hw/etraxfs_ser.c

   1 /*
   2  * QEMU ETRAX System Emulator
   3  *
   4  * Copyright (c) 2007 Edgar E. Iglesias, Axis Communications AB.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "sysbus.h"
  26 #include "char/char.h"
  27 #include "qemu/log.h"
  28
  29 #define D(x)
  30
  31 #define RW_TR_CTRL     (0x00 / 4)
  32 #define RW_TR_DMA_EN   (0x04 / 4)
  33 #define RW_REC_CTRL    (0x08 / 4)
  34 #define RW_DOUT        (0x1c / 4)
  35 #define RS_STAT_DIN    (0x20 / 4)
  36 #define R_STAT_DIN     (0x24 / 4)
  37 #define RW_INTR_MASK   (0x2c / 4)
  38 #define RW_ACK_INTR    (0x30 / 4)
  39 #define R_INTR         (0x34 / 4)
  40 #define R_MASKED_INTR  (0x38 / 4)
  41 #define R_MAX          (0x3c / 4)
  42
  43 #define STAT_DAV     16
  44 #define STAT_TR_IDLE 22
  45 #define STAT_TR_RDY  24
  46
  47 struct etrax_serial
  48 {
  49     SysBusDevice busdev;
  50     MemoryRegion mmio;
  51     CharDriverState *chr;
  52     qemu_irq irq;
  53
  54     int pending_tx;
  55
  56     uint8_t rx_fifo[16];
  57     unsigned int rx_fifo_pos;
  58     unsigned int rx_fifo_len;
  59
  60     /* Control registers.  */
  61     uint32_t regs[R_MAX];
  62 };
  63
  64 static void ser_update_irq(struct etrax_serial *s)
  65 {
  66
  67     if (s->rx_fifo_len) {
  68         s->regs[R_INTR] |= 8;
  69     } else {
  70         s->regs[R_INTR] &= ~8;
  71     }
  72
  73     s->regs[R_MASKED_INTR] = s->regs[R_INTR] & s->regs[RW_INTR_MASK];
  74     qemu_set_irq(s->irq, !!s->regs[R_MASKED_INTR]);
  75 }
  76
  77 static uint64_t
  78 ser_read(void *opaque, hwaddr addr, unsigned int size)
  79 {
  80     struct etrax_serial *s = opaque;
  81     D(CPUCRISState *env = s->env);
  82     uint32_t r = 0;
  83
  84     addr >>= 2;
  85     switch (addr)
  86     {
  87         case R_STAT_DIN:
  88             r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 15];
  89             if (s->rx_fifo_len) {
  90                 r |= 1 << STAT_DAV;
  91             }
  92             r |= 1 << STAT_TR_RDY;
  93             r |= 1 << STAT_TR_IDLE;
  94             break;
  95         case RS_STAT_DIN:
  96             r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 15];
  97             if (s->rx_fifo_len) {
  98                 r |= 1 << STAT_DAV;
  99                 s->rx_fifo_len--;
 100             }
 101             r |= 1 << STAT_TR_RDY;
 102             r |= 1 << STAT_TR_IDLE;
 103             break;
 104         default:
 105             r = s->regs[addr];
 106             D(qemu_log("%s " TARGET_FMT_plx "=%x\n", __func__, addr, r));
 107             break;
 108     }
 109     return r;
 110 }
 111
 112 static void
 113 ser_write(void *opaque, hwaddr addr,
 114           uint64_t val64, unsigned int size)
 115 {
 116     struct etrax_serial *s = opaque;
 117     uint32_t value = val64;
 118     unsigned char ch = val64;
 119     D(CPUCRISState *env = s->env);
 120
 121     D(qemu_log("%s " TARGET_FMT_plx "=%x\n",  __func__, addr, value));
 122     addr >>= 2;
 123     switch (addr)
 124     {
 125         case RW_DOUT:
 126             qemu_chr_fe_write(s->chr, &ch, 1);
 127             s->regs[R_INTR] |= 3;
 128             s->pending_tx = 1;
 129             s->regs[addr] = value;
 130             break;
 131         case RW_ACK_INTR:
 132             if (s->pending_tx) {
 133                 value &= ~1;
 134                 s->pending_tx = 0;
 135                 D(qemu_log("fixedup value=%x r_intr=%x\n",
 136                            value, s->regs[R_INTR]));
 137             }
 138             s->regs[addr] = value;
 139             s->regs[R_INTR] &= ~value;
 140             D(printf("r_intr=%x\n", s->regs[R_INTR]));
 141             break;
 142         default:
 143             s->regs[addr] = value;
 144             break;
 145     }
 146     ser_update_irq(s);
 147 }
 148
 149 static const MemoryRegionOps ser_ops = {
 150     .read = ser_read,
 151     .write = ser_write,
 152     .endianness = DEVICE_NATIVE_ENDIAN,
 153     .valid = {
 154         .min_access_size = 4,
 155         .max_access_size = 4
 156     }
 157 };
 158
 159 static void serial_receive(void *opaque, const uint8_t *buf, int size)
 160 {
 161     struct etrax_serial *s = opaque;
 162     int i;
 163
 164     /* Got a byte.  */
 165     if (s->rx_fifo_len >= 16) {
 166         qemu_log("WARNING: UART dropped char.\n");
 167         return;
 168     }
 169
 170     for (i = 0; i < size; i++) {
 171         s->rx_fifo[s->rx_fifo_pos] = buf[i];
 172         s->rx_fifo_pos++;
 173         s->rx_fifo_pos &= 15;
 174         s->rx_fifo_len++;
 175     }
 176
 177     ser_update_irq(s);
 178 }
 179
 180 static int serial_can_receive(void *opaque)
 181 {
 182     struct etrax_serial *s = opaque;
 183     int r;
 184
 185     /* Is the receiver enabled?  */
 186     if (!(s->regs[RW_REC_CTRL] & (1 << 3))) {
 187         return 0;
 188     }
 189
 190     r = sizeof(s->rx_fifo) - s->rx_fifo_len;
 191     return r;
 192 }
 193
 194 static void serial_event(void *opaque, int event)
 195 {
 196
 197 }
 198
 199 static void etraxfs_ser_reset(DeviceState *d)
 200 {
 201     struct etrax_serial *s = container_of(d, typeof(*s), busdev.qdev);
 202
 203     /* transmitter begins ready and idle.  */
 204     s->regs[RS_STAT_DIN] |= (1 << STAT_TR_RDY);
 205     s->regs[RS_STAT_DIN] |= (1 << STAT_TR_IDLE);
 206
 207     s->regs[RW_REC_CTRL] = 0x10000;
 208
 209 }
 210
 211 static int etraxfs_ser_init(SysBusDevice *dev)
 212 {
 213     struct etrax_serial *s = FROM_SYSBUS(typeof (*s), dev);
 214
 215     sysbus_init_irq(dev, &s->irq);
 216     memory_region_init_io(&s->mmio, &ser_ops, s, "etraxfs-serial", R_MAX * 4);
 217     sysbus_init_mmio(dev, &s->mmio);
 218
 219     s->chr = qemu_char_get_next_serial();
 220     if (s->chr)
 221         qemu_chr_add_handlers(s->chr,
 222                       serial_can_receive, serial_receive,
 223                       serial_event, s);
 224     return 0;
 225 }
 226
 227 static void etraxfs_ser_class_init(ObjectClass *klass, void *data)
 228 {
 229     DeviceClass *dc = DEVICE_CLASS(klass);
 230     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 231
 232     k->init = etraxfs_ser_init;
 233     dc->reset = etraxfs_ser_reset;
 234 }
 235
 236 static const TypeInfo etraxfs_ser_info = {
 237     .name          = "etraxfs,serial",
 238     .parent        = TYPE_SYS_BUS_DEVICE,
 239     .instance_size = sizeof(struct etrax_serial),
 240     .class_init    = etraxfs_ser_class_init,
 241 };
 242
 243 static void etraxfs_serial_register_types(void)
 244 {
 245     type_register_static(&etraxfs_ser_info);
 246 }
 247
 248 type_init(etraxfs_serial_register_types)