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  */
  29 unsigned 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  */
  44 static 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  */
  75 extern 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  */
  90 struct 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  */
 107 static 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__ */