[PATCH v2 2/2] drm: mali-dp: enable gamma support

From: Mihail Atanassov
Date: Wed Feb 01 2017 - 09:49:13 EST

Add gamma via the DRM GAMMA_LUT/GAMMA_LUT_SIZE CRTC
properties. The expected LUT size is 4096 in order
to produce as accurate a set of segments as possible.

This version uses only the green channel's gamma curve
to set the hardware curve on DP550/650. For the sake of
simplicity, it uses the same table of coefficients for
all 3 curves on DP500.

Signed-off-by: Mihail Atanassov <mihail.atanassov@xxxxxxx>
Reviewed-by: Brian Starkey <brian.starkey@xxxxxxx>
---
drivers/gpu/drm/arm/malidp_crtc.c | 132 ++++++++++++++++++++++++++++++++++++--
drivers/gpu/drm/arm/malidp_drv.c | 52 +++++++++++++++
drivers/gpu/drm/arm/malidp_drv.h | 1 +
drivers/gpu/drm/arm/malidp_hw.c | 3 +
drivers/gpu/drm/arm/malidp_hw.h | 2 +
drivers/gpu/drm/arm/malidp_regs.h | 19 ++++--
6 files changed, 199 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/arm/malidp_crtc.c b/drivers/gpu/drm/arm/malidp_crtc.c
index ebf57e6..10f79b6 100644
--- a/drivers/gpu/drm/arm/malidp_crtc.c
+++ b/drivers/gpu/drm/arm/malidp_crtc.c
@@ -82,6 +82,114 @@ static void malidp_crtc_disable(struct drm_crtc *crtc)
clk_disable_unprepare(hwdev->pxlclk);
}

+static const struct gamma_curve_segment {
+ u16 start;
+ u16 end;
+} segments[MALIDP_COEFFTAB_NUM_COEFFS] = {
+ /* sector 0 */
+ { 0, 0 }, { 1, 1 }, { 2, 2 }, { 3, 3 },
+ { 4, 4 }, { 5, 5 }, { 6, 6 }, { 7, 7 },
+ { 8, 8 }, { 9, 9 }, { 10, 10 }, { 11, 11 },
+ { 12, 12 }, { 13, 13 }, { 14, 14 }, { 15, 15 },
+ /* sector 1 */
+ { 16, 19 }, { 20, 23 }, { 24, 27 }, { 28, 31 },
+ /* sector 2 */
+ { 32, 39 }, { 40, 47 }, { 48, 55 }, { 56, 63 },
+ /* sector 3 */
+ { 64, 79 }, { 80, 95 }, { 96, 111 }, { 112, 127 },
+ /* sector 4 */
+ { 128, 159 }, { 160, 191 }, { 192, 223 }, { 224, 255 },
+ /* sector 5 */
+ { 256, 319 }, { 320, 383 }, { 384, 447 }, { 448, 511 },
+ /* sector 6 */
+ { 512, 639 }, { 640, 767 }, { 768, 895 }, { 896, 1023 },
+ { 1024, 1151 }, { 1152, 1279 }, { 1280, 1407 }, { 1408, 1535 },
+ { 1536, 1663 }, { 1664, 1791 }, { 1792, 1919 }, { 1920, 2047 },
+ { 2048, 2175 }, { 2176, 2303 }, { 2304, 2431 }, { 2432, 2559 },
+ { 2560, 2687 }, { 2688, 2815 }, { 2816, 2943 }, { 2944, 3071 },
+ { 3072, 3199 }, { 3200, 3327 }, { 3328, 3455 }, { 3456, 3583 },
+ { 3584, 3711 }, { 3712, 3839 }, { 3840, 3967 }, { 3968, 4095 },
+};
+
+#define DE_COEFTAB_DATA(a, b) ((((a) & 0xfff) << 16) | (((b) & 0xfff)))
+
+static void malidp_generate_gamma_table(struct drm_property_blob *lut_blob,
+ u32 coeffs[MALIDP_COEFFTAB_NUM_COEFFS])
+{
+ struct drm_color_lut *lut = (struct drm_color_lut *)lut_blob->data;
+ int i;
+
+ for (i = 0; i < MALIDP_COEFFTAB_NUM_COEFFS; ++i) {
+ u32 a, b;
+ u32 delta_in;
+ u32 out_start, out_end;
+
+ delta_in = segments[i].end - segments[i].start;
+ /* DP has 12-bit internal precision for its LUTs. */
+ out_start = drm_color_lut_extract(lut[segments[i].start].green,
+ 12);
+ out_end = drm_color_lut_extract(lut[segments[i].end].green, 12);
+ a = (delta_in == 0) ?
+ 0 : ((out_end - out_start) * 256) / delta_in;
+ b = out_start;
+ coeffs[i] = DE_COEFTAB_DATA(a, b);
+ }
+}
+
+/*
+ * Check if there is a new gamma LUT and if it is of an acceptable size. Also,
+ * reject any LUTs that use distinct red, green, and blue curves.
+ */
+static int malidp_crtc_atomic_check_gamma(struct drm_crtc *crtc,
+ struct drm_crtc_state *state)
+{
+ struct malidp_crtc_state *mc = to_malidp_crtc_state(state);
+ struct drm_color_lut *lut;
+ size_t lut_size;
+ int i;
+
+ if (!state->color_mgmt_changed)
+ return 0;
+
+ if (!state->gamma_lut)
+ return 0;
+
+ if (crtc->state->gamma_lut && (crtc->state->gamma_lut->base.id ==
+ state->gamma_lut->base.id))
+ return 0;
+
+ if (state->gamma_lut->length % sizeof(struct drm_color_lut))
+ return -EINVAL;
+
+ lut_size = state->gamma_lut->length / sizeof(struct drm_color_lut);
+ if (lut_size != 4096)
+ return -EINVAL;
+
+ lut = (struct drm_color_lut *)state->gamma_lut->data;
+ for (i = 0; i < lut_size; ++i)
+ if (!((lut[i].red == lut[i].green) &&
+ (lut[i].red == lut[i].blue)))
+ return -EINVAL;
+
+ if (!state->mode_changed) {
+ int ret;
+
+ state->mode_changed = true;
+ /*
+ * Kerneldoc for drm_atomic_helper_check_modeset mandates that
+ * it be invoked when the driver sets ->mode_changed. Since
+ * changing the gamma LUT Doesn't depend on any external
+ * resources, it is safe to call it only once.
+ */
+ ret = drm_atomic_helper_check_modeset(crtc->dev, state->state);
+ if (ret)
+ return ret;
+ }
+
+ malidp_generate_gamma_table(state->gamma_lut, mc->gamma_coeffs);
+ return 0;
+}
+
static int malidp_crtc_atomic_check(struct drm_crtc *crtc,
struct drm_crtc_state *state)
{
@@ -91,6 +199,7 @@ static int malidp_crtc_atomic_check(struct drm_crtc *crtc,
const struct drm_plane_state *pstate;
u32 rot_mem_free, rot_mem_usable;
int rotated_planes = 0;
+ int ret;

/*
* check if there is enough rotation memory available for planes
@@ -157,21 +266,29 @@ static int malidp_crtc_atomic_check(struct drm_crtc *crtc,
}
}

+ ret = malidp_crtc_atomic_check_gamma(crtc, state);
+ if (ret)
+ return ret;
+
return 0;
}

static struct drm_crtc_state *malidp_crtc_duplicate_state(struct drm_crtc *crtc)
{
+ struct malidp_crtc_state *cs;
struct malidp_crtc_state *state;

if (WARN_ON(!crtc->state))
return NULL;

+ cs = to_malidp_crtc_state(crtc->state);
state = kmalloc(sizeof(*state), GFP_KERNEL);
if (!state)
return NULL;

__drm_atomic_helper_crtc_duplicate_state(crtc, &state->base);
+ memcpy(state->gamma_coeffs, cs->gamma_coeffs,
+ sizeof(state->gamma_coeffs));

return &state->base;
}
@@ -201,6 +318,7 @@ static void malidp_crtc_reset(struct drm_crtc *crtc)
};

static const struct drm_crtc_funcs malidp_crtc_funcs = {
+ .gamma_set = drm_atomic_helper_legacy_gamma_set,
.destroy = drm_crtc_cleanup,
.set_config = drm_atomic_helper_set_config,
.page_flip = drm_atomic_helper_page_flip,
@@ -236,11 +354,17 @@ int malidp_crtc_init(struct drm_device *drm)

ret = drm_crtc_init_with_planes(drm, &malidp->crtc, primary, NULL,
&malidp_crtc_funcs, NULL);
+ if (ret)
+ goto crtc_cleanup_planes;

- if (!ret) {
- drm_crtc_helper_add(&malidp->crtc, &malidp_crtc_helper_funcs);
- return 0;
- }
+ drm_crtc_helper_add(&malidp->crtc, &malidp_crtc_helper_funcs);
+ drm_mode_crtc_set_gamma_size(&malidp->crtc, 4096);
+ /* No inverse-gamma and color adjustments yet. */
+ drm_crtc_enable_color_mgmt(&malidp->crtc,
+ 0,
+ false,
+ 4096);
+ return 0;

crtc_cleanup_planes:
malidp_de_planes_destroy(drm);
diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
index 32f746e..a9f787d 100644
--- a/drivers/gpu/drm/arm/malidp_drv.c
+++ b/drivers/gpu/drm/arm/malidp_drv.c
@@ -33,6 +33,51 @@

#define MALIDP_CONF_VALID_TIMEOUT 250

+static void malidp_write_gamma_table(struct malidp_hw_device *hwdev,
+ u32 data[MALIDP_COEFFTAB_NUM_COEFFS])
+{
+ int i;
+ /* Update all channels with a single gamma curve. */
+ const u32 gamma_write_mask = GENMASK(18, 16);
+ /*
+ * Always write an entire table, so the address field in
+ * DE_COEFFTAB_ADDR is 0 and we can use the gamma_write_mask bitmask
+ * directly.
+ */
+ malidp_hw_write(hwdev, gamma_write_mask,
+ hwdev->map.coeffs_base + MALIDP_COEF_TABLE_ADDR);
+ for (i = 0; i < MALIDP_COEFFTAB_NUM_COEFFS; ++i)
+ malidp_hw_write(hwdev, data[i],
+ hwdev->map.coeffs_base +
+ MALIDP_COEF_TABLE_DATA);
+}
+
+static void malidp_atomic_commit_update_gamma(struct drm_crtc *crtc,
+ struct drm_crtc_state *old_state)
+{
+ struct malidp_drm *malidp = crtc_to_malidp_device(crtc);
+ struct malidp_hw_device *hwdev = malidp->dev;
+
+ if (!crtc->state->color_mgmt_changed)
+ return;
+
+ if (!crtc->state->gamma_lut) {
+ malidp_hw_clearbits(hwdev,
+ MALIDP_DISP_FUNC_GAM,
+ MALIDP_DE_DISPLAY_FUNC);
+ } else {
+ struct malidp_crtc_state *mc =
+ to_malidp_crtc_state(crtc->state);
+
+ if (!old_state->gamma_lut || (crtc->state->gamma_lut->base.id !=
+ old_state->gamma_lut->base.id))
+ malidp_write_gamma_table(hwdev, mc->gamma_coeffs);
+
+ malidp_hw_setbits(hwdev, MALIDP_DISP_FUNC_GAM,
+ MALIDP_DE_DISPLAY_FUNC);
+ }
+}
+
/*
* set the "config valid" bit and wait until the hardware acts on it
*/
@@ -89,8 +134,15 @@ static void malidp_atomic_commit_hw_done(struct drm_atomic_state *state)
static void malidp_atomic_commit_tail(struct drm_atomic_state *state)
{
struct drm_device *drm = state->dev;
+ struct drm_crtc *crtc;
+ struct drm_crtc_state *old_crtc_state;
+ int i;

drm_atomic_helper_commit_modeset_disables(drm, state);
+
+ for_each_crtc_in_state(state, crtc, old_crtc_state, i)
+ malidp_atomic_commit_update_gamma(crtc, old_crtc_state);
+
drm_atomic_helper_commit_modeset_enables(drm, state);
drm_atomic_helper_commit_planes(drm, state, 0);

diff --git a/drivers/gpu/drm/arm/malidp_drv.h b/drivers/gpu/drm/arm/malidp_drv.h
index c7a69ae..374d43e 100644
--- a/drivers/gpu/drm/arm/malidp_drv.h
+++ b/drivers/gpu/drm/arm/malidp_drv.h
@@ -49,6 +49,7 @@ struct malidp_plane_state {

struct malidp_crtc_state {
struct drm_crtc_state base;
+ u32 gamma_coeffs[MALIDP_COEFFTAB_NUM_COEFFS];
};

#define to_malidp_crtc_state(x) container_of(x, struct malidp_crtc_state, base)
diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c
index 4bdf531..5ceca17 100644
--- a/drivers/gpu/drm/arm/malidp_hw.c
+++ b/drivers/gpu/drm/arm/malidp_hw.c
@@ -415,6 +415,7 @@ static int malidp650_query_hw(struct malidp_hw_device *hwdev)
const struct malidp_hw_device malidp_device[MALIDP_MAX_DEVICES] = {
[MALIDP_500] = {
.map = {
+ .coeffs_base = MALIDP500_COEFFS_BASE,
.se_base = MALIDP500_SE_BASE,
.dc_base = MALIDP500_DC_BASE,
.out_depth_base = MALIDP500_OUTPUT_DEPTH,
@@ -450,6 +451,7 @@ static int malidp650_query_hw(struct malidp_hw_device *hwdev)
},
[MALIDP_550] = {
.map = {
+ .coeffs_base = MALIDP550_COEFFS_BASE,
.se_base = MALIDP550_SE_BASE,
.dc_base = MALIDP550_DC_BASE,
.out_depth_base = MALIDP550_DE_OUTPUT_DEPTH,
@@ -483,6 +485,7 @@ static int malidp650_query_hw(struct malidp_hw_device *hwdev)
},
[MALIDP_650] = {
.map = {
+ .coeffs_base = MALIDP550_COEFFS_BASE,
.se_base = MALIDP550_SE_BASE,
.dc_base = MALIDP550_DC_BASE,
.out_depth_base = MALIDP550_DE_OUTPUT_DEPTH,
diff --git a/drivers/gpu/drm/arm/malidp_hw.h b/drivers/gpu/drm/arm/malidp_hw.h
index 087e1202..ecff7d4 100644
--- a/drivers/gpu/drm/arm/malidp_hw.h
+++ b/drivers/gpu/drm/arm/malidp_hw.h
@@ -66,6 +66,8 @@ struct malidp_layer {
struct malidp_hw_regmap {
/* address offset of the DE register bank */
/* is always 0x0000 */
+ /* address offset of the DE coefficients registers */
+ const u16 coeffs_base;
/* address offset of the SE registers bank */
const u16 se_base;
/* address offset of the DC registers bank */
diff --git a/drivers/gpu/drm/arm/malidp_regs.h b/drivers/gpu/drm/arm/malidp_regs.h
index 73fecb3..2e213c3 100644
--- a/drivers/gpu/drm/arm/malidp_regs.h
+++ b/drivers/gpu/drm/arm/malidp_regs.h
@@ -63,6 +63,7 @@

/* bit masks that are common between products */
#define MALIDP_CFG_VALID (1 << 0)
+#define MALIDP_DISP_FUNC_GAM (1 << 0)
#define MALIDP_DISP_FUNC_ILACED (1 << 8)

/* register offsets for IRQ management */
@@ -92,6 +93,12 @@
#define MALIDP_DE_H_ACTIVE(x) (((x) & 0x1fff) << 0)
#define MALIDP_DE_V_ACTIVE(x) (((x) & 0x1fff) << 16)

+#define MALIDP_COEFFTAB_NUM_COEFFS 64
+/* register offsets relative to MALIDP5x0_COEFFS_BASE */
+#define MALIDP_COLOR_ADJ_COEF 0x00000
+#define MALIDP_COEF_TABLE_ADDR 0x00030
+#define MALIDP_COEF_TABLE_DATA 0x00034
+
/* register offsets and bits specific to DP500 */
#define MALIDP500_DC_BASE 0x00000
#define MALIDP500_DC_CONTROL 0x0000c
@@ -109,9 +116,11 @@
#define MALIDP500_BGND_COLOR 0x0003c
#define MALIDP500_OUTPUT_DEPTH 0x00044
#define MALIDP500_YUV_RGB_COEF 0x00048
-#define MALIDP500_COLOR_ADJ_COEF 0x00078
-#define MALIDP500_COEF_TABLE_ADDR 0x000a8
-#define MALIDP500_COEF_TABLE_DATA 0x000ac
+/*
+ * To match DP550/650, the start of the coeffs registers is
+ * at COLORADJ_COEFF0 instead of at YUV_RGB_COEF1.
+ */
+#define MALIDP500_COEFFS_BASE 0x00078
#define MALIDP500_DE_LV_BASE 0x00100
#define MALIDP500_DE_LV_PTR_BASE 0x00124
#define MALIDP500_DE_LG1_BASE 0x00200
@@ -136,9 +145,7 @@
#define MALIDP550_DE_DISP_SIDEBAND 0x00040
#define MALIDP550_DE_BGND_COLOR 0x00044
#define MALIDP550_DE_OUTPUT_DEPTH 0x0004c
-#define MALIDP550_DE_COLOR_COEF 0x00050
-#define MALIDP550_DE_COEF_TABLE_ADDR 0x00080
-#define MALIDP550_DE_COEF_TABLE_DATA 0x00084
+#define MALIDP550_COEFFS_BASE 0x00050
#define MALIDP550_DE_LV1_BASE 0x00100
#define MALIDP550_DE_LV1_PTR_BASE 0x00124
#define MALIDP550_DE_LV2_BASE 0x00200
--
1.9.1