The hardware has a single block for applying a CTM prior to gamma lut.
It can be fed with pixels from one of our CRTC at a time and uses a
matrix with S0.9 scalars. Use private atomic state to reject attempts
from userland to apply CTM for more than one CRTC at a time and reject
matrices with scalars that we can't approximate without integer bits.
Signed-off-by: Stefan Schake <stschake@xxxxxxxxx>
---
v3: New in the series
drivers/gpu/drm/vc4/vc4_crtc.c | 6 +-
drivers/gpu/drm/vc4/vc4_drv.h | 3 +
drivers/gpu/drm/vc4/vc4_kms.c | 167 ++++++++++++++++++++++++++++++++++++++++-
3 files changed, 174 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 08fe8dd..32bdf13 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -1016,7 +1016,11 @@ static int vc4_crtc_bind(struct device *dev, struct device *master, void *data)
primary_plane->crtc = crtc;
vc4_crtc->channel = vc4_crtc->data->hvs_channel;
drm_mode_crtc_set_gamma_size(crtc, ARRAY_SIZE(vc4_crtc->lut_r));
- drm_crtc_enable_color_mgmt(crtc, 0, false, crtc->gamma_size);
+
+ /* We support CTM, but only for one CRTC at a time. It's therefore
+ * implemented as private driver state in vc4_kms, not here.
+ */
+ drm_crtc_enable_color_mgmt(crtc, 0, true, crtc->gamma_size);
/* Set up some arbitrary number of planes. We're not limited
* by a set number of physical registers, just the space in
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 4288615..ee22a5b 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -10,6 +10,7 @@
#include <drm/drmP.h>
#include <drm/drm_encoder.h>
#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_atomic.h>
#include "uapi/drm/vc4_drm.h"
@@ -193,6 +194,8 @@ struct vc4_dev {
} hangcheck;
struct semaphore async_modeset;
+
+ struct drm_private_obj ctm_manager;
};
static inline struct vc4_dev *
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index ba60153..f2eca4d 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -23,6 +23,102 @@
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include "vc4_drv.h"
+#include "vc4_regs.h"
+
+struct vc4_ctm_state {
+ struct drm_private_state base;
+ struct drm_color_ctm *ctm;
+ int fifo;
+};
+
+static struct vc4_ctm_state *to_vc4_ctm_state(struct drm_private_state *priv)
+{
+ return container_of(priv, struct vc4_ctm_state, base);
+}
+
+static struct vc4_ctm_state *vc4_get_ctm_state(struct drm_atomic_state *state,
+ struct drm_private_obj *manager)
+{
+ return to_vc4_ctm_state(drm_atomic_get_private_obj_state(state, manager));
+}
+
+static struct drm_private_state *
+vc4_ctm_duplicate_state(struct drm_private_obj *obj)
+{
+ struct vc4_ctm_state *state;
+
+ state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return NULL;
+
+ __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
+
+ return &state->base;
+}
+
+static void vc4_ctm_destroy_state(struct drm_private_obj *obj,
+ struct drm_private_state *state)
+{
+ struct vc4_ctm_state *ctm_state = to_vc4_ctm_state(state);
+
+ kfree(ctm_state);
+}
+
+static const struct drm_private_state_funcs vc4_ctm_state_funcs = {
+ .atomic_duplicate_state = vc4_ctm_duplicate_state,
+ .atomic_destroy_state = vc4_ctm_destroy_state,
+};
+
+/* Converts a DRM S31.32 value to the HW S0.9 format. */
+static u16 vc4_ctm_s31_32_to_s0_9(u64 in)
+{
+ u16 r;
+
+ /* Sign bit. */
+ r = in & BIT_ULL(63) ? BIT(9) : 0;
+ /* We have zero integer bits so we can only saturate here. */
+ if ((in & GENMASK_ULL(62, 32)) > 0)
+ r |= GENMASK(8, 0);
+ /* Otherwise take the 9 most important fractional bits. */
+ else
+ r |= (in >> 22) & GENMASK(8, 0);
+ return r;
+}
+
+static void
+vc4_ctm_commit(struct vc4_dev *vc4, struct drm_atomic_state *state)
+{
+ struct vc4_ctm_state *ctm_state = vc4_get_ctm_state(state,
+ &vc4->ctm_manager);
+ struct drm_color_ctm *ctm = ctm_state->ctm;
+
+ if (ctm_state->fifo) {
+ HVS_WRITE(SCALER_OLEDCOEF2,
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[0]),
+ SCALER_OLEDCOEF2_R_TO_R) |
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[3]),
+ SCALER_OLEDCOEF2_R_TO_G) |
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[6]),
+ SCALER_OLEDCOEF2_R_TO_B));
+ HVS_WRITE(SCALER_OLEDCOEF1,
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[1]),
+ SCALER_OLEDCOEF1_G_TO_R) |
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[4]),
+ SCALER_OLEDCOEF1_G_TO_G) |
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[7]),
+ SCALER_OLEDCOEF1_G_TO_B));
+ HVS_WRITE(SCALER_OLEDCOEF0,
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[2]),
+ SCALER_OLEDCOEF0_B_TO_R) |
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[5]),
+ SCALER_OLEDCOEF0_B_TO_G) |
+ VC4_SET_FIELD(vc4_ctm_s31_32_to_s0_9(ctm->matrix[8]),
+ SCALER_OLEDCOEF0_B_TO_B));
+ }
+
+ HVS_WRITE(SCALER_OLEDOFFS,
+ VC4_SET_FIELD(ctm_state->fifo, SCALER_OLEDOFFS_DISPFIFO));
+}
static void
vc4_atomic_complete_commit(struct drm_atomic_state *state)
@@ -36,6 +132,8 @@ vc4_atomic_complete_commit(struct drm_atomic_state *state)
drm_atomic_helper_commit_modeset_disables(dev, state);
+ vc4_ctm_commit(vc4, state);
+
drm_atomic_helper_commit_planes(dev, state, 0);
drm_atomic_helper_commit_modeset_enables(dev, state);
@@ -187,9 +285,69 @@ static struct drm_framebuffer *vc4_fb_create(struct drm_device *dev,
return drm_gem_fb_create(dev, file_priv, mode_cmd);
}
+/* Our CTM has some peculiar limitations: we can only enable it for one CRTC
+ * at a time and the HW only supports S0.9 scalars. To account for the latter,
+ * we don't allow userland to set a CTM that we have no hope of approximating.
+ */
+static int
+vc4_ctm_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
+{
+ struct vc4_dev *vc4 = to_vc4_dev(dev);
+ struct vc4_ctm_state *ctm_state = vc4_get_ctm_state(state,
+ &vc4->ctm_manager);
+ struct drm_crtc *crtc;
+ struct drm_crtc_state *old_crtc_state, *new_crtc_state;
+ struct drm_color_ctm *ctm;
+ int i;
+
+ ctm_state->fifo = 0;
+ for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
+ if (new_crtc_state->ctm) {
+ /* Check userland isn't trying to turn on CTM for more
+ * than one CRTC at a time.
+ */
+ if (ctm_state->fifo) {
+ DRM_DEBUG_DRIVER("Too many CTM configured\n");
+ return -EINVAL;
+ }
+
+ /* Check we can approximate the specified CTM.
+ * We disallow scalars |c| > 1.0 since the HW has
+ * no integer bits.
+ */
+ ctm = new_crtc_state->ctm->data;
+ for (i = 0; i < ARRAY_SIZE(ctm->matrix); i++) {
+ u64 val = ctm->matrix[i];
+
+ val &= ~BIT_ULL(63);
+ if (val > BIT_ULL(32))
+ return -EINVAL;
+ }
+
+ /* fifo is 1-based since 0 disables CTM. */
+ ctm_state->fifo = to_vc4_crtc(crtc)->channel + 1;
+ ctm_state->ctm = ctm;
+ }
+ }
+
+ return 0;
+}
+
+static int
+vc4_atomic_check(struct drm_device *dev, struct drm_atomic_state *state)
+{
+ int ret;
+
+ ret = vc4_ctm_atomic_check(dev, state);
+ if (ret < 0)
+ return ret;
+
+ return drm_atomic_helper_check(dev, state);
+}
+
static const struct drm_mode_config_funcs vc4_mode_funcs = {
.output_poll_changed = drm_fb_helper_output_poll_changed,
- .atomic_check = drm_atomic_helper_check,
+ .atomic_check = vc4_atomic_check,
.atomic_commit = vc4_atomic_commit,
.fb_create = vc4_fb_create,
};
@@ -197,6 +355,7 @@ static const struct drm_mode_config_funcs vc4_mode_funcs = {
int vc4_kms_load(struct drm_device *dev)
{
struct vc4_dev *vc4 = to_vc4_dev(dev);
+ struct vc4_ctm_state *ctm_state;
int ret;
sema_init(&vc4->async_modeset, 1);
@@ -224,5 +383,11 @@ int vc4_kms_load(struct drm_device *dev)
drm_kms_helper_poll_init(dev);
+ ctm_state = kzalloc(sizeof(*ctm_state), GFP_KERNEL);
+ if (!ctm_state)
+ return -ENOMEM;
+ drm_atomic_private_obj_init(&vc4->ctm_manager, &ctm_state->base,
+ &vc4_ctm_state_funcs);
+
return 0;
}
--
2.7.4
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