1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/init.h> 3 #include <linux/module.h> 4 #include <asm/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 } 45