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/debug.h>
  14 #include <asm/mipsregs.h>
  15
  16 static void build_segment_config(char *str, unsigned int cfg)
  17 {
  18         unsigned int am;
  19         static const char * const am_str[] = {
  20                 "UK", "MK", "MSK", "MUSK", "MUSUK", "USK",
  21                 "RSRVD", "UUSK"};
  22
  23         /* Segment access mode. */
  24         am = (cfg & MIPS_SEGCFG_AM) >> MIPS_SEGCFG_AM_SHIFT;
  25         str += sprintf(str, "%-5s", am_str[am]);
  26
  27         /*
  28          * Access modes MK, MSK and MUSK are mapped segments. Therefore
  29          * there is no direct physical address mapping.
  30          */
  31         if ((am == 0) || (am > 3)) {
  32                 str += sprintf(str, "         %03lx",
  33                         ((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
  34                 str += sprintf(str, "         %01ld",
  35                         ((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
  36         } else {
  37                 str += sprintf(str, "         UND");
  38                 str += sprintf(str, "         U");
  39         }
  40
  41         /* Exception configuration. */
  42         str += sprintf(str, "       %01ld\n",
  43                 ((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
  44 }
  45
  46 static int show_segments(struct seq_file *m, void *v)
  47 {
  48         unsigned int segcfg;
  49         char str[42];
  50
  51         seq_puts(m, "Segment   Virtual    Size   Access Mode   Physical   Caching   EU\n");
  52         seq_puts(m, "-------   -------    ----   -----------   --------   -------   --\n");
  53
  54         segcfg = read_c0_segctl0();
  55         build_segment_config(str, segcfg);
  56         seq_printf(m, "   0      e0000000   512M      %s", str);
  57
  58         segcfg >>= 16;
  59         build_segment_config(str, segcfg);
  60         seq_printf(m, "   1      c0000000   512M      %s", str);
  61
  62         segcfg = read_c0_segctl1();
  63         build_segment_config(str, segcfg);
  64         seq_printf(m, "   2      a0000000   512M      %s", str);
  65
  66         segcfg >>= 16;
  67         build_segment_config(str, segcfg);
  68         seq_printf(m, "   3      80000000   512M      %s", str);
  69
  70         segcfg = read_c0_segctl2();
  71         build_segment_config(str, segcfg);
  72         seq_printf(m, "   4      40000000    1G       %s", str);
  73
  74         segcfg >>= 16;
  75         build_segment_config(str, segcfg);
  76         seq_printf(m, "   5      00000000    1G       %s\n", str);
  77
  78         return 0;
  79 }
  80
  81 static int segments_open(struct inode *inode, struct file *file)
  82 {
  83         return single_open(file, show_segments, NULL);
  84 }
  85
  86 static const struct file_operations segments_fops = {
  87         .open           = segments_open,
  88         .read           = seq_read,
  89         .llseek         = seq_lseek,
  90         .release        = single_release,
  91 };
  92
  93 static int __init segments_info(void)
  94 {
  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);