LXR linux/arch/mips/include/asm/maar.h

   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__ */
 115