1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2007 Google, Inc. 4 * Copyright (C) 2012 Intel, Inc. 5 * Copyright (C) 2017 Imagination Technologies Ltd. 6 */ 7 8 #include <linux/console.h> 9 #include <linux/interrupt.h> 10 #include <linux/platform_device.h> 11 #include <linux/tty.h> 12 #include <linux/tty_flip.h> 13 #include <linux/slab.h> 14 #include <linux/io.h> 15 #include <linux/module.h> 16 #include <linux/goldfish.h> 17 #include <linux/mm.h> 18 #include <linux/dma-mapping.h> 19 #include <linux/serial_core.h> 20 21 /* Goldfish tty register's offsets */ 22 #define GOLDFISH_TTY_REG_BYTES_READY 0x04 23 #define GOLDFISH_TTY_REG_CMD 0x08 24 #define GOLDFISH_TTY_REG_DATA_PTR 0x10 25 #define GOLDFISH_TTY_REG_DATA_LEN 0x14 26 #define GOLDFISH_TTY_REG_DATA_PTR_HIGH 0x18 27 #define GOLDFISH_TTY_REG_VERSION 0x20 28 29 /* Goldfish tty commands */ 30 #define GOLDFISH_TTY_CMD_INT_DISABLE 0 31 #define GOLDFISH_TTY_CMD_INT_ENABLE 1 32 #define GOLDFISH_TTY_CMD_WRITE_BUFFER 2 33 #define GOLDFISH_TTY_CMD_READ_BUFFER 3 34 35 struct goldfish_tty { 36 struct tty_port port; 37 spinlock_t lock; 38 void __iomem *base; 39 u32 irq; 40 int opencount; 41 struct console console; 42 u32 version; 43 struct device *dev; 44 }; 45 46 static DEFINE_MUTEX(goldfish_tty_lock); 47 static struct tty_driver *goldfish_tty_driver; 48 static u32 goldfish_tty_line_count = 8; 49 static u32 goldfish_tty_current_line_count; 50 static struct goldfish_tty *goldfish_ttys; 51 52 static void do_rw_io(struct goldfish_tty *qtty, 53 unsigned long address, 54 unsigned int count, 55 int is_write) 56 { 57 unsigned long irq_flags; 58 void __iomem *base = qtty->base; 59 60 spin_lock_irqsave(&qtty->lock, irq_flags); 61 gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR, 62 base + GOLDFISH_TTY_REG_DATA_PTR_HIGH); 63 writel(count, base + GOLDFISH_TTY_REG_DATA_LEN); 64 65 if (is_write) 66 writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, 67 base + GOLDFISH_TTY_REG_CMD); 68 else 69 writel(GOLDFISH_TTY_CMD_READ_BUFFER, 70 base + GOLDFISH_TTY_REG_CMD); 71 72 spin_unlock_irqrestore(&qtty->lock, irq_flags); 73 } 74 75 static void goldfish_tty_rw(struct goldfish_tty *qtty, 76 unsigned long addr, 77 unsigned int count, 78 int is_write) 79 { 80 dma_addr_t dma_handle; 81 enum dma_data_direction dma_dir; 82 83 dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); 84 if (qtty->version > 0) { 85 /* 86 * Goldfish TTY for Ranchu platform uses 87 * physical addresses and DMA for read/write operations 88 */ 89 unsigned long addr_end = addr + count; 90 91 while (addr < addr_end) { 92 unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE; 93 unsigned long next = 94 pg_end < addr_end ? pg_end : addr_end; 95 unsigned long avail = next - addr; 96 97 /* 98 * Map the buffer's virtual address to the DMA address 99 * so the buffer can be accessed by the device. 100 */ 101 dma_handle = dma_map_single(qtty->dev, (void *)addr, 102 avail, dma_dir); 103 104 if (dma_mapping_error(qtty->dev, dma_handle)) { 105 dev_err(qtty->dev, "tty: DMA mapping error.\n"); 106 return; 107 } 108 do_rw_io(qtty, dma_handle, avail, is_write); 109 110 /* 111 * Unmap the previously mapped region after 112 * the completion of the read/write operation. 113 */ 114 dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir); 115 116 addr += avail; 117 } 118 } else { 119 /* 120 * Old style Goldfish TTY used on the Goldfish platform 121 * uses virtual addresses. 122 */ 123 do_rw_io(qtty, addr, count, is_write); 124 } 125 } 126 127 static void goldfish_tty_do_write(int line, const char *buf, 128 unsigned int count) 129 { 130 struct goldfish_tty *qtty = &goldfish_ttys[line]; 131 unsigned long address = (unsigned long)(void *)buf; 132 133 goldfish_tty_rw(qtty, address, count, 1); 134 } 135 136 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id) 137 { 138 struct goldfish_tty *qtty = dev_id; 139 void __iomem *base = qtty->base; 140 unsigned long address; 141 unsigned char *buf; 142 u32 count; 143 144 count = readl(base + GOLDFISH_TTY_REG_BYTES_READY); 145 if (count == 0) 146 return IRQ_NONE; 147 148 count = tty_prepare_flip_string(&qtty->port, &buf, count); 149 150 address = (unsigned long)(void *)buf; 151 goldfish_tty_rw(qtty, address, count, 0); 152 153 tty_schedule_flip(&qtty->port); 154 return IRQ_HANDLED; 155 } 156 157 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty) 158 { 159 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 160 port); 161 writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 162 return 0; 163 } 164 165 static void goldfish_tty_shutdown(struct tty_port *port) 166 { 167 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 168 port); 169 writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 170 } 171 172 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp) 173 { 174 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 175 return tty_port_open(&qtty->port, tty, filp); 176 } 177 178 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) 179 { 180 tty_port_close(tty->port, tty, filp); 181 } 182 183 static void goldfish_tty_hangup(struct tty_struct *tty) 184 { 185 tty_port_hangup(tty->port); 186 } 187 188 static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf, 189 int count) 190 { 191 goldfish_tty_do_write(tty->index, buf, count); 192 return count; 193 } 194 195 static int goldfish_tty_write_room(struct tty_struct *tty) 196 { 197 return 0x10000; 198 } 199 200 static int goldfish_tty_chars_in_buffer(struct tty_struct *tty) 201 { 202 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 203 void __iomem *base = qtty->base; 204 return readl(base + GOLDFISH_TTY_REG_BYTES_READY); 205 } 206 207 static void goldfish_tty_console_write(struct console *co, const char *b, 208 unsigned count) 209 { 210 goldfish_tty_do_write(co->index, b, count); 211 } 212 213 static struct tty_driver *goldfish_tty_console_device(struct console *c, 214 int *index) 215 { 216 *index = c->index; 217 return goldfish_tty_driver; 218 } 219 220 static int goldfish_tty_console_setup(struct console *co, char *options) 221 { 222 if ((unsigned)co->index >= goldfish_tty_line_count) 223 return -ENODEV; 224 if (!goldfish_ttys[co->index].base) 225 return -ENODEV; 226 return 0; 227 } 228 229 static const struct tty_port_operations goldfish_port_ops = { 230 .activate = goldfish_tty_activate, 231 .shutdown = goldfish_tty_shutdown 232 }; 233 234 static const struct tty_operations goldfish_tty_ops = { 235 .open = goldfish_tty_open, 236 .close = goldfish_tty_close, 237 .hangup = goldfish_tty_hangup, 238 .write = goldfish_tty_write, 239 .write_room = goldfish_tty_write_room, 240 .chars_in_buffer = goldfish_tty_chars_in_buffer, 241 }; 242 243 static int goldfish_tty_create_driver(void) 244 { 245 int ret; 246 struct tty_driver *tty; 247 248 goldfish_ttys = kcalloc(goldfish_tty_line_count, 249 sizeof(*goldfish_ttys), 250 GFP_KERNEL); 251 if (goldfish_ttys == NULL) { 252 ret = -ENOMEM; 253 goto err_alloc_goldfish_ttys_failed; 254 } 255 tty = alloc_tty_driver(goldfish_tty_line_count); 256 if (tty == NULL) { 257 ret = -ENOMEM; 258 goto err_alloc_tty_driver_failed; 259 } 260 tty->driver_name = "goldfish"; 261 tty->name = "ttyGF"; 262 tty->type = TTY_DRIVER_TYPE_SERIAL; 263 tty->subtype = SERIAL_TYPE_NORMAL; 264 tty->init_termios = tty_std_termios; 265 tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | 266 TTY_DRIVER_DYNAMIC_DEV; 267 tty_set_operations(tty, &goldfish_tty_ops); 268 ret = tty_register_driver(tty); 269 if (ret) 270 goto err_tty_register_driver_failed; 271 272 goldfish_tty_driver = tty; 273 return 0; 274 275 err_tty_register_driver_failed: 276 put_tty_driver(tty); 277 err_alloc_tty_driver_failed: 278 kfree(goldfish_ttys); 279 goldfish_ttys = NULL; 280 err_alloc_goldfish_ttys_failed: 281 return ret; 282 } 283 284 static void goldfish_tty_delete_driver(void) 285 { 286 tty_unregister_driver(goldfish_tty_driver); 287 put_tty_driver(goldfish_tty_driver); 288 goldfish_tty_driver = NULL; 289 kfree(goldfish_ttys); 290 goldfish_ttys = NULL; 291 } 292 293 static int goldfish_tty_probe(struct platform_device *pdev) 294 { 295 struct goldfish_tty *qtty; 296 int ret = -ENODEV; 297 struct resource *r; 298 struct device *ttydev; 299 void __iomem *base; 300 u32 irq; 301 unsigned int line; 302 303 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 304 if (!r) { 305 pr_err("goldfish_tty: No MEM resource available!\n"); 306 return -ENOMEM; 307 } 308 309 base = ioremap(r->start, 0x1000); 310 if (!base) { 311 pr_err("goldfish_tty: Unable to ioremap base!\n"); 312 return -ENOMEM; 313 } 314 315 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 316 if (!r) { 317 pr_err("goldfish_tty: No IRQ resource available!\n"); 318 goto err_unmap; 319 } 320 321 irq = r->start; 322 323 mutex_lock(&goldfish_tty_lock); 324 325 if (pdev->id == PLATFORM_DEVID_NONE) 326 line = goldfish_tty_current_line_count; 327 else 328 line = pdev->id; 329 330 if (line >= goldfish_tty_line_count) { 331 pr_err("goldfish_tty: Reached maximum tty number of %d.\n", 332 goldfish_tty_current_line_count); 333 ret = -ENOMEM; 334 goto err_unlock; 335 } 336 337 if (goldfish_tty_current_line_count == 0) { 338 ret = goldfish_tty_create_driver(); 339 if (ret) 340 goto err_unlock; 341 } 342 goldfish_tty_current_line_count++; 343 344 qtty = &goldfish_ttys[line]; 345 spin_lock_init(&qtty->lock); 346 tty_port_init(&qtty->port); 347 qtty->port.ops = &goldfish_port_ops; 348 qtty->base = base; 349 qtty->irq = irq; 350 qtty->dev = &pdev->dev; 351 352 /* 353 * Goldfish TTY device used by the Goldfish emulator 354 * should identify itself with 0, forcing the driver 355 * to use virtual addresses. Goldfish TTY device 356 * on Ranchu emulator (qemu2) returns 1 here and 357 * driver will use physical addresses. 358 */ 359 qtty->version = readl(base + GOLDFISH_TTY_REG_VERSION); 360 361 /* 362 * Goldfish TTY device on Ranchu emulator (qemu2) 363 * will use DMA for read/write IO operations. 364 */ 365 if (qtty->version > 0) { 366 /* 367 * Initialize dma_mask to 32-bits. 368 */ 369 if (!pdev->dev.dma_mask) 370 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; 371 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); 372 if (ret) { 373 dev_err(&pdev->dev, "No suitable DMA available.\n"); 374 goto err_dec_line_count; 375 } 376 } 377 378 writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); 379 380 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, 381 "goldfish_tty", qtty); 382 if (ret) { 383 pr_err("goldfish_tty: No IRQ available!\n"); 384 goto err_dec_line_count; 385 } 386 387 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver, 388 line, &pdev->dev); 389 if (IS_ERR(ttydev)) { 390 ret = PTR_ERR(ttydev); 391 goto err_tty_register_device_failed; 392 } 393 394 strcpy(qtty->console.name, "ttyGF"); 395 qtty->console.write = goldfish_tty_console_write; 396 qtty->console.device = goldfish_tty_console_device; 397 qtty->console.setup = goldfish_tty_console_setup; 398 qtty->console.flags = CON_PRINTBUFFER; 399 qtty->console.index = line; 400 register_console(&qtty->console); 401 platform_set_drvdata(pdev, qtty); 402 403 mutex_unlock(&goldfish_tty_lock); 404 return 0; 405 406 err_tty_register_device_failed: 407 free_irq(irq, qtty); 408 err_dec_line_count: 409 goldfish_tty_current_line_count--; 410 if (goldfish_tty_current_line_count == 0) 411 goldfish_tty_delete_driver(); 412 err_unlock: 413 mutex_unlock(&goldfish_tty_lock); 414 err_unmap: 415 iounmap(base); 416 return ret; 417 } 418 419 static int goldfish_tty_remove(struct platform_device *pdev) 420 { 421 struct goldfish_tty *qtty = platform_get_drvdata(pdev); 422 423 mutex_lock(&goldfish_tty_lock); 424 425 unregister_console(&qtty->console); 426 tty_unregister_device(goldfish_tty_driver, qtty->console.index); 427 iounmap(qtty->base); 428 qtty->base = NULL; 429 free_irq(qtty->irq, pdev); 430 goldfish_tty_current_line_count--; 431 if (goldfish_tty_current_line_count == 0) 432 goldfish_tty_delete_driver(); 433 mutex_unlock(&goldfish_tty_lock); 434 return 0; 435 } 436 437 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE 438 static void gf_early_console_putchar(struct uart_port *port, int ch) 439 { 440 __raw_writel(ch, port->membase); 441 } 442 443 static void gf_early_write(struct console *con, const char *s, unsigned int n) 444 { 445 struct earlycon_device *dev = con->data; 446 447 uart_console_write(&dev->port, s, n, gf_early_console_putchar); 448 } 449 450 static int __init gf_earlycon_setup(struct earlycon_device *device, 451 const char *opt) 452 { 453 if (!device->port.membase) 454 return -ENODEV; 455 456 device->con->write = gf_early_write; 457 return 0; 458 } 459 460 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup); 461 #endif 462 463 static const struct of_device_id goldfish_tty_of_match[] = { 464 { .compatible = "google,goldfish-tty", }, 465 {}, 466 }; 467 468 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match); 469 470 static struct platform_driver goldfish_tty_platform_driver = { 471 .probe = goldfish_tty_probe, 472 .remove = goldfish_tty_remove, 473 .driver = { 474 .name = "goldfish_tty", 475 .of_match_table = goldfish_tty_of_match, 476 } 477 }; 478 479 module_platform_driver(goldfish_tty_platform_driver); 480 481 MODULE_LICENSE("GPL v2"); 482