[Intel-gfx] [PATCH 2/4] drm/i915: Slice Shutdown: Allow setting number of slices on through sysfs

Rodrigo Vivi rodrigo.vivi at gmail.com
Tue Nov 5 23:44:14 CET 2013 

This patch introduces a sysfs interface to easily allow dynamically switch
slice config default behaviour between 1 or 2 slices.

v2: use number of slices on (1,2) instead of half or full strings.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>
---
 drivers/gpu/drm/i915/i915_drv.h   |  1 +
 drivers/gpu/drm/i915/i915_sysfs.c | 53 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h  |  1 +
 drivers/gpu/drm/i915/intel_pm.c   | 64 +++++++++++++++++++++++++++++++++++++--
 4 files changed, 116 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 27073e8..5bd8d6f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1791,6 +1791,7 @@ struct drm_i915_file_private {
 #define HAS_POWER_WELL(dev)	(IS_HASWELL(dev))
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)
 #define HAS_PSR(dev)		(IS_HASWELL(dev))
+#define HAS_SLICE_SHUTDOWN(dev)	(IS_HSW_GT3(dev) && i915_enable_rc6)
 
 #define INTEL_PCH_DEVICE_ID_MASK		0xff00
 #define INTEL_PCH_IBX_DEVICE_ID_TYPE		0x3b00
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index cef38fd..bf6dd95 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -117,6 +117,51 @@ static struct attribute_group rc6_attr_group = {
 	.name = power_group_name,
 	.attrs =  rc6_attrs
 };
+
+static ssize_t gt_slices_show(struct device *kdev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct drm_minor *minor = dev_to_drm_minor(kdev);
+	struct drm_device *dev = minor->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	return sprintf(buf, "%s\n", I915_READ(MI_PREDICATE_RESULT_2) ==
+		       LOWER_SLICE_ENABLED ? "2" : "1");
+}
+
+static ssize_t gt_slices_store(struct device *kdev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct drm_minor *minor = dev_to_drm_minor(kdev);
+	struct drm_device *dev = minor->dev;
+	int ret;
+	int slices;
+
+	ret = kstrtoint(buf, 10, &slices);
+	if (ret)
+		return ret;
+
+	ret = intel_set_gt_slices(dev, slices);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR(gt_slices, S_IRUGO | S_IWUSR, gt_slices_show,
+		   gt_slices_store);
+
+static struct attribute *gt_slices_attrs[] = {
+	&dev_attr_gt_slices.attr,
+	NULL
+};
+
+static struct attribute_group gt_slices_attr_group = {
+	.name = power_group_name,
+	.attrs =  gt_slices_attrs
+};
+
 #endif
 
 static int l3_access_valid(struct drm_device *dev, loff_t offset)
@@ -558,6 +603,12 @@ void i915_setup_sysfs(struct drm_device *dev)
 		if (ret)
 			DRM_ERROR("RC6 residency sysfs setup failed\n");
 	}
+	if (HAS_SLICE_SHUTDOWN(dev)) {
+		ret = sysfs_merge_group(&dev->primary->kdev->kobj,
+					&gt_slices_attr_group);
+		if (ret)
+			DRM_ERROR("GT slice config sysfs setup failed\n");
+	}
 #endif
 	if (HAS_L3_DPF(dev)) {
 		ret = device_create_bin_file(dev->primary->kdev, &dpf_attrs);
@@ -597,5 +648,7 @@ void i915_teardown_sysfs(struct drm_device *dev)
 	device_remove_bin_file(dev->primary->kdev,  &dpf_attrs);
 #ifdef CONFIG_PM
 	sysfs_unmerge_group(&dev->primary->kdev->kobj, &rc6_attr_group);
+	sysfs_unmerge_group(&dev->primary->kdev->kobj,
+			    &gt_slices_attr_group);
 #endif
 }
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 42c3983..cf37741 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -836,6 +836,7 @@ void intel_set_power_well(struct drm_device *dev, bool enable);
 void intel_enable_gt_powersave(struct drm_device *dev);
 void intel_disable_gt_powersave(struct drm_device *dev);
 void ironlake_teardown_rc6(struct drm_device *dev);
+int intel_set_gt_slices(struct drm_device *dev, int slices);
 void intel_init_gt_slices(struct drm_device *dev);
 void gen6_update_ring_freq(struct drm_device *dev);
 void gen6_rps_idle(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 02d1b1f..40ab76a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3869,14 +3869,72 @@ static void gen6_enable_rps(struct drm_device *dev)
 	gen6_gt_force_wake_put(dev_priv);
 }
 
-void intel_init_gt_slices(struct drm_device *dev)
+static int intel_set_gt_full(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (!IS_HSW_GT3(dev))
-		return;
+	I915_WRITE(HSW_GT_SLICE_INFO, SLICE_SEL_BOTH);
 
+	/* Slices are enabled on RC6 exit */
+	gen6_gt_force_wake_get(dev_priv);
+
+	if (wait_for(((I915_READ(HSW_GT_SLICE_INFO) & SLICE_STATUS_MASK) ==
+		      SLICE_STATUS_BOTH_ON), 2000)) {
+		DRM_ERROR("Timeout enabling full gt slices\n");
+		I915_WRITE(HSW_GT_SLICE_INFO, ~SLICE_SEL_BOTH);
+		I915_WRITE(MI_PREDICATE_RESULT_2, LOWER_SLICE_DISABLED);
+		gen6_gt_force_wake_put(dev_priv);
+		return -ETIMEDOUT;
+	}
 	I915_WRITE(MI_PREDICATE_RESULT_2, LOWER_SLICE_ENABLED);
+	gen6_gt_force_wake_put(dev_priv);
+
+	return 0;
+}
+
+static int intel_set_gt_half(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	I915_WRITE(HSW_GT_SLICE_INFO, ~SLICE_SEL_BOTH);
+
+	/* Slices are disabled on RC6 exit */
+	gen6_gt_force_wake_get(dev_priv);
+
+	if (wait_for(((I915_READ(HSW_GT_SLICE_INFO) & SLICE_STATUS_MASK) ==
+		      SLICE_STATUS_MAIN_ON), 2000)) {
+		DRM_ERROR("Timed out disabling half gt slices\n");
+		I915_WRITE(HSW_GT_SLICE_INFO, SLICE_SEL_BOTH);
+		I915_WRITE(MI_PREDICATE_RESULT_2, LOWER_SLICE_ENABLED);
+		gen6_gt_force_wake_put(dev_priv);
+		return -ETIMEDOUT;
+	}
+	I915_WRITE(MI_PREDICATE_RESULT_2, LOWER_SLICE_DISABLED);
+	gen6_gt_force_wake_put(dev_priv);
+	return 0;
+}
+
+int intel_set_gt_slices(struct drm_device *dev, int slices)
+{
+	if (!HAS_SLICE_SHUTDOWN(dev))
+		return -ENODEV;
+
+	switch (slices) {
+	case 1: return intel_set_gt_half(dev);
+	case 2: return intel_set_gt_full(dev);
+	default: return -EINVAL;
+	}
+}
+
+void intel_init_gt_slices(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (IS_HSW_GT3(dev))
+		I915_WRITE(MI_PREDICATE_RESULT_2, LOWER_SLICE_ENABLED);
+
+	if (!HAS_SLICE_SHUTDOWN(dev))
+		return;
 
 	if (i915_gt_slices == 1) {
 		I915_WRITE(HSW_GT_SLICE_INFO, ~SLICE_SEL_BOTH);
-- 
1.7.11.7

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