arch/s390/mm/mem_detect.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright IBM Corp. 2008, 2009
   4  *
   5  * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   6  */
   7
   8 #include <linux/kernel.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 CHUNK_READ_WRITE 0
  18 #define CHUNK_READ_ONLY  1
  19
  20 static inline void memblock_physmem_add(phys_addr_t start, phys_addr_t size)
  21 {
  22         memblock_dbg("memblock_physmem_add: [%#016llx-%#016llx]\n",
  23                      start, start + size - 1);
  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 memsize, rnmax, rzm, addr, size;
  31         int type;
  32
  33         rzm = sclp.rzm;
  34         rnmax = sclp.rnmax;
  35         memsize = rzm * rnmax;
  36         if (!rzm)
  37                 rzm = 1UL << 17;
  38         max_physmem_end = memsize;
  39         addr = 0;
  40         /* keep memblock lists close to the kernel */
  41         memblock_set_bottom_up(true);
  42         do {
  43                 size = 0;
  44                 /* assume lowcore is writable */
  45                 type = addr ? tprot(addr) : CHUNK_READ_WRITE;
  46                 do {
  47                         size += rzm;
  48                         if (max_physmem_end && addr + size >= max_physmem_end)
  49                                 break;
  50                 } while (type == tprot(addr + size));
  51                 if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
  52                         if (max_physmem_end && (addr + size > max_physmem_end))
  53                                 size = max_physmem_end - addr;
  54                         memblock_physmem_add(addr, size);
  55                 }
  56                 addr += size;
  57         } while (addr < max_physmem_end);
  58         memblock_set_bottom_up(false);
  59         if (!max_physmem_end)
  60                 max_physmem_end = memblock_end_of_DRAM();
  61         memblock_dump_all();
  62 }