From debd90749b7440ad5fc02e4f0d1e8a696385f196 Mon Sep 17 00:00:00 2001
From: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Date: Mon, 19 Dec 2011 14:03:44 +0530
Subject: 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>
---
 drivers/video/omap2/dss/dispc_coefs.c | 326 ++++++++++++++++++++++++++++++++++
 1 file changed, 326 insertions(+)
 create mode 100644 drivers/video/omap2/dss/dispc_coefs.c

(limited to 'drivers/video/omap2/dss/dispc_coefs.c')

diff --git a/drivers/video/omap2/dss/dispc_coefs.c b/drivers/video/omap2/dss/dispc_coefs.c
new file mode 100644
index 00000000000..069bccbb3f1
--- /dev/null
+++ b/drivers/video/omap2/dss/dispc_coefs.c
@@ -0,0 +1,326 @@
+/*
+ * linux/drivers/video/omap2/dss/dispc_coefs.c
+ *
+ * Copyright (C) 2011 Texas Instruments
+ * Author: Chandrabhanu Mahapatra <cmahapatra@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <video/omapdss.h>
+#include "dispc.h"
+
+#define ARRAY_LEN(array) (sizeof(array) / sizeof(array[0]))
+
+static const struct dispc_coef coef3_M8[8] = {
+	{ 0,  0, 128,  0, 0 },
+	{ 0, -4, 123,  9, 0 },
+	{ 0, -4, 108, 87, 0 },
+	{ 0, -2,  87, 43, 0 },
+	{ 0, 64,  64,  0, 0 },
+	{ 0, 43,  87, -2, 0 },
+	{ 0, 24, 108, -4, 0 },
+	{ 0,  9, 123, -4, 0 },
+};
+
+static const struct dispc_coef coef3_M9[8] = {
+	{ 0,  6, 116,  6, 0 },
+	{ 0,  0, 112, 16, 0 },
+	{ 0, -2, 100, 30, 0 },
+	{ 0, -2,  83, 47, 0 },
+	{ 0, 64,  64,  0, 0 },
+	{ 0, 47,  83, -2, 0 },
+	{ 0, 30, 100, -2, 0 },
+	{ 0, 16, 112,  0, 0 },
+};
+
+static const struct dispc_coef coef3_M10[8] = {
+	{ 0, 10, 108, 10, 0 },
+	{ 0,  3, 104, 21, 0 },
+	{ 0,  0,  94, 34, 0 },
+	{ 0, -1,  80, 49, 0 },
+	{ 0, 64,  64,  0, 0 },
+	{ 0, 49,  80, -1, 0 },
+	{ 0, 34,  94,  0, 0 },
+	{ 0, 21, 104,  3, 0 },
+};
+
+static const struct dispc_coef coef3_M11[8] = {
+	{ 0, 14, 100, 14, 0 },
+	{ 0,  6,  98, 24, 0 },
+	{ 0,  2,  90, 36, 0 },
+	{ 0,  0,  78, 50, 0 },
+	{ 0, 64,  64,  0, 0 },
+	{ 0, 50,  78,  0, 0 },
+	{ 0, 36,  90,  2, 0 },
+	{ 0, 24,  98,  6, 0 },
+};
+
+static const struct dispc_coef coef3_M12[8] = {
+	{ 0, 16,  96, 16, 0 },
+	{ 0,  9,  93, 26, 0 },
+	{ 0,  4,  86, 38, 0 },
+	{ 0,  1,  76, 51, 0 },
+	{ 0, 64,  64,  0, 0 },
+	{ 0, 51,  76,  1, 0 },
+	{ 0, 38,  86,  4, 0 },
+	{ 0, 26,  93,  9, 0 },
+};
+
+static const struct dispc_coef coef3_M13[8] = {
+	{ 0, 18,  92, 18, 0 },
+	{ 0, 10,  90, 28, 0 },
+	{ 0,  5,  83, 40, 0 },
+	{ 0,  1,  75, 52, 0 },
+	{ 0, 64,  64,  0, 0 },
+	{ 0, 52,  75,  1, 0 },
+	{ 0, 40,  83,  5, 0 },
+	{ 0, 28,  90, 10, 0 },
+};
+
+static const struct dispc_coef coef3_M14[8] = {
+	{ 0, 20, 88, 20, 0 },
+	{ 0, 12, 86, 30, 0 },
+	{ 0,  6, 81, 41, 0 },
+	{ 0,  2, 74, 52, 0 },
+	{ 0, 64, 64,  0, 0 },
+	{ 0, 52, 74,  2, 0 },
+	{ 0, 41, 81,  6, 0 },
+	{ 0, 30, 86, 12, 0 },
+};
+
+static const struct dispc_coef coef3_M16[8] = {
+	{ 0, 22, 84, 22, 0 },
+	{ 0, 14, 82, 32, 0 },
+	{ 0,  8, 78, 42, 0 },
+	{ 0,  3, 72, 53, 0 },
+	{ 0, 64, 64,  0, 0 },
+	{ 0, 53, 72,  3, 0 },
+	{ 0, 42, 78,  8, 0 },
+	{ 0, 32, 82, 14, 0 },
+};
+
+static const struct dispc_coef coef3_M19[8] = {
+	{ 0, 24, 80, 24, 0 },
+	{ 0, 16, 79, 33, 0 },
+	{ 0,  9, 76, 43, 0 },
+	{ 0,  4, 70, 54, 0 },
+	{ 0, 64, 64,  0, 0 },
+	{ 0, 54, 70,  4, 0 },
+	{ 0, 43, 76,  9, 0 },
+	{ 0, 33, 79, 16, 0 },
+};
+
+static const struct dispc_coef coef3_M22[8] = {
+	{ 0, 25, 78, 25, 0 },
+	{ 0, 17, 77, 34, 0 },
+	{ 0, 10, 74, 44, 0 },
+	{ 0,  5, 69, 54, 0 },
+	{ 0, 64, 64,  0, 0 },
+	{ 0, 54, 69,  5, 0 },
+	{ 0, 44, 74, 10, 0 },
+	{ 0, 34, 77, 17, 0 },
+};
+
+static const struct dispc_coef coef3_M26[8] = {
+	{ 0, 26, 76, 26, 0 },
+	{ 0, 19, 74, 35, 0 },
+	{ 0, 11, 72, 45, 0 },
+	{ 0,  5, 69, 54, 0 },
+	{ 0, 64, 64,  0, 0 },
+	{ 0, 54, 69,  5, 0 },
+	{ 0, 45, 72, 11, 0 },
+	{ 0, 35, 74, 19, 0 },
+};
+
+static const struct dispc_coef coef3_M32[8] = {
+	{ 0, 27, 74, 27, 0 },
+	{ 0, 19, 73, 36, 0 },
+	{ 0, 12, 71, 45, 0 },
+	{ 0,  6, 68, 54, 0 },
+	{ 0, 64, 64,  0, 0 },
+	{ 0, 54, 68,  6, 0 },
+	{ 0, 45, 71, 12, 0 },
+	{ 0, 36, 73, 19, 0 },
+};
+
+static const struct dispc_coef coef5_M8[8] = {
+	{   0,   0, 128,   0,   0 },
+	{  -2,  14, 125, -10,   1 },
+	{  -6,  33, 114, -15,   2 },
+	{ -10,  55,  98, -16,   1 },
+	{   0, -14,  78,  78, -14 },
+	{   1, -16,  98,  55, -10 },
+	{   2, -15, 114,  33,  -6 },
+	{   1, -10, 125,  14,  -2 },
+};
+
+static const struct dispc_coef coef5_M9[8] = {
+	{  -3,  10, 114,  10,  -3 },
+	{  -6,  24, 110,   0,  -1 },
+	{  -8,  40, 103,  -7,   0 },
+	{ -11,  58,  91, -11,   1 },
+	{   0, -12,  76,  76, -12 },
+	{   1, -11,  91,  58, -11 },
+	{   0,  -7, 103,  40,  -8 },
+	{  -1,   0, 111,  24,  -6 },
+};
+
+static const struct dispc_coef coef5_M10[8] = {
+	{  -4,  18, 100,  18,  -4 },
+	{  -6,  30,  99,   8,  -3 },
+	{  -8,  44,  93,   0,  -1 },
+	{  -9,  58,  84,  -5,   0 },
+	{   0,  -8,  72,  72,  -8 },
+	{   0,  -5,  84,  58,  -9 },
+	{  -1,   0,  93,  44,  -8 },
+	{  -3,   8,  99,  30,  -6 },
+};
+
+static const struct dispc_coef coef5_M11[8] = {
+	{  -5,  23,  92,  23,  -5 },
+	{  -6,  34,  90,  13,  -3 },
+	{  -6,  45,  85,   6,  -2 },
+	{  -6,  57,  78,   0,  -1 },
+	{   0,  -4,  68,  68,  -4 },
+	{  -1,   0,  78,  57,  -6 },
+	{  -2,   6,  85,  45,  -6 },
+	{  -3,  13,  90,  34,  -6 },
+};
+
+static const struct dispc_coef coef5_M12[8] = {
+	{  -4,  26,  84,  26,  -4 },
+	{  -5,  36,  82,  18,  -3 },
+	{  -4,  46,  78,  10,  -2 },
+	{  -3,  55,  72,   5,  -1 },
+	{   0,   0,  64,  64,   0 },
+	{  -1,   5,  72,  55,  -3 },
+	{  -2,  10,  78,  46,  -4 },
+	{  -3,  18,  82,  36,  -5 },
+};
+
+static const struct dispc_coef coef5_M13[8] = {
+	{  -3,  28,  78,  28,  -3 },
+	{  -3,  37,  76,  21,  -3 },
+	{  -2,  45,  73,  14,  -2 },
+	{   0,  53,  68,   8,  -1 },
+	{   0,   3,  61,  61,   3 },
+	{  -1,   8,  68,  53,   0 },
+	{  -2,  14,  73,  45,  -2 },
+	{  -3,  21,  76,  37,  -3 },
+};
+
+static const struct dispc_coef coef5_M14[8] = {
+	{  -2,  30,  72,  30,  -2 },
+	{  -1,  37,  71,  23,  -2 },
+	{   0,  45,  69,  16,  -2 },
+	{   3,  52,  64,  10,  -1 },
+	{   0,   6,  58,  58,   6 },
+	{  -1,  10,  64,  52,   3 },
+	{  -2,  16,  69,  45,   0 },
+	{  -2,  23,  71,  37,  -1 },
+};
+
+static const struct dispc_coef coef5_M16[8] = {
+	{   0,  31,  66,  31,   0 },
+	{   1,  38,  65,  25,  -1 },
+	{   3,  44,  62,  20,  -1 },
+	{   6,  49,  59,  14,   0 },
+	{   0,  10,  54,  54,  10 },
+	{   0,  14,  59,  49,   6 },
+	{  -1,  20,  62,  44,   3 },
+	{  -1,  25,  65,  38,   1 },
+};
+
+static const struct dispc_coef coef5_M19[8] = {
+	{   3,  32,  58,  32,   3 },
+	{   4,  38,  58,  27,   1 },
+	{   7,  42,  55,  23,   1 },
+	{  10,  46,  54,  18,   0 },
+	{   0,  14,  50,  50,  14 },
+	{   0,  18,  54,  46,  10 },
+	{   1,  23,  55,  42,   7 },
+	{   1,  27,  58,  38,   4 },
+};
+
+static const struct dispc_coef coef5_M22[8] = {
+	{   4,  33,  54,  33,   4 },
+	{   6,  37,  54,  28,   3 },
+	{   9,  41,  53,  24,   1 },
+	{  12,  45,  51,  20,   0 },
+	{   0,  16,  48,  48,  16 },
+	{   0,  20,  51,  45,  12 },
+	{   1,  24,  53,  41,   9 },
+	{   3,  28,  54,  37,   6 },
+};
+
+static const struct dispc_coef coef5_M26[8] = {
+	{   6,  33,  50,  33,   6 },
+	{   8,  36,  51,  29,   4 },
+	{  11,  40,  50,  25,   2 },
+	{  14,  43,  48,  22,   1 },
+	{   0,  18,  46,  46,  18 },
+	{   1,  22,  48,  43,  14 },
+	{   2,  25,  50,  40,  11 },
+	{   4,  29,  51,  36,   8 },
+};
+
+static const struct dispc_coef coef5_M32[8] = {
+	{   7,  33,  48,  33,   7 },
+	{  10,  36,  48,  29,   5 },
+	{  13,  39,  47,  26,   3 },
+	{  16,  42,  46,  23,   1 },
+	{   0,  19,  45,  45,  19 },
+	{   1,  23,  46,  42,  16 },
+	{   3,  26,  47,  39,  13 },
+	{   5,  29,  48,  36,  10 },
+};
+
+const struct dispc_coef *dispc_ovl_get_scale_coef(int inc, int five_taps)
+{
+	int i;
+	static const struct {
+		int Mmin;
+		int Mmax;
+		const struct dispc_coef *coef_3;
+		const struct dispc_coef *coef_5;
+	} coefs[] = {
+		{ 27, 32, coef3_M32, coef5_M32 },
+		{ 23, 26, coef3_M26, coef5_M26 },
+		{ 20, 22, coef3_M22, coef5_M22 },
+		{ 17, 19, coef3_M19, coef5_M19 },
+		{ 15, 16, coef3_M16, coef5_M16 },
+		{ 14, 14, coef3_M14, coef5_M14 },
+		{ 13, 13, coef3_M13, coef5_M13 },
+		{ 12, 12, coef3_M12, coef5_M12 },
+		{ 11, 11, coef3_M11, coef5_M11 },
+		{ 10, 10, coef3_M10, coef5_M10 },
+		{  9,  9,  coef3_M9,  coef5_M9 },
+		{  4,  8,  coef3_M8,  coef5_M8 },
+		/*
+		 * When upscaling more than two times, blockiness and outlines
+		 * around the image are observed when M8 tables are used. M11,
+		 * M16 and M19 tables are used to prevent this.
+		 */
+		{  3,  3, coef3_M11, coef5_M11 },
+		{  2,  2, coef3_M16, coef5_M16 },
+		{  0,  1, coef3_M19, coef5_M19 },
+	};
+
+	inc /= 128;
+	for (i = 0; i < ARRAY_LEN(coefs); ++i)
+		if (inc >= coefs[i].Mmin && inc <= coefs[i].Mmax)
+			return five_taps ? coefs[i].coef_5 : coefs[i].coef_3;
+	return NULL;
+}
-- 
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