[PATCH] drm/malidp: Fix writeback in NV12

[Alexandru Gheorghe]

When we want to writeback to memory in NV12 format we need to program
the RGB2YUV coefficients.
Currently, we don't program the coefficients and the NV12 doesn't work
at all.

This patchset fixes that by programming a sane default(bt709, limited
range) as rgb2yuv coefficients.

In the long run, probably we need to think of a way for userspace to
be able to program that, but for now I think this is better than not
working at all or not advertising NV12 as a supported format for
memwrite.

Reviewed-by: Liviu Dudau <liviu.dudau at arm.com>
Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe at arm.com>
---
 drivers/gpu/drm/arm/malidp_hw.c   | 25 +++++++++++++++++++++++--
 drivers/gpu/drm/arm/malidp_hw.h   |  6 ++++--
 drivers/gpu/drm/arm/malidp_mw.c   | 12 +++++++++++-
 drivers/gpu/drm/arm/malidp_regs.h |  2 ++
 4 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c
index c94a4422e0e9..2781e462c1ed 100644
--- a/drivers/gpu/drm/arm/malidp_hw.c
+++ b/drivers/gpu/drm/arm/malidp_hw.c
@@ -384,7 +384,8 @@ static long malidp500_se_calc_mclk(struct malidp_hw_device *hwdev,
 
 static int malidp500_enable_memwrite(struct malidp_hw_device *hwdev,
 				     dma_addr_t *addrs, s32 *pitches,
-				     int num_planes, u16 w, u16 h, u32 fmt_id)
+				     int num_planes, u16 w, u16 h, u32 fmt_id,
+				     const s16 *rgb2yuv_coeffs)
 {
 	u32 base = MALIDP500_SE_MEMWRITE_BASE;
 	u32 de_base = malidp_get_block_base(hwdev, MALIDP_DE_BLOCK);
@@ -416,6 +417,16 @@ static int malidp500_enable_memwrite(struct malidp_hw_device *hwdev,
 
 	malidp_hw_write(hwdev, MALIDP_DE_H_ACTIVE(w) | MALIDP_DE_V_ACTIVE(h),
 			MALIDP500_SE_MEMWRITE_OUT_SIZE);
+
+	if (rgb2yuv_coeffs) {
+		int i;
+
+		for (i = 0; i < MALIDP_COLORADJ_NUM_COEFFS; i++) {
+			malidp_hw_write(hwdev, rgb2yuv_coeffs[i],
+					MALIDP500_SE_RGB_YUV_COEFFS + i * 4);
+		}
+	}
+
 	malidp_hw_setbits(hwdev, MALIDP_SE_MEMWRITE_EN, MALIDP500_SE_CONTROL);
 
 	return 0;
@@ -658,7 +669,8 @@ static long malidp550_se_calc_mclk(struct malidp_hw_device *hwdev,
 
 static int malidp550_enable_memwrite(struct malidp_hw_device *hwdev,
 				     dma_addr_t *addrs, s32 *pitches,
-				     int num_planes, u16 w, u16 h, u32 fmt_id)
+				     int num_planes, u16 w, u16 h, u32 fmt_id,
+				     const s16 *rgb2yuv_coeffs)
 {
 	u32 base = MALIDP550_SE_MEMWRITE_BASE;
 	u32 de_base = malidp_get_block_base(hwdev, MALIDP_DE_BLOCK);
@@ -689,6 +701,15 @@ static int malidp550_enable_memwrite(struct malidp_hw_device *hwdev,
 	malidp_hw_setbits(hwdev, MALIDP550_SE_MEMWRITE_ONESHOT | MALIDP_SE_MEMWRITE_EN,
 			  MALIDP550_SE_CONTROL);
 
+	if (rgb2yuv_coeffs) {
+		int i;
+
+		for (i = 0; i < MALIDP_COLORADJ_NUM_COEFFS; i++) {
+			malidp_hw_write(hwdev, rgb2yuv_coeffs[i],
+					MALIDP550_SE_RGB_YUV_COEFFS + i * 4);
+		}
+	}
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/arm/malidp_hw.h b/drivers/gpu/drm/arm/malidp_hw.h
index ad2e96915d44..d2ceb70305ca 100644
--- a/drivers/gpu/drm/arm/malidp_hw.h
+++ b/drivers/gpu/drm/arm/malidp_hw.h
@@ -190,8 +190,10 @@ struct malidp_hw {
 	 * @param h - height of the output frame
 	 * @param fmt_id - internal format ID of output buffer
 	 */
-	int (*enable_memwrite)(struct malidp_hw_device *hwdev, dma_addr_t *addrs,
-			       s32 *pitches, int num_planes, u16 w, u16 h, u32 fmt_id);
+	int (*enable_memwrite)(struct malidp_hw_device *hwdev,
+			       dma_addr_t *addrs, s32 *pitches, int num_planes,
+			       u16 w, u16 h, u32 fmt_id,
+			       const s16 *rgb2yuv_coeffs);
 
 	/*
 	 * Disable the writing to memory of the next frame's content.
diff --git a/drivers/gpu/drm/arm/malidp_mw.c b/drivers/gpu/drm/arm/malidp_mw.c
index cfd718e7e97c..0523ba5d27dd 100644
--- a/drivers/gpu/drm/arm/malidp_mw.c
+++ b/drivers/gpu/drm/arm/malidp_mw.c
@@ -213,6 +213,13 @@ int malidp_mw_connector_init(struct drm_device *drm)
 	return 0;
 }
 
+static const s16 rgb2yuv_coeffs_bt709_limited[MALIDP_COLORADJ_NUM_COEFFS] = {
+	47,  157,   16,
+	-26,  -87,  112,
+	112, -102,  -10,
+	16,  128,  128
+};
+
 void malidp_mw_atomic_commit(struct drm_device *drm,
 			     struct drm_atomic_state *old_state)
 {
@@ -242,7 +249,10 @@ void malidp_mw_atomic_commit(struct drm_device *drm,
 
 		hwdev->hw->enable_memwrite(hwdev, mw_state->addrs,
 					   mw_state->pitches, mw_state->n_planes,
-					   fb->width, fb->height, mw_state->format);
+					   fb->width, fb->height,
+					   mw_state->format,
+					   fb->format->is_yuv ?
+					   rgb2yuv_coeffs_bt709_limited : NULL);
 	} else {
 		DRM_DEV_DEBUG_DRIVER(drm->dev, "Disable memwrite\n");
 		hwdev->hw->disable_memwrite(hwdev);
diff --git a/drivers/gpu/drm/arm/malidp_regs.h b/drivers/gpu/drm/arm/malidp_regs.h
index 3579d36b2a71..6ffe849774f2 100644
--- a/drivers/gpu/drm/arm/malidp_regs.h
+++ b/drivers/gpu/drm/arm/malidp_regs.h
@@ -205,6 +205,7 @@
 #define MALIDP500_SE_BASE		0x00c00
 #define MALIDP500_SE_CONTROL		0x00c0c
 #define MALIDP500_SE_MEMWRITE_OUT_SIZE	0x00c2c
+#define MALIDP500_SE_RGB_YUV_COEFFS	0x00C74
 #define MALIDP500_SE_MEMWRITE_BASE	0x00e00
 #define MALIDP500_DC_IRQ_BASE		0x00f00
 #define MALIDP500_CONFIG_VALID		0x00f00
@@ -238,6 +239,7 @@
 #define MALIDP550_SE_CONTROL		0x08010
 #define   MALIDP550_SE_MEMWRITE_ONESHOT	(1 << 7)
 #define MALIDP550_SE_MEMWRITE_OUT_SIZE	0x08030
+#define MALIDP550_SE_RGB_YUV_COEFFS	0x08078
 #define MALIDP550_SE_MEMWRITE_BASE	0x08100
 #define MALIDP550_DC_BASE		0x0c000
 #define MALIDP550_DC_CONTROL		0x0c010
-- 
2.18.0