arch/frv/kernel/sysctl.c

   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 <linux/uaccess.h>
  16
  17 static const char frv_cache_wback[] = "wback";
  18 static const char frv_cache_wthru[] = "wthru";
  19
  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  */
  49 static int procctl_frv_cachemode(struct 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
 124 static int procctl_frv_pin_cxnr(struct 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  */
 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);