1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * bcu.c, Bus Control Unit routines for the NEC VR4100 series.
4 *
5 * Copyright (C) 2002 MontaVista Software Inc.
6 * Author: Yoichi Yuasa <source@mvista.com>
7 * Copyright (C) 2003-2005 Yoichi Yuasa <yuasa@linux-mips.org>
8 */
9 /*
10 * Changes:
11 * MontaVista Software Inc. <source@mvista.com>
12 * - New creation, NEC VR4122 and VR4131 are supported.
13 * - Added support for NEC VR4111 and VR4121.
14 *
15 * Yoichi Yuasa <yuasa@linux-mips.org>
16 * - Added support for NEC VR4133.
17 */
18 #include <linux/export.h>
19 #include <linux/kernel.h>
20 #include <linux/smp.h>
21 #include <linux/types.h>
22
23 #include <asm/cpu-type.h>
24 #include <asm/cpu.h>
25 #include <asm/io.h>
26
27 #define CLKSPEEDREG_TYPE1 (void __iomem *)KSEG1ADDR(0x0b000014)
28 #define CLKSPEEDREG_TYPE2 (void __iomem *)KSEG1ADDR(0x0f000014)
29 #define CLKSP(x) ((x) & 0x001f)
30 #define CLKSP_VR4133(x) ((x) & 0x0007)
31
32 #define DIV2B 0x8000
33 #define DIV3B 0x4000
34 #define DIV4B 0x2000
35
36 #define DIVT(x) (((x) & 0xf000) >> 12)
37 #define DIVVT(x) (((x) & 0x0f00) >> 8)
38
39 #define TDIVMODE(x) (2 << (((x) & 0x1000) >> 12))
40 #define VTDIVMODE(x) (((x) & 0x0700) >> 8)
41
42 static unsigned long vr41xx_vtclock;
43 static unsigned long vr41xx_tclock;
44
vr41xx_get_vtclock_frequency(void)45 unsigned long vr41xx_get_vtclock_frequency(void)
46 {
47 return vr41xx_vtclock;
48 }
49
50 EXPORT_SYMBOL_GPL(vr41xx_get_vtclock_frequency);
51
vr41xx_get_tclock_frequency(void)52 unsigned long vr41xx_get_tclock_frequency(void)
53 {
54 return vr41xx_tclock;
55 }
56
57 EXPORT_SYMBOL_GPL(vr41xx_get_tclock_frequency);
58
read_clkspeed(void)59 static inline uint16_t read_clkspeed(void)
60 {
61 switch (current_cpu_type()) {
62 case CPU_VR4111:
63 case CPU_VR4121: return readw(CLKSPEEDREG_TYPE1);
64 case CPU_VR4122:
65 case CPU_VR4131:
66 case CPU_VR4133: return readw(CLKSPEEDREG_TYPE2);
67 default:
68 printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
69 break;
70 }
71
72 return 0;
73 }
74
calculate_pclock(uint16_t clkspeed)75 static inline unsigned long calculate_pclock(uint16_t clkspeed)
76 {
77 unsigned long pclock = 0;
78
79 switch (current_cpu_type()) {
80 case CPU_VR4111:
81 case CPU_VR4121:
82 pclock = 18432000 * 64;
83 pclock /= CLKSP(clkspeed);
84 break;
85 case CPU_VR4122:
86 pclock = 18432000 * 98;
87 pclock /= CLKSP(clkspeed);
88 break;
89 case CPU_VR4131:
90 pclock = 18432000 * 108;
91 pclock /= CLKSP(clkspeed);
92 break;
93 case CPU_VR4133:
94 switch (CLKSP_VR4133(clkspeed)) {
95 case 0:
96 pclock = 133000000;
97 break;
98 case 1:
99 pclock = 149000000;
100 break;
101 case 2:
102 pclock = 165900000;
103 break;
104 case 3:
105 pclock = 199100000;
106 break;
107 case 4:
108 pclock = 265900000;
109 break;
110 default:
111 printk(KERN_INFO "Unknown PClock speed for NEC VR4133\n");
112 break;
113 }
114 break;
115 default:
116 printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
117 break;
118 }
119
120 printk(KERN_INFO "PClock: %ldHz\n", pclock);
121
122 return pclock;
123 }
124
calculate_vtclock(uint16_t clkspeed,unsigned long pclock)125 static inline unsigned long calculate_vtclock(uint16_t clkspeed, unsigned long pclock)
126 {
127 unsigned long vtclock = 0;
128
129 switch (current_cpu_type()) {
130 case CPU_VR4111:
131 /* The NEC VR4111 doesn't have the VTClock. */
132 break;
133 case CPU_VR4121:
134 vtclock = pclock;
135 /* DIVVT == 9 Divide by 1.5 . VTClock = (PClock * 6) / 9 */
136 if (DIVVT(clkspeed) == 9)
137 vtclock = pclock * 6;
138 /* DIVVT == 10 Divide by 2.5 . VTClock = (PClock * 4) / 10 */
139 else if (DIVVT(clkspeed) == 10)
140 vtclock = pclock * 4;
141 vtclock /= DIVVT(clkspeed);
142 printk(KERN_INFO "VTClock: %ldHz\n", vtclock);
143 break;
144 case CPU_VR4122:
145 if(VTDIVMODE(clkspeed) == 7)
146 vtclock = pclock / 1;
147 else if(VTDIVMODE(clkspeed) == 1)
148 vtclock = pclock / 2;
149 else
150 vtclock = pclock / VTDIVMODE(clkspeed);
151 printk(KERN_INFO "VTClock: %ldHz\n", vtclock);
152 break;
153 case CPU_VR4131:
154 case CPU_VR4133:
155 vtclock = pclock / VTDIVMODE(clkspeed);
156 printk(KERN_INFO "VTClock: %ldHz\n", vtclock);
157 break;
158 default:
159 printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
160 break;
161 }
162
163 return vtclock;
164 }
165
calculate_tclock(uint16_t clkspeed,unsigned long pclock,unsigned long vtclock)166 static inline unsigned long calculate_tclock(uint16_t clkspeed, unsigned long pclock,
167 unsigned long vtclock)
168 {
169 unsigned long tclock = 0;
170
171 switch (current_cpu_type()) {
172 case CPU_VR4111:
173 if (!(clkspeed & DIV2B))
174 tclock = pclock / 2;
175 else if (!(clkspeed & DIV3B))
176 tclock = pclock / 3;
177 else if (!(clkspeed & DIV4B))
178 tclock = pclock / 4;
179 break;
180 case CPU_VR4121:
181 tclock = pclock / DIVT(clkspeed);
182 break;
183 case CPU_VR4122:
184 case CPU_VR4131:
185 case CPU_VR4133:
186 tclock = vtclock / TDIVMODE(clkspeed);
187 break;
188 default:
189 printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
190 break;
191 }
192
193 printk(KERN_INFO "TClock: %ldHz\n", tclock);
194
195 return tclock;
196 }
197
vr41xx_calculate_clock_frequency(void)198 void vr41xx_calculate_clock_frequency(void)
199 {
200 unsigned long pclock;
201 uint16_t clkspeed;
202
203 clkspeed = read_clkspeed();
204
205 pclock = calculate_pclock(clkspeed);
206 vr41xx_vtclock = calculate_vtclock(clkspeed, pclock);
207 vr41xx_tclock = calculate_tclock(clkspeed, pclock, vr41xx_vtclock);
208 }
209
210 EXPORT_SYMBOL_GPL(vr41xx_calculate_clock_frequency);
211