sim/ppc/hw_nvram.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 3 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, see <http://www.gnu.org/licenses/>.
  17
  18     */
  19
  20
  21 #ifndef _HW_NVRAM_C_
  22 #define _HW_NVRAM_C_
  23
  24 #ifndef STATIC_INLINE_HW_NVRAM
  25 #define STATIC_INLINE_HW_NVRAM STATIC_INLINE
  26 #endif
  27
  28 #include "device_table.h"
  29
  30 #include <time.h>
  31 #include <string.h>
  32
  33 /* DEVICE
  34
  35
  36    nvram - non-volatile memory with clock
  37
  38
  39    DESCRIPTION
  40
  41
  42    This device implements a small byte addressable non-volatile
  43    memory.  The top 8 bytes of this memory include a real-time clock.
  44
  45
  46    PROPERTIES
  47
  48
  49    reg = <address> <size> (required)
  50
  51    Specify the address/size of this device within its parents address
  52    space.
  53
  54
  55    timezone = <integer> (optional)
  56
  57    Adjustment to the hosts current GMT (in seconds) that should be
  58    applied when updating the NVRAM's clock.  If no timezone is
  59    specified, zero (GMT or UCT) is assumed.
  60
  61
  62    */
  63
  64 typedef struct _hw_nvram_device {
  65   uint8_t *memory;
  66   unsigned sizeof_memory;
  67   time_t host_time;
  68   unsigned timezone;
  69   /* useful */
  70   unsigned addr_year;
  71   unsigned addr_month;
  72   unsigned addr_date;
  73   unsigned addr_day;
  74   unsigned addr_hour;
  75   unsigned addr_minutes;
  76   unsigned addr_seconds;
  77   unsigned addr_control;
  78 } hw_nvram_device;
  79
  80 static void *
  81 hw_nvram_create(const char *name,
  82                 const device_unit *unit_address,
  83                 const char *args)
  84 {
  85   hw_nvram_device *nvram = ZALLOC(hw_nvram_device);
  86   return nvram;
  87 }
  88
  89 typedef struct _hw_nvram_reg_spec {
  90   uint32_t base;
  91   uint32_t size;
  92 } hw_nvram_reg_spec;
  93
  94 static void
  95 hw_nvram_init_address(device *me)
  96 {
  97   hw_nvram_device *nvram = (hw_nvram_device*)device_data(me);
  98
  99   /* use the generic init code to attach this device to its parent bus */
 100   generic_device_init_address(me);
 101
 102   /* find the first non zero reg property and use that as the device
 103      size */
 104   if (nvram->sizeof_memory == 0) {
 105     reg_property_spec reg;
 106     int reg_nr;
 107     for (reg_nr = 0;
 108          device_find_reg_array_property(me, "reg", reg_nr, &reg);
 109          reg_nr++) {
 110       unsigned attach_size;
 111       if (device_size_to_attach_size(device_parent(me),
 112                                      &reg.size, &attach_size,
 113                                      me)) {
 114         nvram->sizeof_memory = attach_size;
 115         break;
 116       }
 117     }
 118     if (nvram->sizeof_memory == 0)
 119       device_error(me, "reg property must contain a non-zero phys-addr:size tupple");
 120     if (nvram->sizeof_memory < 8)
 121       device_error(me, "NVRAM must be at least 8 bytes in size");
 122   }
 123
 124   /* initialize the hw_nvram */
 125   if (nvram->memory == NULL) {
 126     nvram->memory = zalloc(nvram->sizeof_memory);
 127   }
 128   else
 129     memset(nvram->memory, 0, nvram->sizeof_memory);
 130
 131   if (device_find_property(me, "timezone") == NULL)
 132     nvram->timezone = 0;
 133   else
 134     nvram->timezone = device_find_integer_property(me, "timezone");
 135
 136   nvram->addr_year = nvram->sizeof_memory - 1;
 137   nvram->addr_month = nvram->sizeof_memory - 2;
 138   nvram->addr_date = nvram->sizeof_memory - 3;
 139   nvram->addr_day = nvram->sizeof_memory - 4;
 140   nvram->addr_hour = nvram->sizeof_memory - 5;
 141   nvram->addr_minutes = nvram->sizeof_memory - 6;
 142   nvram->addr_seconds = nvram->sizeof_memory - 7;
 143   nvram->addr_control = nvram->sizeof_memory - 8;
 144
 145 }
 146
 147 static int
 148 hw_nvram_bcd(int val)
 149 {
 150   val = val % 100;
 151   if (val < 0)
 152     val += 100;
 153   return ((val / 10) << 4) + (val % 10);
 154 }
 155
 156
 157 /* If reached an update interval and allowed, update the clock within
 158    the hw_nvram.  While this function could be implemented using events
 159    it isn't on the assumption that the HW_NVRAM will hardly ever be
 160    referenced and hence there is little need in keeping the clock
 161    continually up-to-date */
 162
 163 static void
 164 hw_nvram_update_clock(hw_nvram_device *nvram,
 165                       cpu *processor)
 166 {
 167   if (!(nvram->memory[nvram->addr_control] & 0xc0)) {
 168     time_t host_time = time(NULL);
 169     if (nvram->host_time != host_time) {
 170       time_t nvtime = host_time + nvram->timezone;
 171       struct tm *clock = gmtime(&nvtime);
 172       nvram->host_time = host_time;
 173       nvram->memory[nvram->addr_year] = hw_nvram_bcd(clock->tm_year);
 174       nvram->memory[nvram->addr_month] = hw_nvram_bcd(clock->tm_mon + 1);
 175       nvram->memory[nvram->addr_date] = hw_nvram_bcd(clock->tm_mday);
 176       nvram->memory[nvram->addr_day] = hw_nvram_bcd(clock->tm_wday + 1);
 177       nvram->memory[nvram->addr_hour] = hw_nvram_bcd(clock->tm_hour);
 178       nvram->memory[nvram->addr_minutes] = hw_nvram_bcd(clock->tm_min);
 179       nvram->memory[nvram->addr_seconds] = hw_nvram_bcd(clock->tm_sec);
 180     }
 181   }
 182 }
 183
 184 static void
 185 hw_nvram_set_clock(hw_nvram_device *nvram, cpu *processor)
 186 {
 187   error ("fixme - how do I set the localtime\n");
 188 }
 189
 190 static unsigned
 191 hw_nvram_io_read_buffer(device *me,
 192                         void *dest,
 193                         int space,
 194                         unsigned_word addr,
 195                         unsigned nr_bytes,
 196                         cpu *processor,
 197                         unsigned_word cia)
 198 {
 199   int i;
 200   hw_nvram_device *nvram = (hw_nvram_device*)device_data(me);
 201   for (i = 0; i < nr_bytes; i++) {
 202     unsigned address = (addr + i) % nvram->sizeof_memory;
 203     uint8_t data = nvram->memory[address];
 204     hw_nvram_update_clock(nvram, processor);
 205     ((uint8_t*)dest)[i] = data;
 206   }
 207   return nr_bytes;
 208 }
 209
 210 static unsigned
 211 hw_nvram_io_write_buffer(device *me,
 212                          const void *source,
 213                          int space,
 214                          unsigned_word addr,
 215                          unsigned nr_bytes,
 216                          cpu *processor,
 217                          unsigned_word cia)
 218 {
 219   int i;
 220   hw_nvram_device *nvram = (hw_nvram_device*)device_data(me);
 221   for (i = 0; i < nr_bytes; i++) {
 222     unsigned address = (addr + i) % nvram->sizeof_memory;
 223     uint8_t data = ((uint8_t*)source)[i];
 224     if (address == nvram->addr_control
 225         && (data & 0x80) == 0
 226         && (nvram->memory[address] & 0x80) == 0x80)
 227       hw_nvram_set_clock(nvram, processor);
 228     else
 229       hw_nvram_update_clock(nvram, processor);
 230     nvram->memory[address] = data;
 231   }
 232   return nr_bytes;
 233 }
 234
 235 static device_callbacks const hw_nvram_callbacks = {
 236   { hw_nvram_init_address, },
 237   { NULL, }, /* address */
 238   { hw_nvram_io_read_buffer, hw_nvram_io_write_buffer }, /* IO */
 239 };
 240
 241 const device_descriptor hw_nvram_device_descriptor[] = {
 242   { "nvram", hw_nvram_create, &hw_nvram_callbacks },
 243   { NULL },
 244 };
 245
 246 #endif /* _HW_NVRAM_C_ */