// 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>

  
  #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;

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

  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.
  "
  		 "please boot with early_ioremap_debug and report the dmesg.
  ",
  		 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(%08llx, %08lx) not found slot
  ",
  		 __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
  ",
  	     __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
  ",
  		 addr, size))
  		return;
  
  	if (WARN(prev_size[slot] != size,
  		 "early_iounmap(%p, %08lx) [%d] size not consistent %08lx
  ",
  		 addr, size, slot, prev_size[slot]))
  		return;
  
  	WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]
  ",
  	     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)
  
  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);
  }