xref: /OK3568_Linux_fs/kernel/arch/nds32/include/asm/highmem.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun // Copyright (C) 2005-2017 Andes Technology Corporation
3*4882a593Smuzhiyun 
4*4882a593Smuzhiyun #ifndef _ASM_HIGHMEM_H
5*4882a593Smuzhiyun #define _ASM_HIGHMEM_H
6*4882a593Smuzhiyun 
7*4882a593Smuzhiyun #include <asm/proc-fns.h>
8*4882a593Smuzhiyun #include <asm/kmap_types.h>
9*4882a593Smuzhiyun #include <asm/fixmap.h>
10*4882a593Smuzhiyun 
11*4882a593Smuzhiyun /*
12*4882a593Smuzhiyun  * Right now we initialize only a single pte table. It can be extended
13*4882a593Smuzhiyun  * easily, subsequent pte tables have to be allocated in one physical
14*4882a593Smuzhiyun  * chunk of RAM.
15*4882a593Smuzhiyun  */
16*4882a593Smuzhiyun /*
17*4882a593Smuzhiyun  * Ordering is (from lower to higher memory addresses):
18*4882a593Smuzhiyun  *
19*4882a593Smuzhiyun  * high_memory
20*4882a593Smuzhiyun  *			Persistent kmap area
21*4882a593Smuzhiyun  * PKMAP_BASE
22*4882a593Smuzhiyun  *			fixed_addresses
23*4882a593Smuzhiyun  * FIXADDR_START
24*4882a593Smuzhiyun  * FIXADDR_TOP
25*4882a593Smuzhiyun  *			Vmalloc area
26*4882a593Smuzhiyun  * VMALLOC_START
27*4882a593Smuzhiyun  * VMALLOC_END
28*4882a593Smuzhiyun  */
29*4882a593Smuzhiyun #define PKMAP_BASE		((FIXADDR_START - PGDIR_SIZE) & (PGDIR_MASK))
30*4882a593Smuzhiyun #define LAST_PKMAP		PTRS_PER_PTE
31*4882a593Smuzhiyun #define LAST_PKMAP_MASK		(LAST_PKMAP - 1)
32*4882a593Smuzhiyun #define PKMAP_NR(virt)		(((virt) - (PKMAP_BASE)) >> PAGE_SHIFT)
33*4882a593Smuzhiyun #define PKMAP_ADDR(nr)		(PKMAP_BASE + ((nr) << PAGE_SHIFT))
34*4882a593Smuzhiyun 
flush_cache_kmaps(void)35*4882a593Smuzhiyun static inline void flush_cache_kmaps(void)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun 	cpu_dcache_wbinval_all();
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun 
40*4882a593Smuzhiyun /* declarations for highmem.c */
41*4882a593Smuzhiyun extern unsigned long highstart_pfn, highend_pfn;
42*4882a593Smuzhiyun 
43*4882a593Smuzhiyun extern pte_t *pkmap_page_table;
44*4882a593Smuzhiyun 
45*4882a593Smuzhiyun extern void kmap_init(void);
46*4882a593Smuzhiyun 
47*4882a593Smuzhiyun /*
48*4882a593Smuzhiyun  * The following functions are already defined by <linux/highmem.h>
49*4882a593Smuzhiyun  * when CONFIG_HIGHMEM is not set.
50*4882a593Smuzhiyun  */
51*4882a593Smuzhiyun #ifdef CONFIG_HIGHMEM
52*4882a593Smuzhiyun extern void *kmap_atomic_pfn(unsigned long pfn);
53*4882a593Smuzhiyun #endif
54*4882a593Smuzhiyun 
55*4882a593Smuzhiyun #endif
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