OMAP: DSS2: Fix FIFO threshold and burst size for OMAP4

The DMA FIFO threshold registers and burst size registers have changed
for OMAP4.  The current code only handles OMAP2/3 case, and so the
values are a bit off for OMAP4.  A summary of the differences between
OMAP2/3 and OMAP4:

Burst size:
OMAP2/3: 4 x 32 bits / 8 x 32 bits / 16 x 32 bits
OMAP4: 2 x 128 bits / 4 x 128 bits / 8 x 128 bits

Threshold size:
OMAP2/3: in bytes (8 bit units)
OMAP4: in 128bit units

This patch fixes the issue by creating two new helper functions in
dss_features: dss_feat_get_buffer_size_unit() and
dss_feat_get_burst_size_unit(). These return (in bytes) the unit size
for threshold registers and unit size for burst size register,
respectively, and are used to calculate correct values.

For the threshold size the usage is straightforward. However, the burst
size register has different multipliers for OMAP2/3 and OMAP4. This
patch solves the problem by defining the multipliers for the burst size
as 2x, 4x and 8x, which fit fine for the OMAP4 burst size definition
(i.e. burst size unit for OMAP4 is 128bits), but requires a slight twist
on OMAP2/3 by defining the burst size unit as 64bit.

As the driver in practice always uses the maximum burst size, and no use
case currently exists where we would want to use a smaller burst size,
this patch changes the driver to hardcode the burst size when
initializing DISPC. This makes the threshold configuration code somewhat
simpler.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 4 insertions, 11 deletions

diff --git a/drivers/video/omap2/dss/dss.h b/drivers/video/omap2/dss/dss.h
index 0b4166085b17..0283f48450e6 100644
--- a/drivers/video/omap2/dss/dss.h
+++ b/drivers/video/omap2/dss/dss.h
@@ -97,12 +97,6 @@ extern unsigned int dss_debug;
 #define FLD_MOD(orig, val, start, end) \
 	(((orig) & ~FLD_MASK(start, end)) | FLD_VAL(val, start, end))
 
-enum omap_burst_size {
-	OMAP_DSS_BURST_4x32 = 0,
-	OMAP_DSS_BURST_8x32 = 1,
-	OMAP_DSS_BURST_16x32 = 2,
-};
-
 enum omap_parallel_interface_mode {
 	OMAP_DSS_PARALLELMODE_BYPASS,		/* MIPI DPI */
 	OMAP_DSS_PARALLELMODE_RFBI,		/* MIPI DBI */
@@ -194,7 +188,7 @@ void dss_uninit_device(struct platform_device *pdev,
 bool dss_use_replication(struct omap_dss_device *dssdev,
 		enum omap_color_mode mode);
 void default_get_overlay_fifo_thresholds(enum omap_plane plane,
-		u32 fifo_size, enum omap_burst_size *burst_size,
+		u32 fifo_size, u32 burst_size,
 		u32 *fifo_low, u32 *fifo_high);
 
 /* manager */
@@ -304,7 +298,7 @@ int dsi_pll_init(struct platform_device *dsidev, bool enable_hsclk,
 		bool enable_hsdiv);
 void dsi_pll_uninit(struct platform_device *dsidev, bool disconnect_lanes);
 void dsi_get_overlay_fifo_thresholds(enum omap_plane plane,
-		u32 fifo_size, enum omap_burst_size *burst_size,
+		u32 fifo_size, u32 burst_size,
 		u32 *fifo_low, u32 *fifo_high);
 void dsi_wait_pll_hsdiv_dispc_active(struct platform_device *dsidev);
 void dsi_wait_pll_hsdiv_dsi_active(struct platform_device *dsidev);
@@ -398,10 +392,9 @@ void dispc_enable_fifohandcheck(enum omap_channel channel, bool enable);
 void dispc_set_lcd_size(enum omap_channel channel, u16 width, u16 height);
 void dispc_set_digit_size(u16 width, u16 height);
 u32 dispc_get_plane_fifo_size(enum omap_plane plane);
-void dispc_setup_plane_fifo(enum omap_plane plane, u32 low, u32 high);
+void dispc_set_fifo_threshold(enum omap_plane plane, u32 low, u32 high);
 void dispc_enable_fifomerge(bool enable);
-void dispc_set_burst_size(enum omap_plane plane,
-		enum omap_burst_size burst_size);
+u32 dispc_get_burst_size(enum omap_plane plane);
 void dispc_enable_cpr(enum omap_channel channel, bool enable);
 void dispc_set_cpr_coef(enum omap_channel channel,
 		struct omap_dss_cpr_coefs *coefs);