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 */
25unsigned 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/MIPS_MAAR_VH attributes 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 */
40static 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	/*
52	 * Write the upper address & attributes (both MIPS_MAAR_VL and
53	 * MIPS_MAAR_VH matter)
54	 */
55	write_c0_maari(idx << 1);
56	back_to_back_c0_hazard();
57	write_c0_maar(((upper >> 4) & MIPS_MAAR_ADDR) | attrs);
58	back_to_back_c0_hazard();
59#ifdef CONFIG_XPA
60	upper >>= MIPS_MAARX_ADDR_SHIFT;
61	writex_c0_maar(((upper >> 4) & MIPS_MAARX_ADDR) | MIPS_MAARX_VH);
62	back_to_back_c0_hazard();
63#endif
64
65	/* Write the lower address & attributes */
66	write_c0_maari((idx << 1) | 0x1);
67	back_to_back_c0_hazard();
68	write_c0_maar((lower >> 4) | attrs);
69	back_to_back_c0_hazard();
70#ifdef CONFIG_XPA
71	lower >>= MIPS_MAARX_ADDR_SHIFT;
72	writex_c0_maar(((lower >> 4) & MIPS_MAARX_ADDR) | MIPS_MAARX_VH);
73	back_to_back_c0_hazard();
74#endif
75}
76
77/**
78 * maar_init() - initialise MAARs
79 *
80 * Performs initialisation of MAARs for the current CPU, making use of the
81 * platforms implementation of platform_maar_init where necessary and
82 * duplicating the setup it provides on secondary CPUs.
83 */
84extern void maar_init(void);
85
86/**
87 * struct maar_config - MAAR configuration data
88 * @lower:	The lowest address that the MAAR pair will affect. Must be
89 *		aligned to a 2^16 byte boundary.
90 * @upper:	The highest address that the MAAR pair will affect. Must be
91 *		aligned to one byte before a 2^16 byte boundary.
92 * @attrs:	The accessibility attributes to program, eg. MIPS_MAAR_S. The
93 *		MIPS_MAAR_VL attribute will automatically be set.
94 *
95 * Describes the configuration of a pair of Memory Accessibility Attribute
96 * Registers - applying attributes from attrs to the range of physical
97 * addresses from lower to upper inclusive.
98 */
99struct maar_config {
100	phys_addr_t lower;
101	phys_addr_t upper;
102	unsigned attrs;
103};
104
105/**
106 * maar_config() - configure MAARs according to provided data
107 * @cfg:	Pointer to an array of struct maar_config.
108 * @num_cfg:	The number of structs in the cfg array.
109 * @num_pairs:	The number of MAAR pairs present in the system.
110 *
111 * Configures as many MAARs as are present and specified in the cfg
112 * array with the values taken from the cfg array.
113 *
114 * Return:	The number of MAAR pairs configured.
115 */
116static inline unsigned maar_config(const struct maar_config *cfg,
117				   unsigned num_cfg, unsigned num_pairs)
118{
119	unsigned i;
120
121	for (i = 0; i < min(num_cfg, num_pairs); i++)
122		write_maar_pair(i, cfg[i].lower, cfg[i].upper, cfg[i].attrs);
123
124	return i;
125}
126
127#endif /* __MIPS_ASM_MIPS_MAAR_H__ */
128