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 #include <linux/wordpart.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 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 inline void gf_write_addr(unsigned long addr, void __iomem *portl, void __iomem *porth) 53 { 54 gf_iowrite32(lower_32_bits(addr), portl); 55 #ifdef CONFIG_64BIT 56 gf_iowrite32(upper_32_bits(addr), porth); 57 #endif 58 } 59 60 static void do_rw_io(struct goldfish_tty *qtty, unsigned long address, 61 size_t count, bool is_write) 62 { 63 void __iomem *base = qtty->base; 64 65 guard(spinlock_irqsave)(&qtty->lock); 66 67 gf_write_addr(address, base + GOLDFISH_TTY_REG_DATA_PTR, 68 base + GOLDFISH_TTY_REG_DATA_PTR_HIGH); 69 gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN); 70 71 if (is_write) 72 gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER, 73 base + GOLDFISH_TTY_REG_CMD); 74 else 75 gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER, 76 base + GOLDFISH_TTY_REG_CMD); 77 } 78 79 static void goldfish_tty_rw(struct goldfish_tty *qtty, unsigned long addr, 80 size_t count, bool is_write) 81 { 82 dma_addr_t dma_handle; 83 enum dma_data_direction dma_dir; 84 85 dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); 86 if (qtty->version > 0) { 87 /* 88 * Goldfish TTY for Ranchu platform uses 89 * physical addresses and DMA for read/write operations 90 */ 91 unsigned long addr_end = addr + count; 92 93 while (addr < addr_end) { 94 unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE; 95 unsigned long next = 96 pg_end < addr_end ? pg_end : addr_end; 97 unsigned long avail = next - addr; 98 99 /* 100 * Map the buffer's virtual address to the DMA address 101 * so the buffer can be accessed by the device. 102 */ 103 dma_handle = dma_map_single(qtty->dev, (void *)addr, 104 avail, dma_dir); 105 106 if (dma_mapping_error(qtty->dev, dma_handle)) { 107 dev_err(qtty->dev, "tty: DMA mapping error.\n"); 108 return; 109 } 110 do_rw_io(qtty, dma_handle, avail, is_write); 111 112 /* 113 * Unmap the previously mapped region after 114 * the completion of the read/write operation. 115 */ 116 dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir); 117 118 addr += avail; 119 } 120 } else { 121 /* 122 * Old style Goldfish TTY used on the Goldfish platform 123 * uses virtual addresses. 124 */ 125 do_rw_io(qtty, addr, count, is_write); 126 } 127 } 128 129 static void goldfish_tty_do_write(int line, const u8 *buf, size_t count) 130 { 131 struct goldfish_tty *qtty = &goldfish_ttys[line]; 132 133 goldfish_tty_rw(qtty, (unsigned long)buf, count, true); 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 u8 *buf; 141 u32 count; 142 143 count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY); 144 if (count == 0) 145 return IRQ_NONE; 146 147 count = tty_prepare_flip_string(&qtty->port, &buf, count); 148 149 goldfish_tty_rw(qtty, (unsigned long)buf, count, false); 150 151 tty_flip_buffer_push(&qtty->port); 152 return IRQ_HANDLED; 153 } 154 155 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty) 156 { 157 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 158 port); 159 gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 160 return 0; 161 } 162 163 static void goldfish_tty_shutdown(struct tty_port *port) 164 { 165 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 166 port); 167 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 168 } 169 170 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp) 171 { 172 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 173 return tty_port_open(&qtty->port, tty, filp); 174 } 175 176 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) 177 { 178 tty_port_close(tty->port, tty, filp); 179 } 180 181 static void goldfish_tty_hangup(struct tty_struct *tty) 182 { 183 tty_port_hangup(tty->port); 184 } 185 186 static ssize_t goldfish_tty_write(struct tty_struct *tty, const u8 *buf, 187 size_t count) 188 { 189 goldfish_tty_do_write(tty->index, buf, count); 190 return count; 191 } 192 193 static unsigned int goldfish_tty_write_room(struct tty_struct *tty) 194 { 195 return 0x10000; 196 } 197 198 static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty) 199 { 200 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 201 void __iomem *base = qtty->base; 202 return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY); 203 } 204 205 static void goldfish_tty_console_write(struct console *co, const char *b, 206 unsigned count) 207 { 208 goldfish_tty_do_write(co->index, b, count); 209 } 210 211 static struct tty_driver *goldfish_tty_console_device(struct console *c, 212 int *index) 213 { 214 *index = c->index; 215 return goldfish_tty_driver; 216 } 217 218 static int goldfish_tty_console_setup(struct console *co, char *options) 219 { 220 if ((unsigned)co->index >= goldfish_tty_line_count) 221 return -ENODEV; 222 if (!goldfish_ttys[co->index].base) 223 return -ENODEV; 224 return 0; 225 } 226 227 static const struct tty_port_operations goldfish_port_ops = { 228 .activate = goldfish_tty_activate, 229 .shutdown = goldfish_tty_shutdown 230 }; 231 232 static const struct tty_operations goldfish_tty_ops = { 233 .open = goldfish_tty_open, 234 .close = goldfish_tty_close, 235 .hangup = goldfish_tty_hangup, 236 .write = goldfish_tty_write, 237 .write_room = goldfish_tty_write_room, 238 .chars_in_buffer = goldfish_tty_chars_in_buffer, 239 }; 240 241 static int goldfish_tty_create_driver(void) 242 { 243 int ret; 244 struct tty_driver *tty; 245 246 goldfish_ttys = kzalloc_objs(*goldfish_ttys, goldfish_tty_line_count); 247 if (goldfish_ttys == NULL) { 248 ret = -ENOMEM; 249 goto err_alloc_goldfish_ttys_failed; 250 } 251 tty = tty_alloc_driver(goldfish_tty_line_count, 252 TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | 253 TTY_DRIVER_DYNAMIC_DEV); 254 if (IS_ERR(tty)) { 255 ret = PTR_ERR(tty); 256 goto err_tty_alloc_driver_failed; 257 } 258 tty->driver_name = "goldfish"; 259 tty->name = "ttyGF"; 260 tty->type = TTY_DRIVER_TYPE_SERIAL; 261 tty->subtype = SERIAL_TYPE_NORMAL; 262 tty->init_termios = tty_std_termios; 263 tty_set_operations(tty, &goldfish_tty_ops); 264 ret = tty_register_driver(tty); 265 if (ret) 266 goto err_tty_register_driver_failed; 267 268 goldfish_tty_driver = tty; 269 return 0; 270 271 err_tty_register_driver_failed: 272 tty_driver_kref_put(tty); 273 err_tty_alloc_driver_failed: 274 kfree(goldfish_ttys); 275 goldfish_ttys = NULL; 276 err_alloc_goldfish_ttys_failed: 277 return ret; 278 } 279 280 static void goldfish_tty_delete_driver(void) 281 { 282 tty_unregister_driver(goldfish_tty_driver); 283 tty_driver_kref_put(goldfish_tty_driver); 284 goldfish_tty_driver = NULL; 285 kfree(goldfish_ttys); 286 goldfish_ttys = NULL; 287 } 288 289 static int goldfish_tty_probe(struct platform_device *pdev) 290 { 291 struct goldfish_tty *qtty; 292 int ret = -ENODEV; 293 struct resource *r; 294 struct device *ttydev; 295 void __iomem *base; 296 int irq; 297 unsigned int line; 298 299 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 300 if (!r) { 301 pr_err("goldfish_tty: No MEM resource available!\n"); 302 return -ENOMEM; 303 } 304 305 base = ioremap(r->start, 0x1000); 306 if (!base) { 307 pr_err("goldfish_tty: Unable to ioremap base!\n"); 308 return -ENOMEM; 309 } 310 311 irq = platform_get_irq(pdev, 0); 312 if (irq < 0) { 313 ret = irq; 314 goto err_unmap; 315 } 316 317 mutex_lock(&goldfish_tty_lock); 318 319 if (pdev->id == PLATFORM_DEVID_NONE) 320 line = goldfish_tty_current_line_count; 321 else 322 line = pdev->id; 323 324 if (line >= goldfish_tty_line_count) { 325 pr_err("goldfish_tty: Reached maximum tty number of %d.\n", 326 goldfish_tty_current_line_count); 327 ret = -ENOMEM; 328 goto err_unlock; 329 } 330 331 if (goldfish_tty_current_line_count == 0) { 332 ret = goldfish_tty_create_driver(); 333 if (ret) 334 goto err_unlock; 335 } 336 goldfish_tty_current_line_count++; 337 338 qtty = &goldfish_ttys[line]; 339 spin_lock_init(&qtty->lock); 340 tty_port_init(&qtty->port); 341 qtty->port.ops = &goldfish_port_ops; 342 qtty->base = base; 343 qtty->irq = irq; 344 qtty->dev = &pdev->dev; 345 346 /* 347 * Goldfish TTY device used by the Goldfish emulator 348 * should identify itself with 0, forcing the driver 349 * to use virtual addresses. Goldfish TTY device 350 * on Ranchu emulator (qemu2) returns 1 here and 351 * driver will use physical addresses. 352 */ 353 qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION); 354 355 /* 356 * Goldfish TTY device on Ranchu emulator (qemu2) 357 * will use DMA for read/write IO operations. 358 */ 359 if (qtty->version > 0) { 360 /* 361 * Initialize dma_mask to 32-bits. 362 */ 363 if (!pdev->dev.dma_mask) 364 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; 365 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); 366 if (ret) { 367 dev_err(&pdev->dev, "No suitable DMA available.\n"); 368 goto err_dec_line_count; 369 } 370 } 371 372 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); 373 374 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, 375 "goldfish_tty", qtty); 376 if (ret) { 377 pr_err("goldfish_tty: No IRQ available!\n"); 378 goto err_dec_line_count; 379 } 380 381 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver, 382 line, &pdev->dev); 383 if (IS_ERR(ttydev)) { 384 ret = PTR_ERR(ttydev); 385 goto err_tty_register_device_failed; 386 } 387 388 strcpy(qtty->console.name, "ttyGF"); 389 qtty->console.write = goldfish_tty_console_write; 390 qtty->console.device = goldfish_tty_console_device; 391 qtty->console.setup = goldfish_tty_console_setup; 392 qtty->console.flags = CON_PRINTBUFFER; 393 qtty->console.index = line; 394 register_console(&qtty->console); 395 platform_set_drvdata(pdev, qtty); 396 397 mutex_unlock(&goldfish_tty_lock); 398 return 0; 399 400 err_tty_register_device_failed: 401 free_irq(irq, qtty); 402 err_dec_line_count: 403 tty_port_destroy(&qtty->port); 404 goldfish_tty_current_line_count--; 405 if (goldfish_tty_current_line_count == 0) 406 goldfish_tty_delete_driver(); 407 err_unlock: 408 mutex_unlock(&goldfish_tty_lock); 409 err_unmap: 410 iounmap(base); 411 return ret; 412 } 413 414 static void goldfish_tty_remove(struct platform_device *pdev) 415 { 416 struct goldfish_tty *qtty = platform_get_drvdata(pdev); 417 418 guard(mutex)(&goldfish_tty_lock); 419 420 unregister_console(&qtty->console); 421 tty_unregister_device(goldfish_tty_driver, qtty->console.index); 422 iounmap(qtty->base); 423 qtty->base = NULL; 424 free_irq(qtty->irq, qtty); 425 tty_port_destroy(&qtty->port); 426 goldfish_tty_current_line_count--; 427 if (goldfish_tty_current_line_count == 0) 428 goldfish_tty_delete_driver(); 429 } 430 431 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE 432 static void gf_early_console_putchar(struct uart_port *port, unsigned char ch) 433 { 434 gf_iowrite32(ch, port->membase); 435 } 436 437 static void gf_early_write(struct console *con, const char *s, unsigned int n) 438 { 439 struct earlycon_device *dev = con->data; 440 441 uart_console_write(&dev->port, s, n, gf_early_console_putchar); 442 } 443 444 static int __init gf_earlycon_setup(struct earlycon_device *device, 445 const char *opt) 446 { 447 if (!device->port.membase) 448 return -ENODEV; 449 450 device->con->write = gf_early_write; 451 return 0; 452 } 453 454 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup); 455 #endif 456 457 static const struct of_device_id goldfish_tty_of_match[] = { 458 { .compatible = "google,goldfish-tty", }, 459 {}, 460 }; 461 462 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match); 463 464 static struct platform_driver goldfish_tty_platform_driver = { 465 .probe = goldfish_tty_probe, 466 .remove = goldfish_tty_remove, 467 .driver = { 468 .name = "goldfish_tty", 469 .of_match_table = goldfish_tty_of_match, 470 } 471 }; 472 473 module_platform_driver(goldfish_tty_platform_driver); 474 475 MODULE_DESCRIPTION("Goldfish TTY Driver"); 476 MODULE_LICENSE("GPL v2"); 477