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 
virt_addr_uncached(unsigned long kaddr)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 
uncached_init(void)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 
uncached_resize(unsigned long size)40 void __init uncached_resize(unsigned long size)
41 {
42 	uncached_size = size;
43 	uncached_end = uncached_start + uncached_size;
44 }
45