1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_S390_MEM_DETECT_H
 3#define _ASM_S390_MEM_DETECT_H
 4
 5#include <linux/types.h>
 6
 7enum mem_info_source {
 8	MEM_DETECT_NONE = 0,
 9	MEM_DETECT_SCLP_STOR_INFO,
10	MEM_DETECT_DIAG260,
11	MEM_DETECT_SCLP_READ_INFO,
12	MEM_DETECT_BIN_SEARCH
13};
14
15struct mem_detect_block {
16	u64 start;
17	u64 end;
18};
19
20/*
21 * Storage element id is defined as 1 byte (up to 256 storage elements).
22 * In practise only storage element id 0 and 1 are used).
23 * According to architecture one storage element could have as much as
24 * 1020 subincrements. 255 mem_detect_blocks are embedded in mem_detect_info.
25 * If more mem_detect_blocks are required, a block of memory from already
26 * known mem_detect_block is taken (entries_extended points to it).
27 */
28#define MEM_INLINED_ENTRIES 255 /* (PAGE_SIZE - 16) / 16 */
29
30struct mem_detect_info {
31	u32 count;
32	u8 info_source;
33	struct mem_detect_block entries[MEM_INLINED_ENTRIES];
34	struct mem_detect_block *entries_extended;
35};
36extern struct mem_detect_info mem_detect;
37
38void add_mem_detect_block(u64 start, u64 end);
39
40static inline int __get_mem_detect_block(u32 n, unsigned long *start,
41					 unsigned long *end)
42{
43	if (n >= mem_detect.count) {
44		*start = 0;
45		*end = 0;
46		return -1;
47	}
48
49	if (n < MEM_INLINED_ENTRIES) {
50		*start = (unsigned long)mem_detect.entries[n].start;
51		*end = (unsigned long)mem_detect.entries[n].end;
52	} else {
53		*start = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].start;
54		*end = (unsigned long)mem_detect.entries_extended[n - MEM_INLINED_ENTRIES].end;
55	}
56	return 0;
57}
58
59/**
60 * for_each_mem_detect_block - early online memory range iterator
61 * @i: an integer used as loop variable
62 * @p_start: ptr to unsigned long for start address of the range
63 * @p_end: ptr to unsigned long for end address of the range
64 *
65 * Walks over detected online memory ranges.
66 */
67#define for_each_mem_detect_block(i, p_start, p_end)			\
68	for (i = 0, __get_mem_detect_block(i, p_start, p_end);		\
69	     i < mem_detect.count;					\
70	     i++, __get_mem_detect_block(i, p_start, p_end))
71
72static inline void get_mem_detect_reserved(unsigned long *start,
73					   unsigned long *size)
74{
75	*start = (unsigned long)mem_detect.entries_extended;
76	if (mem_detect.count > MEM_INLINED_ENTRIES)
77		*size = (mem_detect.count - MEM_INLINED_ENTRIES) * sizeof(struct mem_detect_block);
78	else
79		*size = 0;
80}
81
82static inline unsigned long get_mem_detect_end(void)
83{
84	unsigned long start;
85	unsigned long end;
86
87	if (mem_detect.count) {
88		__get_mem_detect_block(mem_detect.count - 1, &start, &end);
89		return end;
90	}
91	return 0;
92}
93
94#endif