1 files changed, 110 insertions, 0 deletions

diff --git a/arch/mips/kernel/segment.c b/arch/mips/kernel/segment.c
new file mode 100644
index 000000000000..076ead2a9859
--- /dev/null
+++ b/arch/mips/kernel/segment.c
@@ -0,0 +1,110 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2013 Imagination Technologies Ltd.
+ */
+
+#include <linux/kernel.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <asm/cpu.h>
+#include <asm/mipsregs.h>
+
+static void build_segment_config(char *str, unsigned int cfg)
+{
+        unsigned int am;
+        static const char * const am_str[] = {
+                "UK", "MK", "MSK", "MUSK", "MUSUK", "USK",
+                "RSRVD", "UUSK"};
+
+        /* Segment access mode. */
+        am = (cfg & MIPS_SEGCFG_AM) >> MIPS_SEGCFG_AM_SHIFT;
+        str += sprintf(str, "%-5s", am_str[am]);
+
+        /*
+         * Access modes MK, MSK and MUSK are mapped segments. Therefore
+         * there is no direct physical address mapping.
+         */
+        if ((am == 0) || (am > 3)) {
+                str += sprintf(str, "         %03lx",
+                        ((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
+                str += sprintf(str, "         %01ld",
+                        ((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
+        } else {
+                str += sprintf(str, "         UND");
+                str += sprintf(str, "         U");
+        }
+
+        /* Exception configuration. */
+        str += sprintf(str, "       %01ld\n",
+                ((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
+}
+
+static int show_segments(struct seq_file *m, void *v)
+{
+        unsigned int segcfg;
+        char str[42];
+
+        seq_puts(m, "Segment   Virtual    Size   Access Mode   Physical   Caching   EU\n");
+        seq_puts(m, "-------   -------    ----   -----------   --------   -------   --\n");
+
+        segcfg = read_c0_segctl0();
+        build_segment_config(str, segcfg);
+        seq_printf(m, "   0      e0000000   512M      %s", str);
+
+        segcfg >>= 16;
+        build_segment_config(str, segcfg);
+        seq_printf(m, "   1      c0000000   512M      %s", str);
+
+        segcfg = read_c0_segctl1();
+        build_segment_config(str, segcfg);
+        seq_printf(m, "   2      a0000000   512M      %s", str);
+
+        segcfg >>= 16;
+        build_segment_config(str, segcfg);
+        seq_printf(m, "   3      80000000   512M      %s", str);
+
+        segcfg = read_c0_segctl2();
+        build_segment_config(str, segcfg);
+        seq_printf(m, "   4      40000000    1G       %s", str);
+
+        segcfg >>= 16;
+        build_segment_config(str, segcfg);
+        seq_printf(m, "   5      00000000    1G       %s\n", str);
+
+        return 0;
+}
+
+static int segments_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, show_segments, NULL);
+}
+
+static const struct file_operations segments_fops = {
+        .open           = segments_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static int __init segments_info(void)
+{
+        extern struct dentry *mips_debugfs_dir;
+        struct dentry *segments;
+
+        if (cpu_has_segments) {
+                if (!mips_debugfs_dir)
+                        return -ENODEV;
+
+                segments = debugfs_create_file("segments", S_IRUGO,
+                                               mips_debugfs_dir, NULL,
+                                               &segments_fops);
+                if (!segments)
+                        return -ENOMEM;
+        }
+        return 0;
+}
+
+device_initcall(segments_info);