read_throttle_reason_pl2(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", pl2);
> +}
> +
> +static ssize_t throttle_reason_pl4_show(struct device *kdev,
> +					struct device_attribute *attr,
> +					char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool pl4 = !!intel_rps_read_throttle_reason_pl4(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", pl4);
> +}
> +
> +static ssize_t throttle_reason_thermal_show(struct device *kdev,
> +					    struct device_attribute *attr,
> +					    char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool thermal = !!intel_rps_read_throttle_reason_thermal(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", thermal);
> +}
> +
> +static ssize_t throttle_reason_prochot_show(struct device *kdev,
> +					    struct device_attribute *attr,
> +					    char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool prochot = !!intel_rps_read_throttle_reason_prochot(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", prochot);
> +}
> +
> +static ssize_t throttle_reason_ratl_show(struct device *kdev,
> +					 struct device_attribute *attr,
> +					 char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool ratl = !!intel_rps_read_throttle_reason_ratl(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", ratl);
> +}
> +
> +static ssize_t throttle_reason_vr_thermalert_show(struct device *kdev,
> +						  struct device_attribute *attr,
> +						  char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool thermalert = !!intel_rps_read_throttle_reason_vr_thermalert(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", thermalert);
> +}
> +
> +static ssize_t throttle_reason_vr_tdc_show(struct device *kdev,
> +					   struct device_attribute *attr,
> +					   char *buff)
> +{
> +	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
> +	struct intel_rps *rps = &dev_priv->gt.rps;
> +	bool tdc = !!intel_rps_read_throttle_reason_vr_tdc(rps);
> +
> +	return scnprintf(buff, PAGE_SIZE, "%u\n", tdc);
> +}
> +
> +static DEVICE_ATTR_RO(punit_req_freq_mhz);
> +static DEVICE_ATTR_RO(throttle_reason_status);
> +static DEVICE_ATTR_RO(throttle_reason_pl1);
> +static DEVICE_ATTR_RO(throttle_reason_pl2);
> +static DEVICE_ATTR_RO(throttle_reason_pl4);
> +static DEVICE_ATTR_RO(throttle_reason_thermal);
> +static DEVICE_ATTR_RO(throttle_reason_prochot);
> +static DEVICE_ATTR_RO(throttle_reason_ratl);
> +static DEVICE_ATTR_RO(throttle_reason_vr_thermalert);
> +static DEVICE_ATTR_RO(throttle_reason_vr_tdc);
> +
> +static const struct attribute *freq_attrs[] = {
> +	&dev_attr_punit_req_freq_mhz.attr,
> +	&dev_attr_throttle_reason_status.attr,
> +	&dev_attr_throttle_reason_pl1.attr,
> +	&dev_attr_throttle_reason_pl2.attr,
> +	&dev_attr_throttle_reason_pl4.attr,
> +	&dev_attr_throttle_reason_thermal.attr,
> +	&dev_attr_throttle_reason_prochot.attr,
> +	&dev_attr_throttle_reason_ratl.attr,
> +	&dev_attr_throttle_reason_vr_thermalert.attr,
> +	&dev_attr_throttle_reason_vr_tdc.attr,
> +	NULL
> +};
> +
>  #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
>  
>  static ssize_t error_state_read(struct file *filp, struct kobject *kobj,

-- 
Jani Nikula, Intel Open Source Graphics Center