// SPDX-License-Identifier: GPL-2.0
/*
 * 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>
#include "internal.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);

#define early_ioremap_dbg(fmt, args...)                 \
        do {                                            \
                if (unlikely(early_ioremap_debug)) {    \
                        pr_warn(fmt, ##args);           \
                        dump_stack();                   \
                }                                       \
        } while (0)

static int after_paging_init __initdata;

pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
                                                    unsigned long size,
                                                    pgprot_t prot)
{
        return prot;
}

void __init early_ioremap_reset(void)
{
        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++) {
                WARN_ON_ONCE(prev_map[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_RUNNING);

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

        if (WARN(slot < 0, "%s(%pa, %08lx) not found slot\n",
                 __func__, &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;

        early_ioremap_dbg("%s(%pa, %08lx) [%d] => %08lx + %08lx\n",
                          __func__, &phys_addr, size, slot, slot_virt[slot], offset);

        /*
         * 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;
        }

        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, "%s(%p, %08lx) not found slot\n",
                  __func__, addr, size))
                return;

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

        early_ioremap_dbg("%s(%p, %08lx) [%d]\n", __func__, 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)
{
        pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
                                                     FIXMAP_PAGE_NORMAL);

        return (__force void *)__early_ioremap(phys_addr, size, prot);
}
#ifdef FIXMAP_PAGE_RO
void __init *
early_memremap_ro(resource_size_t phys_addr, unsigned long size)
{
        pgprot_t prot = early_memremap_pgprot_adjust(phys_addr, size,
                                                     FIXMAP_PAGE_RO);

        return (__force void *)__early_ioremap(phys_addr, size, prot);
}
#endif

#ifdef CONFIG_ARCH_USE_MEMREMAP_PROT
void __init *
early_memremap_prot(resource_size_t phys_addr, unsigned long size,
                    unsigned long prot_val)
{
        return (__force void *)__early_ioremap(phys_addr, size,
                                               __pgprot(prot_val));
}
#endif

#define MAX_MAP_CHUNK   (NR_FIX_BTMAPS << PAGE_SHIFT)

/*
 * If no empty slot, handle that and return -ENOMEM.
 */
int __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);
                if (!p)
                        return -ENOMEM;
                memcpy(dest, p + slop, clen);
                early_memunmap(p, clen + slop);
                dest += clen;
                src += clen;
                size -= clen;
        }
        return 0;
}

#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);
}