1 /* 2 * Copyright (C) 2007 Google, Inc. 3 * Copyright (C) 2012 Intel, Inc. 4 * Copyright (C) 2017 Imagination Technologies Ltd. 5 * 6 * This software is licensed under the terms of the GNU General Public 7 * License version 2, as published by the Free Software Foundation, and 8 * may be copied, distributed, and modified under those terms. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 */ 16 17 #include <linux/console.h> 18 #include <linux/interrupt.h> 19 #include <linux/platform_device.h> 20 #include <linux/tty.h> 21 #include <linux/tty_flip.h> 22 #include <linux/slab.h> 23 #include <linux/io.h> 24 #include <linux/module.h> 25 #include <linux/goldfish.h> 26 #include <linux/mm.h> 27 #include <linux/dma-mapping.h> 28 #include <linux/serial_core.h> 29 30 /* Goldfish tty register's offsets */ 31 #define GOLDFISH_TTY_REG_BYTES_READY 0x04 32 #define GOLDFISH_TTY_REG_CMD 0x08 33 #define GOLDFISH_TTY_REG_DATA_PTR 0x10 34 #define GOLDFISH_TTY_REG_DATA_LEN 0x14 35 #define GOLDFISH_TTY_REG_DATA_PTR_HIGH 0x18 36 #define GOLDFISH_TTY_REG_VERSION 0x20 37 38 /* Goldfish tty commands */ 39 #define GOLDFISH_TTY_CMD_INT_DISABLE 0 40 #define GOLDFISH_TTY_CMD_INT_ENABLE 1 41 #define GOLDFISH_TTY_CMD_WRITE_BUFFER 2 42 #define GOLDFISH_TTY_CMD_READ_BUFFER 3 43 44 struct goldfish_tty { 45 struct tty_port port; 46 spinlock_t lock; 47 void __iomem *base; 48 u32 irq; 49 int opencount; 50 struct console console; 51 u32 version; 52 struct device *dev; 53 }; 54 55 static DEFINE_MUTEX(goldfish_tty_lock); 56 static struct tty_driver *goldfish_tty_driver; 57 static u32 goldfish_tty_line_count = 8; 58 static u32 goldfish_tty_current_line_count; 59 static struct goldfish_tty *goldfish_ttys; 60 61 static void do_rw_io(struct goldfish_tty *qtty, 62 unsigned long address, 63 unsigned int count, 64 int is_write) 65 { 66 unsigned long irq_flags; 67 void __iomem *base = qtty->base; 68 69 spin_lock_irqsave(&qtty->lock, irq_flags); 70 gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR, 71 base + GOLDFISH_TTY_REG_DATA_PTR_HIGH); 72 writel(count, base + GOLDFISH_TTY_REG_DATA_LEN); 73 74 if (is_write) 75 writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, 76 base + GOLDFISH_TTY_REG_CMD); 77 else 78 writel(GOLDFISH_TTY_CMD_READ_BUFFER, 79 base + GOLDFISH_TTY_REG_CMD); 80 81 spin_unlock_irqrestore(&qtty->lock, irq_flags); 82 } 83 84 static void goldfish_tty_rw(struct goldfish_tty *qtty, 85 unsigned long addr, 86 unsigned int count, 87 int is_write) 88 { 89 dma_addr_t dma_handle; 90 enum dma_data_direction dma_dir; 91 92 dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); 93 if (qtty->version > 0) { 94 /* 95 * Goldfish TTY for Ranchu platform uses 96 * physical addresses and DMA for read/write operations 97 */ 98 unsigned long addr_end = addr + count; 99 100 while (addr < addr_end) { 101 unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE; 102 unsigned long next = 103 pg_end < addr_end ? pg_end : addr_end; 104 unsigned long avail = next - addr; 105 106 /* 107 * Map the buffer's virtual address to the DMA address 108 * so the buffer can be accessed by the device. 109 */ 110 dma_handle = dma_map_single(qtty->dev, (void *)addr, 111 avail, dma_dir); 112 113 if (dma_mapping_error(qtty->dev, dma_handle)) { 114 dev_err(qtty->dev, "tty: DMA mapping error.\n"); 115 return; 116 } 117 do_rw_io(qtty, dma_handle, avail, is_write); 118 119 /* 120 * Unmap the previously mapped region after 121 * the completion of the read/write operation. 122 */ 123 dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir); 124 125 addr += avail; 126 } 127 } else { 128 /* 129 * Old style Goldfish TTY used on the Goldfish platform 130 * uses virtual addresses. 131 */ 132 do_rw_io(qtty, addr, count, is_write); 133 } 134 } 135 136 static void goldfish_tty_do_write(int line, const char *buf, 137 unsigned int count) 138 { 139 struct goldfish_tty *qtty = &goldfish_ttys[line]; 140 unsigned long address = (unsigned long)(void *)buf; 141 142 goldfish_tty_rw(qtty, address, count, 1); 143 } 144 145 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id) 146 { 147 struct goldfish_tty *qtty = dev_id; 148 void __iomem *base = qtty->base; 149 unsigned long address; 150 unsigned char *buf; 151 u32 count; 152 153 count = readl(base + GOLDFISH_TTY_REG_BYTES_READY); 154 if (count == 0) 155 return IRQ_NONE; 156 157 count = tty_prepare_flip_string(&qtty->port, &buf, count); 158 159 address = (unsigned long)(void *)buf; 160 goldfish_tty_rw(qtty, address, count, 0); 161 162 tty_schedule_flip(&qtty->port); 163 return IRQ_HANDLED; 164 } 165 166 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty) 167 { 168 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 169 port); 170 writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 171 return 0; 172 } 173 174 static void goldfish_tty_shutdown(struct tty_port *port) 175 { 176 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 177 port); 178 writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 179 } 180 181 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp) 182 { 183 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 184 return tty_port_open(&qtty->port, tty, filp); 185 } 186 187 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) 188 { 189 tty_port_close(tty->port, tty, filp); 190 } 191 192 static void goldfish_tty_hangup(struct tty_struct *tty) 193 { 194 tty_port_hangup(tty->port); 195 } 196 197 static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf, 198 int count) 199 { 200 goldfish_tty_do_write(tty->index, buf, count); 201 return count; 202 } 203 204 static int goldfish_tty_write_room(struct tty_struct *tty) 205 { 206 return 0x10000; 207 } 208 209 static int goldfish_tty_chars_in_buffer(struct tty_struct *tty) 210 { 211 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 212 void __iomem *base = qtty->base; 213 return readl(base + GOLDFISH_TTY_REG_BYTES_READY); 214 } 215 216 static void goldfish_tty_console_write(struct console *co, const char *b, 217 unsigned count) 218 { 219 goldfish_tty_do_write(co->index, b, count); 220 } 221 222 static struct tty_driver *goldfish_tty_console_device(struct console *c, 223 int *index) 224 { 225 *index = c->index; 226 return goldfish_tty_driver; 227 } 228 229 static int goldfish_tty_console_setup(struct console *co, char *options) 230 { 231 if ((unsigned)co->index >= goldfish_tty_line_count) 232 return -ENODEV; 233 if (!goldfish_ttys[co->index].base) 234 return -ENODEV; 235 return 0; 236 } 237 238 static const struct tty_port_operations goldfish_port_ops = { 239 .activate = goldfish_tty_activate, 240 .shutdown = goldfish_tty_shutdown 241 }; 242 243 static const struct tty_operations goldfish_tty_ops = { 244 .open = goldfish_tty_open, 245 .close = goldfish_tty_close, 246 .hangup = goldfish_tty_hangup, 247 .write = goldfish_tty_write, 248 .write_room = goldfish_tty_write_room, 249 .chars_in_buffer = goldfish_tty_chars_in_buffer, 250 }; 251 252 static int goldfish_tty_create_driver(void) 253 { 254 int ret; 255 struct tty_driver *tty; 256 257 goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) * 258 goldfish_tty_line_count, GFP_KERNEL); 259 if (goldfish_ttys == NULL) { 260 ret = -ENOMEM; 261 goto err_alloc_goldfish_ttys_failed; 262 } 263 tty = alloc_tty_driver(goldfish_tty_line_count); 264 if (tty == NULL) { 265 ret = -ENOMEM; 266 goto err_alloc_tty_driver_failed; 267 } 268 tty->driver_name = "goldfish"; 269 tty->name = "ttyGF"; 270 tty->type = TTY_DRIVER_TYPE_SERIAL; 271 tty->subtype = SERIAL_TYPE_NORMAL; 272 tty->init_termios = tty_std_termios; 273 tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | 274 TTY_DRIVER_DYNAMIC_DEV; 275 tty_set_operations(tty, &goldfish_tty_ops); 276 ret = tty_register_driver(tty); 277 if (ret) 278 goto err_tty_register_driver_failed; 279 280 goldfish_tty_driver = tty; 281 return 0; 282 283 err_tty_register_driver_failed: 284 put_tty_driver(tty); 285 err_alloc_tty_driver_failed: 286 kfree(goldfish_ttys); 287 goldfish_ttys = NULL; 288 err_alloc_goldfish_ttys_failed: 289 return ret; 290 } 291 292 static void goldfish_tty_delete_driver(void) 293 { 294 tty_unregister_driver(goldfish_tty_driver); 295 put_tty_driver(goldfish_tty_driver); 296 goldfish_tty_driver = NULL; 297 kfree(goldfish_ttys); 298 goldfish_ttys = NULL; 299 } 300 301 static int goldfish_tty_probe(struct platform_device *pdev) 302 { 303 struct goldfish_tty *qtty; 304 int ret = -ENODEV; 305 struct resource *r; 306 struct device *ttydev; 307 void __iomem *base; 308 u32 irq; 309 unsigned int line; 310 311 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 312 if (!r) { 313 pr_err("goldfish_tty: No MEM resource available!\n"); 314 return -ENOMEM; 315 } 316 317 base = ioremap(r->start, 0x1000); 318 if (!base) { 319 pr_err("goldfish_tty: Unable to ioremap base!\n"); 320 return -ENOMEM; 321 } 322 323 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 324 if (!r) { 325 pr_err("goldfish_tty: No IRQ resource available!\n"); 326 goto err_unmap; 327 } 328 329 irq = r->start; 330 331 mutex_lock(&goldfish_tty_lock); 332 333 if (pdev->id == PLATFORM_DEVID_NONE) 334 line = goldfish_tty_current_line_count; 335 else 336 line = pdev->id; 337 338 if (line >= goldfish_tty_line_count) { 339 pr_err("goldfish_tty: Reached maximum tty number of %d.\n", 340 goldfish_tty_current_line_count); 341 ret = -ENOMEM; 342 goto err_unlock; 343 } 344 345 if (goldfish_tty_current_line_count == 0) { 346 ret = goldfish_tty_create_driver(); 347 if (ret) 348 goto err_unlock; 349 } 350 goldfish_tty_current_line_count++; 351 352 qtty = &goldfish_ttys[line]; 353 spin_lock_init(&qtty->lock); 354 tty_port_init(&qtty->port); 355 qtty->port.ops = &goldfish_port_ops; 356 qtty->base = base; 357 qtty->irq = irq; 358 qtty->dev = &pdev->dev; 359 360 /* 361 * Goldfish TTY device used by the Goldfish emulator 362 * should identify itself with 0, forcing the driver 363 * to use virtual addresses. Goldfish TTY device 364 * on Ranchu emulator (qemu2) returns 1 here and 365 * driver will use physical addresses. 366 */ 367 qtty->version = readl(base + GOLDFISH_TTY_REG_VERSION); 368 369 /* 370 * Goldfish TTY device on Ranchu emulator (qemu2) 371 * will use DMA for read/write IO operations. 372 */ 373 if (qtty->version > 0) { 374 /* 375 * Initialize dma_mask to 32-bits. 376 */ 377 if (!pdev->dev.dma_mask) 378 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; 379 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); 380 if (ret) { 381 dev_err(&pdev->dev, "No suitable DMA available.\n"); 382 goto err_dec_line_count; 383 } 384 } 385 386 writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); 387 388 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, 389 "goldfish_tty", qtty); 390 if (ret) { 391 pr_err("goldfish_tty: No IRQ available!\n"); 392 goto err_dec_line_count; 393 } 394 395 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver, 396 line, &pdev->dev); 397 if (IS_ERR(ttydev)) { 398 ret = PTR_ERR(ttydev); 399 goto err_tty_register_device_failed; 400 } 401 402 strcpy(qtty->console.name, "ttyGF"); 403 qtty->console.write = goldfish_tty_console_write; 404 qtty->console.device = goldfish_tty_console_device; 405 qtty->console.setup = goldfish_tty_console_setup; 406 qtty->console.flags = CON_PRINTBUFFER; 407 qtty->console.index = line; 408 register_console(&qtty->console); 409 platform_set_drvdata(pdev, qtty); 410 411 mutex_unlock(&goldfish_tty_lock); 412 return 0; 413 414 err_tty_register_device_failed: 415 free_irq(irq, qtty); 416 err_dec_line_count: 417 goldfish_tty_current_line_count--; 418 if (goldfish_tty_current_line_count == 0) 419 goldfish_tty_delete_driver(); 420 err_unlock: 421 mutex_unlock(&goldfish_tty_lock); 422 err_unmap: 423 iounmap(base); 424 return ret; 425 } 426 427 static int goldfish_tty_remove(struct platform_device *pdev) 428 { 429 struct goldfish_tty *qtty = platform_get_drvdata(pdev); 430 431 mutex_lock(&goldfish_tty_lock); 432 433 unregister_console(&qtty->console); 434 tty_unregister_device(goldfish_tty_driver, qtty->console.index); 435 iounmap(qtty->base); 436 qtty->base = NULL; 437 free_irq(qtty->irq, pdev); 438 goldfish_tty_current_line_count--; 439 if (goldfish_tty_current_line_count == 0) 440 goldfish_tty_delete_driver(); 441 mutex_unlock(&goldfish_tty_lock); 442 return 0; 443 } 444 445 static void gf_early_console_putchar(struct uart_port *port, int ch) 446 { 447 __raw_writel(ch, port->membase); 448 } 449 450 static void gf_early_write(struct console *con, const char *s, unsigned int n) 451 { 452 struct earlycon_device *dev = con->data; 453 454 uart_console_write(&dev->port, s, n, gf_early_console_putchar); 455 } 456 457 static int __init gf_earlycon_setup(struct earlycon_device *device, 458 const char *opt) 459 { 460 if (!device->port.membase) 461 return -ENODEV; 462 463 device->con->write = gf_early_write; 464 return 0; 465 } 466 467 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup); 468 469 static const struct of_device_id goldfish_tty_of_match[] = { 470 { .compatible = "google,goldfish-tty", }, 471 {}, 472 }; 473 474 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match); 475 476 static struct platform_driver goldfish_tty_platform_driver = { 477 .probe = goldfish_tty_probe, 478 .remove = goldfish_tty_remove, 479 .driver = { 480 .name = "goldfish_tty", 481 .of_match_table = goldfish_tty_of_match, 482 } 483 }; 484 485 module_platform_driver(goldfish_tty_platform_driver); 486 487 MODULE_LICENSE("GPL v2"); 488