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(ptr: (void *)address, portl: base + GOLDFISH_TTY_REG_DATA_PTR, |
63 | porth: 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(lock: &qtty->lock, flags: 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(dev: qtty->dev, dma_addr: dma_handle)) { |
106 | dev_err(qtty->dev, "tty: DMA mapping error.\n" ); |
107 | return; |
108 | } |
109 | do_rw_io(qtty, address: dma_handle, count: 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, address: 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, addr: address, count, is_write: 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(port: &qtty->port, chars: &buf, size: count); |
149 | |
150 | address = (unsigned long)(void *)buf; |
151 | goldfish_tty_rw(qtty, addr: address, count, is_write: 0); |
152 | |
153 | tty_flip_buffer_push(port: &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(port: &qtty->port, tty, filp); |
176 | } |
177 | |
178 | static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) |
179 | { |
180 | tty_port_close(port: tty->port, tty, filp); |
181 | } |
182 | |
183 | static void goldfish_tty_hangup(struct tty_struct *tty) |
184 | { |
185 | tty_port_hangup(port: 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(line: 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(line: co->index, buf: 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(n: goldfish_tty_line_count, |
249 | size: 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(ptr: tty)) { |
259 | ret = PTR_ERR(ptr: 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(driver: tty, op: &goldfish_tty_ops); |
268 | ret = tty_register_driver(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(driver: tty); |
277 | err_tty_alloc_driver_failed: |
278 | kfree(objp: 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(driver: goldfish_tty_driver); |
287 | tty_driver_kref_put(driver: goldfish_tty_driver); |
288 | goldfish_tty_driver = NULL; |
289 | kfree(objp: 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(offset: r->start, size: 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(port: &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(dev: &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, handler: goldfish_tty_interrupt, IRQF_SHARED, |
379 | name: "goldfish_tty" , dev: 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(port: &qtty->port, driver: goldfish_tty_driver, |
386 | index: line, device: &pdev->dev); |
387 | if (IS_ERR(ptr: ttydev)) { |
388 | ret = PTR_ERR(ptr: ttydev); |
389 | goto err_tty_register_device_failed; |
390 | } |
391 | |
392 | strcpy(p: qtty->console.name, q: "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, data: qtty); |
400 | |
401 | mutex_unlock(lock: &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(port: &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(lock: &goldfish_tty_lock); |
413 | err_unmap: |
414 | iounmap(addr: 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(driver: goldfish_tty_driver, index: qtty->console.index); |
426 | iounmap(addr: qtty->base); |
427 | qtty->base = NULL; |
428 | free_irq(qtty->irq, qtty); |
429 | tty_port_destroy(port: &qtty->port); |
430 | goldfish_tty_current_line_count--; |
431 | if (goldfish_tty_current_line_count == 0) |
432 | goldfish_tty_delete_driver(); |
433 | mutex_unlock(lock: &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(port: &dev->port, s, count: n, putchar: 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 | |