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