[PATCH v8 10/10] drm/vc4: Increase the core clock based on HVS load

From: Maxime Ripard
Date: Mon Oct 25 2021 - 11:29:53 EST


Depending on a given HVS output (HVS to PixelValves) and input (planes
attached to a channel) load, the HVS needs for the core clock to be
raised above its boot time default.

Failing to do so will result in a vblank timeout and a stalled display
pipeline.

Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
---
drivers/gpu/drm/vc4/vc4_crtc.c | 15 +++++
drivers/gpu/drm/vc4/vc4_drv.h | 2 +
drivers/gpu/drm/vc4/vc4_kms.c | 110 ++++++++++++++++++++++++++++++---
3 files changed, 118 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 6decaa12a078..287dbc89ad64 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -659,12 +659,27 @@ static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc_state);
struct drm_connector *conn;
struct drm_connector_state *conn_state;
+ struct drm_encoder *encoder;
int ret, i;

ret = vc4_hvs_atomic_check(crtc, state);
if (ret)
return ret;

+ encoder = vc4_get_crtc_encoder(crtc, crtc_state);
+ if (encoder) {
+ const struct drm_display_mode *mode = &crtc_state->adjusted_mode;
+ struct vc4_encoder *vc4_encoder = to_vc4_encoder(encoder);
+
+ mode = &crtc_state->adjusted_mode;
+ if (vc4_encoder->type == VC4_ENCODER_TYPE_HDMI0) {
+ vc4_state->hvs_load = max(mode->clock * mode->hdisplay / mode->htotal + 1000,
+ mode->clock * 9 / 10) * 1000;
+ } else {
+ vc4_state->hvs_load = mode->clock * 1000;
+ }
+ }
+
for_each_new_connector_in_state(state, conn, conn_state,
i) {
if (conn_state->crtc != crtc)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 813c5d0ea98e..4329e09d357c 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -558,6 +558,8 @@ struct vc4_crtc_state {
unsigned int bottom;
} margins;

+ unsigned long hvs_load;
+
/* Transitional state below, only valid during atomic commits */
bool update_muxing;
};
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 41cb4869da50..79d4d9dd1394 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -39,9 +39,11 @@ static struct vc4_ctm_state *to_vc4_ctm_state(struct drm_private_state *priv)

struct vc4_hvs_state {
struct drm_private_state base;
+ unsigned long core_clock_rate;

struct {
unsigned in_use: 1;
+ unsigned long fifo_load;
struct drm_crtc_commit *pending_commit;
} fifo_state[HVS_NUM_CHANNELS];
};
@@ -340,10 +342,19 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
struct vc4_hvs *hvs = vc4->hvs;
struct drm_crtc_state *old_crtc_state;
struct drm_crtc_state *new_crtc_state;
+ struct vc4_hvs_state *new_hvs_state;
struct drm_crtc *crtc;
struct vc4_hvs_state *old_hvs_state;
int i;

+ old_hvs_state = vc4_hvs_get_old_global_state(state);
+ if (WARN_ON(!old_hvs_state))
+ return;
+
+ new_hvs_state = vc4_hvs_get_new_global_state(state);
+ if (WARN_ON(!new_hvs_state))
+ return;
+
for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
struct vc4_crtc_state *vc4_crtc_state;

@@ -354,12 +365,13 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
vc4_hvs_mask_underrun(dev, vc4_crtc_state->assigned_channel);
}

- if (vc4->hvs->hvs5)
- clk_set_min_rate(hvs->core_clk, 500000000);
+ if (vc4->hvs->hvs5) {
+ unsigned long core_rate = max_t(unsigned long,
+ 500000000,
+ new_hvs_state->core_clock_rate);

- old_hvs_state = vc4_hvs_get_old_global_state(state);
- if (!old_hvs_state)
- return;
+ clk_set_min_rate(hvs->core_clk, core_rate);
+ }

for_each_old_crtc_in_state(state, crtc, old_crtc_state, i) {
struct vc4_crtc_state *vc4_crtc_state =
@@ -399,8 +411,12 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)

drm_atomic_helper_cleanup_planes(dev, state);

- if (vc4->hvs->hvs5)
- clk_set_min_rate(hvs->core_clk, 0);
+ if (vc4->hvs->hvs5) {
+ drm_dbg(dev, "Running the core clock at %lu Hz\n",
+ new_hvs_state->core_clock_rate);
+
+ clk_set_min_rate(hvs->core_clk, new_hvs_state->core_clock_rate);
+ }
}

static int vc4_atomic_commit_setup(struct drm_atomic_state *state)
@@ -657,9 +673,9 @@ vc4_hvs_channels_duplicate_state(struct drm_private_obj *obj)

__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);

-
for (i = 0; i < HVS_NUM_CHANNELS; i++) {
state->fifo_state[i].in_use = old_state->fifo_state[i].in_use;
+ state->fifo_state[i].fifo_load = old_state->fifo_state[i].fifo_load;

if (!old_state->fifo_state[i].pending_commit)
continue;
@@ -668,6 +684,8 @@ vc4_hvs_channels_duplicate_state(struct drm_private_obj *obj)
drm_crtc_commit_get(old_state->fifo_state[i].pending_commit);
}

+ state->core_clock_rate = old_state->core_clock_rate;
+
return &state->base;
}

@@ -822,6 +840,76 @@ static int vc4_pv_muxing_atomic_check(struct drm_device *dev,
return 0;
}

+static int
+vc4_core_clock_atomic_check(struct drm_atomic_state *state)
+{
+ struct vc4_dev *vc4 = to_vc4_dev(state->dev);
+ struct drm_private_state *priv_state;
+ struct vc4_hvs_state *hvs_new_state;
+ struct vc4_load_tracker_state *load_state;
+ struct drm_crtc_state *old_crtc_state, *new_crtc_state;
+ struct drm_crtc *crtc;
+ unsigned int num_outputs;
+ unsigned long pixel_rate;
+ unsigned long cob_rate;
+ unsigned int i;
+
+ priv_state = drm_atomic_get_private_obj_state(state,
+ &vc4->load_tracker);
+ if (IS_ERR(priv_state))
+ return PTR_ERR(priv_state);
+
+ load_state = to_vc4_load_tracker_state(priv_state);
+
+ hvs_new_state = vc4_hvs_get_global_state(state);
+ if (!hvs_new_state)
+ return -EINVAL;
+
+ for_each_oldnew_crtc_in_state(state, crtc,
+ old_crtc_state,
+ new_crtc_state,
+ i) {
+ if (old_crtc_state->active) {
+ struct vc4_crtc_state *old_vc4_state =
+ to_vc4_crtc_state(old_crtc_state);
+ unsigned int channel = old_vc4_state->assigned_channel;
+
+ hvs_new_state->fifo_state[channel].fifo_load = 0;
+ }
+
+ if (new_crtc_state->active) {
+ struct vc4_crtc_state *new_vc4_state =
+ to_vc4_crtc_state(new_crtc_state);
+ unsigned int channel = new_vc4_state->assigned_channel;
+
+ hvs_new_state->fifo_state[channel].fifo_load =
+ new_vc4_state->hvs_load;
+ }
+ }
+
+ cob_rate = 0;
+ num_outputs = 0;
+ for (i = 0; i < HVS_NUM_CHANNELS; i++) {
+ if (!hvs_new_state->fifo_state[i].in_use)
+ continue;
+
+ num_outputs++;
+ cob_rate += hvs_new_state->fifo_state[i].fifo_load;
+ }
+
+ pixel_rate = load_state->hvs_load;
+ if (num_outputs > 1) {
+ pixel_rate = (pixel_rate * 40) / 100;
+ } else {
+ pixel_rate = (pixel_rate * 60) / 100;
+ }
+
+ hvs_new_state->core_clock_rate = max(cob_rate, pixel_rate);
+
+ return 0;
+}
+
+
static int
vc4_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
{
@@ -839,7 +927,11 @@ vc4_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
if (ret)
return ret;

- return vc4_load_tracker_atomic_check(state);
+ ret = vc4_load_tracker_atomic_check(state);
+ if (ret)
+ return ret;
+
+ return vc4_core_clock_atomic_check(state);
}

static struct drm_mode_config_helper_funcs vc4_mode_config_helpers = {
--
2.31.1