/*
 * 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.
 *
 * PROM library functions for acquiring/using memory descriptors given to
 * us from the YAMON.
 *
 * Copyright (C) 1999,2000,2012  MIPS Technologies, Inc.
 * All rights reserved.
 * Authors: Carsten Langgaard <carstenl@mips.com>
 *          Steven J. Hill <sjhill@mips.com>
 */
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/string.h>

#include <asm/bootinfo.h>
#include <asm/maar.h>
#include <asm/sections.h>
#include <asm/fw/fw.h>

static fw_memblock_t mdesc[FW_MAX_MEMBLOCKS];

/* determined physical memory size, not overridden by command line args  */
unsigned long physical_memsize = 0L;

fw_memblock_t * __init fw_getmdesc(int eva)
{
        char *memsize_str, *ememsize_str = NULL, *ptr;
        unsigned long memsize = 0, ememsize = 0;
        static char cmdline[COMMAND_LINE_SIZE] __initdata;
        int tmp;

        /* otherwise look in the environment */

        memsize_str = fw_getenv("memsize");
        if (memsize_str) {
                tmp = kstrtoul(memsize_str, 0, &memsize);
                if (tmp)
                        pr_warn("Failed to read the 'memsize' env variable.\n");
        }
        if (eva) {
        /* Look for ememsize for EVA */
                ememsize_str = fw_getenv("ememsize");
                if (ememsize_str) {
                        tmp = kstrtoul(ememsize_str, 0, &ememsize);
                        if (tmp)
                                pr_warn("Failed to read the 'ememsize' env variable.\n");
                }
        }
        if (!memsize && !ememsize) {
                pr_warn("memsize not set in YAMON, set to default (32Mb)\n");
                physical_memsize = 0x02000000;
        } else {
                /* If ememsize is set, then set physical_memsize to that */
                physical_memsize = ememsize ? : memsize;
        }

#ifdef CONFIG_CPU_BIG_ENDIAN
        /* SOC-it swaps, or perhaps doesn't swap, when DMA'ing the last
           word of physical memory */
        physical_memsize -= PAGE_SIZE;
#endif

        /* Check the command line for a memsize directive that overrides
           the physical/default amount */
        strcpy(cmdline, arcs_cmdline);
        ptr = strstr(cmdline, "memsize=");
        if (ptr && (ptr != cmdline) && (*(ptr - 1) != ' '))
                ptr = strstr(ptr, " memsize=");
        /* And now look for ememsize */
        if (eva) {
                ptr = strstr(cmdline, "ememsize=");
                if (ptr && (ptr != cmdline) && (*(ptr - 1) != ' '))
                        ptr = strstr(ptr, " ememsize=");
        }

        if (ptr)
                memsize = memparse(ptr + 8 + (eva ? 1 : 0), &ptr);
        else
                memsize = physical_memsize;

        /* Last 64K for HIGHMEM arithmetics */
        if (memsize > 0x7fff0000)
                memsize = 0x7fff0000;

        memset(mdesc, 0, sizeof(mdesc));

        mdesc[0].type = fw_dontuse;
        mdesc[0].base = PHYS_OFFSET;
        mdesc[0].size = 0x00001000;

        mdesc[1].type = fw_code;
        mdesc[1].base = mdesc[0].base + 0x00001000UL;
        mdesc[1].size = 0x000ef000;

        /*
         * The area 0x000f0000-0x000fffff is allocated for BIOS memory by the
         * south bridge and PCI access always forwarded to the ISA Bus and
         * BIOSCS# is always generated.
         * This mean that this area can't be used as DMA memory for PCI
         * devices.
         */
        mdesc[2].type = fw_dontuse;
        mdesc[2].base = mdesc[0].base + 0x000f0000UL;
        mdesc[2].size = 0x00010000;

        mdesc[3].type = fw_dontuse;
        mdesc[3].base = mdesc[0].base + 0x00100000UL;
        mdesc[3].size = CPHYSADDR(PFN_ALIGN((unsigned long)&_end)) -
                0x00100000UL;

        mdesc[4].type = fw_free;
        mdesc[4].base = mdesc[0].base + CPHYSADDR(PFN_ALIGN(&_end));
        mdesc[4].size = memsize - CPHYSADDR(mdesc[4].base);

        return &mdesc[0];
}

static void free_init_pages_eva_malta(void *begin, void *end)
{
        free_init_pages("unused kernel", __pa_symbol((unsigned long *)begin),
                        __pa_symbol((unsigned long *)end));
}

static int __init fw_memtype_classify(unsigned int type)
{
        switch (type) {
        case fw_free:
                return BOOT_MEM_RAM;
        case fw_code:
                return BOOT_MEM_ROM_DATA;
        default:
                return BOOT_MEM_RESERVED;
        }
}

void __init fw_meminit(void)
{
        fw_memblock_t *p;

        p = fw_getmdesc(config_enabled(CONFIG_EVA));
        free_init_pages_eva = (config_enabled(CONFIG_EVA) ?
                               free_init_pages_eva_malta : NULL);

        while (p->size) {
                long type;
                unsigned long base, size;

                type = fw_memtype_classify(p->type);
                base = p->base;
                size = p->size;

                add_memory_region(base, size, type);
                p++;
        }
}

void __init prom_free_prom_memory(void)
{
        unsigned long addr;
        int i;

        for (i = 0; i < boot_mem_map.nr_map; i++) {
                if (boot_mem_map.map[i].type != BOOT_MEM_ROM_DATA)
                        continue;

                addr = boot_mem_map.map[i].addr;
                free_init_pages("YAMON memory",
                                addr, addr + boot_mem_map.map[i].size);
        }
}

unsigned platform_maar_init(unsigned num_pairs)
{
        phys_addr_t mem_end = (physical_memsize & ~0xffffull) - 1;
        struct maar_config cfg[] = {
                /* DRAM preceding I/O */
                { 0x00000000, 0x0fffffff, MIPS_MAAR_S },

                /* DRAM following I/O */
                { 0x20000000, mem_end, MIPS_MAAR_S },

                /* DRAM alias in upper half of physical */
                { 0x80000000, 0x80000000 + mem_end, MIPS_MAAR_S },
        };
        unsigned i, num_cfg = ARRAY_SIZE(cfg);

        /* If DRAM fits before I/O, drop the region following it */
        if (physical_memsize <= 0x10000000) {
                num_cfg--;
                for (i = 1; i < num_cfg; i++)
                        cfg[i] = cfg[i + 1];
        }

        return maar_config(cfg, num_cfg, num_pairs);
}