OMAPDSS: DISPC: Update Fir Coefficients
The FIR coefficients present in kernel are being updated to new coefficients
consisting of 24 coefficient tables, with 12 each for 3 tap and 5 tap scenario,
which are chosen on the basis of DISPC up/downsampling filters M value. M is
the inverse of low pass cut off frequency of the sampling filter. For vertical
scaling 3 tap or 5 tap tables are used based on the clock rate and width of
the line buffer whereas in OMAP2 3 tap is always used. For horizontal scaling
however 5 tap tables are always used.
New coefficients and the corresponding logic have been tested on OMAP2, OMAP3
and OMAP4. Horizontal and vertical scaling worked fine except for some 3 tap
vs 5 tap issue during vertical upscaling and clock failing issues which is
acknowledged in the next patch. Vertical upscaling was found to perform better
under 5 taps. The 24 coefficient tables have been moved to another file
dispc_coefs.c for proper maintainance.
This code is written based on code written by Lajos Molnar <lajos@ti.com> in
Android Kernel for scaling. Lajos Molnar <lajos@ti.com> had fine tuned the FIR
coefficient selection process and reduced outliness and blockiness around
images when upscaling more than 2 times.
Signed-off-by: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 4d68428..78e51d9 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -64,22 +64,6 @@
u32 mask;
};
-struct dispc_h_coef {
- s8 hc4;
- s8 hc3;
- u8 hc2;
- s8 hc1;
- s8 hc0;
-};
-
-struct dispc_v_coef {
- s8 vc22;
- s8 vc2;
- u8 vc1;
- s8 vc0;
- s8 vc00;
-};
-
enum omap_burst_size {
BURST_SIZE_X2 = 0,
BURST_SIZE_X4 = 1,
@@ -561,105 +545,27 @@
dispc_write_reg(DISPC_OVL_FIR_COEF_V2(plane, reg), value);
}
-static void dispc_ovl_set_scale_coef(enum omap_plane plane, int hscaleup,
- int vscaleup, int five_taps,
- enum omap_color_component color_comp)
+static void dispc_ovl_set_scale_coef(enum omap_plane plane, int fir_hinc,
+ int fir_vinc, int five_taps,
+ enum omap_color_component color_comp)
{
- /* Coefficients for horizontal up-sampling */
- static const struct dispc_h_coef coef_hup[8] = {
- { 0, 0, 128, 0, 0 },
- { -1, 13, 124, -8, 0 },
- { -2, 30, 112, -11, -1 },
- { -5, 51, 95, -11, -2 },
- { 0, -9, 73, 73, -9 },
- { -2, -11, 95, 51, -5 },
- { -1, -11, 112, 30, -2 },
- { 0, -8, 124, 13, -1 },
- };
-
- /* Coefficients for vertical up-sampling */
- static const struct dispc_v_coef coef_vup_3tap[8] = {
- { 0, 0, 128, 0, 0 },
- { 0, 3, 123, 2, 0 },
- { 0, 12, 111, 5, 0 },
- { 0, 32, 89, 7, 0 },
- { 0, 0, 64, 64, 0 },
- { 0, 7, 89, 32, 0 },
- { 0, 5, 111, 12, 0 },
- { 0, 2, 123, 3, 0 },
- };
-
- static const struct dispc_v_coef coef_vup_5tap[8] = {
- { 0, 0, 128, 0, 0 },
- { -1, 13, 124, -8, 0 },
- { -2, 30, 112, -11, -1 },
- { -5, 51, 95, -11, -2 },
- { 0, -9, 73, 73, -9 },
- { -2, -11, 95, 51, -5 },
- { -1, -11, 112, 30, -2 },
- { 0, -8, 124, 13, -1 },
- };
-
- /* Coefficients for horizontal down-sampling */
- static const struct dispc_h_coef coef_hdown[8] = {
- { 0, 36, 56, 36, 0 },
- { 4, 40, 55, 31, -2 },
- { 8, 44, 54, 27, -5 },
- { 12, 48, 53, 22, -7 },
- { -9, 17, 52, 51, 17 },
- { -7, 22, 53, 48, 12 },
- { -5, 27, 54, 44, 8 },
- { -2, 31, 55, 40, 4 },
- };
-
- /* Coefficients for vertical down-sampling */
- static const struct dispc_v_coef coef_vdown_3tap[8] = {
- { 0, 36, 56, 36, 0 },
- { 0, 40, 57, 31, 0 },
- { 0, 45, 56, 27, 0 },
- { 0, 50, 55, 23, 0 },
- { 0, 18, 55, 55, 0 },
- { 0, 23, 55, 50, 0 },
- { 0, 27, 56, 45, 0 },
- { 0, 31, 57, 40, 0 },
- };
-
- static const struct dispc_v_coef coef_vdown_5tap[8] = {
- { 0, 36, 56, 36, 0 },
- { 4, 40, 55, 31, -2 },
- { 8, 44, 54, 27, -5 },
- { 12, 48, 53, 22, -7 },
- { -9, 17, 52, 51, 17 },
- { -7, 22, 53, 48, 12 },
- { -5, 27, 54, 44, 8 },
- { -2, 31, 55, 40, 4 },
- };
-
- const struct dispc_h_coef *h_coef;
- const struct dispc_v_coef *v_coef;
+ const struct dispc_coef *h_coef, *v_coef;
int i;
- if (hscaleup)
- h_coef = coef_hup;
- else
- h_coef = coef_hdown;
-
- if (vscaleup)
- v_coef = five_taps ? coef_vup_5tap : coef_vup_3tap;
- else
- v_coef = five_taps ? coef_vdown_5tap : coef_vdown_3tap;
+ h_coef = dispc_ovl_get_scale_coef(fir_hinc, true);
+ v_coef = dispc_ovl_get_scale_coef(fir_vinc, five_taps);
for (i = 0; i < 8; i++) {
u32 h, hv;
- h = FLD_VAL(h_coef[i].hc0, 7, 0)
- | FLD_VAL(h_coef[i].hc1, 15, 8)
- | FLD_VAL(h_coef[i].hc2, 23, 16)
- | FLD_VAL(h_coef[i].hc3, 31, 24);
- hv = FLD_VAL(h_coef[i].hc4, 7, 0)
- | FLD_VAL(v_coef[i].vc0, 15, 8)
- | FLD_VAL(v_coef[i].vc1, 23, 16)
- | FLD_VAL(v_coef[i].vc2, 31, 24);
+ h = FLD_VAL(h_coef[i].hc0_vc00, 7, 0)
+ | FLD_VAL(h_coef[i].hc1_vc0, 15, 8)
+ | FLD_VAL(h_coef[i].hc2_vc1, 23, 16)
+ | FLD_VAL(h_coef[i].hc3_vc2, 31, 24);
+ hv = FLD_VAL(h_coef[i].hc4_vc22, 7, 0)
+ | FLD_VAL(v_coef[i].hc1_vc0, 15, 8)
+ | FLD_VAL(v_coef[i].hc2_vc1, 23, 16)
+ | FLD_VAL(v_coef[i].hc3_vc2, 31, 24);
if (color_comp == DISPC_COLOR_COMPONENT_RGB_Y) {
dispc_ovl_write_firh_reg(plane, i, h);
@@ -674,8 +580,8 @@
if (five_taps) {
for (i = 0; i < 8; i++) {
u32 v;
- v = FLD_VAL(v_coef[i].vc00, 7, 0)
- | FLD_VAL(v_coef[i].vc22, 15, 8);
+ v = FLD_VAL(v_coef[i].hc0_vc00, 7, 0)
+ | FLD_VAL(v_coef[i].hc4_vc22, 15, 8);
if (color_comp == DISPC_COLOR_COMPONENT_RGB_Y)
dispc_ovl_write_firv_reg(plane, i, v);
else
@@ -1228,17 +1134,12 @@
enum omap_color_component color_comp)
{
int fir_hinc, fir_vinc;
- int hscaleup, vscaleup;
-
- hscaleup = orig_width <= out_width;
- vscaleup = orig_height <= out_height;
-
- dispc_ovl_set_scale_coef(plane, hscaleup, vscaleup, five_taps,
- color_comp);
fir_hinc = 1024 * orig_width / out_width;
fir_vinc = 1024 * orig_height / out_height;
+ dispc_ovl_set_scale_coef(plane, fir_hinc, fir_vinc, five_taps,
+ color_comp);
dispc_ovl_set_fir(plane, fir_hinc, fir_vinc, color_comp);
}