1/*
  2 * Copyright (C) 2014 Imagination Technologies
  3 * Author: Paul Burton <paul.burton@imgtec.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 */
 29unsigned 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_V 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 */
 44static 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_V */
 53	attrs |= MIPS_MAAR_V;
 54
 55	/* Write the upper address & attributes (only MIPS_MAAR_V 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 */
 75extern 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_V 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 */
 90struct 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 */
107static 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__ */