sim/ppc/hw_register.c

   1 /*  This file is part of the program psim.
   2
   3     Copyright (C) 1994-1996, Andrew Cagney <cagney@highland.com.au>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18
  19     */
  20
  21
  22 #ifndef _HW_REGISTER_C_
  23 #define _HW_REGISTER_C_
  24
  25 #include "device_table.h"
  26 #include <stdlib.h>
  27 #include "psim.h"
  28
  29 /* DEVICE
  30
  31
  32    register - dummy device to initialize processor registers
  33
  34
  35    DESCRIPTION
  36
  37    The properties of this device are used, during initialization, to
  38    specify the initial value of various processor registers.  The
  39    property name specifying the register to be initialized with the
  40    special form <cpu-nr>.<register> being used to initialize a
  41    specific processor's register (eg 0.pc).
  42
  43    Because, when the device tree is created, overriding properties are
  44    entered into the tree before any default values, this device must
  45    initialize registers in newest (default) to oldest (overriding)
  46    property order.
  47
  48    The actual registers (for a given target) are defined in the file
  49    registers.c.
  50
  51    This device is normally a child of the /openprom/init node.
  52
  53
  54    EXAMPLES
  55
  56
  57    Given a device tree containing the entry:
  58
  59    |    /openprom/init/register/pc 0xfff00cf0
  60
  61    then specifying the command line option:
  62
  63    |    -o '/openprom/init/register/pc 0x0'
  64
  65    would override the initial value of processor zero's program
  66    counter.  The resultant device tree tree containing:
  67
  68    |    /openprom/init/register/0.pc 0x0
  69    |    /openprom/init/register/pc 0xfff00cf0
  70
  71    and would be processed last to first resulting in the sequence: set
  72    all program counters to 0xfff00cf0; set processor zero's program
  73    counter to zero.
  74
  75    */
  76
  77 static void
  78 do_register_init(device *me,
  79                  const device_property *prop)
  80 {
  81   psim *system = device_system(me);
  82   if (prop != NULL) {
  83     const char *name = prop->name;
  84     unsigned32 value = device_find_integer_property(me, name);
  85     int processor;
  86
  87     do_register_init(me, device_next_property(prop));
  88
  89     if (strchr(name, '.') == NULL) {
  90       processor = -1;
  91       DTRACE(register, ("%s=0x%lx\n", name, (unsigned long)value));
  92     }
  93     else {
  94       char *end;
  95       processor = strtoul(name, &end, 0);
  96       ASSERT(end[0] == '.');
  97       name = end+1;
  98       DTRACE(register, ("%d.%s=0x%lx\n", processor, name,
  99                         (unsigned long)value));
 100     }
 101     psim_write_register(system, processor, /* all processors */
 102                         &value,
 103                         name,
 104                         cooked_transfer);
 105   }
 106 }
 107
 108
 109 static void
 110 register_init_data_callback(device *me)
 111 {
 112   const device_property *prop = device_find_property(me, NULL);
 113   do_register_init(me, prop);
 114 }
 115
 116
 117 static device_callbacks const register_callbacks = {
 118   { NULL, register_init_data_callback, },
 119   { NULL, }, /* address */
 120   { NULL, }, /* IO */
 121   { NULL, }, /* DMA */
 122   { NULL, }, /* interrupt */
 123   { NULL, }, /* unit */
 124 };
 125
 126 const device_descriptor hw_register_device_descriptor[] = {
 127   { "register", NULL, &register_callbacks },
 128   { NULL },
 129 };
 130
 131 #endif _HW_REGISTER_C_