drm/ingenic: Use the highest possible DMA burst size

Until now, when running at the maximum resolution of 1280x720 at 32bpp
on the JZ4770 SoC the output was garbled, the X/Y position of the
top-left corner of the framebuffer warping to a random position with
the whole image being offset accordingly, every time a new frame was
being submitted.

This problem can be eliminated by using a bigger burst size for the DMA.

Set in each soc_info structure the maximum burst size supported by the
corresponding SoC, and use it in the driver.

Set the new value using regmap_update_bits() instead of
regmap_set_bits(), since we do want to override the old value of the
burst size. (Note that regmap_set_bits() wasn't really valid before for
the same reason, but it never seemed to be a problem).

Cc: <stable@vger.kernel.org>
Fixes: 90b86fcc47b4 ("DRM: Add KMS driver for the Ingenic JZ47xx SoCs")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20220702230727.66704-1-paul@crapouillou.net
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Tested-by: Christophe Branchereau <cbranchereau@gmail.com>

diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
index 2c55988..8ad6080 100644 (file)
--- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
+++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
@@ -70,6 +70,7 @@ struct jz_soc_info {
        bool map_noncoherent;
        bool use_extended_hwdesc;
        bool plane_f0_not_working;
+       u32 max_burst;
        unsigned int max_width, max_height;
        const u32 *formats_f0, *formats_f1;
        unsigned int num_formats_f0, num_formats_f1;
@@ -319,8 +320,9 @@ static void ingenic_drm_crtc_update_timings(struct ingenic_drm *priv,
                regmap_write(priv->map, JZ_REG_LCD_REV, mode->htotal << 16);
        }
 
-       regmap_set_bits(priv->map, JZ_REG_LCD_CTRL,
-                       JZ_LCD_CTRL_OFUP | JZ_LCD_CTRL_BURST_16);
+       regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
+                          JZ_LCD_CTRL_OFUP | JZ_LCD_CTRL_BURST_MASK,
+                          JZ_LCD_CTRL_OFUP | priv->soc_info->max_burst);
 
        /*
         * IPU restart - specify how much time the LCDC will wait before
@@ -1519,6 +1521,7 @@ static const struct jz_soc_info jz4740_soc_info = {
        .map_noncoherent = false,
        .max_width = 800,
        .max_height = 600,
+       .max_burst = JZ_LCD_CTRL_BURST_16,
        .formats_f1 = jz4740_formats,
        .num_formats_f1 = ARRAY_SIZE(jz4740_formats),
        /* JZ4740 has only one plane */
@@ -1530,6 +1533,7 @@ static const struct jz_soc_info jz4725b_soc_info = {
        .map_noncoherent = false,
        .max_width = 800,
        .max_height = 600,
+       .max_burst = JZ_LCD_CTRL_BURST_16,
        .formats_f1 = jz4725b_formats_f1,
        .num_formats_f1 = ARRAY_SIZE(jz4725b_formats_f1),
        .formats_f0 = jz4725b_formats_f0,
@@ -1542,6 +1546,7 @@ static const struct jz_soc_info jz4770_soc_info = {
        .map_noncoherent = true,
        .max_width = 1280,
        .max_height = 720,
+       .max_burst = JZ_LCD_CTRL_BURST_64,
        .formats_f1 = jz4770_formats_f1,
        .num_formats_f1 = ARRAY_SIZE(jz4770_formats_f1),
        .formats_f0 = jz4770_formats_f0,
@@ -1556,6 +1561,7 @@ static const struct jz_soc_info jz4780_soc_info = {
        .plane_f0_not_working = true,   /* REVISIT */
        .max_width = 4096,
        .max_height = 2048,
+       .max_burst = JZ_LCD_CTRL_BURST_64,
        .formats_f1 = jz4770_formats_f1,
        .num_formats_f1 = ARRAY_SIZE(jz4770_formats_f1),
        .formats_f0 = jz4770_formats_f0,

diff --git a/drivers/gpu/drm/ingenic/ingenic-drm.h b/drivers/gpu/drm/ingenic/ingenic-drm.h
index cb1d09b..e5bd007 100644 (file)
--- a/drivers/gpu/drm/ingenic/ingenic-drm.h
+++ b/drivers/gpu/drm/ingenic/ingenic-drm.h
@@ -106,6 +106,9 @@
 #define JZ_LCD_CTRL_BURST_4                    (0x0 << 28)
 #define JZ_LCD_CTRL_BURST_8                    (0x1 << 28)
 #define JZ_LCD_CTRL_BURST_16                   (0x2 << 28)
+#define JZ_LCD_CTRL_BURST_32                   (0x3 << 28)
+#define JZ_LCD_CTRL_BURST_64                   (0x4 << 28)
+#define JZ_LCD_CTRL_BURST_MASK                 (0x7 << 28)
 #define JZ_LCD_CTRL_RGB555                     BIT(27)
 #define JZ_LCD_CTRL_OFUP                       BIT(26)
 #define JZ_LCD_CTRL_FRC_GRAYSCALE_16           (0x0 << 24)