/*
   * Copyright (C) 2007-2008 Michal Simek <monstr@monstr.eu>
   * Copyright (C) 2006 Atmark Techno, Inc.
   *
   * 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.
   */
  
  #include <linux/bootmem.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/memblock.h>
  #include <linux/mm.h> /* mem_init */
  #include <linux/initrd.h>
  #include <linux/pagemap.h>
  #include <linux/pfn.h>
  #include <linux/slab.h>
  #include <linux/swap.h>
  #include <linux/export.h>
  
  #include <asm/page.h>
  #include <asm/mmu_context.h>
  #include <asm/pgalloc.h>
  #include <asm/sections.h>
  #include <asm/tlb.h>
  #include <asm/fixmap.h>
  
  /* Use for MMU and noMMU because of PCI generic code */
  int mem_init_done;
  
  #ifndef CONFIG_MMU
  unsigned int __page_offset;
  EXPORT_SYMBOL(__page_offset);
  
  #else
  static int init_bootmem_done;
  #endif /* CONFIG_MMU */
  
  char *klimit = _end;
  
  /*
   * Initialize the bootmem system and give it all the memory we
   * have available.
   */
  unsigned long memory_start;
  EXPORT_SYMBOL(memory_start);
  unsigned long memory_size;
  EXPORT_SYMBOL(memory_size);
  unsigned long lowmem_size;
  
  #ifdef CONFIG_HIGHMEM
  pte_t *kmap_pte;
  EXPORT_SYMBOL(kmap_pte);
  pgprot_t kmap_prot;
  EXPORT_SYMBOL(kmap_prot);
  
  static inline pte_t *virt_to_kpte(unsigned long vaddr)
  {
  	return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
  			vaddr), vaddr);
  }
  
  static void __init highmem_init(void)
  {
  	pr_debug("%x
  ", (u32)PKMAP_BASE);
  	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
  	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
  
  	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
  	kmap_prot = PAGE_KERNEL;
  }
  
  static void highmem_setup(void)
  {
  	unsigned long pfn;
  
  	for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
  		struct page *page = pfn_to_page(pfn);
  
  		/* FIXME not sure about */
  		if (!memblock_is_reserved(pfn << PAGE_SHIFT))
  			free_highmem_page(page);
  	}
  }
  #endif /* CONFIG_HIGHMEM */
  
  /*
   * paging_init() sets up the page tables - in fact we've already done this.
   */
  static void __init paging_init(void)
  {
  	unsigned long zones_size[MAX_NR_ZONES];
  #ifdef CONFIG_MMU
  	int idx;
  
  	/* Setup fixmaps */
  	for (idx = 0; idx < __end_of_fixed_addresses; idx++)
  		clear_fixmap(idx);
  #endif
  
  	/* Clean every zones */
  	memset(zones_size, 0, sizeof(zones_size));
  
  #ifdef CONFIG_HIGHMEM
  	highmem_init();
  
  	zones_size[ZONE_DMA] = max_low_pfn;
  	zones_size[ZONE_HIGHMEM] = max_pfn;
  #else
  	zones_size[ZONE_DMA] = max_pfn;
  #endif
  
  	/* We don't have holes in memory map */
  	free_area_init_nodes(zones_size);
  }
  
  void __init setup_memory(void)
  {
  	unsigned long map_size;
  	struct memblock_region *reg;
  
  #ifndef CONFIG_MMU
  	u32 kernel_align_start, kernel_align_size;
  
  	/* Find main memory where is the kernel */
  	for_each_memblock(memory, reg) {
  		memory_start = (u32)reg->base;
  		lowmem_size = reg->size;
  		if ((memory_start <= (u32)_text) &&
  			((u32)_text <= (memory_start + lowmem_size - 1))) {
  			memory_size = lowmem_size;
  			PAGE_OFFSET = memory_start;
  			pr_info("%s: Main mem: 0x%x, size 0x%08x
  ",
  				__func__, (u32) memory_start,
  					(u32) memory_size);
  			break;
  		}
  	}
  
  	if (!memory_start || !memory_size) {
  		panic("%s: Missing memory setting 0x%08x, size=0x%08x
  ",
  			__func__, (u32) memory_start, (u32) memory_size);
  	}
  
  	/* reservation of region where is the kernel */
  	kernel_align_start = PAGE_DOWN((u32)_text);
  	/* ALIGN can be remove because _end in vmlinux.lds.S is align */
  	kernel_align_size = PAGE_UP((u32)klimit) - kernel_align_start;
  	pr_info("%s: kernel addr:0x%08x-0x%08x size=0x%08x
  ",
  		__func__, kernel_align_start, kernel_align_start
  			+ kernel_align_size, kernel_align_size);
  	memblock_reserve(kernel_align_start, kernel_align_size);
  #endif
  	/*
  	 * Kernel:
  	 * start: base phys address of kernel - page align
  	 * end: base phys address of kernel - page align
  	 *
  	 * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
  	 * max_low_pfn
  	 * max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
  	 */
  
  	/* memory start is from the kernel end (aligned) to higher addr */
  	min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
  	/* RAM is assumed contiguous */
  	max_mapnr = memory_size >> PAGE_SHIFT;
  	max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
  	max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;
  
  	pr_info("%s: max_mapnr: %#lx
  ", __func__, max_mapnr);
  	pr_info("%s: min_low_pfn: %#lx
  ", __func__, min_low_pfn);
  	pr_info("%s: max_low_pfn: %#lx
  ", __func__, max_low_pfn);
  	pr_info("%s: max_pfn: %#lx
  ", __func__, max_pfn);
  
  	/*
  	 * Find an area to use for the bootmem bitmap.
  	 * We look for the first area which is at least
  	 * 128kB in length (128kB is enough for a bitmap
  	 * for 4GB of memory, using 4kB pages), plus 1 page
  	 * (in case the address isn't page-aligned).
  	 */
  	map_size = init_bootmem_node(NODE_DATA(0),
  		PFN_UP(TOPHYS((u32)klimit)), min_low_pfn, max_low_pfn);
  	memblock_reserve(PFN_UP(TOPHYS((u32)klimit)) << PAGE_SHIFT, map_size);
  
  	/* Add active regions with valid PFNs */
  	for_each_memblock(memory, reg) {
  		unsigned long start_pfn, end_pfn;
  
  		start_pfn = memblock_region_memory_base_pfn(reg);
  		end_pfn = memblock_region_memory_end_pfn(reg);
  		memblock_set_node(start_pfn << PAGE_SHIFT,
  				  (end_pfn - start_pfn) << PAGE_SHIFT,
  				  &memblock.memory, 0);
  	}
  
  	/* free bootmem is whole main memory */
  	free_bootmem_with_active_regions(0, max_low_pfn);
  
  	/* reserve allocate blocks */
  	for_each_memblock(reserved, reg) {
  		unsigned long top = reg->base + reg->size - 1;
  
  		pr_debug("reserved - 0x%08x-0x%08x, %lx, %lx
  ",
  			 (u32) reg->base, (u32) reg->size, top,
  						memory_start + lowmem_size - 1);
  
  		if (top <= (memory_start + lowmem_size - 1)) {
  			reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
  		} else if (reg->base < (memory_start + lowmem_size - 1)) {
  			unsigned long trunc_size = memory_start + lowmem_size -
  								reg->base;
  			reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
  		}
  	}
  
  	/* XXX need to clip this if using highmem? */
  	sparse_memory_present_with_active_regions(0);
  
  #ifdef CONFIG_MMU
  	init_bootmem_done = 1;
  #endif
  	paging_init();
  }
  
  #ifdef CONFIG_BLK_DEV_INITRD
  void free_initrd_mem(unsigned long start, unsigned long end)
  {
  	free_reserved_area((void *)start, (void *)end, -1, "initrd");
  }
  #endif
  
  void free_initmem(void)
  {
  	free_initmem_default(-1);
  }
  
  void __init mem_init(void)
  {
  	high_memory = (void *)__va(memory_start + lowmem_size - 1);
  
  	/* this will put all memory onto the freelists */
  	free_all_bootmem();
  #ifdef CONFIG_HIGHMEM
  	highmem_setup();
  #endif
  
  	mem_init_print_info(NULL);
  #ifdef CONFIG_MMU
  	pr_info("Kernel virtual memory layout:
  ");
  	pr_info("  * 0x%08lx..0x%08lx  : fixmap
  ", FIXADDR_START, FIXADDR_TOP);
  #ifdef CONFIG_HIGHMEM
  	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs
  ",
  		PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
  #endif /* CONFIG_HIGHMEM */
  	pr_info("  * 0x%08lx..0x%08lx  : early ioremap
  ",
  		ioremap_bot, ioremap_base);
  	pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap
  ",
  		(unsigned long)VMALLOC_START, VMALLOC_END);
  #endif
  	mem_init_done = 1;
  }
  
  #ifndef CONFIG_MMU
  int page_is_ram(unsigned long pfn)
  {
  	return __range_ok(pfn, 0);
  }
  #else
  int page_is_ram(unsigned long pfn)
  {
  	return pfn < max_low_pfn;
  }
  
  /*
   * Check for command-line options that affect what MMU_init will do.
   */
  static void mm_cmdline_setup(void)
  {
  	unsigned long maxmem = 0;
  	char *p = cmd_line;
  
  	/* Look for mem= option on command line */
  	p = strstr(cmd_line, "mem=");
  	if (p) {
  		p += 4;
  		maxmem = memparse(p, &p);
  		if (maxmem && memory_size > maxmem) {
  			memory_size = maxmem;
  			memblock.memory.regions[0].size = memory_size;
  		}
  	}
  }
  
  /*
   * MMU_init_hw does the chip-specific initialization of the MMU hardware.
   */
  static void __init mmu_init_hw(void)
  {
  	/*
  	 * The Zone Protection Register (ZPR) defines how protection will
  	 * be applied to every page which is a member of a given zone. At
  	 * present, we utilize only two of the zones.
  	 * The zone index bits (of ZSEL) in the PTE are used for software
  	 * indicators, except the LSB.  For user access, zone 1 is used,
  	 * for kernel access, zone 0 is used.  We set all but zone 1
  	 * to zero, allowing only kernel access as indicated in the PTE.
  	 * For zone 1, we set a 01 binary (a value of 10 will not work)
  	 * to allow user access as indicated in the PTE.  This also allows
  	 * kernel access as indicated in the PTE.
  	 */
  	__asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
  			"mts rzpr, r11;"
  			: : : "r11");
  }
  
  /*
   * MMU_init sets up the basic memory mappings for the kernel,
   * including both RAM and possibly some I/O regions,
   * and sets up the page tables and the MMU hardware ready to go.
   */
  
  /* called from head.S */
  asmlinkage void __init mmu_init(void)
  {
  	unsigned int kstart, ksize;
  
  	if (!memblock.reserved.cnt) {
  		pr_emerg("Error memory count
  ");
  		machine_restart(NULL);
  	}
  
  	if ((u32) memblock.memory.regions[0].size < 0x400000) {
  		pr_emerg("Memory must be greater than 4MB
  ");
  		machine_restart(NULL);
  	}
  
  	if ((u32) memblock.memory.regions[0].size < kernel_tlb) {
  		pr_emerg("Kernel size is greater than memory node
  ");
  		machine_restart(NULL);
  	}
  
  	/* Find main memory where the kernel is */
  	memory_start = (u32) memblock.memory.regions[0].base;
  	lowmem_size = memory_size = (u32) memblock.memory.regions[0].size;
  
  	if (lowmem_size > CONFIG_LOWMEM_SIZE) {
  		lowmem_size = CONFIG_LOWMEM_SIZE;
  #ifndef CONFIG_HIGHMEM
  		memory_size = lowmem_size;
  #endif
  	}
  
  	mm_cmdline_setup(); /* FIXME parse args from command line - not used */
  
  	/*
  	 * Map out the kernel text/data/bss from the available physical
  	 * memory.
  	 */
  	kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
  	/* kernel size */
  	ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
  	memblock_reserve(kstart, ksize);
  
  #if defined(CONFIG_BLK_DEV_INITRD)
  	/* Remove the init RAM disk from the available memory. */
  	if (initrd_start) {
  		unsigned long size;
  		size = initrd_end - initrd_start;
  		memblock_reserve(virt_to_phys(initrd_start), size);
  	}
  #endif /* CONFIG_BLK_DEV_INITRD */
  
  	/* Initialize the MMU hardware */
  	mmu_init_hw();
  
  	/* Map in all of RAM starting at CONFIG_KERNEL_START */
  	mapin_ram();
  
  	/* Extend vmalloc and ioremap area as big as possible */
  #ifdef CONFIG_HIGHMEM
  	ioremap_base = ioremap_bot = PKMAP_BASE;
  #else
  	ioremap_base = ioremap_bot = FIXADDR_START;
  #endif
  
  	/* Initialize the context management stuff */
  	mmu_context_init();
  
  	/* Shortly after that, the entire linear mapping will be available */
  	/* This will also cause that unflatten device tree will be allocated
  	 * inside 768MB limit */
  	memblock_set_current_limit(memory_start + lowmem_size - 1);
  }
  
  /* This is only called until mem_init is done. */
  void __init *early_get_page(void)
  {
  	void *p;
  	if (init_bootmem_done) {
  		p = alloc_bootmem_pages(PAGE_SIZE);
  	} else {
  		/*
  		 * Mem start + kernel_tlb -> here is limit
  		 * because of mem mapping from head.S
  		 */
  		p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
  					memory_start + kernel_tlb));
  	}
  	return p;
  }
  
  #endif /* CONFIG_MMU */
  
  void * __init_refok alloc_maybe_bootmem(size_t size, gfp_t mask)
  {
  	if (mem_init_done)
  		return kmalloc(size, mask);
  	else
  		return alloc_bootmem(size);
  }
  
  void * __init_refok zalloc_maybe_bootmem(size_t size, gfp_t mask)
  {
  	void *p;
  
  	if (mem_init_done)
  		p = kzalloc(size, mask);
  	else {
  		p = alloc_bootmem(size);
  		if (p)
  			memset(p, 0, size);
  	}
  	return p;
  }