/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/sched.h>
#include <linux/console.h>
#include <linux/ioport.h>
#include <linux/bootmem.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/pfn.h>
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/kernel.h>

#include <asm/sections.h>
#include <asm/processor.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/sysreg.h>

#include <mach/board.h>
#include <mach/init.h>

extern int root_mountflags;

/*
 * Initialize loops_per_jiffy as 5000000 (500MIPS).
 * Better make it too large than too small...
 */
struct avr32_cpuinfo boot_cpu_data = {
        .loops_per_jiffy = 5000000
};
EXPORT_SYMBOL(boot_cpu_data);

static char __initdata command_line[COMMAND_LINE_SIZE];

/*
 * Standard memory resources
 */
static struct resource __initdata kernel_data = {
        .name   = "Kernel data",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_MEM,
};
static struct resource __initdata kernel_code = {
        .name   = "Kernel code",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_MEM,
        .sibling = &kernel_data,
};

/*
 * Available system RAM and reserved regions as singly linked
 * lists. These lists are traversed using the sibling pointer in
 * struct resource and are kept sorted at all times.
 */
static struct resource *__initdata system_ram;
static struct resource *__initdata reserved = &kernel_code;

/*
 * We need to allocate these before the bootmem allocator is up and
 * running, so we need this "cache". 32 entries are probably enough
 * for all but the most insanely complex systems.
 */
static struct resource __initdata res_cache[32];
static unsigned int __initdata res_cache_next_free;

static void __init resource_init(void)
{
        struct resource *mem, *res;
        struct resource *new;

        kernel_code.start = __pa(init_mm.start_code);

        for (mem = system_ram; mem; mem = mem->sibling) {
                new = alloc_bootmem_low(sizeof(struct resource));
                memcpy(new, mem, sizeof(struct resource));

                new->sibling = NULL;
                if (request_resource(&iomem_resource, new))
                        printk(KERN_WARNING "Bad RAM resource %08x-%08x\n",
                               mem->start, mem->end);
        }

        for (res = reserved; res; res = res->sibling) {
                new = alloc_bootmem_low(sizeof(struct resource));
                memcpy(new, res, sizeof(struct resource));

                new->sibling = NULL;
                if (insert_resource(&iomem_resource, new))
                        printk(KERN_WARNING
                               "Bad reserved resource %s (%08x-%08x)\n",
                               res->name, res->start, res->end);
        }
}

static void __init
add_physical_memory(resource_size_t start, resource_size_t end)
{
        struct resource *new, *next, **pprev;

        for (pprev = &system_ram, next = system_ram; next;
             pprev = &next->sibling, next = next->sibling) {
                if (end < next->start)
                        break;
                if (start <= next->end) {
                        printk(KERN_WARNING
                               "Warning: Physical memory map is broken\n");
                        printk(KERN_WARNING
                               "Warning: %08x-%08x overlaps %08x-%08x\n",
                               start, end, next->start, next->end);
                        return;
                }
        }

        if (res_cache_next_free >= ARRAY_SIZE(res_cache)) {
                printk(KERN_WARNING
                       "Warning: Failed to add physical memory %08x-%08x\n",
                       start, end);
                return;
        }

        new = &res_cache[res_cache_next_free++];
        new->start = start;
        new->end = end;
        new->name = "System RAM";
        new->flags = IORESOURCE_MEM;

        *pprev = new;
}

static int __init
add_reserved_region(resource_size_t start, resource_size_t end,
                    const char *name)
{
        struct resource *new, *next, **pprev;

        if (end < start)
                return -EINVAL;

        if (res_cache_next_free >= ARRAY_SIZE(res_cache))
                return -ENOMEM;

        for (pprev = &reserved, next = reserved; next;
             pprev = &next->sibling, next = next->sibling) {
                if (end < next->start)
                        break;
                if (start <= next->end)
                        return -EBUSY;
        }

        new = &res_cache[res_cache_next_free++];
        new->start = start;
        new->end = end;
        new->name = name;
        new->sibling = next;
        new->flags = IORESOURCE_MEM;

        *pprev = new;

        return 0;
}

static unsigned long __init
find_free_region(const struct resource *mem, resource_size_t size,
                 resource_size_t align)
{
        struct resource *res;
        unsigned long target;

        target = ALIGN(mem->start, align);
        for (res = reserved; res; res = res->sibling) {
                if ((target + size) <= res->start)
                        break;
                if (target <= res->end)
                        target = ALIGN(res->end + 1, align);
        }

        if ((target + size) > (mem->end + 1))
                return mem->end + 1;

        return target;
}

static int __init
alloc_reserved_region(resource_size_t *start, resource_size_t size,
                      resource_size_t align, const char *name)
{
        struct resource *mem;
        resource_size_t target;
        int ret;

        for (mem = system_ram; mem; mem = mem->sibling) {
                target = find_free_region(mem, size, align);
                if (target <= mem->end) {
                        ret = add_reserved_region(target, target + size - 1,
                                                  name);
                        if (!ret)
                                *start = target;
                        return ret;
                }
        }

        return -ENOMEM;
}

/*
 * Early framebuffer allocation. Works as follows:
 *   - If fbmem_size is zero, nothing will be allocated or reserved.
 *   - If fbmem_start is zero when setup_bootmem() is called,
 *     a block of fbmem_size bytes will be reserved before bootmem
 *     initialization. It will be aligned to the largest page size
 *     that fbmem_size is a multiple of.
 *   - If fbmem_start is nonzero, an area of size fbmem_size will be
 *     reserved at the physical address fbmem_start if possible. If
 *     it collides with other reserved memory, a different block of
 *     same size will be allocated, just as if fbmem_start was zero.
 *
 * Board-specific code may use these variables to set up platform data
 * for the framebuffer driver if fbmem_size is nonzero.
 */
resource_size_t __initdata fbmem_start;
resource_size_t __initdata fbmem_size;

/*
 * "fbmem=xxx[kKmM]" allocates the specified amount of boot memory for
 * use as framebuffer.
 *
 * "fbmem=xxx[kKmM]@yyy[kKmM]" defines a memory region of size xxx and
 * starting at yyy to be reserved for use as framebuffer.
 *
 * The kernel won't verify that the memory region starting at yyy
 * actually contains usable RAM.
 */
static int __init early_parse_fbmem(char *p)
{
        int ret;
        unsigned long align;

        fbmem_size = memparse(p, &p);
        if (*p == '@') {
                fbmem_start = memparse(p + 1, &p);
                ret = add_reserved_region(fbmem_start,
                                          fbmem_start + fbmem_size - 1,
                                          "Framebuffer");
                if (ret) {
                        printk(KERN_WARNING
                               "Failed to reserve framebuffer memory\n");
                        fbmem_start = 0;
                }
        }

        if (!fbmem_start) {
                if ((fbmem_size & 0x000fffffUL) == 0)
                        align = 0x100000;       /* 1 MiB */
                else if ((fbmem_size & 0x0000ffffUL) == 0)
                        align = 0x10000;        /* 64 KiB */
                else
                        align = 0x1000;         /* 4 KiB */

                ret = alloc_reserved_region(&fbmem_start, fbmem_size,
                                            align, "Framebuffer");
                if (ret) {
                        printk(KERN_WARNING
                               "Failed to allocate framebuffer memory\n");
                        fbmem_size = 0;
                } else {
                        memset(__va(fbmem_start), 0, fbmem_size);
                }
        }

        return 0;
}
early_param("fbmem", early_parse_fbmem);

/*
 * Pick out the memory size.  We look for mem=size@start,
 * where start and size are "size[KkMmGg]"
 */
static int __init early_mem(char *p)
{
        resource_size_t size, start;

        start = system_ram->start;
        size  = memparse(p, &p);
        if (*p == '@')
                start = memparse(p + 1, &p);

        system_ram->start = start;
        system_ram->end = system_ram->start + size - 1;
        return 0;
}
early_param("mem", early_mem);

static int __init parse_tag_core(struct tag *tag)
{
        if (tag->hdr.size > 2) {
                if ((tag->u.core.flags & 1) == 0)
                        root_mountflags &= ~MS_RDONLY;
                ROOT_DEV = new_decode_dev(tag->u.core.rootdev);
        }
        return 0;
}
__tagtable(ATAG_CORE, parse_tag_core);

static int __init parse_tag_mem(struct tag *tag)
{
        unsigned long start, end;

        /*
         * Ignore zero-sized entries. If we're running standalone, the
         * SDRAM code may emit such entries if something goes
         * wrong...
         */
        if (tag->u.mem_range.size == 0)
                return 0;

        start = tag->u.mem_range.addr;
        end = tag->u.mem_range.addr + tag->u.mem_range.size - 1;

        add_physical_memory(start, end);
        return 0;
}
__tagtable(ATAG_MEM, parse_tag_mem);

static int __init parse_tag_rdimg(struct tag *tag)
{
#ifdef CONFIG_BLK_DEV_INITRD
        struct tag_mem_range *mem = &tag->u.mem_range;
        int ret;

        if (initrd_start) {
                printk(KERN_WARNING
                       "Warning: Only the first initrd image will be used\n");
                return 0;
        }

        ret = add_reserved_region(mem->addr, mem->addr + mem->size - 1,
                                  "initrd");
        if (ret) {
                printk(KERN_WARNING
                       "Warning: Failed to reserve initrd memory\n");
                return ret;
        }

        initrd_start = (unsigned long)__va(mem->addr);
        initrd_end = initrd_start + mem->size;
#else
        printk(KERN_WARNING "RAM disk image present, but "
               "no initrd support in kernel, ignoring\n");
#endif

        return 0;
}
__tagtable(ATAG_RDIMG, parse_tag_rdimg);

static int __init parse_tag_rsvd_mem(struct tag *tag)
{
        struct tag_mem_range *mem = &tag->u.mem_range;

        return add_reserved_region(mem->addr, mem->addr + mem->size - 1,
                                   "Reserved");
}
__tagtable(ATAG_RSVD_MEM, parse_tag_rsvd_mem);

static int __init parse_tag_cmdline(struct tag *tag)
{
        strlcpy(boot_command_line, tag->u.cmdline.cmdline, COMMAND_LINE_SIZE);
        return 0;
}
__tagtable(ATAG_CMDLINE, parse_tag_cmdline);

static int __init parse_tag_clock(struct tag *tag)
{
        /*
         * We'll figure out the clocks by peeking at the system
         * manager regs directly.
         */
        return 0;
}
__tagtable(ATAG_CLOCK, parse_tag_clock);

/*
 * The board_number correspond to the bd->bi_board_number in U-Boot. This
 * parameter is only available during initialisation and can be used in some
 * kind of board identification.
 */
u32 __initdata board_number;

static int __init parse_tag_boardinfo(struct tag *tag)
{
        board_number = tag->u.boardinfo.board_number;

        return 0;
}
__tagtable(ATAG_BOARDINFO, parse_tag_boardinfo);

/*
 * Scan the tag table for this tag, and call its parse function. The
 * tag table is built by the linker from all the __tagtable
 * declarations.
 */
static int __init parse_tag(struct tag *tag)
{
        extern struct tagtable __tagtable_begin, __tagtable_end;
        struct tagtable *t;

        for (t = &__tagtable_begin; t < &__tagtable_end; t++)
                if (tag->hdr.tag == t->tag) {
                        t->parse(tag);
                        break;
                }

        return t < &__tagtable_end;
}

/*
 * Parse all tags in the list we got from the boot loader
 */
static void __init parse_tags(struct tag *t)
{
        for (; t->hdr.tag != ATAG_NONE; t = tag_next(t))
                if (!parse_tag(t))
                        printk(KERN_WARNING
                               "Ignoring unrecognised tag 0x%08x\n",
                               t->hdr.tag);
}

/*
 * Find a free memory region large enough for storing the
 * bootmem bitmap.
 */
static unsigned long __init
find_bootmap_pfn(const struct resource *mem)
{
        unsigned long bootmap_pages, bootmap_len;
        unsigned long node_pages = PFN_UP(mem->end - mem->start + 1);
        unsigned long bootmap_start;

        bootmap_pages = bootmem_bootmap_pages(node_pages);
        bootmap_len = bootmap_pages << PAGE_SHIFT;

        /*
         * Find a large enough region without reserved pages for
         * storing the bootmem bitmap. We can take advantage of the
         * fact that all lists have been sorted.
         *
         * We have to check that we don't collide with any reserved
         * regions, which includes the kernel image and any RAMDISK
         * images.
         */
        bootmap_start = find_free_region(mem, bootmap_len, PAGE_SIZE);

        return bootmap_start >> PAGE_SHIFT;
}

#define MAX_LOWMEM      HIGHMEM_START
#define MAX_LOWMEM_PFN  PFN_DOWN(MAX_LOWMEM)

static void __init setup_bootmem(void)
{
        unsigned bootmap_size;
        unsigned long first_pfn, bootmap_pfn, pages;
        unsigned long max_pfn, max_low_pfn;
        unsigned node = 0;
        struct resource *res;

        printk(KERN_INFO "Physical memory:\n");
        for (res = system_ram; res; res = res->sibling)
                printk("  %08x-%08x\n", res->start, res->end);
        printk(KERN_INFO "Reserved memory:\n");
        for (res = reserved; res; res = res->sibling)
                printk("  %08x-%08x: %s\n",
                       res->start, res->end, res->name);

        nodes_clear(node_online_map);

        if (system_ram->sibling)
                printk(KERN_WARNING "Only using first memory bank\n");

        for (res = system_ram; res; res = NULL) {
                first_pfn = PFN_UP(res->start);
                max_low_pfn = max_pfn = PFN_DOWN(res->end + 1);
                bootmap_pfn = find_bootmap_pfn(res);
                if (bootmap_pfn > max_pfn)
                        panic("No space for bootmem bitmap!\n");

                if (max_low_pfn > MAX_LOWMEM_PFN) {
                        max_low_pfn = MAX_LOWMEM_PFN;
#ifndef CONFIG_HIGHMEM
                        /*
                         * Lowmem is memory that can be addressed
                         * directly through P1/P2
                         */
                        printk(KERN_WARNING
                               "Node %u: Only %ld MiB of memory will be used.\n",
                               node, MAX_LOWMEM >> 20);
                        printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
#else
#error HIGHMEM is not supported by AVR32 yet
#endif
                }

                /* Initialize the boot-time allocator with low memory only. */
                bootmap_size = init_bootmem_node(NODE_DATA(node), bootmap_pfn,
                                                 first_pfn, max_low_pfn);

                /*
                 * Register fully available RAM pages with the bootmem
                 * allocator.
                 */
                pages = max_low_pfn - first_pfn;
                free_bootmem_node (NODE_DATA(node), PFN_PHYS(first_pfn),
                                   PFN_PHYS(pages));

                /* Reserve space for the bootmem bitmap... */
                reserve_bootmem_node(NODE_DATA(node),
                                     PFN_PHYS(bootmap_pfn),
                                     bootmap_size,
                                     BOOTMEM_DEFAULT);

                /* ...and any other reserved regions. */
                for (res = reserved; res; res = res->sibling) {
                        if (res->start > PFN_PHYS(max_pfn))
                                break;

                        /*
                         * resource_init will complain about partial
                         * overlaps, so we'll just ignore such
                         * resources for now.
                         */
                        if (res->start >= PFN_PHYS(first_pfn)
                            && res->end < PFN_PHYS(max_pfn))
                                reserve_bootmem_node(
                                        NODE_DATA(node), res->start,
                                        res->end - res->start + 1,
                                        BOOTMEM_DEFAULT);
                }

                node_set_online(node);
        }
}

void __init setup_arch (char **cmdline_p)
{
        struct clk *cpu_clk;

        init_mm.start_code = (unsigned long)_text;
        init_mm.end_code = (unsigned long)_etext;
        init_mm.end_data = (unsigned long)_edata;
        init_mm.brk = (unsigned long)_end;

        /*
         * Include .init section to make allocations easier. It will
         * be removed before the resource is actually requested.
         */
        kernel_code.start = __pa(__init_begin);
        kernel_code.end = __pa(init_mm.end_code - 1);
        kernel_data.start = __pa(init_mm.end_code);
        kernel_data.end = __pa(init_mm.brk - 1);

        parse_tags(bootloader_tags);

        setup_processor();
        setup_platform();
        setup_board();

        cpu_clk = clk_get(NULL, "cpu");
        if (IS_ERR(cpu_clk)) {
                printk(KERN_WARNING "Warning: Unable to get CPU clock\n");
        } else {
                unsigned long cpu_hz = clk_get_rate(cpu_clk);

                /*
                 * Well, duh, but it's probably a good idea to
                 * increment the use count.
                 */
                clk_enable(cpu_clk);

                boot_cpu_data.clk = cpu_clk;
                boot_cpu_data.loops_per_jiffy = cpu_hz * 4;
                printk("CPU: Running at %lu.%03lu MHz\n",
                       ((cpu_hz + 500) / 1000) / 1000,
                       ((cpu_hz + 500) / 1000) % 1000);
        }

        strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
        *cmdline_p = command_line;
        parse_early_param();

        setup_bootmem();

#ifdef CONFIG_VT
        conswitchp = &dummy_con;
#endif

        paging_init();
        resource_init();
}