drm/meson: viu: fix setting the OSD burst length in VIU_OSD1_FIFO_CTRL_STAT

The burst length is configured in VIU_OSD1_FIFO_CTRL_STAT[31] and
VIU_OSD1_FIFO_CTRL_STAT[11:10]. The public S905D3 datasheet describes
this as:
- 0x0 = up to 24 per burst
- 0x1 = up to 32 per burst
- 0x2 = up to 48 per burst
- 0x3 = up to 64 per burst
- 0x4 = up to 96 per burst
- 0x5 = up to 128 per burst

The lower two bits map to VIU_OSD1_FIFO_CTRL_STAT[11:10] while the upper
bit maps to VIU_OSD1_FIFO_CTRL_STAT[31].

Replace meson_viu_osd_burst_length_reg() with pre-defined macros which
set these values. meson_viu_osd_burst_length_reg() always returned 0
(for the two used values: 32 and 64 at least) and thus incorrectly set
the burst size to 24.

Fixes: 147ae1cb ("drm: meson: viu: use proper macros instead of magic constants")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200620155752.21065-1-martin.blumenstingl@googlemail.com

drivers/gpu/drm/meson/meson_registers.h

@@ -261,6 +261,12 @@
 #define VIU_OSD_FIFO_DEPTH_VAL(val)      ((val & 0x7f) << 12)
 #define VIU_OSD_WORDS_PER_BURST(words)   (((words & 0x4) >> 1) << 22)
 #define VIU_OSD_FIFO_LIMITS(size)        ((size & 0xf) << 24)
+#define VIU_OSD_BURST_LENGTH_24          (0x0 << 31 | 0x0 << 10)
+#define VIU_OSD_BURST_LENGTH_32          (0x0 << 31 | 0x1 << 10)
+#define VIU_OSD_BURST_LENGTH_48          (0x0 << 31 | 0x2 << 10)
+#define VIU_OSD_BURST_LENGTH_64          (0x0 << 31 | 0x3 << 10)
+#define VIU_OSD_BURST_LENGTH_96          (0x1 << 31 | 0x0 << 10)
+#define VIU_OSD_BURST_LENGTH_128         (0x1 << 31 | 0x1 << 10)
 
 #define VD1_IF0_GEN_REG 0x1a50
 #define VD1_IF0_CANVAS0 0x1a51

drivers/gpu/drm/meson/meson_viu.c

@@ -411,13 +411,6 @@ void meson_viu_gxm_disable_osd1_afbc(struct meson_drm *priv)
 			    priv->io_base + _REG(VIU_MISC_CTRL1));
 }
 
-static inline uint32_t meson_viu_osd_burst_length_reg(uint32_t length)
-{
-	uint32_t val = (((length & 0x80) % 24) / 12);
-
-	return (((val & 0x3) << 10) | (((val & 0x4) >> 2) << 31));
-}
-
 void meson_viu_init(struct meson_drm *priv)
 {
 	uint32_t reg;
@@ -444,9 +437,9 @@ void meson_viu_init(struct meson_drm *priv)
 		VIU_OSD_FIFO_LIMITS(2);      /* fifo_lim: 2*16=32 */
 
 	if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A))
-		reg |= meson_viu_osd_burst_length_reg(32);
+		reg |= VIU_OSD_BURST_LENGTH_32;
 	else
-		reg |= meson_viu_osd_burst_length_reg(64);
+		reg |= VIU_OSD_BURST_LENGTH_64;
 
 	writel_relaxed(reg, priv->io_base + _REG(VIU_OSD1_FIFO_CTRL_STAT));
 	writel_relaxed(reg, priv->io_base + _REG(VIU_OSD2_FIFO_CTRL_STAT));