1/*
  2 * Copyright IBM Corp. 2008, 2009
  3 *
  4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
  5 */
  6
  7#include <linux/kernel.h>
  8#include <linux/module.h>
  9#include <asm/ipl.h>
 10#include <asm/sclp.h>
 11#include <asm/setup.h>
 12
 13#define ADDR2G (1ULL << 31)
 14
 15static void find_memory_chunks(struct mem_chunk chunk[])
 16{
 17	unsigned long long memsize, rnmax, rzm;
 18	unsigned long addr = 0, size;
 19	int i = 0, type;
 20
 21	rzm = sclp_get_rzm();
 22	rnmax = sclp_get_rnmax();
 23	memsize = rzm * rnmax;
 24	if (!rzm)
 25		rzm = 1ULL << 17;
 26	if (sizeof(long) == 4) {
 27		rzm = min(ADDR2G, rzm);
 28		memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
 29	}
 30	do {
 31		size = 0;
 32		type = tprot(addr);
 33		do {
 34			size += rzm;
 35			if (memsize && addr + size >= memsize)
 36				break;
 37		} while (type == tprot(addr + size));
 38		if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
 39			chunk[i].addr = addr;
 40			chunk[i].size = size;
 41			chunk[i].type = type;
 42			i++;
 43		}
 44		addr += size;
 45	} while (addr < memsize && i < MEMORY_CHUNKS);
 46}
 47
 48void detect_memory_layout(struct mem_chunk chunk[])
 49{
 50	unsigned long flags, cr0;
 51
 52	memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
 53	/* Disable IRQs, DAT and low address protection so tprot does the
 54	 * right thing and we don't get scheduled away with low address
 55	 * protection disabled.
 56	 */
 57	flags = __arch_local_irq_stnsm(0xf8);
 58	__ctl_store(cr0, 0, 0);
 59	__ctl_clear_bit(0, 28);
 60	find_memory_chunks(chunk);
 61	__ctl_load(cr0, 0, 0);
 62	arch_local_irq_restore(flags);
 63}
 64EXPORT_SYMBOL(detect_memory_layout);
 65
 66/*
 67 * Move memory chunks array from index "from" to index "to"
 68 */
 69static void mem_chunk_move(struct mem_chunk chunk[], int to, int from)
 70{
 71	int cnt = MEMORY_CHUNKS - to;
 72
 73	memmove(&chunk[to], &chunk[from], cnt * sizeof(struct mem_chunk));
 74}
 75
 76/*
 77 * Initialize memory chunk
 78 */
 79static void mem_chunk_init(struct mem_chunk *chunk, unsigned long addr,
 80			   unsigned long size, int type)
 81{
 82	chunk->type = type;
 83	chunk->addr = addr;
 84	chunk->size = size;
 85}
 86
 87/*
 88 * Create memory hole with given address, size, and type
 89 */
 90void create_mem_hole(struct mem_chunk chunk[], unsigned long addr,
 91		     unsigned long size, int type)
 92{
 93	unsigned long lh_start, lh_end, lh_size, ch_start, ch_end, ch_size;
 94	int i, ch_type;
 95
 96	for (i = 0; i < MEMORY_CHUNKS; i++) {
 97		if (chunk[i].size == 0)
 98			continue;
 99
100		/* Define chunk properties */
101		ch_start = chunk[i].addr;
102		ch_size = chunk[i].size;
103		ch_end = ch_start + ch_size - 1;
104		ch_type = chunk[i].type;
105
106		/* Is memory chunk hit by memory hole? */
107		if (addr + size <= ch_start)
108			continue; /* No: memory hole in front of chunk */
109		if (addr > ch_end)
110			continue; /* No: memory hole after chunk */
111
112		/* Yes: Define local hole properties */
113		lh_start = max(addr, chunk[i].addr);
114		lh_end = min(addr + size - 1, ch_end);
115		lh_size = lh_end - lh_start + 1;
116
117		if (lh_start == ch_start && lh_end == ch_end) {
118			/* Hole covers complete memory chunk */
119			mem_chunk_init(&chunk[i], lh_start, lh_size, type);
120		} else if (lh_end == ch_end) {
121			/* Hole starts in memory chunk and convers chunk end */
122			mem_chunk_move(chunk, i + 1, i);
123			mem_chunk_init(&chunk[i], ch_start, ch_size - lh_size,
124				       ch_type);
125			mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
126			i += 1;
127		} else if (lh_start == ch_start) {
128			/* Hole ends in memory chunk */
129			mem_chunk_move(chunk, i + 1, i);
130			mem_chunk_init(&chunk[i], lh_start, lh_size, type);
131			mem_chunk_init(&chunk[i + 1], lh_end + 1,
132				       ch_size - lh_size, ch_type);
133			break;
134		} else {
135			/* Hole splits memory chunk */
136			mem_chunk_move(chunk, i + 2, i);
137			mem_chunk_init(&chunk[i], ch_start,
138				       lh_start - ch_start, ch_type);
139			mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
140			mem_chunk_init(&chunk[i + 2], lh_end + 1,
141				       ch_end - lh_end, ch_type);
142			break;
143		}
144	}
145}