drm/ingenic: Add support for OSD mode

All Ingenic SoCs starting from the JZ4725B support OSD mode.

In this mode, two separate planes can be used. They can have different
positions and sizes, and one can be overlayed on top of the other.

v2: Use fallthrough; instead of /* fall-through */

v3: - Add custom atomic_tail function to handle case where HW gives no
      VBLANK
    - Use regmap_set_bits() / regmap_clear_bits() when possible
    - Use dma_hwdesc_f{0,1} fields in priv structure instead of array
    - Use dmam_alloc_coherent() instead of dma_alloc_coherent()
    - Use more meaningful 0xf0 / 0xf1 values as DMA descriptors IDs
    - Add a bit more code comments
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200716163846.174790-9-paul@crapouillou.net

drivers/gpu/drm/ingenic/ingenic-drm.h

@@ -30,6 +30,18 @@
 #define JZ_REG_LCD_SA1				0x54
 #define JZ_REG_LCD_FID1				0x58
 #define JZ_REG_LCD_CMD1				0x5C
+#define JZ_REG_LCD_OSDC				0x100
+#define JZ_REG_LCD_OSDCTRL			0x104
+#define JZ_REG_LCD_OSDS				0x108
+#define JZ_REG_LCD_BGC				0x10c
+#define JZ_REG_LCD_KEY0				0x110
+#define JZ_REG_LCD_KEY1				0x114
+#define JZ_REG_LCD_ALPHA			0x118
+#define JZ_REG_LCD_IPUR				0x11c
+#define JZ_REG_LCD_XYP0				0x120
+#define JZ_REG_LCD_XYP1				0x124
+#define JZ_REG_LCD_SIZE0			0x128
+#define JZ_REG_LCD_SIZE1			0x12c
 
 #define JZ_LCD_CFG_SLCD				BIT(31)
 #define JZ_LCD_CFG_PS_DISABLE			BIT(23)
@@ -123,4 +135,27 @@
 #define JZ_LCD_STATE_SOF_IRQ			BIT(4)
 #define JZ_LCD_STATE_DISABLED			BIT(0)
 
+#define JZ_LCD_OSDC_OSDEN			BIT(0)
+#define JZ_LCD_OSDC_F0EN			BIT(3)
+#define JZ_LCD_OSDC_F1EN			BIT(4)
+
+#define JZ_LCD_OSDCTRL_IPU			BIT(15)
+#define JZ_LCD_OSDCTRL_RGB555			BIT(4)
+#define JZ_LCD_OSDCTRL_CHANGE			BIT(3)
+#define JZ_LCD_OSDCTRL_BPP_15_16		0x4
+#define JZ_LCD_OSDCTRL_BPP_18_24		0x5
+#define JZ_LCD_OSDCTRL_BPP_30			0x7
+#define JZ_LCD_OSDCTRL_BPP_MASK			(JZ_LCD_OSDCTRL_RGB555 | 0x7)
+
+#define JZ_LCD_OSDS_READY			BIT(0)
+
+#define JZ_LCD_IPUR_IPUREN			BIT(31)
+#define JZ_LCD_IPUR_IPUR_LSB			0
+
+#define JZ_LCD_XYP01_XPOS_LSB			0
+#define JZ_LCD_XYP01_YPOS_LSB			16
+
+#define JZ_LCD_SIZE01_WIDTH_LSB			0
+#define JZ_LCD_SIZE01_HEIGHT_LSB		16
+
 #endif /* DRIVERS_GPU_DRM_INGENIC_INGENIC_DRM_H */