arch/s390/mm/mem_detect.c

   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 <linux/memblock.h>
  10 #include <linux/init.h>
  11 #include <linux/debugfs.h>
  12 #include <linux/seq_file.h>
  13 #include <asm/ipl.h>
  14 #include <asm/sclp.h>
  15 #include <asm/setup.h>
  16
  17 #define ADDR2G (1ULL << 31)
  18
  19 #define CHUNK_READ_WRITE 0
  20 #define CHUNK_READ_ONLY  1
  21
  22 static inline void memblock_physmem_add(phys_addr_t start, phys_addr_t size)
  23 {
  24         memblock_add_range(&memblock.memory, start, size, 0, 0);
  25         memblock_add_range(&memblock.physmem, start, size, 0, 0);
  26 }
  27
  28 void __init detect_memory_memblock(void)
  29 {
  30         unsigned long long memsize, rnmax, rzm;
  31         unsigned long addr, size;
  32         int type;
  33
  34         rzm = sclp_get_rzm();
  35         rnmax = sclp_get_rnmax();
  36         memsize = rzm * rnmax;
  37         if (!rzm)
  38                 rzm = 1ULL << 17;
  39         if (IS_ENABLED(CONFIG_32BIT)) {
  40                 rzm = min(ADDR2G, rzm);
  41                 memsize = min(ADDR2G, memsize);
  42         }
  43         max_physmem_end = memsize;
  44         addr = 0;
  45         /* keep memblock lists close to the kernel */
  46         memblock_set_bottom_up(true);
  47         do {
  48                 size = 0;
  49                 type = tprot(addr);
  50                 do {
  51                         size += rzm;
  52                         if (max_physmem_end && addr + size >= max_physmem_end)
  53                                 break;
  54                 } while (type == tprot(addr + size));
  55                 if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
  56                         if (max_physmem_end && (addr + size > max_physmem_end))
  57                                 size = max_physmem_end - addr;
  58                         memblock_physmem_add(addr, size);
  59                 }
  60                 addr += size;
  61         } while (addr < max_physmem_end);
  62         memblock_set_bottom_up(false);
  63         if (!max_physmem_end)
  64                 max_physmem_end = memblock_end_of_DRAM();
  65 }