arch/mips/kernel/segment.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2013 Imagination Technologies Ltd.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/debugfs.h>
  11 #include <linux/seq_file.h>
  12 #include <asm/cpu.h>
  13 #include <asm/mipsregs.h>
  14
  15 static void build_segment_config(char *str, unsigned int cfg)
  16 {
  17         unsigned int am;
  18         static const char * const am_str[] = {
  19                 "UK", "MK", "MSK", "MUSK", "MUSUK", "USK",
  20                 "RSRVD", "UUSK"};
  21
  22         /* Segment access mode. */
  23         am = (cfg & MIPS_SEGCFG_AM) >> MIPS_SEGCFG_AM_SHIFT;
  24         str += sprintf(str, "%-5s", am_str[am]);
  25
  26         /*
  27          * Access modes MK, MSK and MUSK are mapped segments. Therefore
  28          * there is no direct physical address mapping.
  29          */
  30         if ((am == 0) || (am > 3)) {
  31                 str += sprintf(str, "         %03lx",
  32                         ((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
  33                 str += sprintf(str, "         %01ld",
  34                         ((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
  35         } else {
  36                 str += sprintf(str, "         UND");
  37                 str += sprintf(str, "         U");
  38         }
  39
  40         /* Exception configuration. */
  41         str += sprintf(str, "       %01ld\n",
  42                 ((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
  43 }
  44
  45 static int show_segments(struct seq_file *m, void *v)
  46 {
  47         unsigned int segcfg;
  48         char str[42];
  49
  50         seq_puts(m, "Segment   Virtual    Size   Access Mode   Physical   Caching   EU\n");
  51         seq_puts(m, "-------   -------    ----   -----------   --------   -------   --\n");
  52
  53         segcfg = read_c0_segctl0();
  54         build_segment_config(str, segcfg);
  55         seq_printf(m, "   0      e0000000   512M      %s", str);
  56
  57         segcfg >>= 16;
  58         build_segment_config(str, segcfg);
  59         seq_printf(m, "   1      c0000000   512M      %s", str);
  60
  61         segcfg = read_c0_segctl1();
  62         build_segment_config(str, segcfg);
  63         seq_printf(m, "   2      a0000000   512M      %s", str);
  64
  65         segcfg >>= 16;
  66         build_segment_config(str, segcfg);
  67         seq_printf(m, "   3      80000000   512M      %s", str);
  68
  69         segcfg = read_c0_segctl2();
  70         build_segment_config(str, segcfg);
  71         seq_printf(m, "   4      40000000    1G       %s", str);
  72
  73         segcfg >>= 16;
  74         build_segment_config(str, segcfg);
  75         seq_printf(m, "   5      00000000    1G       %s\n", str);
  76
  77         return 0;
  78 }
  79
  80 static int segments_open(struct inode *inode, struct file *file)
  81 {
  82         return single_open(file, show_segments, NULL);
  83 }
  84
  85 static const struct file_operations segments_fops = {
  86         .open           = segments_open,
  87         .read           = seq_read,
  88         .llseek         = seq_lseek,
  89         .release        = single_release,
  90 };
  91
  92 static int __init segments_info(void)
  93 {
  94         extern struct dentry *mips_debugfs_dir;
  95         struct dentry *segments;
  96
  97         if (cpu_has_segments) {
  98                 if (!mips_debugfs_dir)
  99                         return -ENODEV;
 100
 101                 segments = debugfs_create_file("segments", S_IRUGO,
 102                                                mips_debugfs_dir, NULL,
 103                                                &segments_fops);
 104                 if (!segments)
 105                         return -ENOMEM;
 106         }
 107         return 0;
 108 }
 109
 110 device_initcall(segments_info);