hw/char/goldfish_tty.c

   1 /*
   2  * SPDX-License-Identifer: GPL-2.0-or-later
   3  *
   4  * Goldfish TTY
   5  *
   6  * (c) 2020 Laurent Vivier <laurent@vivier.eu>
   7  *
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "hw/irq.h"
  12 #include "hw/qdev-properties-system.h"
  13 #include "hw/sysbus.h"
  14 #include "migration/vmstate.h"
  15 #include "chardev/char-fe.h"
  16 #include "qemu/log.h"
  17 #include "trace.h"
  18 #include "exec/address-spaces.h"
  19 #include "hw/char/goldfish_tty.h"
  20
  21 #define GOLDFISH_TTY_VERSION 1
  22
  23 /* registers */
  24
  25 enum {
  26     REG_PUT_CHAR      = 0x00,
  27     REG_BYTES_READY   = 0x04,
  28     REG_CMD           = 0x08,
  29     REG_DATA_PTR      = 0x10,
  30     REG_DATA_LEN      = 0x14,
  31     REG_DATA_PTR_HIGH = 0x18,
  32     REG_VERSION       = 0x20,
  33 };
  34
  35 /* commands */
  36
  37 enum {
  38     CMD_INT_DISABLE   = 0x00,
  39     CMD_INT_ENABLE    = 0x01,
  40     CMD_WRITE_BUFFER  = 0x02,
  41     CMD_READ_BUFFER   = 0x03,
  42 };
  43
  44 static uint64_t goldfish_tty_read(void *opaque, hwaddr addr,
  45                                   unsigned size)
  46 {
  47     GoldfishTTYState *s = opaque;
  48     uint64_t value = 0;
  49
  50     switch (addr) {
  51     case REG_BYTES_READY:
  52         value = fifo8_num_used(&s->rx_fifo);
  53         break;
  54     case REG_VERSION:
  55         value = GOLDFISH_TTY_VERSION;
  56         break;
  57     default:
  58         qemu_log_mask(LOG_UNIMP,
  59                       "%s: unimplemented register read 0x%02"HWADDR_PRIx"\n",
  60                       __func__, addr);
  61         break;
  62     }
  63
  64     trace_goldfish_tty_read(s, addr, size, value);
  65
  66     return value;
  67 }
  68
  69 static void goldfish_tty_cmd(GoldfishTTYState *s, uint32_t cmd)
  70 {
  71     uint32_t to_copy;
  72     uint8_t *buf;
  73     uint8_t data_out[GOLFISH_TTY_BUFFER_SIZE];
  74     int len;
  75     uint64_t ptr;
  76
  77     switch (cmd) {
  78     case CMD_INT_DISABLE:
  79         if (s->int_enabled) {
  80             if (!fifo8_is_empty(&s->rx_fifo)) {
  81                 qemu_set_irq(s->irq, 0);
  82             }
  83             s->int_enabled = false;
  84         }
  85         break;
  86     case CMD_INT_ENABLE:
  87         if (!s->int_enabled) {
  88             if (!fifo8_is_empty(&s->rx_fifo)) {
  89                 qemu_set_irq(s->irq, 1);
  90             }
  91             s->int_enabled = true;
  92         }
  93         break;
  94     case CMD_WRITE_BUFFER:
  95         len = s->data_len;
  96         ptr = s->data_ptr;
  97         while (len) {
  98             to_copy = MIN(GOLFISH_TTY_BUFFER_SIZE, len);
  99
 100             address_space_rw(&address_space_memory, ptr,
 101                              MEMTXATTRS_UNSPECIFIED, data_out, to_copy, 0);
 102             qemu_chr_fe_write_all(&s->chr, data_out, to_copy);
 103
 104             len -= to_copy;
 105             ptr += to_copy;
 106         }
 107         break;
 108     case CMD_READ_BUFFER:
 109         len = s->data_len;
 110         ptr = s->data_ptr;
 111         while (len && !fifo8_is_empty(&s->rx_fifo)) {
 112             buf = (uint8_t *)fifo8_pop_buf(&s->rx_fifo, len, &to_copy);
 113             address_space_rw(&address_space_memory, ptr,
 114                             MEMTXATTRS_UNSPECIFIED, buf, to_copy, 1);
 115
 116             len -= to_copy;
 117             ptr += to_copy;
 118         }
 119         if (s->int_enabled && fifo8_is_empty(&s->rx_fifo)) {
 120             qemu_set_irq(s->irq, 0);
 121         }
 122         break;
 123     }
 124 }
 125
 126 static void goldfish_tty_write(void *opaque, hwaddr addr,
 127                                uint64_t value, unsigned size)
 128 {
 129     GoldfishTTYState *s = opaque;
 130     unsigned char c;
 131
 132     trace_goldfish_tty_write(s, addr, size, value);
 133
 134     switch (addr) {
 135     case REG_PUT_CHAR:
 136         c = value;
 137         qemu_chr_fe_write_all(&s->chr, &c, sizeof(c));
 138         break;
 139     case REG_CMD:
 140         goldfish_tty_cmd(s, value);
 141         break;
 142     case REG_DATA_PTR:
 143         s->data_ptr = value;
 144         break;
 145     case REG_DATA_PTR_HIGH:
 146         s->data_ptr = deposit64(s->data_ptr, 32, 32, value);
 147         break;
 148     case REG_DATA_LEN:
 149         s->data_len = value;
 150         break;
 151     default:
 152         qemu_log_mask(LOG_UNIMP,
 153                       "%s: unimplemented register write 0x%02"HWADDR_PRIx"\n",
 154                       __func__, addr);
 155         break;
 156     }
 157 }
 158
 159 static const MemoryRegionOps goldfish_tty_ops = {
 160     .read = goldfish_tty_read,
 161     .write = goldfish_tty_write,
 162     .endianness = DEVICE_NATIVE_ENDIAN,
 163     .valid.max_access_size = 4,
 164     .impl.max_access_size = 4,
 165     .impl.min_access_size = 4,
 166 };
 167
 168 static int goldfish_tty_can_receive(void *opaque)
 169 {
 170     GoldfishTTYState *s = opaque;
 171     int available = fifo8_num_free(&s->rx_fifo);
 172
 173     trace_goldfish_tty_can_receive(s, available);
 174
 175     return available;
 176 }
 177
 178 static void goldfish_tty_receive(void *opaque, const uint8_t *buffer, int size)
 179 {
 180     GoldfishTTYState *s = opaque;
 181
 182     trace_goldfish_tty_receive(s, size);
 183
 184     g_assert(size <= fifo8_num_free(&s->rx_fifo));
 185
 186     fifo8_push_all(&s->rx_fifo, buffer, size);
 187
 188     if (s->int_enabled && !fifo8_is_empty(&s->rx_fifo)) {
 189         qemu_set_irq(s->irq, 1);
 190     }
 191 }
 192
 193 static void goldfish_tty_reset(DeviceState *dev)
 194 {
 195     GoldfishTTYState *s = GOLDFISH_TTY(dev);
 196
 197     trace_goldfish_tty_reset(s);
 198
 199     fifo8_reset(&s->rx_fifo);
 200     s->int_enabled = false;
 201     s->data_ptr = 0;
 202     s->data_len = 0;
 203 }
 204
 205 static void goldfish_tty_realize(DeviceState *dev, Error **errp)
 206 {
 207     GoldfishTTYState *s = GOLDFISH_TTY(dev);
 208
 209     trace_goldfish_tty_realize(s);
 210
 211     fifo8_create(&s->rx_fifo, GOLFISH_TTY_BUFFER_SIZE);
 212     memory_region_init_io(&s->iomem, OBJECT(s), &goldfish_tty_ops, s,
 213                           "goldfish_tty", 0x24);
 214
 215     if (qemu_chr_fe_backend_connected(&s->chr)) {
 216         qemu_chr_fe_set_handlers(&s->chr, goldfish_tty_can_receive,
 217                                  goldfish_tty_receive, NULL, NULL,
 218                                  s, NULL, true);
 219     }
 220 }
 221
 222 static void goldfish_tty_unrealize(DeviceState *dev)
 223 {
 224     GoldfishTTYState *s = GOLDFISH_TTY(dev);
 225
 226     trace_goldfish_tty_unrealize(s);
 227
 228     fifo8_destroy(&s->rx_fifo);
 229 }
 230
 231 static const VMStateDescription vmstate_goldfish_tty = {
 232     .name = "goldfish_tty",
 233     .version_id = 1,
 234     .minimum_version_id = 1,
 235     .fields = (VMStateField[]) {
 236         VMSTATE_UINT32(data_len, GoldfishTTYState),
 237         VMSTATE_UINT64(data_ptr, GoldfishTTYState),
 238         VMSTATE_BOOL(int_enabled, GoldfishTTYState),
 239         VMSTATE_FIFO8(rx_fifo, GoldfishTTYState),
 240         VMSTATE_END_OF_LIST()
 241     }
 242 };
 243
 244 static Property goldfish_tty_properties[] = {
 245     DEFINE_PROP_CHR("chardev", GoldfishTTYState, chr),
 246     DEFINE_PROP_END_OF_LIST(),
 247 };
 248
 249 static void goldfish_tty_instance_init(Object *obj)
 250 {
 251     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
 252     GoldfishTTYState *s = GOLDFISH_TTY(obj);
 253
 254     trace_goldfish_tty_instance_init(s);
 255
 256     sysbus_init_mmio(dev, &s->iomem);
 257     sysbus_init_irq(dev, &s->irq);
 258 }
 259
 260 static void goldfish_tty_class_init(ObjectClass *oc, void *data)
 261 {
 262     DeviceClass *dc = DEVICE_CLASS(oc);
 263
 264     device_class_set_props(dc, goldfish_tty_properties);
 265     dc->reset = goldfish_tty_reset;
 266     dc->realize = goldfish_tty_realize;
 267     dc->unrealize = goldfish_tty_unrealize;
 268     dc->vmsd = &vmstate_goldfish_tty;
 269     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 270 }
 271
 272 static const TypeInfo goldfish_tty_info = {
 273     .name = TYPE_GOLDFISH_TTY,
 274     .parent = TYPE_SYS_BUS_DEVICE,
 275     .class_init = goldfish_tty_class_init,
 276     .instance_init = goldfish_tty_instance_init,
 277     .instance_size = sizeof(GoldfishTTYState),
 278 };
 279
 280 static void goldfish_tty_register_types(void)
 281 {
 282     type_register_static(&goldfish_tty_info);
 283 }
 284
 285 type_init(goldfish_tty_register_types)