1 #include "kvm/8250-serial.h" 2 3 #include "kvm/read-write.h" 4 #include "kvm/ioport.h" 5 #include "kvm/mutex.h" 6 #include "kvm/util.h" 7 #include "kvm/term.h" 8 #include "kvm/kvm.h" 9 10 #include <linux/types.h> 11 #include <linux/serial_reg.h> 12 13 #include <pthread.h> 14 15 /* 16 * This fakes a U6_16550A. The fifo len needs to be 64 as the kernel 17 * expects that for autodetection. 18 */ 19 #define FIFO_LEN 64 20 #define FIFO_MASK (FIFO_LEN - 1) 21 22 #define UART_IIR_TYPE_BITS 0xc0 23 24 struct serial8250_device { 25 struct mutex mutex; 26 u8 id; 27 28 u16 iobase; 29 u8 irq; 30 u8 irq_state; 31 int txcnt; 32 int rxcnt; 33 int rxdone; 34 char txbuf[FIFO_LEN]; 35 char rxbuf[FIFO_LEN]; 36 37 u8 dll; 38 u8 dlm; 39 u8 iir; 40 u8 ier; 41 u8 fcr; 42 u8 lcr; 43 u8 mcr; 44 u8 lsr; 45 u8 msr; 46 u8 scr; 47 }; 48 49 #define SERIAL_REGS_SETTING \ 50 .iir = UART_IIR_NO_INT, \ 51 .lsr = UART_LSR_TEMT | UART_LSR_THRE, \ 52 .msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS, \ 53 .mcr = UART_MCR_OUT2, 54 55 static struct serial8250_device devices[] = { 56 /* ttyS0 */ 57 [0] = { 58 .mutex = MUTEX_INITIALIZER, 59 60 .id = 0, 61 .iobase = 0x3f8, 62 .irq = 4, 63 64 SERIAL_REGS_SETTING 65 }, 66 /* ttyS1 */ 67 [1] = { 68 .mutex = MUTEX_INITIALIZER, 69 70 .id = 1, 71 .iobase = 0x2f8, 72 .irq = 3, 73 74 SERIAL_REGS_SETTING 75 }, 76 /* ttyS2 */ 77 [2] = { 78 .mutex = MUTEX_INITIALIZER, 79 80 .id = 2, 81 .iobase = 0x3e8, 82 .irq = 4, 83 84 SERIAL_REGS_SETTING 85 }, 86 /* ttyS3 */ 87 [3] = { 88 .mutex = MUTEX_INITIALIZER, 89 90 .id = 3, 91 .iobase = 0x2e8, 92 .irq = 3, 93 94 SERIAL_REGS_SETTING 95 }, 96 }; 97 98 static void serial8250_flush_tx(struct kvm *kvm, struct serial8250_device *dev) 99 { 100 dev->lsr |= UART_LSR_TEMT | UART_LSR_THRE; 101 102 if (dev->txcnt) { 103 term_putc(dev->txbuf, dev->txcnt, dev->id); 104 dev->txcnt = 0; 105 } 106 } 107 108 static void serial8250_update_irq(struct kvm *kvm, struct serial8250_device *dev) 109 { 110 u8 iir = 0; 111 112 /* Handle clear rx */ 113 if (dev->lcr & UART_FCR_CLEAR_RCVR) { 114 dev->lcr &= ~UART_FCR_CLEAR_RCVR; 115 dev->rxcnt = dev->rxdone = 0; 116 dev->lsr &= ~UART_LSR_DR; 117 } 118 119 /* Handle clear tx */ 120 if (dev->lcr & UART_FCR_CLEAR_XMIT) { 121 dev->lcr &= ~UART_FCR_CLEAR_XMIT; 122 dev->txcnt = 0; 123 dev->lsr |= UART_LSR_TEMT | UART_LSR_THRE; 124 } 125 126 /* Data ready and rcv interrupt enabled ? */ 127 if ((dev->ier & UART_IER_RDI) && (dev->lsr & UART_LSR_DR)) 128 iir |= UART_IIR_RDI; 129 130 /* Transmitter empty and interrupt enabled ? */ 131 if ((dev->ier & UART_IER_THRI) && (dev->lsr & UART_LSR_TEMT)) 132 iir |= UART_IIR_THRI; 133 134 /* Now update the irq line, if necessary */ 135 if (!iir) { 136 dev->iir = UART_IIR_NO_INT; 137 if (dev->irq_state) 138 kvm__irq_line(kvm, dev->irq, 0); 139 } else { 140 dev->iir = iir; 141 if (!dev->irq_state) 142 kvm__irq_line(kvm, dev->irq, 1); 143 } 144 dev->irq_state = iir; 145 146 /* 147 * If the kernel disabled the tx interrupt, we know that there 148 * is nothing more to transmit, so we can reset our tx logic 149 * here. 150 */ 151 if (!(dev->ier & UART_IER_THRI)) 152 serial8250_flush_tx(kvm, dev); 153 } 154 155 #define SYSRQ_PENDING_NONE 0 156 157 static int sysrq_pending; 158 159 static void serial8250__sysrq(struct kvm *kvm, struct serial8250_device *dev) 160 { 161 dev->lsr |= UART_LSR_DR | UART_LSR_BI; 162 dev->rxbuf[dev->rxcnt++] = sysrq_pending; 163 sysrq_pending = SYSRQ_PENDING_NONE; 164 } 165 166 static void serial8250__receive(struct kvm *kvm, struct serial8250_device *dev, 167 bool handle_sysrq) 168 { 169 int c; 170 171 /* 172 * If the guest transmitted a full fifo, we clear the 173 * TEMT/THRE bits to let the kernel escape from the 8250 174 * interrupt handler. We come here only once a ms, so that 175 * should give the kernel the desired pause. That also flushes 176 * the tx fifo to the terminal. 177 */ 178 serial8250_flush_tx(kvm, dev); 179 180 if (dev->mcr & UART_MCR_LOOP) 181 return; 182 183 if ((dev->lsr & UART_LSR_DR) || dev->rxcnt) 184 return; 185 186 if (handle_sysrq && sysrq_pending) { 187 serial8250__sysrq(kvm, dev); 188 return; 189 } 190 191 if (kvm->cfg.active_console != CONSOLE_8250) 192 return; 193 194 while (term_readable(dev->id) && 195 dev->rxcnt < FIFO_LEN) { 196 197 c = term_getc(kvm, dev->id); 198 199 if (c < 0) 200 break; 201 dev->rxbuf[dev->rxcnt++] = c; 202 dev->lsr |= UART_LSR_DR; 203 } 204 } 205 206 void serial8250__update_consoles(struct kvm *kvm) 207 { 208 unsigned int i; 209 210 for (i = 0; i < ARRAY_SIZE(devices); i++) { 211 struct serial8250_device *dev = &devices[i]; 212 213 mutex_lock(&dev->mutex); 214 215 /* Restrict sysrq injection to the first port */ 216 serial8250__receive(kvm, dev, i == 0); 217 218 serial8250_update_irq(kvm, dev); 219 220 mutex_unlock(&dev->mutex); 221 } 222 } 223 224 void serial8250__inject_sysrq(struct kvm *kvm, char sysrq) 225 { 226 sysrq_pending = sysrq; 227 } 228 229 static struct serial8250_device *find_device(u16 port) 230 { 231 unsigned int i; 232 233 for (i = 0; i < ARRAY_SIZE(devices); i++) { 234 struct serial8250_device *dev = &devices[i]; 235 236 if (dev->iobase == (port & ~0x7)) 237 return dev; 238 } 239 return NULL; 240 } 241 242 static bool serial8250_out(struct ioport *ioport, struct kvm *kvm, u16 port, 243 void *data, int size) 244 { 245 struct serial8250_device *dev; 246 u16 offset; 247 bool ret = true; 248 char *addr = data; 249 250 dev = find_device(port); 251 if (!dev) 252 return false; 253 254 mutex_lock(&dev->mutex); 255 256 offset = port - dev->iobase; 257 258 switch (offset) { 259 case UART_TX: 260 if (dev->lcr & UART_LCR_DLAB) { 261 dev->dll = ioport__read8(data); 262 break; 263 } 264 265 /* Loopback mode */ 266 if (dev->mcr & UART_MCR_LOOP) { 267 if (dev->rxcnt < FIFO_LEN) { 268 dev->rxbuf[dev->rxcnt++] = *addr; 269 dev->lsr |= UART_LSR_DR; 270 } 271 break; 272 } 273 274 if (dev->txcnt < FIFO_LEN) { 275 dev->txbuf[dev->txcnt++] = *addr; 276 dev->lsr &= ~UART_LSR_TEMT; 277 if (dev->txcnt == FIFO_LEN / 2) 278 dev->lsr &= ~UART_LSR_THRE; 279 } else { 280 /* Should never happpen */ 281 dev->lsr &= ~(UART_LSR_TEMT | UART_LSR_THRE); 282 } 283 break; 284 case UART_IER: 285 if (!(dev->lcr & UART_LCR_DLAB)) 286 dev->ier = ioport__read8(data) & 0x0f; 287 else 288 dev->dlm = ioport__read8(data); 289 break; 290 case UART_FCR: 291 dev->fcr = ioport__read8(data); 292 break; 293 case UART_LCR: 294 dev->lcr = ioport__read8(data); 295 break; 296 case UART_MCR: 297 dev->mcr = ioport__read8(data); 298 break; 299 case UART_LSR: 300 /* Factory test */ 301 break; 302 case UART_MSR: 303 /* Not used */ 304 break; 305 case UART_SCR: 306 dev->scr = ioport__read8(data); 307 break; 308 default: 309 ret = false; 310 break; 311 } 312 313 serial8250_update_irq(kvm, dev); 314 315 mutex_unlock(&dev->mutex); 316 317 return ret; 318 } 319 320 static void serial8250_rx(struct serial8250_device *dev, void *data) 321 { 322 if (dev->rxdone == dev->rxcnt) 323 return; 324 325 /* Break issued ? */ 326 if (dev->lsr & UART_LSR_BI) { 327 dev->lsr &= ~UART_LSR_BI; 328 ioport__write8(data, 0); 329 return; 330 } 331 332 ioport__write8(data, dev->rxbuf[dev->rxdone++]); 333 if (dev->rxcnt == dev->rxdone) { 334 dev->lsr &= ~UART_LSR_DR; 335 dev->rxcnt = dev->rxdone = 0; 336 } 337 } 338 339 static bool serial8250_in(struct ioport *ioport, struct kvm *kvm, u16 port, void *data, int size) 340 { 341 struct serial8250_device *dev; 342 u16 offset; 343 bool ret = true; 344 345 dev = find_device(port); 346 if (!dev) 347 return false; 348 349 mutex_lock(&dev->mutex); 350 351 offset = port - dev->iobase; 352 353 switch (offset) { 354 case UART_RX: 355 if (dev->lcr & UART_LCR_DLAB) 356 ioport__write8(data, dev->dll); 357 else 358 serial8250_rx(dev, data); 359 break; 360 case UART_IER: 361 if (dev->lcr & UART_LCR_DLAB) 362 ioport__write8(data, dev->dlm); 363 else 364 ioport__write8(data, dev->ier); 365 break; 366 case UART_IIR: 367 ioport__write8(data, dev->iir | UART_IIR_TYPE_BITS); 368 break; 369 case UART_LCR: 370 ioport__write8(data, dev->lcr); 371 break; 372 case UART_MCR: 373 ioport__write8(data, dev->mcr); 374 break; 375 case UART_LSR: 376 ioport__write8(data, dev->lsr); 377 break; 378 case UART_MSR: 379 ioport__write8(data, dev->msr); 380 break; 381 case UART_SCR: 382 ioport__write8(data, dev->scr); 383 break; 384 default: 385 ret = false; 386 break; 387 } 388 389 serial8250_update_irq(kvm, dev); 390 391 mutex_unlock(&dev->mutex); 392 393 return ret; 394 } 395 396 static struct ioport_operations serial8250_ops = { 397 .io_in = serial8250_in, 398 .io_out = serial8250_out, 399 }; 400 401 static int serial8250__device_init(struct kvm *kvm, struct serial8250_device *dev) 402 { 403 int r; 404 405 ioport__map_irq(&dev->irq); 406 r = ioport__register(kvm, dev->iobase, &serial8250_ops, 8, NULL); 407 kvm__irq_line(kvm, dev->irq, 0); 408 409 return r; 410 } 411 412 int serial8250__init(struct kvm *kvm) 413 { 414 unsigned int i, j; 415 int r = 0; 416 417 for (i = 0; i < ARRAY_SIZE(devices); i++) { 418 struct serial8250_device *dev = &devices[i]; 419 420 r = serial8250__device_init(kvm, dev); 421 if (r < 0) 422 goto cleanup; 423 } 424 425 return r; 426 cleanup: 427 for (j = 0; j <= i; j++) { 428 struct serial8250_device *dev = &devices[j]; 429 430 ioport__unregister(kvm, dev->iobase); 431 } 432 433 return r; 434 } 435 dev_init(serial8250__init); 436 437 int serial8250__exit(struct kvm *kvm) 438 { 439 unsigned int i; 440 int r; 441 442 for (i = 0; i < ARRAY_SIZE(devices); i++) { 443 struct serial8250_device *dev = &devices[i]; 444 445 r = ioport__unregister(kvm, dev->iobase); 446 if (r < 0) 447 return r; 448 } 449 450 return 0; 451 } 452 dev_exit(serial8250__exit); 453