1 /*
2 * Copyright (C) 2014 Imagination Technologies
3 * Author: Paul Burton <paul.burton@mips.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
9 */
10
11 #ifndef __MIPS_ASM_MIPS_MAAR_H__
12 #define __MIPS_ASM_MIPS_MAAR_H__
13
14 #include <asm/hazards.h>
15 #include <asm/mipsregs.h>
16
17 /**
18 * platform_maar_init() - perform platform-level MAAR configuration
19 * @num_pairs: The number of MAAR pairs present in the system.
20 *
21 * Platforms should implement this function such that it configures as many
22 * MAAR pairs as required, from 0 up to the maximum of num_pairs-1, and returns
23 * the number that were used. Any further MAARs will be configured to be
24 * invalid. The default implementation of this function will simply indicate
25 * that it has configured 0 MAAR pairs.
26 *
27 * Return: The number of MAAR pairs configured.
28 */
29 unsigned platform_maar_init(unsigned num_pairs);
30
31 /**
32 * write_maar_pair() - write to a pair of MAARs
33 * @idx: The index of the pair (ie. use MAARs idx*2 & (idx*2)+1).
34 * @lower: The lowest address that the MAAR pair will affect. Must be
35 * aligned to a 2^16 byte boundary.
36 * @upper: The highest address that the MAAR pair will affect. Must be
37 * aligned to one byte before a 2^16 byte boundary.
38 * @attrs: The accessibility attributes to program, eg. MIPS_MAAR_S. The
39 * MIPS_MAAR_VL attribute will automatically be set.
40 *
41 * Program the pair of MAAR registers specified by idx to apply the attributes
42 * specified by attrs to the range of addresses from lower to higher.
43 */
write_maar_pair(unsigned idx,phys_addr_t lower,phys_addr_t upper,unsigned attrs)44 static inline void write_maar_pair(unsigned idx, phys_addr_t lower,
45 phys_addr_t upper, unsigned attrs)
46 {
47 /* Addresses begin at bit 16, but are shifted right 4 bits */
48 BUG_ON(lower & (0xffff | ~(MIPS_MAAR_ADDR << 4)));
49 BUG_ON(((upper & 0xffff) != 0xffff)
50 || ((upper & ~0xffffull) & ~(MIPS_MAAR_ADDR << 4)));
51
52 /* Automatically set MIPS_MAAR_VL */
53 attrs |= MIPS_MAAR_VL;
54
55 /* Write the upper address & attributes (only MIPS_MAAR_VL matters) */
56 write_c0_maari(idx << 1);
57 back_to_back_c0_hazard();
58 write_c0_maar(((upper >> 4) & MIPS_MAAR_ADDR) | attrs);
59 back_to_back_c0_hazard();
60
61 /* Write the lower address & attributes */
62 write_c0_maari((idx << 1) | 0x1);
63 back_to_back_c0_hazard();
64 write_c0_maar((lower >> 4) | attrs);
65 back_to_back_c0_hazard();
66 }
67
68 /**
69 * maar_init() - initialise MAARs
70 *
71 * Performs initialisation of MAARs for the current CPU, making use of the
72 * platforms implementation of platform_maar_init where necessary and
73 * duplicating the setup it provides on secondary CPUs.
74 */
75 extern void maar_init(void);
76
77 /**
78 * struct maar_config - MAAR configuration data
79 * @lower: The lowest address that the MAAR pair will affect. Must be
80 * aligned to a 2^16 byte boundary.
81 * @upper: The highest address that the MAAR pair will affect. Must be
82 * aligned to one byte before a 2^16 byte boundary.
83 * @attrs: The accessibility attributes to program, eg. MIPS_MAAR_S. The
84 * MIPS_MAAR_VL attribute will automatically be set.
85 *
86 * Describes the configuration of a pair of Memory Accessibility Attribute
87 * Registers - applying attributes from attrs to the range of physical
88 * addresses from lower to upper inclusive.
89 */
90 struct maar_config {
91 phys_addr_t lower;
92 phys_addr_t upper;
93 unsigned attrs;
94 };
95
96 /**
97 * maar_config() - configure MAARs according to provided data
98 * @cfg: Pointer to an array of struct maar_config.
99 * @num_cfg: The number of structs in the cfg array.
100 * @num_pairs: The number of MAAR pairs present in the system.
101 *
102 * Configures as many MAARs as are present and specified in the cfg
103 * array with the values taken from the cfg array.
104 *
105 * Return: The number of MAAR pairs configured.
106 */
maar_config(const struct maar_config * cfg,unsigned num_cfg,unsigned num_pairs)107 static inline unsigned maar_config(const struct maar_config *cfg,
108 unsigned num_cfg, unsigned num_pairs)
109 {
110 unsigned i;
111
112 for (i = 0; i < min(num_cfg, num_pairs); i++)
113 write_maar_pair(i, cfg[i].lower, cfg[i].upper, cfg[i].attrs);
114
115 return i;
116 }
117
118 #endif /* __MIPS_ASM_MIPS_MAAR_H__ */
119
