Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 281 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c
new file mode 100644
index 0000000000..dd33fec5aa
--- /dev/null
+++ b/drivers/gpu/drm/drm_self_refresh_helper.c
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (C) 2019 Google, Inc.
+ *
+ * Authors:
+ * Sean Paul <seanpaul@chromium.org>
+ */
+#include <linux/average.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_device.h>
+#include <drm/drm_mode_config.h>
+#include <drm/drm_modeset_lock.h>
+#include <drm/drm_print.h>
+#include <drm/drm_self_refresh_helper.h>
+
+/**
+ * DOC: overview
+ *
+ * This helper library provides an easy way for drivers to leverage the atomic
+ * framework to implement panel self refresh (SR) support. Drivers are
+ * responsible for initializing and cleaning up the SR helpers on load/unload
+ * (see &drm_self_refresh_helper_init/&drm_self_refresh_helper_cleanup).
+ * The connector is responsible for setting
+ * &drm_connector_state.self_refresh_aware to true at runtime if it is SR-aware
+ * (meaning it knows how to initiate self refresh on the panel).
+ *
+ * Once a crtc has enabled SR using &drm_self_refresh_helper_init, the
+ * helpers will monitor activity and call back into the driver to enable/disable
+ * SR as appropriate. The best way to think about this is that it's a DPMS
+ * on/off request with &drm_crtc_state.self_refresh_active set in crtc state
+ * that tells you to disable/enable SR on the panel instead of power-cycling it.
+ *
+ * During SR, drivers may choose to fully disable their crtc/encoder/bridge
+ * hardware (in which case no driver changes are necessary), or they can inspect
+ * &drm_crtc_state.self_refresh_active if they want to enter low power mode
+ * without full disable (in case full disable/enable is too slow).
+ *
+ * SR will be deactivated if there are any atomic updates affecting the
+ * pipe that is in SR mode. If a crtc is driving multiple connectors, all
+ * connectors must be SR aware and all will enter/exit SR mode at the same time.
+ *
+ * If the crtc and connector are SR aware, but the panel connected does not
+ * support it (or is otherwise unable to enter SR), the driver should fail
+ * atomic_check when &drm_crtc_state.self_refresh_active is true.
+ */
+
+#define SELF_REFRESH_AVG_SEED_MS 200
+
+DECLARE_EWMA(psr_time, 4, 4)
+
+struct drm_self_refresh_data {
+	struct drm_crtc *crtc;
+	struct delayed_work entry_work;
+
+	struct mutex avg_mutex;
+	struct ewma_psr_time entry_avg_ms;
+	struct ewma_psr_time exit_avg_ms;
+};
+
+static void drm_self_refresh_helper_entry_work(struct work_struct *work)
+{
+	struct drm_self_refresh_data *sr_data = container_of(
+				to_delayed_work(work),
+				struct drm_self_refresh_data, entry_work);
+	struct drm_crtc *crtc = sr_data->crtc;
+	struct drm_device *dev = crtc->dev;
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_atomic_state *state;
+	struct drm_connector *conn;
+	struct drm_connector_state *conn_state;
+	struct drm_crtc_state *crtc_state;
+	int i, ret = 0;
+
+	drm_modeset_acquire_init(&ctx, 0);
+
+	state = drm_atomic_state_alloc(dev);
+	if (!state) {
+		ret = -ENOMEM;
+		goto out_drop_locks;
+	}
+
+retry:
+	state->acquire_ctx = &ctx;
+
+	crtc_state = drm_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto out;
+	}
+
+	if (!crtc_state->enable)
+		goto out;
+
+	ret = drm_atomic_add_affected_connectors(state, crtc);
+	if (ret)
+		goto out;
+
+	for_each_new_connector_in_state(state, conn, conn_state, i) {
+		if (!conn_state->self_refresh_aware)
+			goto out;
+	}
+
+	crtc_state->active = false;
+	crtc_state->self_refresh_active = true;
+
+	ret = drm_atomic_commit(state);
+	if (ret)
+		goto out;
+
+out:
+	if (ret == -EDEADLK) {
+		drm_atomic_state_clear(state);
+		ret = drm_modeset_backoff(&ctx);
+		if (!ret)
+			goto retry;
+	}
+
+	drm_atomic_state_put(state);
+
+out_drop_locks:
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+}
+
+/**
+ * drm_self_refresh_helper_update_avg_times - Updates a crtc's SR time averages
+ * @state: the state which has just been applied to hardware
+ * @commit_time_ms: the amount of time in ms that this commit took to complete
+ * @new_self_refresh_mask: bitmask of crtc's that have self_refresh_active in
+ *    new state
+ *
+ * Called after &drm_mode_config_funcs.atomic_commit_tail, this function will
+ * update the average entry/exit self refresh times on self refresh transitions.
+ * These averages will be used when calculating how long to delay before
+ * entering self refresh mode after activity.
+ */
+void
+drm_self_refresh_helper_update_avg_times(struct drm_atomic_state *state,
+					 unsigned int commit_time_ms,
+					 unsigned int new_self_refresh_mask)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *old_crtc_state;
+	int i;
+
+	for_each_old_crtc_in_state(state, crtc, old_crtc_state, i) {
+		bool new_self_refresh_active = new_self_refresh_mask & BIT(i);
+		struct drm_self_refresh_data *sr_data = crtc->self_refresh_data;
+		struct ewma_psr_time *time;
+
+		if (old_crtc_state->self_refresh_active ==
+		    new_self_refresh_active)
+			continue;
+
+		if (new_self_refresh_active)
+			time = &sr_data->entry_avg_ms;
+		else
+			time = &sr_data->exit_avg_ms;
+
+		mutex_lock(&sr_data->avg_mutex);
+		ewma_psr_time_add(time, commit_time_ms);
+		mutex_unlock(&sr_data->avg_mutex);
+	}
+}
+EXPORT_SYMBOL(drm_self_refresh_helper_update_avg_times);
+
+/**
+ * drm_self_refresh_helper_alter_state - Alters the atomic state for SR exit
+ * @state: the state currently being checked
+ *
+ * Called at the end of atomic check. This function checks the state for flags
+ * incompatible with self refresh exit and changes them. This is a bit
+ * disingenuous since userspace is expecting one thing and we're giving it
+ * another. However in order to keep self refresh entirely hidden from
+ * userspace, this is required.
+ *
+ * At the end, we queue up the self refresh entry work so we can enter PSR after
+ * the desired delay.
+ */
+void drm_self_refresh_helper_alter_state(struct drm_atomic_state *state)
+{
+	struct drm_crtc *crtc;
+	struct drm_crtc_state *crtc_state;
+	int i;
+
+	if (state->async_update || !state->allow_modeset) {
+		for_each_old_crtc_in_state(state, crtc, crtc_state, i) {
+			if (crtc_state->self_refresh_active) {
+				state->async_update = false;
+				state->allow_modeset = true;
+				break;
+			}
+		}
+	}
+
+	for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
+		struct drm_self_refresh_data *sr_data;
+		unsigned int delay;
+
+		/* Don't trigger the entry timer when we're already in SR */
+		if (crtc_state->self_refresh_active)
+			continue;
+
+		sr_data = crtc->self_refresh_data;
+		if (!sr_data)
+			continue;
+
+		mutex_lock(&sr_data->avg_mutex);
+		delay = (ewma_psr_time_read(&sr_data->entry_avg_ms) +
+			 ewma_psr_time_read(&sr_data->exit_avg_ms)) * 2;
+		mutex_unlock(&sr_data->avg_mutex);
+
+		mod_delayed_work(system_wq, &sr_data->entry_work,
+				 msecs_to_jiffies(delay));
+	}
+}
+EXPORT_SYMBOL(drm_self_refresh_helper_alter_state);
+
+/**
+ * drm_self_refresh_helper_init - Initializes self refresh helpers for a crtc
+ * @crtc: the crtc which supports self refresh supported displays
+ *
+ * Returns zero if successful or -errno on failure
+ */
+int drm_self_refresh_helper_init(struct drm_crtc *crtc)
+{
+	struct drm_self_refresh_data *sr_data = crtc->self_refresh_data;
+
+	/* Helper is already initialized */
+	if (WARN_ON(sr_data))
+		return -EINVAL;
+
+	sr_data = kzalloc(sizeof(*sr_data), GFP_KERNEL);
+	if (!sr_data)
+		return -ENOMEM;
+
+	INIT_DELAYED_WORK(&sr_data->entry_work,
+			  drm_self_refresh_helper_entry_work);
+	sr_data->crtc = crtc;
+	mutex_init(&sr_data->avg_mutex);
+	ewma_psr_time_init(&sr_data->entry_avg_ms);
+	ewma_psr_time_init(&sr_data->exit_avg_ms);
+
+	/*
+	 * Seed the averages so they're non-zero (and sufficiently large
+	 * for even poorly performing panels). As time goes on, this will be
+	 * averaged out and the values will trend to their true value.
+	 */
+	ewma_psr_time_add(&sr_data->entry_avg_ms, SELF_REFRESH_AVG_SEED_MS);
+	ewma_psr_time_add(&sr_data->exit_avg_ms, SELF_REFRESH_AVG_SEED_MS);
+
+	crtc->self_refresh_data = sr_data;
+	return 0;
+}
+EXPORT_SYMBOL(drm_self_refresh_helper_init);
+
+/**
+ * drm_self_refresh_helper_cleanup - Cleans up self refresh helpers for a crtc
+ * @crtc: the crtc to cleanup
+ */
+void drm_self_refresh_helper_cleanup(struct drm_crtc *crtc)
+{
+	struct drm_self_refresh_data *sr_data = crtc->self_refresh_data;
+
+	/* Helper is already uninitialized */
+	if (!sr_data)
+		return;
+
+	crtc->self_refresh_data = NULL;
+
+	cancel_delayed_work_sync(&sr_data->entry_work);
+	kfree(sr_data);
+}
+EXPORT_SYMBOL(drm_self_refresh_helper_cleanup);