drm/i915/gt: Add sysfs throttle frequency interfaces

Throttling here refers to the GT frequency being clipped. Each of
the throttle reason attributes will have a 0 or 1 value depending
upon whether there is throttling and also the specific reason for
it.

The following is a brief description of the sysfs throttle
frequency attributes added:

 - throttle_reason_status: when set indicates that there is GT
   frequency clipping.

 - throttle_reason_pl1: when set indicates that PBM PL1 (platform
   or package PL1) has caused GT frequency clipping.

 - throttle_reason_pl2: when set indicates that PBM PL2 or PL3
   (platform or package PL2 or PL3) has caused GT frequency
   clipping.

 - throttle_reason_pl4: when set indicates that PL4 or IccMax has
   caused GT frequency clipping.

 - throttle_reason_thermal: when set indicates that Thermal event
   has caused GT frequency clipping.

 - throttle_reason_prochot: when set indicates that PROCHOT# has
   caused GT frequency clipping.

 - throttle_reason_ratl: when set indicates that Running Average
   Thermal Limit has caused GT frequency clipping.

 - throttle_reason_vr_thermalert: when set indicates that Hot VR
   (any processor VR)  has caused GT frequency clipping.

 - throttle_reason_vr_tdc: when set indicates that VR TDC
   (Thermal Design Current)  has caused GT frequency clipping.
Signed-off-by: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Dale B Stimson <dale.b.stimson@intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220318233938.149744-8-andi.shyti@linux.intel.com

drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c

@@ -8,6 +8,7 @@
 #include <linux/printk.h>
 
 #include "i915_drv.h"
+#include "i915_reg.h"
 #include "i915_sysfs.h"
 #include "intel_gt.h"
 #include "intel_gt_regs.h"
@@ -493,6 +494,69 @@ static DEVICE_ATTR_RO(vlv_rpe_freq_mhz);
 static const struct attribute * const gen6_rps_attrs[] = GEN6_RPS_ATTR;
 static const struct attribute * const gen6_gt_attrs[]  = GEN6_GT_ATTR;
 
+static ssize_t punit_req_freq_mhz_show(struct device *dev,
+				       struct device_attribute *attr,
+				       char *buff)
+{
+	struct intel_gt *gt = intel_gt_sysfs_get_drvdata(dev, attr->attr.name);
+	u32 preq = intel_rps_read_punit_req_frequency(&gt->rps);
+
+	return sysfs_emit(buff, "%u\n", preq);
+}
+
+struct intel_gt_bool_throttle_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct device *dev, struct device_attribute *attr,
+			char *buf);
+	i915_reg_t reg32;
+	u32 mask;
+};
+
+static ssize_t throttle_reason_bool_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_gt_bool_throttle_attr *t_attr =
+				(struct intel_gt_bool_throttle_attr *) attr;
+	bool val = rps_read_mask_mmio(&gt->rps, t_attr->reg32, t_attr->mask);
+
+	return sysfs_emit(buff, "%u\n", val);
+}
+
+#define INTEL_GT_RPS_BOOL_ATTR_RO(sysfs_func__, mask__) \
+struct intel_gt_bool_throttle_attr attr_##sysfs_func__ = { \
+	.attr = { .name = __stringify(sysfs_func__), .mode = 0444 }, \
+	.show = throttle_reason_bool_show, \
+	.reg32 = GT0_PERF_LIMIT_REASONS, \
+	.mask = mask__, \
+}
+
+static DEVICE_ATTR_RO(punit_req_freq_mhz);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_status, GT0_PERF_LIMIT_REASONS_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_pl1, POWER_LIMIT_1_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_pl2, POWER_LIMIT_2_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_pl4, POWER_LIMIT_4_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_thermal, THERMAL_LIMIT_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_prochot, PROCHOT_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_ratl, RATL_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_thermalert, VR_THERMALERT_MASK);
+static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_tdc, VR_TDC_MASK);
+
+static const struct attribute *freq_attrs[] = {
+	&dev_attr_punit_req_freq_mhz.attr,
+	&attr_throttle_reason_status.attr,
+	&attr_throttle_reason_pl1.attr,
+	&attr_throttle_reason_pl2.attr,
+	&attr_throttle_reason_pl4.attr,
+	&attr_throttle_reason_thermal.attr,
+	&attr_throttle_reason_prochot.attr,
+	&attr_throttle_reason_ratl.attr,
+	&attr_throttle_reason_vr_thermalert.attr,
+	&attr_throttle_reason_vr_tdc.attr,
+	NULL
+};
+
 static int intel_sysfs_rps_init(struct intel_gt *gt, struct kobject *kobj,
 				const struct attribute * const *attrs)
 {
@@ -524,4 +588,14 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj)
 		drm_warn(&gt->i915->drm,
 			 "failed to create gt%u RPS sysfs files (%pe)",
 			 gt->info.id, ERR_PTR(ret));
+
+	/* end of the legacy interfaces */
+	if (!is_object_gt(kobj))
+		return;
+
+	ret = sysfs_create_files(kobj, freq_attrs);
+	if (ret)
+		drm_warn(&gt->i915->drm,
+			 "failed to create gt%u throttle sysfs files (%pe)",
+			 gt->info.id, ERR_PTR(ret));
 }

drivers/gpu/drm/i915/gt/intel_rps.c

@@ -2286,6 +2286,24 @@ void intel_rps_lower_unslice(struct intel_rps *rps)
 	mutex_unlock(&rps->lock);
 }
 
+static u32 rps_read_mmio(struct intel_rps *rps, i915_reg_t reg32)
+{
+	struct intel_gt *gt = rps_to_gt(rps);
+	intel_wakeref_t wakeref;
+	u32 val;
+
+	with_intel_runtime_pm(gt->uncore->rpm, wakeref)
+		val = intel_uncore_read(gt->uncore, reg32);
+
+	return val;
+}
+
+bool rps_read_mask_mmio(struct intel_rps *rps,
+			i915_reg_t reg32, u32 mask)
+{
+	return rps_read_mmio(rps, reg32) & mask;
+}
+
 /* External interface for intel_ips.ko */
 
 static struct drm_i915_private __rcu *ips_mchdev;

drivers/gpu/drm/i915/gt/intel_rps.h

@@ -7,6 +7,7 @@
 #define INTEL_RPS_H
 
 #include "intel_rps_types.h"
+#include "i915_reg_defs.h"
 
 struct i915_request;
 
@@ -48,6 +49,9 @@ u32 intel_rps_read_state_cap(struct intel_rps *rps);
 void intel_rps_raise_unslice(struct intel_rps *rps);
 void intel_rps_lower_unslice(struct intel_rps *rps);
 
+u32 intel_rps_read_throttle_reason(struct intel_rps *rps);
+bool rps_read_mask_mmio(struct intel_rps *rps, i915_reg_t reg32, u32 mask);
+
 void gen5_rps_irq_handler(struct intel_rps *rps);
 void gen6_rps_irq_handler(struct intel_rps *rps, u32 pm_iir);
 void gen11_rps_irq_handler(struct intel_rps *rps, u32 pm_iir);

drivers/gpu/drm/i915/i915_reg.h

@@ -1837,6 +1837,17 @@
 #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	0xde3
+#define   PROCHOT_MASK			REG_BIT(1)
+#define   THERMAL_LIMIT_MASK		REG_BIT(2)
+#define   RATL_MASK			REG_BIT(6)
+#define   VR_THERMALERT_MASK		REG_BIT(7)
+#define   VR_TDC_MASK			REG_BIT(8)
+#define   POWER_LIMIT_4_MASK		REG_BIT(9)
+#define   POWER_LIMIT_1_MASK		REG_BIT(11)
+#define   POWER_LIMIT_2_MASK		REG_BIT(12)
+
 #define CHV_CLK_CTL1			_MMIO(0x101100)
 #define VLV_CLK_CTL2			_MMIO(0x101104)
 #define   CLK_CTL2_CZCOUNT_30NS_SHIFT	28