/*
 * Provide common bits of early_ioremap() support for architectures needing
 * temporary mappings during boot before ioremap() is available.
 *
 * This is mostly a direct copy of the x86 early_ioremap implementation.
 *
 * (C) Copyright 1995 1996, 2014 Linus Torvalds
 *
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <asm/fixmap.h>
#include <asm/early_ioremap.h>

#ifdef CONFIG_MMU
static int early_ioremap_debug __initdata;

static int __init early_ioremap_debug_setup(char *str)
{
        early_ioremap_debug = 1;

        return 0;
}
early_param("early_ioremap_debug", early_ioremap_debug_setup);

static int after_paging_init __initdata;

void __init __weak early_ioremap_shutdown(void)
{
}

void __init early_ioremap_reset(void)
{
        early_ioremap_shutdown();
        after_paging_init = 1;
}

/*
 * Generally, ioremap() is available after paging_init() has been called.
 * Architectures wanting to allow early_ioremap after paging_init() can
 * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
 */
#ifndef __late_set_fixmap
static inline void __init __late_set_fixmap(enum fixed_addresses idx,
                                            phys_addr_t phys, pgprot_t prot)
{
        BUG();
}
#endif

#ifndef __late_clear_fixmap
static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
{
        BUG();
}
#endif

static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;

void __init early_ioremap_setup(void)
{
        int i;

        for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
                if (WARN_ON(prev_map[i]))
                        break;

        for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
                slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
}

static int __init check_early_ioremap_leak(void)
{
        int count = 0;
        int i;

        for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
                if (prev_map[i])
                        count++;

        if (WARN(count, KERN_WARNING
                 "Debug warning: early ioremap leak of %d areas detected.\n"
                 "please boot with early_ioremap_debug and report the dmesg.\n",
                 count))
                return 1;
        return 0;
}
late_initcall(check_early_ioremap_leak);

static void __init __iomem *
__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
{
        unsigned long offset;
        resource_size_t last_addr;
        unsigned int nrpages;
        enum fixed_addresses idx;
        int i, slot;

        WARN_ON(system_state != SYSTEM_BOOTING);

        slot = -1;
        for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
                if (!prev_map[i]) {
                        slot = i;
                        break;
                }
        }

        if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
                 __func__, (u64)phys_addr, size))
                return NULL;

        /* Don't allow wraparound or zero size */
        last_addr = phys_addr + size - 1;
        if (WARN_ON(!size || last_addr < phys_addr))
                return NULL;

        prev_size[slot] = size;
        /*
         * Mappings have to be page-aligned
         */
        offset = offset_in_page(phys_addr);
        phys_addr &= PAGE_MASK;
        size = PAGE_ALIGN(last_addr + 1) - phys_addr;

        /*
         * Mappings have to fit in the FIX_BTMAP area.
         */
        nrpages = size >> PAGE_SHIFT;
        if (WARN_ON(nrpages > NR_FIX_BTMAPS))
                return NULL;

        /*
         * Ok, go for it..
         */
        idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
        while (nrpages > 0) {
                if (after_paging_init)
                        __late_set_fixmap(idx, phys_addr, prot);
                else
                        __early_set_fixmap(idx, phys_addr, prot);
                phys_addr += PAGE_SIZE;
                --idx;
                --nrpages;
        }
        WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
             __func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);

        prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
        return prev_map[slot];
}

void __init early_iounmap(void __iomem *addr, unsigned long size)
{
        unsigned long virt_addr;
        unsigned long offset;
        unsigned int nrpages;
        enum fixed_addresses idx;
        int i, slot;

        slot = -1;
        for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
                if (prev_map[i] == addr) {
                        slot = i;
                        break;
                }
        }

        if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
                 addr, size))
                return;

        if (WARN(prev_size[slot] != size,
                 "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
                 addr, size, slot, prev_size[slot]))
                return;

        WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
             addr, size, slot);

        virt_addr = (unsigned long)addr;
        if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
                return;

        offset = offset_in_page(virt_addr);
        nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;

        idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
        while (nrpages > 0) {
                if (after_paging_init)
                        __late_clear_fixmap(idx);
                else
                        __early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
                --idx;
                --nrpages;
        }
        prev_map[slot] = NULL;
}

/* Remap an IO device */
void __init __iomem *
early_ioremap(resource_size_t phys_addr, unsigned long size)
{
        return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
}

/* Remap memory */
void __init *
early_memremap(resource_size_t phys_addr, unsigned long size)
{
        return (__force void *)__early_ioremap(phys_addr, size,
                                               FIXMAP_PAGE_NORMAL);
}
#ifdef FIXMAP_PAGE_RO
void __init *
early_memremap_ro(resource_size_t phys_addr, unsigned long size)
{
        return (__force void *)__early_ioremap(phys_addr, size, FIXMAP_PAGE_RO);
}
#endif

#define MAX_MAP_CHUNK   (NR_FIX_BTMAPS << PAGE_SHIFT)

void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
{
        unsigned long slop, clen;
        char *p;

        while (size) {
                slop = offset_in_page(src);
                clen = size;
                if (clen > MAX_MAP_CHUNK - slop)
                        clen = MAX_MAP_CHUNK - slop;
                p = early_memremap(src & PAGE_MASK, clen + slop);
                memcpy(dest, p + slop, clen);
                early_memunmap(p, clen + slop);
                dest += clen;
                src += clen;
                size -= clen;
        }
}

#else /* CONFIG_MMU */

void __init __iomem *
early_ioremap(resource_size_t phys_addr, unsigned long size)
{
        return (__force void __iomem *)phys_addr;
}

/* Remap memory */
void __init *
early_memremap(resource_size_t phys_addr, unsigned long size)
{
        return (void *)phys_addr;
}
void __init *
early_memremap_ro(resource_size_t phys_addr, unsigned long size)
{
        return (void *)phys_addr;
}

void __init early_iounmap(void __iomem *addr, unsigned long size)
{
}

#endif /* CONFIG_MMU */


void __init early_memunmap(void *addr, unsigned long size)
{
        early_iounmap((__force void __iomem *)addr, size);
}