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(ptr: (void *)address, portl: base + GOLDFISH_TTY_REG_DATA_PTR, |
61 | porth: 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(lock: &qtty->lock, flags: 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(dev: qtty->dev, dma_addr: dma_handle)) { |
102 | dev_err(qtty->dev, "tty: DMA mapping error.\n" ); |
103 | return; |
104 | } |
105 | do_rw_io(qtty, address: dma_handle, count: 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, address: 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, addr: (unsigned long)buf, count, is_write: 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(port: &qtty->port, chars: &buf, size: count); |
143 | |
144 | goldfish_tty_rw(qtty, addr: (unsigned long)buf, count, is_write: false); |
145 | |
146 | tty_flip_buffer_push(port: &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(port: &qtty->port, tty, filp); |
169 | } |
170 | |
171 | static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) |
172 | { |
173 | tty_port_close(port: tty->port, tty, filp); |
174 | } |
175 | |
176 | static void goldfish_tty_hangup(struct tty_struct *tty) |
177 | { |
178 | tty_port_hangup(port: 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(line: 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(line: co->index, buf: 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 = kcalloc(n: goldfish_tty_line_count, |
242 | size: sizeof(*goldfish_ttys), |
243 | GFP_KERNEL); |
244 | if (goldfish_ttys == NULL) { |
245 | ret = -ENOMEM; |
246 | goto err_alloc_goldfish_ttys_failed; |
247 | } |
248 | tty = tty_alloc_driver(goldfish_tty_line_count, |
249 | TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | |
250 | TTY_DRIVER_DYNAMIC_DEV); |
251 | if (IS_ERR(ptr: tty)) { |
252 | ret = PTR_ERR(ptr: tty); |
253 | goto err_tty_alloc_driver_failed; |
254 | } |
255 | tty->driver_name = "goldfish" ; |
256 | tty->name = "ttyGF" ; |
257 | tty->type = TTY_DRIVER_TYPE_SERIAL; |
258 | tty->subtype = SERIAL_TYPE_NORMAL; |
259 | tty->init_termios = tty_std_termios; |
260 | tty_set_operations(driver: tty, op: &goldfish_tty_ops); |
261 | ret = tty_register_driver(driver: tty); |
262 | if (ret) |
263 | goto err_tty_register_driver_failed; |
264 | |
265 | goldfish_tty_driver = tty; |
266 | return 0; |
267 | |
268 | err_tty_register_driver_failed: |
269 | tty_driver_kref_put(driver: tty); |
270 | err_tty_alloc_driver_failed: |
271 | kfree(objp: goldfish_ttys); |
272 | goldfish_ttys = NULL; |
273 | err_alloc_goldfish_ttys_failed: |
274 | return ret; |
275 | } |
276 | |
277 | static void goldfish_tty_delete_driver(void) |
278 | { |
279 | tty_unregister_driver(driver: goldfish_tty_driver); |
280 | tty_driver_kref_put(driver: goldfish_tty_driver); |
281 | goldfish_tty_driver = NULL; |
282 | kfree(objp: goldfish_ttys); |
283 | goldfish_ttys = NULL; |
284 | } |
285 | |
286 | static int goldfish_tty_probe(struct platform_device *pdev) |
287 | { |
288 | struct goldfish_tty *qtty; |
289 | int ret = -ENODEV; |
290 | struct resource *r; |
291 | struct device *ttydev; |
292 | void __iomem *base; |
293 | int irq; |
294 | unsigned int line; |
295 | |
296 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
297 | if (!r) { |
298 | pr_err("goldfish_tty: No MEM resource available!\n" ); |
299 | return -ENOMEM; |
300 | } |
301 | |
302 | base = ioremap(offset: r->start, size: 0x1000); |
303 | if (!base) { |
304 | pr_err("goldfish_tty: Unable to ioremap base!\n" ); |
305 | return -ENOMEM; |
306 | } |
307 | |
308 | irq = platform_get_irq(pdev, 0); |
309 | if (irq < 0) { |
310 | ret = irq; |
311 | goto err_unmap; |
312 | } |
313 | |
314 | mutex_lock(&goldfish_tty_lock); |
315 | |
316 | if (pdev->id == PLATFORM_DEVID_NONE) |
317 | line = goldfish_tty_current_line_count; |
318 | else |
319 | line = pdev->id; |
320 | |
321 | if (line >= goldfish_tty_line_count) { |
322 | pr_err("goldfish_tty: Reached maximum tty number of %d.\n" , |
323 | goldfish_tty_current_line_count); |
324 | ret = -ENOMEM; |
325 | goto err_unlock; |
326 | } |
327 | |
328 | if (goldfish_tty_current_line_count == 0) { |
329 | ret = goldfish_tty_create_driver(); |
330 | if (ret) |
331 | goto err_unlock; |
332 | } |
333 | goldfish_tty_current_line_count++; |
334 | |
335 | qtty = &goldfish_ttys[line]; |
336 | spin_lock_init(&qtty->lock); |
337 | tty_port_init(port: &qtty->port); |
338 | qtty->port.ops = &goldfish_port_ops; |
339 | qtty->base = base; |
340 | qtty->irq = irq; |
341 | qtty->dev = &pdev->dev; |
342 | |
343 | /* |
344 | * Goldfish TTY device used by the Goldfish emulator |
345 | * should identify itself with 0, forcing the driver |
346 | * to use virtual addresses. Goldfish TTY device |
347 | * on Ranchu emulator (qemu2) returns 1 here and |
348 | * driver will use physical addresses. |
349 | */ |
350 | qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION); |
351 | |
352 | /* |
353 | * Goldfish TTY device on Ranchu emulator (qemu2) |
354 | * will use DMA for read/write IO operations. |
355 | */ |
356 | if (qtty->version > 0) { |
357 | /* |
358 | * Initialize dma_mask to 32-bits. |
359 | */ |
360 | if (!pdev->dev.dma_mask) |
361 | pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; |
362 | ret = dma_set_mask(dev: &pdev->dev, DMA_BIT_MASK(32)); |
363 | if (ret) { |
364 | dev_err(&pdev->dev, "No suitable DMA available.\n" ); |
365 | goto err_dec_line_count; |
366 | } |
367 | } |
368 | |
369 | gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); |
370 | |
371 | ret = request_irq(irq, handler: goldfish_tty_interrupt, IRQF_SHARED, |
372 | name: "goldfish_tty" , dev: qtty); |
373 | if (ret) { |
374 | pr_err("goldfish_tty: No IRQ available!\n" ); |
375 | goto err_dec_line_count; |
376 | } |
377 | |
378 | ttydev = tty_port_register_device(port: &qtty->port, driver: goldfish_tty_driver, |
379 | index: line, device: &pdev->dev); |
380 | if (IS_ERR(ptr: ttydev)) { |
381 | ret = PTR_ERR(ptr: ttydev); |
382 | goto err_tty_register_device_failed; |
383 | } |
384 | |
385 | strcpy(p: qtty->console.name, q: "ttyGF" ); |
386 | qtty->console.write = goldfish_tty_console_write; |
387 | qtty->console.device = goldfish_tty_console_device; |
388 | qtty->console.setup = goldfish_tty_console_setup; |
389 | qtty->console.flags = CON_PRINTBUFFER; |
390 | qtty->console.index = line; |
391 | register_console(&qtty->console); |
392 | platform_set_drvdata(pdev, data: qtty); |
393 | |
394 | mutex_unlock(lock: &goldfish_tty_lock); |
395 | return 0; |
396 | |
397 | err_tty_register_device_failed: |
398 | free_irq(irq, qtty); |
399 | err_dec_line_count: |
400 | tty_port_destroy(port: &qtty->port); |
401 | goldfish_tty_current_line_count--; |
402 | if (goldfish_tty_current_line_count == 0) |
403 | goldfish_tty_delete_driver(); |
404 | err_unlock: |
405 | mutex_unlock(lock: &goldfish_tty_lock); |
406 | err_unmap: |
407 | iounmap(addr: base); |
408 | return ret; |
409 | } |
410 | |
411 | static void goldfish_tty_remove(struct platform_device *pdev) |
412 | { |
413 | struct goldfish_tty *qtty = platform_get_drvdata(pdev); |
414 | |
415 | mutex_lock(&goldfish_tty_lock); |
416 | |
417 | unregister_console(&qtty->console); |
418 | tty_unregister_device(driver: goldfish_tty_driver, index: qtty->console.index); |
419 | iounmap(addr: qtty->base); |
420 | qtty->base = NULL; |
421 | free_irq(qtty->irq, qtty); |
422 | tty_port_destroy(port: &qtty->port); |
423 | goldfish_tty_current_line_count--; |
424 | if (goldfish_tty_current_line_count == 0) |
425 | goldfish_tty_delete_driver(); |
426 | mutex_unlock(lock: &goldfish_tty_lock); |
427 | } |
428 | |
429 | #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE |
430 | static void gf_early_console_putchar(struct uart_port *port, unsigned char ch) |
431 | { |
432 | gf_iowrite32(ch, port->membase); |
433 | } |
434 | |
435 | static void gf_early_write(struct console *con, const char *s, unsigned int n) |
436 | { |
437 | struct earlycon_device *dev = con->data; |
438 | |
439 | uart_console_write(port: &dev->port, s, count: n, putchar: gf_early_console_putchar); |
440 | } |
441 | |
442 | static int __init gf_earlycon_setup(struct earlycon_device *device, |
443 | const char *opt) |
444 | { |
445 | if (!device->port.membase) |
446 | return -ENODEV; |
447 | |
448 | device->con->write = gf_early_write; |
449 | return 0; |
450 | } |
451 | |
452 | OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty" , gf_earlycon_setup); |
453 | #endif |
454 | |
455 | static const struct of_device_id goldfish_tty_of_match[] = { |
456 | { .compatible = "google,goldfish-tty" , }, |
457 | {}, |
458 | }; |
459 | |
460 | MODULE_DEVICE_TABLE(of, goldfish_tty_of_match); |
461 | |
462 | static struct platform_driver goldfish_tty_platform_driver = { |
463 | .probe = goldfish_tty_probe, |
464 | .remove_new = goldfish_tty_remove, |
465 | .driver = { |
466 | .name = "goldfish_tty" , |
467 | .of_match_table = goldfish_tty_of_match, |
468 | } |
469 | }; |
470 | |
471 | module_platform_driver(goldfish_tty_platform_driver); |
472 | |
473 | MODULE_LICENSE("GPL v2" ); |
474 | |