xref: /openbmc/linux/arch/xtensa/mm/highmem.c (revision 27ab1c1c)
1 /*
2  * High memory support for Xtensa architecture
3  *
4  * This file is subject to the terms and conditions of the GNU General
5  * Public License.  See the file "COPYING" in the main directory of
6  * this archive for more details.
7  *
8  * Copyright (C) 2014 Cadence Design Systems Inc.
9  */
10 
11 #include <linux/export.h>
12 #include <linux/highmem.h>
13 #include <asm/tlbflush.h>
14 
15 #if DCACHE_WAY_SIZE > PAGE_SIZE
16 unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS];
17 wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS];
18 
19 static void __init kmap_waitqueues_init(void)
20 {
21 	unsigned int i;
22 
23 	for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i)
24 		init_waitqueue_head(pkmap_map_wait_arr + i);
25 }
26 
27 static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
28 {
29 	int idx = (type + KM_MAX_IDX * smp_processor_id()) * DCACHE_N_COLORS;
30 
31 	/*
32 	 * The fixmap operates top down, so the color offset needs to be
33 	 * reverse as well.
34 	 */
35 	return idx + DCACHE_N_COLORS - 1 - color;
36 }
37 
38 enum fixed_addresses kmap_local_map_idx(int type, unsigned long pfn)
39 {
40 	return kmap_idx(type, DCACHE_ALIAS(pfn << PAGE_SHIFT));
41 }
42 
43 enum fixed_addresses kmap_local_unmap_idx(int type, unsigned long addr)
44 {
45 	return kmap_idx(type, DCACHE_ALIAS(addr));
46 }
47 
48 #else
49 static inline void kmap_waitqueues_init(void) { }
50 #endif
51 
52 void __init kmap_init(void)
53 {
54 	/* Check if this memory layout is broken because PKMAP overlaps
55 	 * page table.
56 	 */
57 	BUILD_BUG_ON(PKMAP_BASE < TLBTEMP_BASE_1 + TLBTEMP_SIZE);
58 	kmap_waitqueues_init();
59 }
60