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  */
  25 unsigned 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  */
  40 static 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  */
  71 extern 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  */
  86 struct 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  */
 103 static 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__ */