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 gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN); 65 66 if (is_write) 67 gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER, 68 base + GOLDFISH_TTY_REG_CMD); 69 else 70 gf_iowrite32(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 u8 *buf, 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 = gf_ioread32(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_flip_buffer_push(&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 gf_iowrite32(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 gf_iowrite32(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 ssize_t goldfish_tty_write(struct tty_struct *tty, const u8 *buf, 189 size_t count) 190 { 191 goldfish_tty_do_write(tty->index, buf, count); 192 return count; 193 } 194 195 static unsigned int goldfish_tty_write_room(struct tty_struct *tty) 196 { 197 return 0x10000; 198 } 199 200 static unsigned 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 gf_ioread32(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 = tty_alloc_driver(goldfish_tty_line_count, 256 TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | 257 TTY_DRIVER_DYNAMIC_DEV); 258 if (IS_ERR(tty)) { 259 ret = PTR_ERR(tty); 260 goto err_tty_alloc_driver_failed; 261 } 262 tty->driver_name = "goldfish"; 263 tty->name = "ttyGF"; 264 tty->type = TTY_DRIVER_TYPE_SERIAL; 265 tty->subtype = SERIAL_TYPE_NORMAL; 266 tty->init_termios = tty_std_termios; 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 tty_driver_kref_put(tty); 277 err_tty_alloc_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 tty_driver_kref_put(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 int 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 irq = platform_get_irq(pdev, 0); 316 if (irq < 0) { 317 ret = irq; 318 goto err_unmap; 319 } 320 321 mutex_lock(&goldfish_tty_lock); 322 323 if (pdev->id == PLATFORM_DEVID_NONE) 324 line = goldfish_tty_current_line_count; 325 else 326 line = pdev->id; 327 328 if (line >= goldfish_tty_line_count) { 329 pr_err("goldfish_tty: Reached maximum tty number of %d.\n", 330 goldfish_tty_current_line_count); 331 ret = -ENOMEM; 332 goto err_unlock; 333 } 334 335 if (goldfish_tty_current_line_count == 0) { 336 ret = goldfish_tty_create_driver(); 337 if (ret) 338 goto err_unlock; 339 } 340 goldfish_tty_current_line_count++; 341 342 qtty = &goldfish_ttys[line]; 343 spin_lock_init(&qtty->lock); 344 tty_port_init(&qtty->port); 345 qtty->port.ops = &goldfish_port_ops; 346 qtty->base = base; 347 qtty->irq = irq; 348 qtty->dev = &pdev->dev; 349 350 /* 351 * Goldfish TTY device used by the Goldfish emulator 352 * should identify itself with 0, forcing the driver 353 * to use virtual addresses. Goldfish TTY device 354 * on Ranchu emulator (qemu2) returns 1 here and 355 * driver will use physical addresses. 356 */ 357 qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION); 358 359 /* 360 * Goldfish TTY device on Ranchu emulator (qemu2) 361 * will use DMA for read/write IO operations. 362 */ 363 if (qtty->version > 0) { 364 /* 365 * Initialize dma_mask to 32-bits. 366 */ 367 if (!pdev->dev.dma_mask) 368 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; 369 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); 370 if (ret) { 371 dev_err(&pdev->dev, "No suitable DMA available.\n"); 372 goto err_dec_line_count; 373 } 374 } 375 376 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); 377 378 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, 379 "goldfish_tty", qtty); 380 if (ret) { 381 pr_err("goldfish_tty: No IRQ available!\n"); 382 goto err_dec_line_count; 383 } 384 385 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver, 386 line, &pdev->dev); 387 if (IS_ERR(ttydev)) { 388 ret = PTR_ERR(ttydev); 389 goto err_tty_register_device_failed; 390 } 391 392 strcpy(qtty->console.name, "ttyGF"); 393 qtty->console.write = goldfish_tty_console_write; 394 qtty->console.device = goldfish_tty_console_device; 395 qtty->console.setup = goldfish_tty_console_setup; 396 qtty->console.flags = CON_PRINTBUFFER; 397 qtty->console.index = line; 398 register_console(&qtty->console); 399 platform_set_drvdata(pdev, qtty); 400 401 mutex_unlock(&goldfish_tty_lock); 402 return 0; 403 404 err_tty_register_device_failed: 405 free_irq(irq, qtty); 406 err_dec_line_count: 407 tty_port_destroy(&qtty->port); 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, qtty); 429 tty_port_destroy(&qtty->port); 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, unsigned char ch) 439 { 440 gf_iowrite32(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