/*
 * 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/debug.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 unless it becomes
         * unmapped uncached at error level due to EU.
         */
        if ((am == 0) || (am > 3) || (cfg & MIPS_SEGCFG_EU))
                str += sprintf(str, "         %03lx",
                        ((cfg & MIPS_SEGCFG_PA) >> MIPS_SEGCFG_PA_SHIFT));
        else
                str += sprintf(str, "         UND");

        if ((am == 0) || (am > 3))
                str += sprintf(str, "         %01ld",
                        ((cfg & MIPS_SEGCFG_C) >> MIPS_SEGCFG_C_SHIFT));
        else
                str += sprintf(str, "         U");

        /* Exception configuration. */
        str += sprintf(str, "       %01ld\n",
                ((cfg & MIPS_SEGCFG_EU) >> MIPS_SEGCFG_EU_SHIFT));
}

static int segments_show(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;
}
DEFINE_SHOW_ATTRIBUTE(segments);

static int __init segments_info(void)
{
        if (cpu_has_segments)
                debugfs_create_file("segments", S_IRUGO, mips_debugfs_dir, NULL,
                                    &segments_fops);
        return 0;
}

device_initcall(segments_info);