1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Copyright (C) 2014 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com>
5 */
6
7 #ifndef __MIPS_ASM_MIPS_MAAR_H__
8 #define __MIPS_ASM_MIPS_MAAR_H__
9
10 #include <asm/hazards.h>
11 #include <asm/mipsregs.h>
12
13 /**
14 * platform_maar_init() - perform platform-level MAAR configuration
15 * @num_pairs: The number of MAAR pairs present in the system.
16 *
17 * Platforms should implement this function such that it configures as many
18 * MAAR pairs as required, from 0 up to the maximum of num_pairs-1, and returns
19 * the number that were used. Any further MAARs will be configured to be
20 * invalid. The default implementation of this function will simply indicate
21 * that it has configured 0 MAAR pairs.
22 *
23 * Return: The number of MAAR pairs configured.
24 */
25 unsigned platform_maar_init(unsigned num_pairs);
26
27 /**
28 * write_maar_pair() - write to a pair of MAARs
29 * @idx: The index of the pair (ie. use MAARs idx*2 & (idx*2)+1).
30 * @lower: The lowest address that the MAAR pair will affect. Must be
31 * aligned to a 2^16 byte boundary.
32 * @upper: The highest address that the MAAR pair will affect. Must be
33 * aligned to one byte before a 2^16 byte boundary.
34 * @attrs: The accessibility attributes to program, eg. MIPS_MAAR_S. The
35 * MIPS_MAAR_VL attribute will automatically be set.
36 *
37 * Program the pair of MAAR registers specified by idx to apply the attributes
38 * specified by attrs to the range of addresses from lower to higher.
39 */
40 static inline void write_maar_pair(unsigned idx, phys_addr_t lower,
41 phys_addr_t upper, unsigned attrs)
42 {
43 /* Addresses begin at bit 16, but are shifted right 4 bits */
44 BUG_ON(lower & (0xffff | ~(MIPS_MAAR_ADDR << 4)));
45 BUG_ON(((upper & 0xffff) != 0xffff)
46 || ((upper & ~0xffffull) & ~(MIPS_MAAR_ADDR << 4)));
47
48 /* Automatically set MIPS_MAAR_VL */
49 attrs |= MIPS_MAAR_VL;
50
51 /* Write the upper address & attributes (only MIPS_MAAR_VL matters) */
52 write_c0_maari(idx << 1);
53 back_to_back_c0_hazard();
54 write_c0_maar(((upper >> 4) & MIPS_MAAR_ADDR) | attrs);
55 back_to_back_c0_hazard();
56
57 /* Write the lower address & attributes */
58 write_c0_maari((idx << 1) | 0x1);
59 back_to_back_c0_hazard();
60 write_c0_maar((lower >> 4) | attrs);
61 back_to_back_c0_hazard();
62 }
63
64 /**
65 * maar_init() - initialise MAARs
66 *
67 * Performs initialisation of MAARs for the current CPU, making use of the
68 * platforms implementation of platform_maar_init where necessary and
69 * duplicating the setup it provides on secondary CPUs.
70 */
71 extern void maar_init(void);
72
73 /**
74 * struct maar_config - MAAR configuration data
75 * @lower: The lowest address that the MAAR pair will affect. Must be
76 * aligned to a 2^16 byte boundary.
77 * @upper: The highest address that the MAAR pair will affect. Must be
78 * aligned to one byte before a 2^16 byte boundary.
79 * @attrs: The accessibility attributes to program, eg. MIPS_MAAR_S. The
80 * MIPS_MAAR_VL attribute will automatically be set.
81 *
82 * Describes the configuration of a pair of Memory Accessibility Attribute
83 * Registers - applying attributes from attrs to the range of physical
84 * addresses from lower to upper inclusive.
85 */
86 struct maar_config {
87 phys_addr_t lower;
88 phys_addr_t upper;
89 unsigned attrs;
90 };
91
92 /**
93 * maar_config() - configure MAARs according to provided data
94 * @cfg: Pointer to an array of struct maar_config.
95 * @num_cfg: The number of structs in the cfg array.
96 * @num_pairs: The number of MAAR pairs present in the system.
97 *
98 * Configures as many MAARs as are present and specified in the cfg
99 * array with the values taken from the cfg array.
100 *
101 * Return: The number of MAAR pairs configured.
102 */
103 static inline unsigned maar_config(const struct maar_config *cfg,
104 unsigned num_cfg, unsigned num_pairs)
105 {
106 unsigned i;
107
108 for (i = 0; i < min(num_cfg, num_pairs); i++)
109 write_maar_pair(i, cfg[i].lower, cfg[i].upper, cfg[i].attrs);
110
111 return i;
112 }
113
114 #endif /* __MIPS_ASM_MIPS_MAAR_H__ */