1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Support for Intel Camera Imaging ISP subsystem.
4  * Copyright (c) 2015, Intel Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  */
15 
16 #include "ia_css_types.h"
17 #include "sh_css_defs.h"
18 #include "ia_css_debug.h"
19 #include "assert_support.h"
20 
21 #include "ctc/ctc_1.0/ia_css_ctc.host.h"
22 #include "ia_css_ctc1_5.host.h"
23 
ctc_gradient(int * dydx,int * shift,int y1,int y0,int x1,int x0)24 static void ctc_gradient(
25     int *dydx, int *shift,
26     int y1, int y0, int x1, int x0)
27 {
28 	int frc_bits = max(IA_CSS_CTC_COEF_SHIFT, 16);
29 	int dy = y1 - y0;
30 	int dx = x1 - x0;
31 	int dydx_int;
32 	int dydx_frc;
33 	int sft;
34 	/* max_dydx = the maxinum gradient = the maximum y (gain) */
35 	int max_dydx = (1 << IA_CSS_CTC_COEF_SHIFT) - 1;
36 
37 	if (dx == 0) {
38 		ia_css_debug_dtrace(IA_CSS_DEBUG_TRACE_PRIVATE,
39 				    "ctc_gradient() error, illegal division operation\n");
40 		return;
41 	} else {
42 		dydx_int = dy / dx;
43 		dydx_frc = ((dy - dydx_int * dx) << frc_bits) / dx;
44 	}
45 
46 	assert(y0 >= 0 && y0 <= max_dydx);
47 	assert(y1 >= 0 && y1 <= max_dydx);
48 	assert(x0 < x1);
49 	assert(dydx);
50 	assert(shift);
51 
52 	ia_css_debug_dtrace(IA_CSS_DEBUG_TRACE_PRIVATE, "ctc_gradient() enter:\n");
53 
54 	/* search "sft" which meets this condition:
55 		   (1 << (IA_CSS_CTC_COEF_SHIFT - 1))
56 		<= (((float)dy / (float)dx) * (1 << sft))
57 		<= ((1 << IA_CSS_CTC_COEF_SHIFT) - 1) */
58 	for (sft = 0; sft <= IA_CSS_CTC_COEF_SHIFT; sft++) {
59 		int tmp_dydx = (dydx_int << sft)
60 			       + (dydx_frc >> (frc_bits - sft));
61 		if (tmp_dydx <= max_dydx) {
62 			*dydx = tmp_dydx;
63 			*shift = sft;
64 		}
65 		if (tmp_dydx >= max_dydx)
66 			break;
67 	}
68 
69 	ia_css_debug_dtrace(IA_CSS_DEBUG_TRACE_PRIVATE, "ctc_gradient() leave:\n");
70 }
71 
72 void
ia_css_ctc_encode(struct sh_css_isp_ctc_params * to,const struct ia_css_ctc_config * from,unsigned int size)73 ia_css_ctc_encode(
74     struct sh_css_isp_ctc_params *to,
75     const struct ia_css_ctc_config *from,
76     unsigned int size)
77 {
78 	(void)size;
79 	to->y0 = from->y0;
80 	to->y1 = from->y1;
81 	to->y2 = from->y2;
82 	to->y3 = from->y3;
83 	to->y4 = from->y4;
84 	to->y5 = from->y5;
85 
86 	to->ce_gain_exp = from->ce_gain_exp;
87 
88 	to->x1 = from->x1;
89 	to->x2 = from->x2;
90 	to->x3 = from->x3;
91 	to->x4 = from->x4;
92 
93 	ctc_gradient(&to->dydx0,
94 		     &to->dydx0_shift,
95 		     from->y1, from->y0,
96 		     from->x1, 0);
97 
98 	ctc_gradient(&to->dydx1,
99 		     &to->dydx1_shift,
100 		     from->y2, from->y1,
101 		     from->x2, from->x1);
102 
103 	ctc_gradient(&to->dydx2,
104 		     &to->dydx2_shift,
105 		     from->y3, from->y2,
106 		     from->x3, from->x2);
107 
108 	ctc_gradient(&to->dydx3,
109 		     &to->dydx3_shift,
110 		     from->y4, from->y3,
111 		     from->x4, from->x3);
112 
113 	ctc_gradient(&to->dydx4,
114 		     &to->dydx4_shift,
115 		     from->y5, from->y4,
116 		     SH_CSS_BAYER_MAXVAL, from->x4);
117 }
118 
119 void
120 ia_css_ctc_dump(
121     const struct sh_css_isp_ctc_params *ctc,
122     unsigned int level);
123