1 files changed, 404 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_drrs.c b/drivers/gpu/drm/i915/display/intel_drrs.c
new file mode 100644
index 000000000..0d35b6be5
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_drrs.c
@@ -0,0 +1,404 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "i915_reg.h"
+#include "intel_atomic.h"
+#include "intel_de.h"
+#include "intel_display_types.h"
+#include "intel_drrs.h"
+#include "intel_panel.h"
+
+/**
+ * DOC: Display Refresh Rate Switching (DRRS)
+ *
+ * Display Refresh Rate Switching (DRRS) is a power conservation feature
+ * which enables swtching between low and high refresh rates,
+ * dynamically, based on the usage scenario. This feature is applicable
+ * for internal panels.
+ *
+ * Indication that the panel supports DRRS is given by the panel EDID, which
+ * would list multiple refresh rates for one resolution.
+ *
+ * DRRS is of 2 types - static and seamless.
+ * Static DRRS involves changing refresh rate (RR) by doing a full modeset
+ * (may appear as a blink on screen) and is used in dock-undock scenario.
+ * Seamless DRRS involves changing RR without any visual effect to the user
+ * and can be used during normal system usage. This is done by programming
+ * certain registers.
+ *
+ * Support for static/seamless DRRS may be indicated in the VBT based on
+ * inputs from the panel spec.
+ *
+ * DRRS saves power by switching to low RR based on usage scenarios.
+ *
+ * The implementation is based on frontbuffer tracking implementation.  When
+ * there is a disturbance on the screen triggered by user activity or a periodic
+ * system activity, DRRS is disabled (RR is changed to high RR).  When there is
+ * no movement on screen, after a timeout of 1 second, a switch to low RR is
+ * made.
+ *
+ * For integration with frontbuffer tracking code, intel_drrs_invalidate()
+ * and intel_drrs_flush() are called.
+ *
+ * DRRS can be further extended to support other internal panels and also
+ * the scenario of video playback wherein RR is set based on the rate
+ * requested by userspace.
+ */
+
+const char *intel_drrs_type_str(enum drrs_type drrs_type)
+{
+	static const char * const str[] = {
+		[DRRS_TYPE_NONE] = "none",
+		[DRRS_TYPE_STATIC] = "static",
+		[DRRS_TYPE_SEAMLESS] = "seamless",
+	};
+
+	if (drrs_type >= ARRAY_SIZE(str))
+		return "<invalid>";
+
+	return str[drrs_type];
+}
+
+static void
+intel_drrs_set_refresh_rate_pipeconf(struct intel_crtc *crtc,
+				     enum drrs_refresh_rate refresh_rate)
+{
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	enum transcoder cpu_transcoder = crtc->drrs.cpu_transcoder;
+	u32 bit;
+
+	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+		bit = TRANSCONF_REFRESH_RATE_ALT_VLV;
+	else
+		bit = TRANSCONF_REFRESH_RATE_ALT_ILK;
+
+	intel_de_rmw(dev_priv, TRANSCONF(cpu_transcoder),
+		     bit, refresh_rate == DRRS_REFRESH_RATE_LOW ? bit : 0);
+}
+
+static void
+intel_drrs_set_refresh_rate_m_n(struct intel_crtc *crtc,
+				enum drrs_refresh_rate refresh_rate)
+{
+	intel_cpu_transcoder_set_m1_n1(crtc, crtc->drrs.cpu_transcoder,
+				       refresh_rate == DRRS_REFRESH_RATE_LOW ?
+				       &crtc->drrs.m2_n2 : &crtc->drrs.m_n);
+}
+
+bool intel_drrs_is_active(struct intel_crtc *crtc)
+{
+	return crtc->drrs.cpu_transcoder != INVALID_TRANSCODER;
+}
+
+static void intel_drrs_set_state(struct intel_crtc *crtc,
+				 enum drrs_refresh_rate refresh_rate)
+{
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+
+	if (refresh_rate == crtc->drrs.refresh_rate)
+		return;
+
+	if (intel_cpu_transcoder_has_m2_n2(dev_priv, crtc->drrs.cpu_transcoder))
+		intel_drrs_set_refresh_rate_pipeconf(crtc, refresh_rate);
+	else
+		intel_drrs_set_refresh_rate_m_n(crtc, refresh_rate);
+
+	crtc->drrs.refresh_rate = refresh_rate;
+}
+
+static void intel_drrs_schedule_work(struct intel_crtc *crtc)
+{
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+
+	mod_delayed_work(i915->unordered_wq, &crtc->drrs.work, msecs_to_jiffies(1000));
+}
+
+static unsigned int intel_drrs_frontbuffer_bits(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	unsigned int frontbuffer_bits;
+
+	frontbuffer_bits = INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+
+	for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc,
+					 crtc_state->bigjoiner_pipes)
+		frontbuffer_bits |= INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
+
+	return frontbuffer_bits;
+}
+
+/**
+ * intel_drrs_activate - activate DRRS
+ * @crtc_state: the crtc state
+ *
+ * Activates DRRS on the crtc.
+ */
+void intel_drrs_activate(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+
+	if (!crtc_state->has_drrs)
+		return;
+
+	if (!crtc_state->hw.active)
+		return;
+
+	if (intel_crtc_is_bigjoiner_slave(crtc_state))
+		return;
+
+	mutex_lock(&crtc->drrs.mutex);
+
+	crtc->drrs.cpu_transcoder = crtc_state->cpu_transcoder;
+	crtc->drrs.m_n = crtc_state->dp_m_n;
+	crtc->drrs.m2_n2 = crtc_state->dp_m2_n2;
+	crtc->drrs.frontbuffer_bits = intel_drrs_frontbuffer_bits(crtc_state);
+	crtc->drrs.busy_frontbuffer_bits = 0;
+
+	intel_drrs_schedule_work(crtc);
+
+	mutex_unlock(&crtc->drrs.mutex);
+}
+
+/**
+ * intel_drrs_deactivate - deactivate DRRS
+ * @old_crtc_state: the old crtc state
+ *
+ * Deactivates DRRS on the crtc.
+ */
+void intel_drrs_deactivate(const struct intel_crtc_state *old_crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
+
+	if (!old_crtc_state->has_drrs)
+		return;
+
+	if (!old_crtc_state->hw.active)
+		return;
+
+	if (intel_crtc_is_bigjoiner_slave(old_crtc_state))
+		return;
+
+	mutex_lock(&crtc->drrs.mutex);
+
+	if (intel_drrs_is_active(crtc))
+		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_HIGH);
+
+	crtc->drrs.cpu_transcoder = INVALID_TRANSCODER;
+	crtc->drrs.frontbuffer_bits = 0;
+	crtc->drrs.busy_frontbuffer_bits = 0;
+
+	mutex_unlock(&crtc->drrs.mutex);
+
+	cancel_delayed_work_sync(&crtc->drrs.work);
+}
+
+static void intel_drrs_downclock_work(struct work_struct *work)
+{
+	struct intel_crtc *crtc = container_of(work, typeof(*crtc), drrs.work.work);
+
+	mutex_lock(&crtc->drrs.mutex);
+
+	if (intel_drrs_is_active(crtc) && !crtc->drrs.busy_frontbuffer_bits)
+		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_LOW);
+
+	mutex_unlock(&crtc->drrs.mutex);
+}
+
+static void intel_drrs_frontbuffer_update(struct drm_i915_private *dev_priv,
+					  unsigned int all_frontbuffer_bits,
+					  bool invalidate)
+{
+	struct intel_crtc *crtc;
+
+	for_each_intel_crtc(&dev_priv->drm, crtc) {
+		unsigned int frontbuffer_bits;
+
+		mutex_lock(&crtc->drrs.mutex);
+
+		frontbuffer_bits = all_frontbuffer_bits & crtc->drrs.frontbuffer_bits;
+		if (!frontbuffer_bits) {
+			mutex_unlock(&crtc->drrs.mutex);
+			continue;
+		}
+
+		if (invalidate)
+			crtc->drrs.busy_frontbuffer_bits |= frontbuffer_bits;
+		else
+			crtc->drrs.busy_frontbuffer_bits &= ~frontbuffer_bits;
+
+		/* flush/invalidate means busy screen hence upclock */
+		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_HIGH);
+
+		/*
+		 * flush also means no more activity hence schedule downclock, if all
+		 * other fbs are quiescent too
+		 */
+		if (!crtc->drrs.busy_frontbuffer_bits)
+			intel_drrs_schedule_work(crtc);
+		else
+			cancel_delayed_work(&crtc->drrs.work);
+
+		mutex_unlock(&crtc->drrs.mutex);
+	}
+}
+
+/**
+ * intel_drrs_invalidate - Disable Idleness DRRS
+ * @dev_priv: i915 device
+ * @frontbuffer_bits: frontbuffer plane tracking bits
+ *
+ * This function gets called everytime rendering on the given planes start.
+ * Hence DRRS needs to be Upclocked, i.e. (LOW_RR -> HIGH_RR).
+ *
+ * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
+ */
+void intel_drrs_invalidate(struct drm_i915_private *dev_priv,
+			   unsigned int frontbuffer_bits)
+{
+	intel_drrs_frontbuffer_update(dev_priv, frontbuffer_bits, true);
+}
+
+/**
+ * intel_drrs_flush - Restart Idleness DRRS
+ * @dev_priv: i915 device
+ * @frontbuffer_bits: frontbuffer plane tracking bits
+ *
+ * This function gets called every time rendering on the given planes has
+ * completed or flip on a crtc is completed. So DRRS should be upclocked
+ * (LOW_RR -> HIGH_RR). And also Idleness detection should be started again,
+ * if no other planes are dirty.
+ *
+ * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
+ */
+void intel_drrs_flush(struct drm_i915_private *dev_priv,
+		      unsigned int frontbuffer_bits)
+{
+	intel_drrs_frontbuffer_update(dev_priv, frontbuffer_bits, false);
+}
+
+/**
+ * intel_drrs_crtc_init - Init DRRS for CRTC
+ * @crtc: crtc
+ *
+ * This function is called only once at driver load to initialize basic
+ * DRRS stuff.
+ *
+ */
+void intel_drrs_crtc_init(struct intel_crtc *crtc)
+{
+	INIT_DELAYED_WORK(&crtc->drrs.work, intel_drrs_downclock_work);
+	mutex_init(&crtc->drrs.mutex);
+	crtc->drrs.cpu_transcoder = INVALID_TRANSCODER;
+}
+
+static int intel_drrs_debugfs_status_show(struct seq_file *m, void *unused)
+{
+	struct intel_crtc *crtc = m->private;
+	const struct intel_crtc_state *crtc_state;
+	int ret;
+
+	ret = drm_modeset_lock_single_interruptible(&crtc->base.mutex);
+	if (ret)
+		return ret;
+
+	crtc_state = to_intel_crtc_state(crtc->base.state);
+
+	mutex_lock(&crtc->drrs.mutex);
+
+	seq_printf(m, "DRRS enabled: %s\n",
+		   str_yes_no(crtc_state->has_drrs));
+
+	seq_printf(m, "DRRS active: %s\n",
+		   str_yes_no(intel_drrs_is_active(crtc)));
+
+	seq_printf(m, "DRRS refresh rate: %s\n",
+		   crtc->drrs.refresh_rate == DRRS_REFRESH_RATE_LOW ?
+		   "low" : "high");
+
+	seq_printf(m, "DRRS busy frontbuffer bits: 0x%x\n",
+		   crtc->drrs.busy_frontbuffer_bits);
+
+	mutex_unlock(&crtc->drrs.mutex);
+
+	drm_modeset_unlock(&crtc->base.mutex);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(intel_drrs_debugfs_status);
+
+static int intel_drrs_debugfs_ctl_set(void *data, u64 val)
+{
+	struct intel_crtc *crtc = data;
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
+	struct intel_crtc_state *crtc_state;
+	struct drm_crtc_commit *commit;
+	int ret;
+
+	ret = drm_modeset_lock_single_interruptible(&crtc->base.mutex);
+	if (ret)
+		return ret;
+
+	crtc_state = to_intel_crtc_state(crtc->base.state);
+
+	if (!crtc_state->hw.active ||
+	    !crtc_state->has_drrs)
+		goto out;
+
+	commit = crtc_state->uapi.commit;
+	if (commit) {
+		ret = wait_for_completion_interruptible(&commit->hw_done);
+		if (ret)
+			goto out;
+	}
+
+	drm_dbg(&i915->drm,
+		"Manually %sactivating DRRS\n", val ? "" : "de");
+
+	if (val)
+		intel_drrs_activate(crtc_state);
+	else
+		intel_drrs_deactivate(crtc_state);
+
+out:
+	drm_modeset_unlock(&crtc->base.mutex);
+
+	return ret;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(intel_drrs_debugfs_ctl_fops,
+			 NULL, intel_drrs_debugfs_ctl_set, "%llu\n");
+
+void intel_drrs_crtc_debugfs_add(struct intel_crtc *crtc)
+{
+	debugfs_create_file("i915_drrs_status", 0444, crtc->base.debugfs_entry,
+			    crtc, &intel_drrs_debugfs_status_fops);
+
+	debugfs_create_file_unsafe("i915_drrs_ctl", 0644, crtc->base.debugfs_entry,
+				   crtc, &intel_drrs_debugfs_ctl_fops);
+}
+
+static int intel_drrs_debugfs_type_show(struct seq_file *m, void *unused)
+{
+	struct intel_connector *connector = m->private;
+
+	seq_printf(m, "DRRS type: %s\n",
+		   intel_drrs_type_str(intel_panel_drrs_type(connector)));
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(intel_drrs_debugfs_type);
+
+void intel_drrs_connector_debugfs_add(struct intel_connector *connector)
+{
+	if (intel_panel_drrs_type(connector) == DRRS_TYPE_NONE)
+		return;
+
+	debugfs_create_file("i915_drrs_type", 0444, connector->base.debugfs_entry,
+			    connector, &intel_drrs_debugfs_type_fops);
+}