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

   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 */
  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_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 */
  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_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 */
  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_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 */
  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__ */
 119