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/config.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysctl.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/init.h>
  17 #include <asm/uaccess.h>
  18
  19 static const char frv_cache_wback[] = "wback";
  20 static const char frv_cache_wthru[] = "wthru";
  21
  22 static void frv_change_dcache_mode(unsigned long newmode)
  23 {
  24         unsigned long flags, hsr0;
  25
  26         local_irq_save(flags);
  27
  28         hsr0 = __get_HSR(0);
  29         hsr0 &= ~HSR0_DCE;
  30         __set_HSR(0, hsr0);
  31
  32         asm volatile("  dcef    @(gr0,gr0),#1   \n"
  33                      "  membar                  \n"
  34                      : : : "memory"
  35                      );
  36
  37         hsr0 = (hsr0 & ~HSR0_CBM) | newmode;
  38         __set_HSR(0, hsr0);
  39         hsr0 |= HSR0_DCE;
  40         __set_HSR(0, hsr0);
  41
  42         local_irq_restore(flags);
  43
  44         //printk("HSR0 now %08lx\n", hsr0);
  45 }
  46
  47 /*****************************************************************************/
  48 /*
  49  * handle requests to dynamically switch the write caching mode delivered by /proc
  50  */
  51 static int procctl_frv_cachemode(ctl_table *table, int write, struct file *filp,
  52                                  void *buffer, size_t *lenp, loff_t *ppos)
  53 {
  54         unsigned long hsr0;
  55         char buff[8];
  56         int len;
  57
  58         len = *lenp;
  59
  60         if (write) {
  61                 /* potential state change */
  62                 if (len <= 1 || len > sizeof(buff) - 1)
  63                         return -EINVAL;
  64
  65                 if (copy_from_user(buff, buffer, len) != 0)
  66                         return -EFAULT;
  67
  68                 if (buff[len - 1] == '\n')
  69                         buff[len - 1] = '\0';
  70                 else
  71                         buff[len] = '\0';
  72
  73                 if (strcmp(buff, frv_cache_wback) == 0) {
  74                         /* switch dcache into write-back mode */
  75                         frv_change_dcache_mode(HSR0_CBM_COPY_BACK);
  76                         return 0;
  77                 }
  78
  79                 if (strcmp(buff, frv_cache_wthru) == 0) {
  80                         /* switch dcache into write-through mode */
  81                         frv_change_dcache_mode(HSR0_CBM_WRITE_THRU);
  82                         return 0;
  83                 }
  84
  85                 return -EINVAL;
  86         }
  87
  88         /* read the state */
  89         if (filp->f_pos > 0) {
  90                 *lenp = 0;
  91                 return 0;
  92         }
  93
  94         hsr0 = __get_HSR(0);
  95         switch (hsr0 & HSR0_CBM) {
  96         case HSR0_CBM_WRITE_THRU:
  97                 memcpy(buff, frv_cache_wthru, sizeof(frv_cache_wthru) - 1);
  98                 buff[sizeof(frv_cache_wthru) - 1] = '\n';
  99                 len = sizeof(frv_cache_wthru);
 100                 break;
 101         default:
 102                 memcpy(buff, frv_cache_wback, sizeof(frv_cache_wback) - 1);
 103                 buff[sizeof(frv_cache_wback) - 1] = '\n';
 104                 len = sizeof(frv_cache_wback);
 105                 break;
 106         }
 107
 108         if (len > *lenp)
 109                 len = *lenp;
 110
 111         if (copy_to_user(buffer, buff, len) != 0)
 112                 return -EFAULT;
 113
 114         *lenp = len;
 115         filp->f_pos = len;
 116         return 0;
 117
 118 } /* end procctl_frv_cachemode() */
 119
 120 /*****************************************************************************/
 121 /*
 122  * permit the mm_struct the nominated process is using have its MMU context ID pinned
 123  */
 124 #ifdef CONFIG_MMU
 125 static int procctl_frv_pin_cxnr(ctl_table *table, int write, struct file *filp,
 126                                 void *buffer, size_t *lenp, 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 (filp->f_pos > 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         filp->f_pos = 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         { 1, "cache-mode",      NULL, 0, 0644, NULL, &procctl_frv_cachemode },
 180 #ifdef CONFIG_MMU
 181         { 2, "pin-cxnr",        NULL, 0, 0644, NULL, &procctl_frv_pin_cxnr },
 182 #endif
 183         { 0 }
 184 };
 185
 186 /*
 187  * Use a temporary sysctl number. Horrid, but will be cleaned up in 2.6
 188  * when all the PM interfaces exist nicely.
 189  */
 190 #define CTL_FRV 9898
 191 static struct ctl_table frv_dir_table[] =
 192 {
 193         {CTL_FRV, "frv", NULL, 0, 0555, frv_table},
 194         {0}
 195 };
 196
 197 /*
 198  * Initialize power interface
 199  */
 200 static int __init frv_sysctl_init(void)
 201 {
 202         register_sysctl_table(frv_dir_table, 1);
 203         return 0;
 204 }
 205
 206 __initcall(frv_sysctl_init);