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
36struct 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
47static DEFINE_MUTEX(goldfish_tty_lock);
48static struct tty_driver *goldfish_tty_driver;
49static u32 goldfish_tty_line_count = 8;
50static u32 goldfish_tty_current_line_count;
51static struct goldfish_tty *goldfish_ttys;
52
53static 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 writel(count, base + GOLDFISH_TTY_REG_DATA_LEN);
65
66 if (is_write)
67 writel(GOLDFISH_TTY_CMD_WRITE_BUFFER,
68 base + GOLDFISH_TTY_REG_CMD);
69 else
70 writel(GOLDFISH_TTY_CMD_READ_BUFFER,
71 base + GOLDFISH_TTY_REG_CMD);
72
73 spin_unlock_irqrestore(&qtty->lock, irq_flags);
74}
75
76static 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
128static void goldfish_tty_do_write(int line, const char *buf,
129 unsigned int count)
130{
131 struct goldfish_tty *qtty = &goldfish_ttys[line];
132 unsigned long address = (unsigned long)(void *)buf;
133
134 goldfish_tty_rw(qtty, address, count, 1);
135}
136
137static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
138{
139 struct goldfish_tty *qtty = dev_id;
140 void __iomem *base = qtty->base;
141 unsigned long address;
142 unsigned char *buf;
143 u32 count;
144
145 count = readl(base + GOLDFISH_TTY_REG_BYTES_READY);
146 if (count == 0)
147 return IRQ_NONE;
148
149 count = tty_prepare_flip_string(&qtty->port, &buf, count);
150
151 address = (unsigned long)(void *)buf;
152 goldfish_tty_rw(qtty, address, count, 0);
153
154 tty_schedule_flip(&qtty->port);
155 return IRQ_HANDLED;
156}
157
158static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
159{
160 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
161 port);
162 writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
163 return 0;
164}
165
166static void goldfish_tty_shutdown(struct tty_port *port)
167{
168 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
169 port);
170 writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
171}
172
173static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
174{
175 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
176 return tty_port_open(&qtty->port, tty, filp);
177}
178
179static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
180{
181 tty_port_close(tty->port, tty, filp);
182}
183
184static void goldfish_tty_hangup(struct tty_struct *tty)
185{
186 tty_port_hangup(tty->port);
187}
188
189static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf,
190 int count)
191{
192 goldfish_tty_do_write(tty->index, buf, count);
193 return count;
194}
195
196static int goldfish_tty_write_room(struct tty_struct *tty)
197{
198 return 0x10000;
199}
200
201static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
202{
203 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
204 void __iomem *base = qtty->base;
205 return readl(base + GOLDFISH_TTY_REG_BYTES_READY);
206}
207
208static void goldfish_tty_console_write(struct console *co, const char *b,
209 unsigned count)
210{
211 goldfish_tty_do_write(co->index, b, count);
212}
213
214static struct tty_driver *goldfish_tty_console_device(struct console *c,
215 int *index)
216{
217 *index = c->index;
218 return goldfish_tty_driver;
219}
220
221static int goldfish_tty_console_setup(struct console *co, char *options)
222{
223 if ((unsigned)co->index >= goldfish_tty_line_count)
224 return -ENODEV;
225 if (!goldfish_ttys[co->index].base)
226 return -ENODEV;
227 return 0;
228}
229
230static const struct tty_port_operations goldfish_port_ops = {
231 .activate = goldfish_tty_activate,
232 .shutdown = goldfish_tty_shutdown
233};
234
235static const struct tty_operations goldfish_tty_ops = {
236 .open = goldfish_tty_open,
237 .close = goldfish_tty_close,
238 .hangup = goldfish_tty_hangup,
239 .write = goldfish_tty_write,
240 .write_room = goldfish_tty_write_room,
241 .chars_in_buffer = goldfish_tty_chars_in_buffer,
242};
243
244static int goldfish_tty_create_driver(void)
245{
246 int ret;
247 struct tty_driver *tty;
248
249 goldfish_ttys = kcalloc(goldfish_tty_line_count,
250 sizeof(*goldfish_ttys),
251 GFP_KERNEL);
252 if (goldfish_ttys == NULL) {
253 ret = -ENOMEM;
254 goto err_alloc_goldfish_ttys_failed;
255 }
256 tty = alloc_tty_driver(goldfish_tty_line_count);
257 if (tty == NULL) {
258 ret = -ENOMEM;
259 goto err_alloc_tty_driver_failed;
260 }
261 tty->driver_name = "goldfish";
262 tty->name = "ttyGF";
263 tty->type = TTY_DRIVER_TYPE_SERIAL;
264 tty->subtype = SERIAL_TYPE_NORMAL;
265 tty->init_termios = tty_std_termios;
266 tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
267 TTY_DRIVER_DYNAMIC_DEV;
268 tty_set_operations(tty, &goldfish_tty_ops);
269 ret = tty_register_driver(tty);
270 if (ret)
271 goto err_tty_register_driver_failed;
272
273 goldfish_tty_driver = tty;
274 return 0;
275
276err_tty_register_driver_failed:
277 put_tty_driver(tty);
278err_alloc_tty_driver_failed:
279 kfree(goldfish_ttys);
280 goldfish_ttys = NULL;
281err_alloc_goldfish_ttys_failed:
282 return ret;
283}
284
285static void goldfish_tty_delete_driver(void)
286{
287 tty_unregister_driver(goldfish_tty_driver);
288 put_tty_driver(goldfish_tty_driver);
289 goldfish_tty_driver = NULL;
290 kfree(goldfish_ttys);
291 goldfish_ttys = NULL;
292}
293
294static int goldfish_tty_probe(struct platform_device *pdev)
295{
296 struct goldfish_tty *qtty;
297 int ret = -ENODEV;
298 struct resource *r;
299 struct device *ttydev;
300 void __iomem *base;
301 u32 irq;
302 unsigned int line;
303
304 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
305 if (!r) {
306 pr_err("goldfish_tty: No MEM resource available!\n");
307 return -ENOMEM;
308 }
309
310 base = ioremap(r->start, 0x1000);
311 if (!base) {
312 pr_err("goldfish_tty: Unable to ioremap base!\n");
313 return -ENOMEM;
314 }
315
316 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
317 if (!r) {
318 pr_err("goldfish_tty: No IRQ resource available!\n");
319 goto err_unmap;
320 }
321
322 irq = r->start;
323
324 mutex_lock(&goldfish_tty_lock);
325
326 if (pdev->id == PLATFORM_DEVID_NONE)
327 line = goldfish_tty_current_line_count;
328 else
329 line = pdev->id;
330
331 if (line >= goldfish_tty_line_count) {
332 pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
333 goldfish_tty_current_line_count);
334 ret = -ENOMEM;
335 goto err_unlock;
336 }
337
338 if (goldfish_tty_current_line_count == 0) {
339 ret = goldfish_tty_create_driver();
340 if (ret)
341 goto err_unlock;
342 }
343 goldfish_tty_current_line_count++;
344
345 qtty = &goldfish_ttys[line];
346 spin_lock_init(&qtty->lock);
347 tty_port_init(&qtty->port);
348 qtty->port.ops = &goldfish_port_ops;
349 qtty->base = base;
350 qtty->irq = irq;
351 qtty->dev = &pdev->dev;
352
353 /*
354 * Goldfish TTY device used by the Goldfish emulator
355 * should identify itself with 0, forcing the driver
356 * to use virtual addresses. Goldfish TTY device
357 * on Ranchu emulator (qemu2) returns 1 here and
358 * driver will use physical addresses.
359 */
360 qtty->version = readl(base + GOLDFISH_TTY_REG_VERSION);
361
362 /*
363 * Goldfish TTY device on Ranchu emulator (qemu2)
364 * will use DMA for read/write IO operations.
365 */
366 if (qtty->version > 0) {
367 /*
368 * Initialize dma_mask to 32-bits.
369 */
370 if (!pdev->dev.dma_mask)
371 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
372 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
373 if (ret) {
374 dev_err(&pdev->dev, "No suitable DMA available.\n");
375 goto err_dec_line_count;
376 }
377 }
378
379 writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
380
381 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
382 "goldfish_tty", qtty);
383 if (ret) {
384 pr_err("goldfish_tty: No IRQ available!\n");
385 goto err_dec_line_count;
386 }
387
388 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
389 line, &pdev->dev);
390 if (IS_ERR(ttydev)) {
391 ret = PTR_ERR(ttydev);
392 goto err_tty_register_device_failed;
393 }
394
395 strcpy(qtty->console.name, "ttyGF");
396 qtty->console.write = goldfish_tty_console_write;
397 qtty->console.device = goldfish_tty_console_device;
398 qtty->console.setup = goldfish_tty_console_setup;
399 qtty->console.flags = CON_PRINTBUFFER;
400 qtty->console.index = line;
401 register_console(&qtty->console);
402 platform_set_drvdata(pdev, qtty);
403
404 mutex_unlock(&goldfish_tty_lock);
405 return 0;
406
407err_tty_register_device_failed:
408 free_irq(irq, qtty);
409err_dec_line_count:
410 goldfish_tty_current_line_count--;
411 if (goldfish_tty_current_line_count == 0)
412 goldfish_tty_delete_driver();
413err_unlock:
414 mutex_unlock(&goldfish_tty_lock);
415err_unmap:
416 iounmap(base);
417 return ret;
418}
419
420static int goldfish_tty_remove(struct platform_device *pdev)
421{
422 struct goldfish_tty *qtty = platform_get_drvdata(pdev);
423
424 mutex_lock(&goldfish_tty_lock);
425
426 unregister_console(&qtty->console);
427 tty_unregister_device(goldfish_tty_driver, qtty->console.index);
428 iounmap(qtty->base);
429 qtty->base = NULL;
430 free_irq(qtty->irq, pdev);
431 goldfish_tty_current_line_count--;
432 if (goldfish_tty_current_line_count == 0)
433 goldfish_tty_delete_driver();
434 mutex_unlock(&goldfish_tty_lock);
435 return 0;
436}
437
438#ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
439static void gf_early_console_putchar(struct uart_port *port, int ch)
440{
441 __raw_writel(ch, port->membase);
442}
443
444static void gf_early_write(struct console *con, const char *s, unsigned int n)
445{
446 struct earlycon_device *dev = con->data;
447
448 uart_console_write(&dev->port, s, n, gf_early_console_putchar);
449}
450
451static int __init gf_earlycon_setup(struct earlycon_device *device,
452 const char *opt)
453{
454 if (!device->port.membase)
455 return -ENODEV;
456
457 device->con->write = gf_early_write;
458 return 0;
459}
460
461OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
462#endif
463
464static const struct of_device_id goldfish_tty_of_match[] = {
465 { .compatible = "google,goldfish-tty", },
466 {},
467};
468
469MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
470
471static struct platform_driver goldfish_tty_platform_driver = {
472 .probe = goldfish_tty_probe,
473 .remove = goldfish_tty_remove,
474 .driver = {
475 .name = "goldfish_tty",
476 .of_match_table = goldfish_tty_of_match,
477 }
478};
479
480module_platform_driver(goldfish_tty_platform_driver);
481
482MODULE_LICENSE("GPL v2");
483