/*

   * Copyright IBM Corp. 2008, 2009
   *
   * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>

   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <asm/ipl.h>
  #include <asm/sclp.h>
  #include <asm/setup.h>

  #define ADDR2G (1ULL << 31)
  
  static void find_memory_chunks(struct mem_chunk chunk[])
  {
  	unsigned long long memsize, rnmax, rzm;
  	unsigned long addr = 0, size;
  	int i = 0, type;
  
  	rzm = sclp_get_rzm();
  	rnmax = sclp_get_rnmax();
  	memsize = rzm * rnmax;
  	if (!rzm)
  		rzm = 1ULL << 17;
  	if (sizeof(long) == 4) {
  		rzm = min(ADDR2G, rzm);
  		memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
  	}
  	do {
  		size = 0;
  		type = tprot(addr);
  		do {
  			size += rzm;
  			if (memsize && addr + size >= memsize)
  				break;
  		} while (type == tprot(addr + size));
  		if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
  			chunk[i].addr = addr;
  			chunk[i].size = size;
  			chunk[i].type = type;
  			i++;
  		}
  		addr += size;
  	} while (addr < memsize && i < MEMORY_CHUNKS);
  }
  
  void detect_memory_layout(struct mem_chunk chunk[])
  {
  	unsigned long flags, cr0;
  
  	memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));

  	/* Disable IRQs, DAT and low address protection so tprot does the
  	 * right thing and we don't get scheduled away with low address
  	 * protection disabled.
  	 */

  	flags = __arch_local_irq_stnsm(0xf8);

  	__ctl_store(cr0, 0, 0);
  	__ctl_clear_bit(0, 28);
  	find_memory_chunks(chunk);
  	__ctl_load(cr0, 0, 0);

  	arch_local_irq_restore(flags);

  }
  EXPORT_SYMBOL(detect_memory_layout);

  
  /*

   * Move memory chunks array from index "from" to index "to"
   */
  static void mem_chunk_move(struct mem_chunk chunk[], int to, int from)
  {
  	int cnt = MEMORY_CHUNKS - to;
  
  	memmove(&chunk[to], &chunk[from], cnt * sizeof(struct mem_chunk));
  }
  
  /*
   * Initialize memory chunk
   */
  static void mem_chunk_init(struct mem_chunk *chunk, unsigned long addr,
  			   unsigned long size, int type)
  {
  	chunk->type = type;
  	chunk->addr = addr;
  	chunk->size = size;
  }
  
  /*

   * Create memory hole with given address, size, and type
   */

  void create_mem_hole(struct mem_chunk chunk[], unsigned long addr,

  		     unsigned long size, int type)
  {

  	unsigned long lh_start, lh_end, lh_size, ch_start, ch_end, ch_size;
  	int i, ch_type;

  
  	for (i = 0; i < MEMORY_CHUNKS; i++) {

  		if (chunk[i].size == 0)

  			continue;

  
  		/* Define chunk properties */
  		ch_start = chunk[i].addr;
  		ch_size = chunk[i].size;
  		ch_end = ch_start + ch_size - 1;
  		ch_type = chunk[i].type;
  
  		/* Is memory chunk hit by memory hole? */
  		if (addr + size <= ch_start)
  			continue; /* No: memory hole in front of chunk */
  		if (addr > ch_end)
  			continue; /* No: memory hole after chunk */
  
  		/* Yes: Define local hole properties */
  		lh_start = max(addr, chunk[i].addr);
  		lh_end = min(addr + size - 1, ch_end);
  		lh_size = lh_end - lh_start + 1;
  
  		if (lh_start == ch_start && lh_end == ch_end) {
  			/* Hole covers complete memory chunk */
  			mem_chunk_init(&chunk[i], lh_start, lh_size, type);
  		} else if (lh_end == ch_end) {
  			/* Hole starts in memory chunk and convers chunk end */
  			mem_chunk_move(chunk, i + 1, i);
  			mem_chunk_init(&chunk[i], ch_start, ch_size - lh_size,
  				       ch_type);
  			mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);

  			i += 1;

  		} else if (lh_start == ch_start) {
  			/* Hole ends in memory chunk */
  			mem_chunk_move(chunk, i + 1, i);
  			mem_chunk_init(&chunk[i], lh_start, lh_size, type);
  			mem_chunk_init(&chunk[i + 1], lh_end + 1,
  				       ch_size - lh_size, ch_type);
  			break;

  		} else {

  			/* Hole splits memory chunk */
  			mem_chunk_move(chunk, i + 2, i);
  			mem_chunk_init(&chunk[i], ch_start,
  				       lh_start - ch_start, ch_type);
  			mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
  			mem_chunk_init(&chunk[i + 2], lh_end + 1,
  				       ch_end - lh_end, ch_type);
  			break;

  		}
  	}
  }