hw/milkymist-memcard.c

   1 /*
   2  *  QEMU model of the Milkymist SD Card Controller.
   3  *
   4  *  Copyright (c) 2010 Michael Walle <michael@walle.cc>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  *
  20  * Specification available at:
  21  *   http://www.milkymist.org/socdoc/memcard.pdf
  22  */
  23
  24 #include "hw.h"
  25 #include "sysbus.h"
  26 #include "sysemu/sysemu.h"
  27 #include "trace.h"
  28 #include "qemu/error-report.h"
  29 #include "sysemu/blockdev.h"
  30 #include "sd.h"
  31
  32 enum {
  33     ENABLE_CMD_TX   = (1<<0),
  34     ENABLE_CMD_RX   = (1<<1),
  35     ENABLE_DAT_TX   = (1<<2),
  36     ENABLE_DAT_RX   = (1<<3),
  37 };
  38
  39 enum {
  40     PENDING_CMD_TX   = (1<<0),
  41     PENDING_CMD_RX   = (1<<1),
  42     PENDING_DAT_TX   = (1<<2),
  43     PENDING_DAT_RX   = (1<<3),
  44 };
  45
  46 enum {
  47     START_CMD_TX    = (1<<0),
  48     START_DAT_RX    = (1<<1),
  49 };
  50
  51 enum {
  52     R_CLK2XDIV = 0,
  53     R_ENABLE,
  54     R_PENDING,
  55     R_START,
  56     R_CMD,
  57     R_DAT,
  58     R_MAX
  59 };
  60
  61 struct MilkymistMemcardState {
  62     SysBusDevice busdev;
  63     MemoryRegion regs_region;
  64     SDState *card;
  65
  66     int command_write_ptr;
  67     int response_read_ptr;
  68     int response_len;
  69     int ignore_next_cmd;
  70     int enabled;
  71     uint8_t command[6];
  72     uint8_t response[17];
  73     uint32_t regs[R_MAX];
  74 };
  75 typedef struct MilkymistMemcardState MilkymistMemcardState;
  76
  77 static void update_pending_bits(MilkymistMemcardState *s)
  78 {
  79     /* transmits are instantaneous, thus tx pending bits are never set */
  80     s->regs[R_PENDING] = 0;
  81     /* if rx is enabled the corresponding pending bits are always set */
  82     if (s->regs[R_ENABLE] & ENABLE_CMD_RX) {
  83         s->regs[R_PENDING] |= PENDING_CMD_RX;
  84     }
  85     if (s->regs[R_ENABLE] & ENABLE_DAT_RX) {
  86         s->regs[R_PENDING] |= PENDING_DAT_RX;
  87     }
  88 }
  89
  90 static void memcard_sd_command(MilkymistMemcardState *s)
  91 {
  92     SDRequest req;
  93
  94     req.cmd = s->command[0] & 0x3f;
  95     req.arg = (s->command[1] << 24) | (s->command[2] << 16)
  96               | (s->command[3] << 8) | s->command[4];
  97     req.crc = s->command[5];
  98
  99     s->response[0] = req.cmd;
 100     s->response_len = sd_do_command(s->card, &req, s->response+1);
 101     s->response_read_ptr = 0;
 102
 103     if (s->response_len == 16) {
 104         /* R2 response */
 105         s->response[0] = 0x3f;
 106         s->response_len += 1;
 107     } else if (s->response_len == 4) {
 108         /* no crc calculation, insert dummy byte */
 109         s->response[5] = 0;
 110         s->response_len += 2;
 111     }
 112
 113     if (req.cmd == 0) {
 114         /* next write is a dummy byte to clock the initialization of the sd
 115          * card */
 116         s->ignore_next_cmd = 1;
 117     }
 118 }
 119
 120 static uint64_t memcard_read(void *opaque, hwaddr addr,
 121                              unsigned size)
 122 {
 123     MilkymistMemcardState *s = opaque;
 124     uint32_t r = 0;
 125
 126     addr >>= 2;
 127     switch (addr) {
 128     case R_CMD:
 129         if (!s->enabled) {
 130             r = 0xff;
 131         } else {
 132             r = s->response[s->response_read_ptr++];
 133             if (s->response_read_ptr > s->response_len) {
 134                 error_report("milkymist_memcard: "
 135                         "read more cmd bytes than available. Clipping.");
 136                 s->response_read_ptr = 0;
 137             }
 138         }
 139         break;
 140     case R_DAT:
 141         if (!s->enabled) {
 142             r = 0xffffffff;
 143         } else {
 144             r = 0;
 145             r |= sd_read_data(s->card) << 24;
 146             r |= sd_read_data(s->card) << 16;
 147             r |= sd_read_data(s->card) << 8;
 148             r |= sd_read_data(s->card);
 149         }
 150         break;
 151     case R_CLK2XDIV:
 152     case R_ENABLE:
 153     case R_PENDING:
 154     case R_START:
 155         r = s->regs[addr];
 156         break;
 157
 158     default:
 159         error_report("milkymist_memcard: read access to unknown register 0x"
 160                 TARGET_FMT_plx, addr << 2);
 161         break;
 162     }
 163
 164     trace_milkymist_memcard_memory_read(addr << 2, r);
 165
 166     return r;
 167 }
 168
 169 static void memcard_write(void *opaque, hwaddr addr, uint64_t value,
 170                           unsigned size)
 171 {
 172     MilkymistMemcardState *s = opaque;
 173
 174     trace_milkymist_memcard_memory_write(addr, value);
 175
 176     addr >>= 2;
 177     switch (addr) {
 178     case R_PENDING:
 179         /* clear rx pending bits */
 180         s->regs[R_PENDING] &= ~(value & (PENDING_CMD_RX | PENDING_DAT_RX));
 181         update_pending_bits(s);
 182         break;
 183     case R_CMD:
 184         if (!s->enabled) {
 185             break;
 186         }
 187         if (s->ignore_next_cmd) {
 188             s->ignore_next_cmd = 0;
 189             break;
 190         }
 191         s->command[s->command_write_ptr] = value & 0xff;
 192         s->command_write_ptr = (s->command_write_ptr + 1) % 6;
 193         if (s->command_write_ptr == 0) {
 194             memcard_sd_command(s);
 195         }
 196         break;
 197     case R_DAT:
 198         if (!s->enabled) {
 199             break;
 200         }
 201         sd_write_data(s->card, (value >> 24) & 0xff);
 202         sd_write_data(s->card, (value >> 16) & 0xff);
 203         sd_write_data(s->card, (value >> 8) & 0xff);
 204         sd_write_data(s->card, value & 0xff);
 205         break;
 206     case R_ENABLE:
 207         s->regs[addr] = value;
 208         update_pending_bits(s);
 209         break;
 210     case R_CLK2XDIV:
 211     case R_START:
 212         s->regs[addr] = value;
 213         break;
 214
 215     default:
 216         error_report("milkymist_memcard: write access to unknown register 0x"
 217                 TARGET_FMT_plx, addr << 2);
 218         break;
 219     }
 220 }
 221
 222 static const MemoryRegionOps memcard_mmio_ops = {
 223     .read = memcard_read,
 224     .write = memcard_write,
 225     .valid = {
 226         .min_access_size = 4,
 227         .max_access_size = 4,
 228     },
 229     .endianness = DEVICE_NATIVE_ENDIAN,
 230 };
 231
 232 static void milkymist_memcard_reset(DeviceState *d)
 233 {
 234     MilkymistMemcardState *s =
 235             container_of(d, MilkymistMemcardState, busdev.qdev);
 236     int i;
 237
 238     s->command_write_ptr = 0;
 239     s->response_read_ptr = 0;
 240     s->response_len = 0;
 241
 242     for (i = 0; i < R_MAX; i++) {
 243         s->regs[i] = 0;
 244     }
 245 }
 246
 247 static int milkymist_memcard_init(SysBusDevice *dev)
 248 {
 249     MilkymistMemcardState *s = FROM_SYSBUS(typeof(*s), dev);
 250     DriveInfo *dinfo;
 251
 252     dinfo = drive_get_next(IF_SD);
 253     s->card = sd_init(dinfo ? dinfo->bdrv : NULL, 0);
 254     s->enabled = dinfo ? bdrv_is_inserted(dinfo->bdrv) : 0;
 255
 256     memory_region_init_io(&s->regs_region, &memcard_mmio_ops, s,
 257             "milkymist-memcard", R_MAX * 4);
 258     sysbus_init_mmio(dev, &s->regs_region);
 259
 260     return 0;
 261 }
 262
 263 static const VMStateDescription vmstate_milkymist_memcard = {
 264     .name = "milkymist-memcard",
 265     .version_id = 1,
 266     .minimum_version_id = 1,
 267     .minimum_version_id_old = 1,
 268     .fields      = (VMStateField[]) {
 269         VMSTATE_INT32(command_write_ptr, MilkymistMemcardState),
 270         VMSTATE_INT32(response_read_ptr, MilkymistMemcardState),
 271         VMSTATE_INT32(response_len, MilkymistMemcardState),
 272         VMSTATE_INT32(ignore_next_cmd, MilkymistMemcardState),
 273         VMSTATE_INT32(enabled, MilkymistMemcardState),
 274         VMSTATE_UINT8_ARRAY(command, MilkymistMemcardState, 6),
 275         VMSTATE_UINT8_ARRAY(response, MilkymistMemcardState, 17),
 276         VMSTATE_UINT32_ARRAY(regs, MilkymistMemcardState, R_MAX),
 277         VMSTATE_END_OF_LIST()
 278     }
 279 };
 280
 281 static void milkymist_memcard_class_init(ObjectClass *klass, void *data)
 282 {
 283     DeviceClass *dc = DEVICE_CLASS(klass);
 284     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 285
 286     k->init = milkymist_memcard_init;
 287     dc->reset = milkymist_memcard_reset;
 288     dc->vmsd = &vmstate_milkymist_memcard;
 289 }
 290
 291 static TypeInfo milkymist_memcard_info = {
 292     .name          = "milkymist-memcard",
 293     .parent        = TYPE_SYS_BUS_DEVICE,
 294     .instance_size = sizeof(MilkymistMemcardState),
 295     .class_init    = milkymist_memcard_class_init,
 296 };
 297
 298 static void milkymist_memcard_register_types(void)
 299 {
 300     type_register_static(&milkymist_memcard_info);
 301 }
 302
 303 type_init(milkymist_memcard_register_types)