hw/arm/s3c24xx_serial.c

   1 /* hw/s3c24xx_serial.c
   2  *
   3  * Samsung S3C24XX Serial block
   4  *
   5  * Copyright 2006, 2007 Daniel Silverstone and Vincent Sanders
   6  *
   7  * Copyright 2010, 2013 Stefan Weil
   8  *
   9  * This file is under the terms of the GNU General Public License Version 2.
  10  */
  11
  12 #include "qemu/osdep.h"
  13 #include "cpu.h"
  14 #include "hw/hw.h"
  15 #include "exec/address-spaces.h" /* get_system_memory */
  16 #include "chardev/char-fe.h"     /* qemu_chr_fe_write */
  17 #include "sysemu/sysemu.h"
  18
  19 #include "s3c24xx.h"
  20
  21 #if 0
  22 # define DEBUG_S3C24XX
  23 #endif
  24
  25 #if defined(DEBUG_S3C24XX)
  26 # define logout(fmt, ...) \
  27     fprintf(stderr, "S3C24xx\t%-24s" fmt, __func__, ##__VA_ARGS__)
  28 #else
  29 # define logout(fmt, ...) (void)0
  30 #endif
  31
  32 /* S3C24XX serial port registers */
  33
  34 /* Line control         RW WORD */
  35 #define S3C_SERIAL_ULCON 0x00
  36 /* General control      RW WORD */
  37 #define S3C_SERIAL_UCON  0x04
  38 /* Fifo control         RW WORD */
  39 #define S3C_SERIAL_UFCON 0x08
  40 /* Modem control        RW WORD */
  41 #define S3C_SERIAL_UMCON 0x0C
  42 /* TX/RX Status         RO WORD */
  43 #define S3C_SERIAL_UTRSTAT 0x10
  44 /* Receive Error Status RO WORD */
  45 #define S3C_SERIAL_UERSTAT 0x14
  46 /* FiFo Status          RO WORD */
  47 #define S3C_SERIAL_UFSTAT 0x18
  48 /* Modem Status         RO WORD */
  49 #define S3C_SERIAL_UMSTAT 0x1C
  50 /* TX buffer            WR BYTE */
  51 #define S3C_SERIAL_UTXH 0x20
  52 /* RX buffer            RO BYTE */
  53 #define S3C_SERIAL_URXH 0x24
  54 /* BAUD Divisor         RW WORD */
  55 #define S3C_SERIAL_UBRDIV 0x28
  56
  57 /* S3C24XX serial port state */
  58 typedef struct s3c24xx_serial_dev_s {
  59     MemoryRegion mmio;
  60     uint32_t ulcon, ucon, ufcon, umcon, ubrdiv;
  61     unsigned char rx_byte;
  62     /* Byte is available to be read */
  63     unsigned int rx_available : 1;
  64     CharBackend chr;
  65     qemu_irq tx_irq;
  66     qemu_irq rx_irq;
  67     qemu_irq tx_level;
  68     qemu_irq rx_level;
  69 } s3c24xx_serial_dev;
  70
  71 static void s3c24xx_serial_write(void *opaque, hwaddr addr,
  72                                  uint64_t value, unsigned size)
  73 {
  74     s3c24xx_serial_dev *s = opaque;
  75     int reg = addr & 0x3f;
  76
  77     logout("0x" TARGET_FMT_plx " 0x%08x\n", addr, value);
  78
  79     switch(reg) {
  80     case S3C_SERIAL_ULCON:
  81         s->ulcon = value;
  82         break;
  83
  84     case S3C_SERIAL_UCON:
  85         s->ucon = value;
  86         if( s->ucon & 1<<9 ) {
  87             qemu_set_irq(s->tx_level, 1);
  88         } else {
  89             qemu_set_irq(s->tx_level, 0);
  90         }
  91         if( !(s->ucon & 1<<8) ) {
  92             qemu_set_irq(s->rx_level, 0);
  93         }
  94         break;
  95
  96     case S3C_SERIAL_UFCON:
  97         s->ufcon = (value & ~6);
  98         break;
  99
 100     case S3C_SERIAL_UMCON:
 101         s->umcon = value;
 102         break;
 103
 104     case S3C_SERIAL_UTRSTAT:
 105         break;
 106
 107     case S3C_SERIAL_UERSTAT:
 108         break;
 109
 110     case S3C_SERIAL_UFSTAT:
 111         break;
 112
 113     case S3C_SERIAL_UMSTAT:
 114         break;
 115
 116     case S3C_SERIAL_UTXH: {
 117         unsigned char ch = value & 0xff;
 118         if ((s->ucon & 1 << 5) == 0) {
 119             qemu_chr_fe_write(&s->chr, &ch, 1);
 120         } else {
 121             s->rx_byte = ch;
 122             s->rx_available = 1;
 123             if( s->ucon & 1<<8 ) {
 124                 qemu_set_irq(s->rx_level, 1);
 125             } else {
 126                 qemu_set_irq(s->rx_irq, 1);
 127             }
 128         }
 129         if (s->ucon & 1<<9) {
 130             qemu_set_irq(s->tx_level, 1);
 131         } else {
 132             qemu_set_irq(s->tx_irq, 1);
 133         }
 134         break;
 135     }
 136
 137     case S3C_SERIAL_URXH:
 138         break;
 139
 140     case S3C_SERIAL_UBRDIV:
 141         s->ubrdiv = value;
 142         break;
 143
 144     default:
 145         break;
 146     };
 147 }
 148
 149 static uint64_t s3c24xx_serial_read(void *opaque, hwaddr addr,
 150                                     unsigned size)
 151 {
 152     s3c24xx_serial_dev *s = opaque;
 153     int reg = addr & 0x3f;
 154
 155     logout("0x" TARGET_FMT_plx "\n", addr);
 156
 157     switch (reg) {
 158     case S3C_SERIAL_ULCON:
 159         return s->ulcon;
 160
 161     case S3C_SERIAL_UCON:
 162         return s->ucon;
 163
 164     case S3C_SERIAL_UFCON:
 165         return s->ufcon & ~0x8; /* bit 3 is reserved, must be zero */
 166
 167     case S3C_SERIAL_UMCON:
 168         return s->umcon & 0x11; /* Rest are reserved, must be zero */
 169
 170     case S3C_SERIAL_UTRSTAT:
 171         return 6 | s->rx_available; /* TX always clear, RX when available */
 172
 173     case S3C_SERIAL_UERSTAT:
 174         return 0; /* Later, break detect comes in here */
 175
 176     case S3C_SERIAL_UFSTAT:
 177         return s->rx_available; /* TXFIFO, always empty, RXFIFO 0 or 1 bytes */
 178
 179     case S3C_SERIAL_UMSTAT:
 180         return 0;
 181
 182     case S3C_SERIAL_UTXH:
 183         return 0;
 184
 185     case S3C_SERIAL_URXH:
 186         s->rx_available = 0;
 187         if (s->ucon & 1<<8) {
 188             qemu_set_irq(s->rx_level, 0);
 189         }
 190         return s->rx_byte;
 191
 192     case S3C_SERIAL_UBRDIV:
 193         return s->ubrdiv;
 194
 195     default:
 196         return 0;
 197     };
 198 }
 199
 200 static const MemoryRegionOps s3c24xx_serial_ops = {
 201     .read = s3c24xx_serial_read,
 202     .write = s3c24xx_serial_write,
 203     .endianness = DEVICE_NATIVE_ENDIAN,
 204     .valid = {
 205         .min_access_size = 1,
 206         .max_access_size = 4
 207     }
 208 };
 209
 210 static void s3c24xx_serial_event(void *opaque, int event)
 211 {
 212 }
 213
 214 static int
 215 s3c24xx_serial_can_receive(void *opaque)
 216 {
 217     s3c24xx_serial_dev *s = opaque;
 218
 219     /* If there's no byte to be read, we can receive a new one */
 220     return !s->rx_available;
 221 }
 222
 223 static void
 224 s3c24xx_serial_receive(void *opaque, const uint8_t *buf, int size)
 225 {
 226     s3c24xx_serial_dev *s = opaque;
 227     s->rx_byte = buf[0];
 228     s->rx_available = 1;
 229     if ( s->ucon & 1 << 8 ) {
 230         qemu_set_irq(s->rx_level, 1);
 231     } else {
 232         /* Is there something we can do here to ensure it's just a pulse ? */
 233         qemu_set_irq(s->rx_irq, 1);
 234     }
 235 }
 236
 237 /* Create a S3C serial port, the port implementation is common to all
 238  * current s3c devices only differing in the I/O base address and number of
 239  * ports.
 240  */
 241 struct s3c24xx_serial_dev_s *
 242 s3c24xx_serial_init(S3CState *soc,
 243                     Chardev *chr,
 244                     hwaddr base_addr,
 245                     int irqn)
 246 {
 247     /* Initialise a serial port at the given port address */
 248     s3c24xx_serial_dev *s = g_new0(s3c24xx_serial_dev, 1);
 249
 250     /* initialise serial port context */
 251     s->rx_irq = s3c24xx_get_irq(soc->irq, irqn);
 252     s->rx_level = s3c24xx_get_irq(soc->irq, irqn + 64);
 253
 254     s->tx_irq = s3c24xx_get_irq(soc->irq, irqn + 1);
 255     s->tx_level = s3c24xx_get_irq(soc->irq, irqn + 1 + 64);
 256
 257     /* Register the MMIO region. */
 258     memory_region_init_io(&s->mmio, OBJECT(s), &s3c24xx_serial_ops, s,
 259                           "s3c24xx.serial", 44);
 260     memory_region_add_subregion(get_system_memory(), base_addr, &s->mmio);
 261
 262     qemu_chr_fe_set_handlers(&s->chr,
 263                              s3c24xx_serial_can_receive,
 264                              s3c24xx_serial_receive,
 265                              s3c24xx_serial_event,
 266                              NULL, s, NULL, true);
 267
 268     return s;
 269 }