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 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 */
 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	/* 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 */
 71extern 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 */
 86struct 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 */
103static 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__ */