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 unless it becomes
  30          * unmapped uncached at error level due to EU.
  31          */
  32         if ((am == 0) || (am > 3) || (cfg & MIPS_SEGCFG_EU))
  33                 str += sprintf(str, "         %03lx",
  34                         ((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
  35         else
  36                 str += sprintf(str, "         UND");
  37
  38         if ((am == 0) || (am > 3))
  39                 str += sprintf(str, "         %01ld",
  40                         ((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
  41         else
  42                 str += sprintf(str, "         U");
  43
  44         /* Exception configuration. */
  45         str += sprintf(str, "       %01ld\n",
  46                 ((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
  47 }
  48
  49 static int show_segments(struct seq_file *m, void *v)
  50 {
  51         unsigned int segcfg;
  52         char str[42];
  53
  54         seq_puts(m, "Segment   Virtual    Size   Access Mode   Physical   Caching   EU\n");
  55         seq_puts(m, "-------   -------    ----   -----------   --------   -------   --\n");
  56
  57         segcfg = read_c0_segctl0();
  58         build_segment_config(str, segcfg);
  59         seq_printf(m, "   0      e0000000   512M      %s", str);
  60
  61         segcfg >>= 16;
  62         build_segment_config(str, segcfg);
  63         seq_printf(m, "   1      c0000000   512M      %s", str);
  64
  65         segcfg = read_c0_segctl1();
  66         build_segment_config(str, segcfg);
  67         seq_printf(m, "   2      a0000000   512M      %s", str);
  68
  69         segcfg >>= 16;
  70         build_segment_config(str, segcfg);
  71         seq_printf(m, "   3      80000000   512M      %s", str);
  72
  73         segcfg = read_c0_segctl2();
  74         build_segment_config(str, segcfg);
  75         seq_printf(m, "   4      40000000    1G       %s", str);
  76
  77         segcfg >>= 16;
  78         build_segment_config(str, segcfg);
  79         seq_printf(m, "   5      00000000    1G       %s\n", str);
  80
  81         return 0;
  82 }
  83
  84 static int segments_open(struct inode *inode, struct file *file)
  85 {
  86         return single_open(file, show_segments, NULL);
  87 }
  88
  89 static const struct file_operations segments_fops = {
  90         .open           = segments_open,
  91         .read           = seq_read,
  92         .llseek         = seq_lseek,
  93         .release        = single_release,
  94 };
  95
  96 static int __init segments_info(void)
  97 {
  98         struct dentry *segments;
  99
 100         if (cpu_has_segments) {
 101                 if (!mips_debugfs_dir)
 102                         return -ENODEV;
 103
 104                 segments = debugfs_create_file("segments", S_IRUGO,
 105                                                mips_debugfs_dir, NULL,
 106                                                &segments_fops);
 107                 if (!segments)
 108                         return -ENOMEM;
 109         }
 110         return 0;
 111 }
 112
 113 device_initcall(segments_info);