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bcu.c
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1 /*
2  * bcu.c, Bus Control Unit routines for the NEC VR4100 series.
3  *
4  * Copyright (C) 2002 MontaVista Software Inc.
5  * Author: Yoichi Yuasa <[email protected]>
6  * Copyright (C) 2003-2005 Yoichi Yuasa <[email protected]>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21  */
22 /*
23  * Changes:
24  * MontaVista Software Inc. <[email protected]>
25  * - New creation, NEC VR4122 and VR4131 are supported.
26  * - Added support for NEC VR4111 and VR4121.
27  *
28  * Yoichi Yuasa <[email protected]>
29  * - Added support for NEC VR4133.
30  */
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/smp.h>
34 #include <linux/types.h>
35 
36 #include <asm/cpu.h>
37 #include <asm/io.h>
38 
39 #define CLKSPEEDREG_TYPE1 (void __iomem *)KSEG1ADDR(0x0b000014)
40 #define CLKSPEEDREG_TYPE2 (void __iomem *)KSEG1ADDR(0x0f000014)
41  #define CLKSP(x) ((x) & 0x001f)
42  #define CLKSP_VR4133(x) ((x) & 0x0007)
43 
44  #define DIV2B 0x8000
45  #define DIV3B 0x4000
46  #define DIV4B 0x2000
47 
48  #define DIVT(x) (((x) & 0xf000) >> 12)
49  #define DIVVT(x) (((x) & 0x0f00) >> 8)
50 
51  #define TDIVMODE(x) (2 << (((x) & 0x1000) >> 12))
52  #define VTDIVMODE(x) (((x) & 0x0700) >> 8)
53 
54 static unsigned long vr41xx_vtclock;
55 static unsigned long vr41xx_tclock;
56 
57 unsigned long vr41xx_get_vtclock_frequency(void)
58 {
59  return vr41xx_vtclock;
60 }
61 
63 
64 unsigned long vr41xx_get_tclock_frequency(void)
65 {
66  return vr41xx_tclock;
67 }
68 
70 
71 static inline uint16_t read_clkspeed(void)
72 {
73  switch (current_cpu_type()) {
74  case CPU_VR4111:
75  case CPU_VR4121: return readw(CLKSPEEDREG_TYPE1);
76  case CPU_VR4122:
77  case CPU_VR4131:
78  case CPU_VR4133: return readw(CLKSPEEDREG_TYPE2);
79  default:
80  printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
81  break;
82  }
83 
84  return 0;
85 }
86 
87 static inline unsigned long calculate_pclock(uint16_t clkspeed)
88 {
89  unsigned long pclock = 0;
90 
91  switch (current_cpu_type()) {
92  case CPU_VR4111:
93  case CPU_VR4121:
94  pclock = 18432000 * 64;
95  pclock /= CLKSP(clkspeed);
96  break;
97  case CPU_VR4122:
98  pclock = 18432000 * 98;
99  pclock /= CLKSP(clkspeed);
100  break;
101  case CPU_VR4131:
102  pclock = 18432000 * 108;
103  pclock /= CLKSP(clkspeed);
104  break;
105  case CPU_VR4133:
106  switch (CLKSP_VR4133(clkspeed)) {
107  case 0:
108  pclock = 133000000;
109  break;
110  case 1:
111  pclock = 149000000;
112  break;
113  case 2:
114  pclock = 165900000;
115  break;
116  case 3:
117  pclock = 199100000;
118  break;
119  case 4:
120  pclock = 265900000;
121  break;
122  default:
123  printk(KERN_INFO "Unknown PClock speed for NEC VR4133\n");
124  break;
125  }
126  break;
127  default:
128  printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
129  break;
130  }
131 
132  printk(KERN_INFO "PClock: %ldHz\n", pclock);
133 
134  return pclock;
135 }
136 
137 static inline unsigned long calculate_vtclock(uint16_t clkspeed, unsigned long pclock)
138 {
139  unsigned long vtclock = 0;
140 
141  switch (current_cpu_type()) {
142  case CPU_VR4111:
143  /* The NEC VR4111 doesn't have the VTClock. */
144  break;
145  case CPU_VR4121:
146  vtclock = pclock;
147  /* DIVVT == 9 Divide by 1.5 . VTClock = (PClock * 6) / 9 */
148  if (DIVVT(clkspeed) == 9)
149  vtclock = pclock * 6;
150  /* DIVVT == 10 Divide by 2.5 . VTClock = (PClock * 4) / 10 */
151  else if (DIVVT(clkspeed) == 10)
152  vtclock = pclock * 4;
153  vtclock /= DIVVT(clkspeed);
154  printk(KERN_INFO "VTClock: %ldHz\n", vtclock);
155  break;
156  case CPU_VR4122:
157  if(VTDIVMODE(clkspeed) == 7)
158  vtclock = pclock / 1;
159  else if(VTDIVMODE(clkspeed) == 1)
160  vtclock = pclock / 2;
161  else
162  vtclock = pclock / VTDIVMODE(clkspeed);
163  printk(KERN_INFO "VTClock: %ldHz\n", vtclock);
164  break;
165  case CPU_VR4131:
166  case CPU_VR4133:
167  vtclock = pclock / VTDIVMODE(clkspeed);
168  printk(KERN_INFO "VTClock: %ldHz\n", vtclock);
169  break;
170  default:
171  printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
172  break;
173  }
174 
175  return vtclock;
176 }
177 
178 static inline unsigned long calculate_tclock(uint16_t clkspeed, unsigned long pclock,
179  unsigned long vtclock)
180 {
181  unsigned long tclock = 0;
182 
183  switch (current_cpu_type()) {
184  case CPU_VR4111:
185  if (!(clkspeed & DIV2B))
186  tclock = pclock / 2;
187  else if (!(clkspeed & DIV3B))
188  tclock = pclock / 3;
189  else if (!(clkspeed & DIV4B))
190  tclock = pclock / 4;
191  break;
192  case CPU_VR4121:
193  tclock = pclock / DIVT(clkspeed);
194  break;
195  case CPU_VR4122:
196  case CPU_VR4131:
197  case CPU_VR4133:
198  tclock = vtclock / TDIVMODE(clkspeed);
199  break;
200  default:
201  printk(KERN_INFO "Unexpected CPU of NEC VR4100 series\n");
202  break;
203  }
204 
205  printk(KERN_INFO "TClock: %ldHz\n", tclock);
206 
207  return tclock;
208 }
209 
211 {
212  unsigned long pclock;
213  uint16_t clkspeed;
214 
215  clkspeed = read_clkspeed();
216 
217  pclock = calculate_pclock(clkspeed);
218  vr41xx_vtclock = calculate_vtclock(clkspeed, pclock);
219  vr41xx_tclock = calculate_tclock(clkspeed, pclock, vr41xx_vtclock);
220 }
221