arch/sh/mm/uncached.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/init.h>
   3 #include <linux/module.h>
   4 #include <linux/sizes.h>
   5 #include <asm/page.h>
   6 #include <asm/addrspace.h>
   7
   8 /*
   9  * This is the offset of the uncached section from its cached alias.
  10  *
  11  * Legacy platforms handle trivial transitions between cached and
  12  * uncached segments by making use of the 1:1 mapping relationship in
  13  * 512MB lowmem, others via a special uncached mapping.
  14  *
  15  * Default value only valid in 29 bit mode, in 32bit mode this will be
  16  * updated by the early PMB initialization code.
  17  */
  18 unsigned long cached_to_uncached = SZ_512M;
  19 unsigned long uncached_size = SZ_512M;
  20 unsigned long uncached_start, uncached_end;
  21 EXPORT_SYMBOL(uncached_start);
  22 EXPORT_SYMBOL(uncached_end);
  23
  24 int virt_addr_uncached(unsigned long kaddr)
  25 {
  26         return (kaddr >= uncached_start) && (kaddr < uncached_end);
  27 }
  28 EXPORT_SYMBOL(virt_addr_uncached);
  29
  30 void __init uncached_init(void)
  31 {
  32 #if defined(CONFIG_29BIT) || !defined(CONFIG_MMU)
  33         uncached_start = P2SEG;
  34 #else
  35         uncached_start = memory_end;
  36 #endif
  37         uncached_end = uncached_start + uncached_size;
  38 }
  39
  40 void __init uncached_resize(unsigned long size)
  41 {
  42         uncached_size = size;
  43         uncached_end = uncached_start + uncached_size;
  44 }