From: Kieran Bingham <kieran.bing...@ideasonboard.com>

The LCDIF includes a color space converter that supports YUV input. Use
it to support YUV planes, either through the converter if the output
format is RGB, or in conversion bypass mode otherwise.

Signed-off-by: Kieran Bingham <kieran.bing...@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
---
Changes since v1:

- Support all YCbCr encodings and quantization ranges
- Drop incorrect comment
---
 drivers/gpu/drm/mxsfb/lcdif_kms.c  | 183 +++++++++++++++++++++++++----
 drivers/gpu/drm/mxsfb/lcdif_regs.h |   5 +-
 2 files changed, 164 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c 
b/drivers/gpu/drm/mxsfb/lcdif_kms.c
index c3622be0c587..b469a90fd50f 100644
--- a/drivers/gpu/drm/mxsfb/lcdif_kms.c
+++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c
@@ -15,6 +15,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_color_mgmt.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_framebuffer.h>
@@ -32,13 +33,77 @@
 /* 
-----------------------------------------------------------------------------
  * CRTC
  */
+
+/*
+ * Despite the reference manual stating the opposite, the D1, D2 and D3 offset
+ * values are added to Y, U and V, not subtracted. They must thus be programmed
+ * with negative values.
+ */
+static const u32 lcdif_yuv2rgb_coeffs[3][2][6] = {
+       [DRM_COLOR_YCBCR_BT601] = {
+               [DRM_COLOR_YCBCR_LIMITED_RANGE] = {
+                       CSC0_COEF0_A1(0x012a) | CSC0_COEF0_A2(0x0000),
+                       CSC0_COEF1_A3(0x01a2) | CSC0_COEF1_B1(0x0123),
+                       CSC0_COEF2_B2(0x079c) | CSC0_COEF2_B3(0x0730),
+                       CSC0_COEF3_C1(0x0124) | CSC0_COEF3_C2(0x0204),
+                       CSC0_COEF4_C3(0x0000) | CSC0_COEF4_D1(0x01f0),
+                       CSC0_COEF5_D2(0x0180) | CSC0_COEF5_D3(0x0180),
+               },
+               [DRM_COLOR_YCBCR_FULL_RANGE] = {
+                       CSC0_COEF0_A1(0x0100) | CSC0_COEF0_A2(0x0000),
+                       CSC0_COEF1_A3(0x0167) | CSC0_COEF1_B1(0x0100),
+                       CSC0_COEF2_B2(0x07a8) | CSC0_COEF2_B3(0x0749),
+                       CSC0_COEF3_C1(0x0100) | CSC0_COEF3_C2(0x01c6),
+                       CSC0_COEF4_C3(0x0000) | CSC0_COEF4_D1(0x0000),
+                       CSC0_COEF5_D2(0x0180) | CSC0_COEF5_D3(0x0180),
+               },
+       },
+       [DRM_COLOR_YCBCR_BT709] = {
+               [DRM_COLOR_YCBCR_LIMITED_RANGE] = {
+                       CSC0_COEF0_A1(0x012a) | CSC0_COEF0_A2(0x0000),
+                       CSC0_COEF1_A3(0x01d6) | CSC0_COEF1_B1(0x0123),
+                       CSC0_COEF2_B2(0x07c9) | CSC0_COEF2_B3(0x0778),
+                       CSC0_COEF3_C1(0x0123) | CSC0_COEF3_C2(0x021d),
+                       CSC0_COEF4_C3(0x0000) | CSC0_COEF4_D1(0x01f0),
+                       CSC0_COEF5_D2(0x0180) | CSC0_COEF5_D3(0x0180),
+               },
+               [DRM_COLOR_YCBCR_FULL_RANGE] = {
+                       CSC0_COEF0_A1(0x0100) | CSC0_COEF0_A2(0x0000),
+                       CSC0_COEF1_A3(0x0193) | CSC0_COEF1_B1(0x0100),
+                       CSC0_COEF2_B2(0x07d0) | CSC0_COEF2_B3(0x0788),
+                       CSC0_COEF3_C1(0x0100) | CSC0_COEF3_C2(0x01db),
+                       CSC0_COEF4_C3(0x0000) | CSC0_COEF4_D1(0x0000),
+                       CSC0_COEF5_D2(0x0180) | CSC0_COEF5_D3(0x0180),
+               },
+       },
+       [DRM_COLOR_YCBCR_BT2020] = {
+               [DRM_COLOR_YCBCR_LIMITED_RANGE] = {
+                       CSC0_COEF0_A1(0x012a) | CSC0_COEF0_A2(0x0000),
+                       CSC0_COEF1_A3(0x01b8) | CSC0_COEF1_B1(0x0123),
+                       CSC0_COEF2_B2(0x07d0) | CSC0_COEF2_B3(0x075a),
+                       CSC0_COEF3_C1(0x0124) | CSC0_COEF3_C2(0x0224),
+                       CSC0_COEF4_C3(0x0000) | CSC0_COEF4_D1(0x01f0),
+                       CSC0_COEF5_D2(0x0180) | CSC0_COEF5_D3(0x0180),
+               },
+               [DRM_COLOR_YCBCR_FULL_RANGE] = {
+                       CSC0_COEF0_A1(0x0100) | CSC0_COEF0_A2(0x0000),
+                       CSC0_COEF1_A3(0x0179) | CSC0_COEF1_B1(0x0100),
+                       CSC0_COEF2_B2(0x07d6) | CSC0_COEF2_B3(0x076e),
+                       CSC0_COEF3_C1(0x0100) | CSC0_COEF3_C2(0x01e2),
+                       CSC0_COEF4_C3(0x0000) | CSC0_COEF4_D1(0x0000),
+                       CSC0_COEF5_D2(0x0180) | CSC0_COEF5_D3(0x0180),
+               },
+       },
+};
+
 static void lcdif_set_formats(struct lcdif_drm_private *lcdif,
+                             struct drm_plane_state *plane_state,
                              const u32 bus_format)
 {
        struct drm_device *drm = lcdif->drm;
-       const u32 format = lcdif->crtc.primary->state->fb->format->format;
-
-       writel(CSC0_CTRL_BYPASS, lcdif->base + LCDC_V8_CSC0_CTRL);
+       const u32 format = plane_state->fb->format->format;
+       bool in_yuv = false;
+       bool out_yuv = false;
 
        switch (bus_format) {
        case MEDIA_BUS_FMT_RGB565_1X16:
@@ -52,24 +117,7 @@ static void lcdif_set_formats(struct lcdif_drm_private 
*lcdif,
        case MEDIA_BUS_FMT_UYVY8_1X16:
                writel(DISP_PARA_LINE_PATTERN_UYVY_H,
                       lcdif->base + LCDC_V8_DISP_PARA);
-
-               /* CSC: BT.601 Limited Range RGB to YCbCr coefficients. */
-               writel(CSC0_COEF0_A2(0x081) | CSC0_COEF0_A1(0x041),
-                      lcdif->base + LCDC_V8_CSC0_COEF0);
-               writel(CSC0_COEF1_B1(0x7db) | CSC0_COEF1_A3(0x019),
-                      lcdif->base + LCDC_V8_CSC0_COEF1);
-               writel(CSC0_COEF2_B3(0x070) | CSC0_COEF2_B2(0x7b6),
-                      lcdif->base + LCDC_V8_CSC0_COEF2);
-               writel(CSC0_COEF3_C2(0x7a2) | CSC0_COEF3_C1(0x070),
-                      lcdif->base + LCDC_V8_CSC0_COEF3);
-               writel(CSC0_COEF4_D1(0x010) | CSC0_COEF4_C3(0x7ee),
-                      lcdif->base + LCDC_V8_CSC0_COEF4);
-               writel(CSC0_COEF5_D3(0x080) | CSC0_COEF5_D2(0x080),
-                      lcdif->base + LCDC_V8_CSC0_COEF5);
-
-               writel(CSC0_CTRL_CSC_MODE_RGB2YCbCr,
-                      lcdif->base + LCDC_V8_CSC0_CTRL);
-
+               out_yuv = true;
                break;
        default:
                dev_err(drm->dev, "Unknown media bus format 0x%x\n", 
bus_format);
@@ -77,6 +125,7 @@ static void lcdif_set_formats(struct lcdif_drm_private 
*lcdif,
        }
 
        switch (format) {
+       /* RGB Formats */
        case DRM_FORMAT_RGB565:
                writel(CTRLDESCL0_5_BPP_16_RGB565,
                       lcdif->base + LCDC_V8_CTRLDESCL0_5);
@@ -101,10 +150,78 @@ static void lcdif_set_formats(struct lcdif_drm_private 
*lcdif,
                writel(CTRLDESCL0_5_BPP_32_ARGB8888,
                       lcdif->base + LCDC_V8_CTRLDESCL0_5);
                break;
+
+       /* YUYV Formats */
+       case DRM_FORMAT_YUYV:
+               writel(CTRLDESCL0_5_BPP_YCbCr422 | 
CTRLDESCL0_5_YUV_FORMAT_VY2UY1,
+                      lcdif->base + LCDC_V8_CTRLDESCL0_5);
+               in_yuv = true;
+               break;
+       case DRM_FORMAT_YVYU:
+               writel(CTRLDESCL0_5_BPP_YCbCr422 | 
CTRLDESCL0_5_YUV_FORMAT_UY2VY1,
+                      lcdif->base + LCDC_V8_CTRLDESCL0_5);
+               in_yuv = true;
+               break;
+       case DRM_FORMAT_UYVY:
+               writel(CTRLDESCL0_5_BPP_YCbCr422 | 
CTRLDESCL0_5_YUV_FORMAT_Y2VY1U,
+                      lcdif->base + LCDC_V8_CTRLDESCL0_5);
+               in_yuv = true;
+               break;
+       case DRM_FORMAT_VYUY:
+               writel(CTRLDESCL0_5_BPP_YCbCr422 | 
CTRLDESCL0_5_YUV_FORMAT_Y2UY1V,
+                      lcdif->base + LCDC_V8_CTRLDESCL0_5);
+               in_yuv = true;
+               break;
+
        default:
                dev_err(drm->dev, "Unknown pixel format 0x%x\n", format);
                break;
        }
+
+       /*
+        * The CSC differentiates between "YCbCr" and "YUV", but the reference
+        * manual doesn't detail how they differ. Experiments showed that the
+        * luminance value is unaffected, only the calculations involving chroma
+        * values differ. The YCbCr mode behaves as expected, with chroma values
+        * being offset by 128. The YUV mode isn't fully understood.
+        */
+       if (!in_yuv && out_yuv) {
+               /* RGB -> YCbCr */
+               writel(CSC0_CTRL_CSC_MODE_RGB2YCbCr,
+                      lcdif->base + LCDC_V8_CSC0_CTRL);
+
+               /* CSC: BT.601 Limited Range RGB to YCbCr coefficients. */
+               writel(CSC0_COEF0_A2(0x081) | CSC0_COEF0_A1(0x041),
+                      lcdif->base + LCDC_V8_CSC0_COEF0);
+               writel(CSC0_COEF1_B1(0x7db) | CSC0_COEF1_A3(0x019),
+                      lcdif->base + LCDC_V8_CSC0_COEF1);
+               writel(CSC0_COEF2_B3(0x070) | CSC0_COEF2_B2(0x7b6),
+                      lcdif->base + LCDC_V8_CSC0_COEF2);
+               writel(CSC0_COEF3_C2(0x7a2) | CSC0_COEF3_C1(0x070),
+                      lcdif->base + LCDC_V8_CSC0_COEF3);
+               writel(CSC0_COEF4_D1(0x010) | CSC0_COEF4_C3(0x7ee),
+                      lcdif->base + LCDC_V8_CSC0_COEF4);
+               writel(CSC0_COEF5_D3(0x080) | CSC0_COEF5_D2(0x080),
+                      lcdif->base + LCDC_V8_CSC0_COEF5);
+       } else if (in_yuv && !out_yuv) {
+               /* YCbCr -> RGB */
+               const u32 *coeffs =
+                       lcdif_yuv2rgb_coeffs[plane_state->color_encoding]
+                                           [plane_state->color_range];
+
+               writel(CSC0_CTRL_CSC_MODE_YCbCr2RGB,
+                      lcdif->base + LCDC_V8_CSC0_CTRL);
+
+               writel(coeffs[0], lcdif->base + LCDC_V8_CSC0_COEF0);
+               writel(coeffs[1], lcdif->base + LCDC_V8_CSC0_COEF1);
+               writel(coeffs[2], lcdif->base + LCDC_V8_CSC0_COEF2);
+               writel(coeffs[3], lcdif->base + LCDC_V8_CSC0_COEF3);
+               writel(coeffs[4], lcdif->base + LCDC_V8_CSC0_COEF4);
+               writel(coeffs[5], lcdif->base + LCDC_V8_CSC0_COEF5);
+       } else {
+               /* RGB -> RGB, YCbCr -> YCbCr: bypass colorspace converter. */
+               writel(CSC0_CTRL_BYPASS, lcdif->base + LCDC_V8_CSC0_CTRL);
+       }
 }
 
 static void lcdif_set_mode(struct lcdif_drm_private *lcdif, u32 bus_flags)
@@ -201,6 +318,7 @@ static void lcdif_reset_block(struct lcdif_drm_private 
*lcdif)
 }
 
 static void lcdif_crtc_mode_set_nofb(struct lcdif_drm_private *lcdif,
+                                    struct drm_plane_state *plane_state,
                                     struct drm_bridge_state *bridge_state,
                                     const u32 bus_format)
 {
@@ -223,7 +341,7 @@ static void lcdif_crtc_mode_set_nofb(struct 
lcdif_drm_private *lcdif,
        /* Mandatory eLCDIF reset as per the Reference Manual */
        lcdif_reset_block(lcdif);
 
-       lcdif_set_formats(lcdif, bus_format);
+       lcdif_set_formats(lcdif, plane_state, bus_format);
 
        lcdif_set_mode(lcdif, bus_flags);
 }
@@ -306,7 +424,7 @@ static void lcdif_crtc_atomic_enable(struct drm_crtc *crtc,
 
        pm_runtime_get_sync(drm->dev);
 
-       lcdif_crtc_mode_set_nofb(lcdif, bridge_state, bus_format);
+       lcdif_crtc_mode_set_nofb(lcdif, new_pstate, bridge_state, bus_format);
 
        /* Write cur_buf as well to avoid an initial corrupt frame */
        paddr = drm_fb_cma_get_gem_addr(new_pstate->fb, new_pstate, 0);
@@ -456,6 +574,12 @@ static const u32 lcdif_primary_plane_formats[] = {
        DRM_FORMAT_XRGB1555,
        DRM_FORMAT_XRGB4444,
        DRM_FORMAT_XRGB8888,
+
+       /* packed YCbCr */
+       DRM_FORMAT_YUYV,
+       DRM_FORMAT_YVYU,
+       DRM_FORMAT_UYVY,
+       DRM_FORMAT_VYUY,
 };
 
 static const u64 lcdif_modifiers[] = {
@@ -469,6 +593,11 @@ static const u64 lcdif_modifiers[] = {
 
 int lcdif_kms_init(struct lcdif_drm_private *lcdif)
 {
+       const u32 supported_encodings = BIT(DRM_COLOR_YCBCR_BT601)
+                                     | BIT(DRM_COLOR_YCBCR_BT709)
+                                     | BIT(DRM_COLOR_YCBCR_BT2020);
+       const u32 supported_ranges = BIT(DRM_COLOR_YCBCR_LIMITED_RANGE)
+                                  | BIT(DRM_COLOR_YCBCR_FULL_RANGE);
        struct drm_encoder *encoder = &lcdif->encoder;
        struct drm_crtc *crtc = &lcdif->crtc;
        int ret;
@@ -484,6 +613,14 @@ int lcdif_kms_init(struct lcdif_drm_private *lcdif)
        if (ret)
                return ret;
 
+       ret = drm_plane_create_color_properties(&lcdif->planes.primary,
+                                               supported_encodings,
+                                               supported_ranges,
+                                               DRM_COLOR_YCBCR_BT601,
+                                               DRM_COLOR_YCBCR_LIMITED_RANGE);
+       if (ret)
+               return ret;
+
        drm_crtc_helper_add(crtc, &lcdif_crtc_helper_funcs);
        ret = drm_crtc_init_with_planes(lcdif->drm, crtc,
                                        &lcdif->planes.primary, NULL,
diff --git a/drivers/gpu/drm/mxsfb/lcdif_regs.h 
b/drivers/gpu/drm/mxsfb/lcdif_regs.h
index 0d5d9bedd94a..fb74eb5ccbf1 100644
--- a/drivers/gpu/drm/mxsfb/lcdif_regs.h
+++ b/drivers/gpu/drm/mxsfb/lcdif_regs.h
@@ -216,7 +216,10 @@
 #define CTRLDESCL0_5_YUV_FORMAT_UY2VY1 (0x3 << 14)
 #define CTRLDESCL0_5_YUV_FORMAT_MASK   GENMASK(15, 14)
 
-#define CSC0_CTRL_CSC_MODE_RGB2YCbCr   GENMASK(2, 1)
+#define CSC0_CTRL_CSC_MODE_YUV2RGB     (0x0 << 1)
+#define CSC0_CTRL_CSC_MODE_YCbCr2RGB   (0x1 << 1)
+#define CSC0_CTRL_CSC_MODE_RGB2YUV     (0x2 << 1)
+#define CSC0_CTRL_CSC_MODE_RGB2YCbCr   (0x3 << 1)
 #define CSC0_CTRL_CSC_MODE_MASK                GENMASK(2, 1)
 #define CSC0_CTRL_BYPASS               BIT(0)
 
-- 
Regards,

Laurent Pinchart

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