1 /* sysctl.c: implementation of /proc/sys files relating to FRV specifically
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/sysctl.h>
13 #include <linux/proc_fs.h>
14 #include <linux/init.h>
15 #include <asm/uaccess.h>
16
17 static const char frv_cache_wback[] = "wback";
18 static const char frv_cache_wthru[] = "wthru";
19
frv_change_dcache_mode(unsigned long newmode)20 static void frv_change_dcache_mode(unsigned long newmode)
21 {
22 unsigned long flags, hsr0;
23
24 local_irq_save(flags);
25
26 hsr0 = __get_HSR(0);
27 hsr0 &= ~HSR0_DCE;
28 __set_HSR(0, hsr0);
29
30 asm volatile(" dcef @(gr0,gr0),#1 \n"
31 " membar \n"
32 : : : "memory"
33 );
34
35 hsr0 = (hsr0 & ~HSR0_CBM) | newmode;
36 __set_HSR(0, hsr0);
37 hsr0 |= HSR0_DCE;
38 __set_HSR(0, hsr0);
39
40 local_irq_restore(flags);
41
42 //printk("HSR0 now %08lx\n", hsr0);
43 }
44
45 /*****************************************************************************/
46 /*
47 * handle requests to dynamically switch the write caching mode delivered by /proc
48 */
procctl_frv_cachemode(ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)49 static int procctl_frv_cachemode(ctl_table *table, int write,
50 void __user *buffer, size_t *lenp,
51 loff_t *ppos)
52 {
53 unsigned long hsr0;
54 char buff[8];
55 int len;
56
57 len = *lenp;
58
59 if (write) {
60 /* potential state change */
61 if (len <= 1 || len > sizeof(buff) - 1)
62 return -EINVAL;
63
64 if (copy_from_user(buff, buffer, len) != 0)
65 return -EFAULT;
66
67 if (buff[len - 1] == '\n')
68 buff[len - 1] = '\0';
69 else
70 buff[len] = '\0';
71
72 if (strcmp(buff, frv_cache_wback) == 0) {
73 /* switch dcache into write-back mode */
74 frv_change_dcache_mode(HSR0_CBM_COPY_BACK);
75 return 0;
76 }
77
78 if (strcmp(buff, frv_cache_wthru) == 0) {
79 /* switch dcache into write-through mode */
80 frv_change_dcache_mode(HSR0_CBM_WRITE_THRU);
81 return 0;
82 }
83
84 return -EINVAL;
85 }
86
87 /* read the state */
88 if (*ppos > 0) {
89 *lenp = 0;
90 return 0;
91 }
92
93 hsr0 = __get_HSR(0);
94 switch (hsr0 & HSR0_CBM) {
95 case HSR0_CBM_WRITE_THRU:
96 memcpy(buff, frv_cache_wthru, sizeof(frv_cache_wthru) - 1);
97 buff[sizeof(frv_cache_wthru) - 1] = '\n';
98 len = sizeof(frv_cache_wthru);
99 break;
100 default:
101 memcpy(buff, frv_cache_wback, sizeof(frv_cache_wback) - 1);
102 buff[sizeof(frv_cache_wback) - 1] = '\n';
103 len = sizeof(frv_cache_wback);
104 break;
105 }
106
107 if (len > *lenp)
108 len = *lenp;
109
110 if (copy_to_user(buffer, buff, len) != 0)
111 return -EFAULT;
112
113 *lenp = len;
114 *ppos = len;
115 return 0;
116
117 } /* end procctl_frv_cachemode() */
118
119 /*****************************************************************************/
120 /*
121 * permit the mm_struct the nominated process is using have its MMU context ID pinned
122 */
123 #ifdef CONFIG_MMU
procctl_frv_pin_cxnr(ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)124 static int procctl_frv_pin_cxnr(ctl_table *table, int write,
125 void __user *buffer, size_t *lenp,
126 loff_t *ppos)
127 {
128 pid_t pid;
129 char buff[16], *p;
130 int len;
131
132 len = *lenp;
133
134 if (write) {
135 /* potential state change */
136 if (len <= 1 || len > sizeof(buff) - 1)
137 return -EINVAL;
138
139 if (copy_from_user(buff, buffer, len) != 0)
140 return -EFAULT;
141
142 if (buff[len - 1] == '\n')
143 buff[len - 1] = '\0';
144 else
145 buff[len] = '\0';
146
147 pid = simple_strtoul(buff, &p, 10);
148 if (*p)
149 return -EINVAL;
150
151 return cxn_pin_by_pid(pid);
152 }
153
154 /* read the currently pinned CXN */
155 if (*ppos > 0) {
156 *lenp = 0;
157 return 0;
158 }
159
160 len = snprintf(buff, sizeof(buff), "%d\n", cxn_pinned);
161 if (len > *lenp)
162 len = *lenp;
163
164 if (copy_to_user(buffer, buff, len) != 0)
165 return -EFAULT;
166
167 *lenp = len;
168 *ppos = len;
169 return 0;
170
171 } /* end procctl_frv_pin_cxnr() */
172 #endif
173
174 /*
175 * FR-V specific sysctls
176 */
177 static struct ctl_table frv_table[] =
178 {
179 {
180 .procname = "cache-mode",
181 .data = NULL,
182 .maxlen = 0,
183 .mode = 0644,
184 .proc_handler = procctl_frv_cachemode,
185 },
186 #ifdef CONFIG_MMU
187 {
188 .procname = "pin-cxnr",
189 .data = NULL,
190 .maxlen = 0,
191 .mode = 0644,
192 .proc_handler = procctl_frv_pin_cxnr
193 },
194 #endif
195 {}
196 };
197
198 /*
199 * Use a temporary sysctl number. Horrid, but will be cleaned up in 2.6
200 * when all the PM interfaces exist nicely.
201 */
202 static struct ctl_table frv_dir_table[] =
203 {
204 {
205 .procname = "frv",
206 .mode = 0555,
207 .child = frv_table
208 },
209 {}
210 };
211
212 /*
213 * Initialize power interface
214 */
frv_sysctl_init(void)215 static int __init frv_sysctl_init(void)
216 {
217 register_sysctl_table(frv_dir_table);
218 return 0;
219 }
220
221 __initcall(frv_sysctl_init);
222