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 <asm/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(ctl_table *table, int write, struct file *filp,
  50                                  void __user *buffer, size_t *lenp, loff_t *ppos)
  51 {
  52         unsigned long hsr0;
  53         char buff[8];
  54         int len;
  55
  56         len = *lenp;
  57
  58         if (write) {
  59                 /* potential state change */
  60                 if (len <= 1 || len > sizeof(buff) - 1)
  61                         return -EINVAL;
  62
  63                 if (copy_from_user(buff, buffer, len) != 0)
  64                         return -EFAULT;
  65
  66                 if (buff[len - 1] == '\n')
  67                         buff[len - 1] = '\0';
  68                 else
  69                         buff[len] = '\0';
  70
  71                 if (strcmp(buff, frv_cache_wback) == 0) {
  72                         /* switch dcache into write-back mode */
  73                         frv_change_dcache_mode(HSR0_CBM_COPY_BACK);
  74                         return 0;
  75                 }
  76
  77                 if (strcmp(buff, frv_cache_wthru) == 0) {
  78                         /* switch dcache into write-through mode */
  79                         frv_change_dcache_mode(HSR0_CBM_WRITE_THRU);
  80                         return 0;
  81                 }
  82
  83                 return -EINVAL;
  84         }
  85
  86         /* read the state */
  87         if (filp->f_pos > 0) {
  88                 *lenp = 0;
  89                 return 0;
  90         }
  91
  92         hsr0 = __get_HSR(0);
  93         switch (hsr0 & HSR0_CBM) {
  94         case HSR0_CBM_WRITE_THRU:
  95                 memcpy(buff, frv_cache_wthru, sizeof(frv_cache_wthru) - 1);
  96                 buff[sizeof(frv_cache_wthru) - 1] = '\n';
  97                 len = sizeof(frv_cache_wthru);
  98                 break;
  99         default:
 100                 memcpy(buff, frv_cache_wback, sizeof(frv_cache_wback) - 1);
 101                 buff[sizeof(frv_cache_wback) - 1] = '\n';
 102                 len = sizeof(frv_cache_wback);
 103                 break;
 104         }
 105
 106         if (len > *lenp)
 107                 len = *lenp;
 108
 109         if (copy_to_user(buffer, buff, len) != 0)
 110                 return -EFAULT;
 111
 112         *lenp = len;
 113         filp->f_pos = len;
 114         return 0;
 115
 116 } /* end procctl_frv_cachemode() */
 117
 118 /*****************************************************************************/
 119 /*
 120  * permit the mm_struct the nominated process is using have its MMU context ID pinned
 121  */
 122 #ifdef CONFIG_MMU
 123 static int procctl_frv_pin_cxnr(ctl_table *table, int write, struct file *filp,
 124                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 125 {
 126         pid_t pid;
 127         char buff[16], *p;
 128         int len;
 129
 130         len = *lenp;
 131
 132         if (write) {
 133                 /* potential state change */
 134                 if (len <= 1 || len > sizeof(buff) - 1)
 135                         return -EINVAL;
 136
 137                 if (copy_from_user(buff, buffer, len) != 0)
 138                         return -EFAULT;
 139
 140                 if (buff[len - 1] == '\n')
 141                         buff[len - 1] = '\0';
 142                 else
 143                         buff[len] = '\0';
 144
 145                 pid = simple_strtoul(buff, &p, 10);
 146                 if (*p)
 147                         return -EINVAL;
 148
 149                 return cxn_pin_by_pid(pid);
 150         }
 151
 152         /* read the currently pinned CXN */
 153         if (filp->f_pos > 0) {
 154                 *lenp = 0;
 155                 return 0;
 156         }
 157
 158         len = snprintf(buff, sizeof(buff), "%d\n", cxn_pinned);
 159         if (len > *lenp)
 160                 len = *lenp;
 161
 162         if (copy_to_user(buffer, buff, len) != 0)
 163                 return -EFAULT;
 164
 165         *lenp = len;
 166         filp->f_pos = len;
 167         return 0;
 168
 169 } /* end procctl_frv_pin_cxnr() */
 170 #endif
 171
 172 /*
 173  * FR-V specific sysctls
 174  */
 175 static struct ctl_table frv_table[] =
 176 {
 177         {
 178                 .procname       = "cache-mode",
 179                 .data           = NULL,
 180                 .maxlen         = 0,
 181                 .mode           = 0644,
 182                 .proc_handler   = procctl_frv_cachemode,
 183         },
 184 #ifdef CONFIG_MMU
 185         {
 186                 .procname       = "pin-cxnr",
 187                 .data           = NULL,
 188                 .maxlen         = 0,
 189                 .mode           = 0644,
 190                 .proc_handler   = procctl_frv_pin_cxnr
 191         },
 192 #endif
 193         {}
 194 };
 195
 196 /*
 197  * Use a temporary sysctl number. Horrid, but will be cleaned up in 2.6
 198  * when all the PM interfaces exist nicely.
 199  */
 200 static struct ctl_table frv_dir_table[] =
 201 {
 202         {
 203                 .procname       = "frv",
 204                 .mode           = 0555,
 205                 .child          = frv_table
 206         },
 207         {}
 208 };
 209
 210 /*
 211  * Initialize power interface
 212  */
 213 static int __init frv_sysctl_init(void)
 214 {
 215         register_sysctl_table(frv_dir_table);
 216         return 0;
 217 }
 218
 219 __initcall(frv_sysctl_init);