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/*
* Copyright IBM Corp. 2008
* 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>
static int memory_fast_detect(struct mem_chunk *chunk)
{
unsigned long val0 = 0;
unsigned long val1 = 0xc;
int rc = -EOPNOTSUPP;
if (ipl_flags & IPL_NSS_VALID)
return -EOPNOTSUPP;
asm volatile(
" diag %1,%2,0x260\n"
"0: lhi %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "+d" (rc), "+d" (val0), "+d" (val1) : : "cc");
if (rc || val0 != val1)
return -EOPNOTSUPP;
chunk->size = val0 + 1;
return 0;
}
static inline int tprot(unsigned long addr)
{
int rc = -EFAULT;
asm volatile(
" tprot 0(%1),0\n"
"0: ipm %0\n"
" srl %0,28\n"
"1:\n"
EX_TABLE(0b,1b)
: "+d" (rc) : "a" (addr) : "cc");
return rc;
}
#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));
if (memory_fast_detect(&chunk[0]) == 0)
return;
/* 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 = __raw_local_irq_stnsm(0xf8);
__ctl_store(cr0, 0, 0);
__ctl_clear_bit(0, 28);
find_memory_chunks(chunk);
__ctl_load(cr0, 0, 0);
__raw_local_irq_ssm(flags);
}
EXPORT_SYMBOL(detect_memory_layout);
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