include/hw/register.h

   1 /*
   2  * Register Definition API
   3  *
   4  * Copyright (c) 2016 Xilinx Inc.
   5  * Copyright (c) 2013 Peter Crosthwaite <peter.crosthwaite@xilinx.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2.  See
   8  * the COPYING file in the top-level directory.
   9  */
  10
  11 #ifndef REGISTER_H
  12 #define REGISTER_H
  13
  14 #include "exec/memory.h"
  15
  16 typedef struct RegisterInfo RegisterInfo;
  17 typedef struct RegisterAccessInfo RegisterAccessInfo;
  18
  19 /**
  20  * Access description for a register that is part of guest accessible device
  21  * state.
  22  *
  23  * @name: String name of the register
  24  * @ro: whether or not the bit is read-only
  25  * @w1c: bits with the common write 1 to clear semantic.
  26  * @reset: reset value.
  27  * @cor: Bits that are clear on read
  28  * @rsvd: Bits that are reserved and should not be changed
  29  *
  30  * @pre_write: Pre write callback. Passed the value that's to be written,
  31  * immediately before the actual write. The returned value is what is written,
  32  * giving the handler a chance to modify the written value.
  33  * @post_write: Post write callback. Passed the written value. Most write side
  34  * effects should be implemented here.
  35  *
  36  * @post_read: Post read callback. Passes the value that is about to be returned
  37  * for a read. The return value from this function is what is ultimately read,
  38  * allowing this function to modify the value before return to the client.
  39  */
  40
  41 struct RegisterAccessInfo {
  42     const char *name;
  43     uint64_t ro;
  44     uint64_t w1c;
  45     uint64_t reset;
  46     uint64_t cor;
  47     uint64_t rsvd;
  48     uint64_t unimp;
  49
  50     uint64_t (*pre_write)(RegisterInfo *reg, uint64_t val);
  51     void (*post_write)(RegisterInfo *reg, uint64_t val);
  52
  53     uint64_t (*post_read)(RegisterInfo *reg, uint64_t val);
  54 };
  55
  56 /**
  57  * A register that is part of guest accessible state
  58  * @data: pointer to the register data. Will be cast
  59  * to the relevant uint type depending on data_size.
  60  * @data_size: Size of the register in bytes. Must be
  61  * 1, 2, 4 or 8
  62  *
  63  * @access: Access description of this register
  64  *
  65  * @debug: Whether or not verbose debug is enabled
  66  * @prefix: String prefix for log and debug messages
  67  *
  68  * @opaque: Opaque data for the register
  69  */
  70
  71 struct RegisterInfo {
  72     /* <public> */
  73     void *data;
  74     int data_size;
  75
  76     const RegisterAccessInfo *access;
  77
  78     void *opaque;
  79 };
  80
  81 /**
  82  * write a value to a register, subject to its restrictions
  83  * @reg: register to write to
  84  * @val: value to write
  85  * @we: write enable mask
  86  * @prefix: The device prefix that should be printed before the register name
  87  * @debug: Should the write operation debug information be printed?
  88  */
  89
  90 void register_write(RegisterInfo *reg, uint64_t val, uint64_t we,
  91                     const char *prefix, bool debug);
  92
  93 /**
  94  * read a value from a register, subject to its restrictions
  95  * @reg: register to read from
  96  * @re: read enable mask
  97  * @prefix: The device prefix that should be printed before the register name
  98  * @debug: Should the read operation debug information be printed?
  99  * returns: value read
 100  */
 101
 102 uint64_t register_read(RegisterInfo *reg, uint64_t re, const char* prefix,
 103                        bool debug);
 104
 105 /**
 106  * reset a register
 107  * @reg: register to reset
 108  */
 109
 110 void register_reset(RegisterInfo *reg);
 111
 112 #endif