hw/misc/bcm2835_mbox.c

   1 /*
   2  * Raspberry Pi emulation (c) 2012 Gregory Estrade
   3  *
   4  * This file models the system mailboxes, which are used for
   5  * communication with low-bandwidth GPU peripherals. Refs:
   6  *   https://github.com/raspberrypi/firmware/wiki/Mailboxes
   7  *   https://github.com/raspberrypi/firmware/wiki/Accessing-mailboxes
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qapi/error.h"
  15 #include "hw/irq.h"
  16 #include "hw/misc/bcm2835_mbox.h"
  17 #include "migration/vmstate.h"
  18 #include "qemu/log.h"
  19 #include "qemu/module.h"
  20 #include "trace.h"
  21
  22 #define MAIL0_PEEK   0x90
  23 #define MAIL0_SENDER 0x94
  24 #define MAIL1_STATUS 0xb8
  25
  26 /* Mailbox status register */
  27 #define MAIL0_STATUS 0x98
  28 #define ARM_MS_FULL       0x80000000
  29 #define ARM_MS_EMPTY      0x40000000
  30 #define ARM_MS_LEVEL      0x400000FF /* Max. value depends on mailbox depth */
  31
  32 /* MAILBOX config/status register */
  33 #define MAIL0_CONFIG 0x9c
  34 /* ANY write to this register clears the error bits! */
  35 #define ARM_MC_IHAVEDATAIRQEN    0x00000001 /* mbox irq enable:  has data */
  36 #define ARM_MC_IHAVESPACEIRQEN   0x00000002 /* mbox irq enable:  has space */
  37 #define ARM_MC_OPPISEMPTYIRQEN   0x00000004 /* mbox irq enable: Opp is empty */
  38 #define ARM_MC_MAIL_CLEAR        0x00000008 /* mbox clear write 1, then  0 */
  39 #define ARM_MC_IHAVEDATAIRQPEND  0x00000010 /* mbox irq pending:  has space */
  40 #define ARM_MC_IHAVESPACEIRQPEND 0x00000020 /* mbox irq pending: Opp is empty */
  41 #define ARM_MC_OPPISEMPTYIRQPEND 0x00000040 /* mbox irq pending */
  42 /* Bit 7 is unused */
  43 #define ARM_MC_ERRNOOWN   0x00000100 /* error : none owner read from mailbox */
  44 #define ARM_MC_ERROVERFLW 0x00000200 /* error : write to fill mailbox */
  45 #define ARM_MC_ERRUNDRFLW 0x00000400 /* error : read from empty mailbox */
  46
  47 static void mbox_update_status(BCM2835Mbox *mb)
  48 {
  49     mb->status &= ~(ARM_MS_EMPTY | ARM_MS_FULL);
  50     if (mb->count == 0) {
  51         mb->status |= ARM_MS_EMPTY;
  52     } else if (mb->count == MBOX_SIZE) {
  53         mb->status |= ARM_MS_FULL;
  54     }
  55 }
  56
  57 static void mbox_reset(BCM2835Mbox *mb)
  58 {
  59     int n;
  60
  61     mb->count = 0;
  62     mb->config = 0;
  63     for (n = 0; n < MBOX_SIZE; n++) {
  64         mb->reg[n] = MBOX_INVALID_DATA;
  65     }
  66     mbox_update_status(mb);
  67 }
  68
  69 static uint32_t mbox_pull(BCM2835Mbox *mb, int index)
  70 {
  71     int n;
  72     uint32_t val;
  73
  74     assert(mb->count > 0);
  75     assert(index < mb->count);
  76
  77     val = mb->reg[index];
  78     for (n = index + 1; n < mb->count; n++) {
  79         mb->reg[n - 1] = mb->reg[n];
  80     }
  81     mb->count--;
  82     mb->reg[mb->count] = MBOX_INVALID_DATA;
  83
  84     mbox_update_status(mb);
  85
  86     return val;
  87 }
  88
  89 static void mbox_push(BCM2835Mbox *mb, uint32_t val)
  90 {
  91     assert(mb->count < MBOX_SIZE);
  92     mb->reg[mb->count++] = val;
  93     mbox_update_status(mb);
  94 }
  95
  96 static void bcm2835_mbox_update(BCM2835MboxState *s)
  97 {
  98     uint32_t value;
  99     bool set;
 100     int n;
 101
 102     s->mbox_irq_disabled = true;
 103
 104     /* Get pending responses and put them in the vc->arm mbox,
 105      * as long as it's not full
 106      */
 107     for (n = 0; n < MBOX_CHAN_COUNT; n++) {
 108         while (s->available[n] && !(s->mbox[0].status & ARM_MS_FULL)) {
 109             value = ldl_le_phys(&s->mbox_as, n << MBOX_AS_CHAN_SHIFT);
 110             assert(value != MBOX_INVALID_DATA); /* Pending interrupt but no data */
 111             mbox_push(&s->mbox[0], value);
 112         }
 113     }
 114
 115     /* TODO (?): Try to push pending requests from the arm->vc mbox */
 116
 117     /* Re-enable calls from the IRQ routine */
 118     s->mbox_irq_disabled = false;
 119
 120     /* Update ARM IRQ status */
 121     set = false;
 122     s->mbox[0].config &= ~ARM_MC_IHAVEDATAIRQPEND;
 123     if (!(s->mbox[0].status & ARM_MS_EMPTY)) {
 124         s->mbox[0].config |= ARM_MC_IHAVEDATAIRQPEND;
 125         if (s->mbox[0].config & ARM_MC_IHAVEDATAIRQEN) {
 126             set = true;
 127         }
 128     }
 129     trace_bcm2835_mbox_irq(set);
 130     qemu_set_irq(s->arm_irq, set);
 131 }
 132
 133 static void bcm2835_mbox_set_irq(void *opaque, int irq, int level)
 134 {
 135     BCM2835MboxState *s = opaque;
 136
 137     s->available[irq] = level;
 138
 139     /* avoid recursively calling bcm2835_mbox_update when the interrupt
 140      * status changes due to the ldl_phys call within that function
 141      */
 142     if (!s->mbox_irq_disabled) {
 143         bcm2835_mbox_update(s);
 144     }
 145 }
 146
 147 static uint64_t bcm2835_mbox_read(void *opaque, hwaddr offset, unsigned size)
 148 {
 149     BCM2835MboxState *s = opaque;
 150     uint32_t res = 0;
 151
 152     offset &= 0xff;
 153
 154     switch (offset) {
 155     case 0x80 ... 0x8c: /* MAIL0_READ */
 156         if (s->mbox[0].status & ARM_MS_EMPTY) {
 157             res = MBOX_INVALID_DATA;
 158         } else {
 159             res = mbox_pull(&s->mbox[0], 0);
 160         }
 161         break;
 162
 163     case MAIL0_PEEK:
 164         res = s->mbox[0].reg[0];
 165         break;
 166
 167     case MAIL0_SENDER:
 168         break;
 169
 170     case MAIL0_STATUS:
 171         res = s->mbox[0].status;
 172         break;
 173
 174     case MAIL0_CONFIG:
 175         res = s->mbox[0].config;
 176         break;
 177
 178     case MAIL1_STATUS:
 179         res = s->mbox[1].status;
 180         break;
 181
 182     default:
 183         qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx"\n",
 184                       __func__, offset);
 185         trace_bcm2835_mbox_read(size, offset, res);
 186         return 0;
 187     }
 188     trace_bcm2835_mbox_read(size, offset, res);
 189
 190     bcm2835_mbox_update(s);
 191
 192     return res;
 193 }
 194
 195 static void bcm2835_mbox_write(void *opaque, hwaddr offset,
 196                                uint64_t value, unsigned size)
 197 {
 198     BCM2835MboxState *s = opaque;
 199     hwaddr childaddr;
 200     uint8_t ch;
 201
 202     offset &= 0xff;
 203
 204     trace_bcm2835_mbox_write(size, offset, value);
 205     switch (offset) {
 206     case MAIL0_SENDER:
 207         break;
 208
 209     case MAIL0_CONFIG:
 210         s->mbox[0].config &= ~ARM_MC_IHAVEDATAIRQEN;
 211         s->mbox[0].config |= value & ARM_MC_IHAVEDATAIRQEN;
 212         break;
 213
 214     case 0xa0 ... 0xac: /* MAIL1_WRITE */
 215         if (s->mbox[1].status & ARM_MS_FULL) {
 216             /* Mailbox full */
 217             qemu_log_mask(LOG_GUEST_ERROR, "%s: mailbox full\n", __func__);
 218         } else {
 219             ch = value & 0xf;
 220             if (ch < MBOX_CHAN_COUNT) {
 221                 childaddr = ch << MBOX_AS_CHAN_SHIFT;
 222                 if (ldl_le_phys(&s->mbox_as, childaddr + MBOX_AS_PENDING)) {
 223                     /* Child busy, push delayed. Push it in the arm->vc mbox */
 224                     mbox_push(&s->mbox[1], value);
 225                 } else {
 226                     /* Push it directly to the child device */
 227                     stl_le_phys(&s->mbox_as, childaddr, value);
 228                 }
 229             } else {
 230                 /* Invalid channel number */
 231                 qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid channel %u\n",
 232                               __func__, ch);
 233             }
 234         }
 235         break;
 236
 237     default:
 238         qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx
 239                                  " value 0x%"PRIx64"\n",
 240                       __func__, offset, value);
 241         return;
 242     }
 243
 244     bcm2835_mbox_update(s);
 245 }
 246
 247 static const MemoryRegionOps bcm2835_mbox_ops = {
 248     .read = bcm2835_mbox_read,
 249     .write = bcm2835_mbox_write,
 250     .endianness = DEVICE_NATIVE_ENDIAN,
 251     .valid.min_access_size = 4,
 252     .valid.max_access_size = 4,
 253 };
 254
 255 /* vmstate of a single mailbox */
 256 static const VMStateDescription vmstate_bcm2835_mbox_box = {
 257     .name = TYPE_BCM2835_MBOX "_box",
 258     .version_id = 1,
 259     .minimum_version_id = 1,
 260     .fields = (VMStateField[]) {
 261         VMSTATE_UINT32_ARRAY(reg, BCM2835Mbox, MBOX_SIZE),
 262         VMSTATE_UINT32(count, BCM2835Mbox),
 263         VMSTATE_UINT32(status, BCM2835Mbox),
 264         VMSTATE_UINT32(config, BCM2835Mbox),
 265         VMSTATE_END_OF_LIST()
 266     }
 267 };
 268
 269 /* vmstate of the entire device */
 270 static const VMStateDescription vmstate_bcm2835_mbox = {
 271     .name = TYPE_BCM2835_MBOX,
 272     .version_id = 1,
 273     .minimum_version_id = 1,
 274     .minimum_version_id_old = 1,
 275     .fields      = (VMStateField[]) {
 276         VMSTATE_BOOL_ARRAY(available, BCM2835MboxState, MBOX_CHAN_COUNT),
 277         VMSTATE_STRUCT_ARRAY(mbox, BCM2835MboxState, 2, 1,
 278                              vmstate_bcm2835_mbox_box, BCM2835Mbox),
 279         VMSTATE_END_OF_LIST()
 280     }
 281 };
 282
 283 static void bcm2835_mbox_init(Object *obj)
 284 {
 285     BCM2835MboxState *s = BCM2835_MBOX(obj);
 286
 287     memory_region_init_io(&s->iomem, obj, &bcm2835_mbox_ops, s,
 288                           TYPE_BCM2835_MBOX, 0x400);
 289     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
 290     sysbus_init_irq(SYS_BUS_DEVICE(s), &s->arm_irq);
 291     qdev_init_gpio_in(DEVICE(s), bcm2835_mbox_set_irq, MBOX_CHAN_COUNT);
 292 }
 293
 294 static void bcm2835_mbox_reset(DeviceState *dev)
 295 {
 296     BCM2835MboxState *s = BCM2835_MBOX(dev);
 297     int n;
 298
 299     mbox_reset(&s->mbox[0]);
 300     mbox_reset(&s->mbox[1]);
 301     s->mbox_irq_disabled = false;
 302     for (n = 0; n < MBOX_CHAN_COUNT; n++) {
 303         s->available[n] = false;
 304     }
 305 }
 306
 307 static void bcm2835_mbox_realize(DeviceState *dev, Error **errp)
 308 {
 309     BCM2835MboxState *s = BCM2835_MBOX(dev);
 310     Object *obj;
 311     Error *err = NULL;
 312
 313     obj = object_property_get_link(OBJECT(dev), "mbox-mr", &err);
 314     if (obj == NULL) {
 315         error_setg(errp, "%s: required mbox-mr link not found: %s",
 316                    __func__, error_get_pretty(err));
 317         return;
 318     }
 319
 320     s->mbox_mr = MEMORY_REGION(obj);
 321     address_space_init(&s->mbox_as, s->mbox_mr, TYPE_BCM2835_MBOX "-memory");
 322     bcm2835_mbox_reset(dev);
 323 }
 324
 325 static void bcm2835_mbox_class_init(ObjectClass *klass, void *data)
 326 {
 327     DeviceClass *dc = DEVICE_CLASS(klass);
 328
 329     dc->realize = bcm2835_mbox_realize;
 330     dc->reset = bcm2835_mbox_reset;
 331     dc->vmsd = &vmstate_bcm2835_mbox;
 332 }
 333
 334 static TypeInfo bcm2835_mbox_info = {
 335     .name          = TYPE_BCM2835_MBOX,
 336     .parent        = TYPE_SYS_BUS_DEVICE,
 337     .instance_size = sizeof(BCM2835MboxState),
 338     .class_init    = bcm2835_mbox_class_init,
 339     .instance_init = bcm2835_mbox_init,
 340 };
 341
 342 static void bcm2835_mbox_register_types(void)
 343 {
 344     type_register_static(&bcm2835_mbox_info);
 345 }
 346
 347 type_init(bcm2835_mbox_register_types)