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, unsigned long address, 54 size_t count, bool is_write) 55 { 56 unsigned long irq_flags; 57 void __iomem *base = qtty->base; 58 59 spin_lock_irqsave(&qtty->lock, irq_flags); 60 gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR, 61 base + GOLDFISH_TTY_REG_DATA_PTR_HIGH); 62 gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN); 63 64 if (is_write) 65 gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER, 66 base + GOLDFISH_TTY_REG_CMD); 67 else 68 gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER, 69 base + GOLDFISH_TTY_REG_CMD); 70 71 spin_unlock_irqrestore(&qtty->lock, irq_flags); 72 } 73 74 static void goldfish_tty_rw(struct goldfish_tty *qtty, unsigned long addr, 75 size_t count, bool is_write) 76 { 77 dma_addr_t dma_handle; 78 enum dma_data_direction dma_dir; 79 80 dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); 81 if (qtty->version > 0) { 82 /* 83 * Goldfish TTY for Ranchu platform uses 84 * physical addresses and DMA for read/write operations 85 */ 86 unsigned long addr_end = addr + count; 87 88 while (addr < addr_end) { 89 unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE; 90 unsigned long next = 91 pg_end < addr_end ? pg_end : addr_end; 92 unsigned long avail = next - addr; 93 94 /* 95 * Map the buffer's virtual address to the DMA address 96 * so the buffer can be accessed by the device. 97 */ 98 dma_handle = dma_map_single(qtty->dev, (void *)addr, 99 avail, dma_dir); 100 101 if (dma_mapping_error(qtty->dev, dma_handle)) { 102 dev_err(qtty->dev, "tty: DMA mapping error.\n"); 103 return; 104 } 105 do_rw_io(qtty, dma_handle, avail, is_write); 106 107 /* 108 * Unmap the previously mapped region after 109 * the completion of the read/write operation. 110 */ 111 dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir); 112 113 addr += avail; 114 } 115 } else { 116 /* 117 * Old style Goldfish TTY used on the Goldfish platform 118 * uses virtual addresses. 119 */ 120 do_rw_io(qtty, addr, count, is_write); 121 } 122 } 123 124 static void goldfish_tty_do_write(int line, const u8 *buf, size_t count) 125 { 126 struct goldfish_tty *qtty = &goldfish_ttys[line]; 127 128 goldfish_tty_rw(qtty, (unsigned long)buf, count, true); 129 } 130 131 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id) 132 { 133 struct goldfish_tty *qtty = dev_id; 134 void __iomem *base = qtty->base; 135 u8 *buf; 136 u32 count; 137 138 count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY); 139 if (count == 0) 140 return IRQ_NONE; 141 142 count = tty_prepare_flip_string(&qtty->port, &buf, count); 143 144 goldfish_tty_rw(qtty, (unsigned long)buf, count, false); 145 146 tty_flip_buffer_push(&qtty->port); 147 return IRQ_HANDLED; 148 } 149 150 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty) 151 { 152 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 153 port); 154 gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 155 return 0; 156 } 157 158 static void goldfish_tty_shutdown(struct tty_port *port) 159 { 160 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, 161 port); 162 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD); 163 } 164 165 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp) 166 { 167 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 168 return tty_port_open(&qtty->port, tty, filp); 169 } 170 171 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) 172 { 173 tty_port_close(tty->port, tty, filp); 174 } 175 176 static void goldfish_tty_hangup(struct tty_struct *tty) 177 { 178 tty_port_hangup(tty->port); 179 } 180 181 static ssize_t goldfish_tty_write(struct tty_struct *tty, const u8 *buf, 182 size_t count) 183 { 184 goldfish_tty_do_write(tty->index, buf, count); 185 return count; 186 } 187 188 static unsigned int goldfish_tty_write_room(struct tty_struct *tty) 189 { 190 return 0x10000; 191 } 192 193 static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty) 194 { 195 struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; 196 void __iomem *base = qtty->base; 197 return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY); 198 } 199 200 static void goldfish_tty_console_write(struct console *co, const char *b, 201 unsigned count) 202 { 203 goldfish_tty_do_write(co->index, b, count); 204 } 205 206 static struct tty_driver *goldfish_tty_console_device(struct console *c, 207 int *index) 208 { 209 *index = c->index; 210 return goldfish_tty_driver; 211 } 212 213 static int goldfish_tty_console_setup(struct console *co, char *options) 214 { 215 if ((unsigned)co->index >= goldfish_tty_line_count) 216 return -ENODEV; 217 if (!goldfish_ttys[co->index].base) 218 return -ENODEV; 219 return 0; 220 } 221 222 static const struct tty_port_operations goldfish_port_ops = { 223 .activate = goldfish_tty_activate, 224 .shutdown = goldfish_tty_shutdown 225 }; 226 227 static const struct tty_operations goldfish_tty_ops = { 228 .open = goldfish_tty_open, 229 .close = goldfish_tty_close, 230 .hangup = goldfish_tty_hangup, 231 .write = goldfish_tty_write, 232 .write_room = goldfish_tty_write_room, 233 .chars_in_buffer = goldfish_tty_chars_in_buffer, 234 }; 235 236 static int goldfish_tty_create_driver(void) 237 { 238 int ret; 239 struct tty_driver *tty; 240 241 goldfish_ttys = kzalloc_objs(*goldfish_ttys, goldfish_tty_line_count); 242 if (goldfish_ttys == NULL) { 243 ret = -ENOMEM; 244 goto err_alloc_goldfish_ttys_failed; 245 } 246 tty = tty_alloc_driver(goldfish_tty_line_count, 247 TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | 248 TTY_DRIVER_DYNAMIC_DEV); 249 if (IS_ERR(tty)) { 250 ret = PTR_ERR(tty); 251 goto err_tty_alloc_driver_failed; 252 } 253 tty->driver_name = "goldfish"; 254 tty->name = "ttyGF"; 255 tty->type = TTY_DRIVER_TYPE_SERIAL; 256 tty->subtype = SERIAL_TYPE_NORMAL; 257 tty->init_termios = tty_std_termios; 258 tty_set_operations(tty, &goldfish_tty_ops); 259 ret = tty_register_driver(tty); 260 if (ret) 261 goto err_tty_register_driver_failed; 262 263 goldfish_tty_driver = tty; 264 return 0; 265 266 err_tty_register_driver_failed: 267 tty_driver_kref_put(tty); 268 err_tty_alloc_driver_failed: 269 kfree(goldfish_ttys); 270 goldfish_ttys = NULL; 271 err_alloc_goldfish_ttys_failed: 272 return ret; 273 } 274 275 static void goldfish_tty_delete_driver(void) 276 { 277 tty_unregister_driver(goldfish_tty_driver); 278 tty_driver_kref_put(goldfish_tty_driver); 279 goldfish_tty_driver = NULL; 280 kfree(goldfish_ttys); 281 goldfish_ttys = NULL; 282 } 283 284 static int goldfish_tty_probe(struct platform_device *pdev) 285 { 286 struct goldfish_tty *qtty; 287 int ret = -ENODEV; 288 struct resource *r; 289 struct device *ttydev; 290 void __iomem *base; 291 int irq; 292 unsigned int line; 293 294 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 295 if (!r) { 296 pr_err("goldfish_tty: No MEM resource available!\n"); 297 return -ENOMEM; 298 } 299 300 base = ioremap(r->start, 0x1000); 301 if (!base) { 302 pr_err("goldfish_tty: Unable to ioremap base!\n"); 303 return -ENOMEM; 304 } 305 306 irq = platform_get_irq(pdev, 0); 307 if (irq < 0) { 308 ret = irq; 309 goto err_unmap; 310 } 311 312 mutex_lock(&goldfish_tty_lock); 313 314 if (pdev->id == PLATFORM_DEVID_NONE) 315 line = goldfish_tty_current_line_count; 316 else 317 line = pdev->id; 318 319 if (line >= goldfish_tty_line_count) { 320 pr_err("goldfish_tty: Reached maximum tty number of %d.\n", 321 goldfish_tty_current_line_count); 322 ret = -ENOMEM; 323 goto err_unlock; 324 } 325 326 if (goldfish_tty_current_line_count == 0) { 327 ret = goldfish_tty_create_driver(); 328 if (ret) 329 goto err_unlock; 330 } 331 goldfish_tty_current_line_count++; 332 333 qtty = &goldfish_ttys[line]; 334 spin_lock_init(&qtty->lock); 335 tty_port_init(&qtty->port); 336 qtty->port.ops = &goldfish_port_ops; 337 qtty->base = base; 338 qtty->irq = irq; 339 qtty->dev = &pdev->dev; 340 341 /* 342 * Goldfish TTY device used by the Goldfish emulator 343 * should identify itself with 0, forcing the driver 344 * to use virtual addresses. Goldfish TTY device 345 * on Ranchu emulator (qemu2) returns 1 here and 346 * driver will use physical addresses. 347 */ 348 qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION); 349 350 /* 351 * Goldfish TTY device on Ranchu emulator (qemu2) 352 * will use DMA for read/write IO operations. 353 */ 354 if (qtty->version > 0) { 355 /* 356 * Initialize dma_mask to 32-bits. 357 */ 358 if (!pdev->dev.dma_mask) 359 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; 360 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); 361 if (ret) { 362 dev_err(&pdev->dev, "No suitable DMA available.\n"); 363 goto err_dec_line_count; 364 } 365 } 366 367 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); 368 369 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, 370 "goldfish_tty", qtty); 371 if (ret) { 372 pr_err("goldfish_tty: No IRQ available!\n"); 373 goto err_dec_line_count; 374 } 375 376 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver, 377 line, &pdev->dev); 378 if (IS_ERR(ttydev)) { 379 ret = PTR_ERR(ttydev); 380 goto err_tty_register_device_failed; 381 } 382 383 strcpy(qtty->console.name, "ttyGF"); 384 qtty->console.write = goldfish_tty_console_write; 385 qtty->console.device = goldfish_tty_console_device; 386 qtty->console.setup = goldfish_tty_console_setup; 387 qtty->console.flags = CON_PRINTBUFFER; 388 qtty->console.index = line; 389 register_console(&qtty->console); 390 platform_set_drvdata(pdev, qtty); 391 392 mutex_unlock(&goldfish_tty_lock); 393 return 0; 394 395 err_tty_register_device_failed: 396 free_irq(irq, qtty); 397 err_dec_line_count: 398 tty_port_destroy(&qtty->port); 399 goldfish_tty_current_line_count--; 400 if (goldfish_tty_current_line_count == 0) 401 goldfish_tty_delete_driver(); 402 err_unlock: 403 mutex_unlock(&goldfish_tty_lock); 404 err_unmap: 405 iounmap(base); 406 return ret; 407 } 408 409 static void goldfish_tty_remove(struct platform_device *pdev) 410 { 411 struct goldfish_tty *qtty = platform_get_drvdata(pdev); 412 413 mutex_lock(&goldfish_tty_lock); 414 415 unregister_console(&qtty->console); 416 tty_unregister_device(goldfish_tty_driver, qtty->console.index); 417 iounmap(qtty->base); 418 qtty->base = NULL; 419 free_irq(qtty->irq, qtty); 420 tty_port_destroy(&qtty->port); 421 goldfish_tty_current_line_count--; 422 if (goldfish_tty_current_line_count == 0) 423 goldfish_tty_delete_driver(); 424 mutex_unlock(&goldfish_tty_lock); 425 } 426 427 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE 428 static void gf_early_console_putchar(struct uart_port *port, unsigned char ch) 429 { 430 gf_iowrite32(ch, port->membase); 431 } 432 433 static void gf_early_write(struct console *con, const char *s, unsigned int n) 434 { 435 struct earlycon_device *dev = con->data; 436 437 uart_console_write(&dev->port, s, n, gf_early_console_putchar); 438 } 439 440 static int __init gf_earlycon_setup(struct earlycon_device *device, 441 const char *opt) 442 { 443 if (!device->port.membase) 444 return -ENODEV; 445 446 device->con->write = gf_early_write; 447 return 0; 448 } 449 450 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup); 451 #endif 452 453 static const struct of_device_id goldfish_tty_of_match[] = { 454 { .compatible = "google,goldfish-tty", }, 455 {}, 456 }; 457 458 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match); 459 460 static struct platform_driver goldfish_tty_platform_driver = { 461 .probe = goldfish_tty_probe, 462 .remove = goldfish_tty_remove, 463 .driver = { 464 .name = "goldfish_tty", 465 .of_match_table = goldfish_tty_of_match, 466 } 467 }; 468 469 module_platform_driver(goldfish_tty_platform_driver); 470 471 MODULE_DESCRIPTION("Goldfish TTY Driver"); 472 MODULE_LICENSE("GPL v2"); 473