summaryrefslogtreecommitdiff
path: root/drivers/tty/goldfish.c
blob: d27979eabfdfbee1397140db3e30f0ee8ab7467c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2007 Google, Inc.
 * Copyright (C) 2012 Intel, Inc.
 * Copyright (C) 2017 Imagination Technologies Ltd.
 */

#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/goldfish.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/serial_core.h>

/* Goldfish tty register's offsets */
#define	GOLDFISH_TTY_REG_BYTES_READY	0x04
#define	GOLDFISH_TTY_REG_CMD		0x08
#define	GOLDFISH_TTY_REG_DATA_PTR	0x10
#define	GOLDFISH_TTY_REG_DATA_LEN	0x14
#define	GOLDFISH_TTY_REG_DATA_PTR_HIGH	0x18
#define	GOLDFISH_TTY_REG_VERSION	0x20

/* Goldfish tty commands */
#define	GOLDFISH_TTY_CMD_INT_DISABLE	0
#define	GOLDFISH_TTY_CMD_INT_ENABLE	1
#define	GOLDFISH_TTY_CMD_WRITE_BUFFER	2
#define	GOLDFISH_TTY_CMD_READ_BUFFER	3

struct goldfish_tty {
	struct tty_port port;
	spinlock_t lock;
	void __iomem *base;
	u32 irq;
	int opencount;
	struct console console;
	u32 version;
	struct device *dev;
};

static DEFINE_MUTEX(goldfish_tty_lock);
static struct tty_driver *goldfish_tty_driver;
static u32 goldfish_tty_line_count = 8;
static u32 goldfish_tty_current_line_count;
static struct goldfish_tty *goldfish_ttys;

static void do_rw_io(struct goldfish_tty *qtty, unsigned long address,
		     size_t count, bool is_write)
{
	unsigned long irq_flags;
	void __iomem *base = qtty->base;

	spin_lock_irqsave(&qtty->lock, irq_flags);
	gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,
		     base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);
	gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN);

	if (is_write)
		gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER,
		       base + GOLDFISH_TTY_REG_CMD);
	else
		gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER,
		       base + GOLDFISH_TTY_REG_CMD);

	spin_unlock_irqrestore(&qtty->lock, irq_flags);
}

static void goldfish_tty_rw(struct goldfish_tty *qtty, unsigned long addr,
			    size_t count, bool is_write)
{
	dma_addr_t dma_handle;
	enum dma_data_direction dma_dir;

	dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	if (qtty->version > 0) {
		/*
		 * Goldfish TTY for Ranchu platform uses
		 * physical addresses and DMA for read/write operations
		 */
		unsigned long addr_end = addr + count;

		while (addr < addr_end) {
			unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;
			unsigned long next =
					pg_end < addr_end ? pg_end : addr_end;
			unsigned long avail = next - addr;

			/*
			 * Map the buffer's virtual address to the DMA address
			 * so the buffer can be accessed by the device.
			 */
			dma_handle = dma_map_single(qtty->dev, (void *)addr,
						    avail, dma_dir);

			if (dma_mapping_error(qtty->dev, dma_handle)) {
				dev_err(qtty->dev, "tty: DMA mapping error.\n");
				return;
			}
			do_rw_io(qtty, dma_handle, avail, is_write);

			/*
			 * Unmap the previously mapped region after
			 * the completion of the read/write operation.
			 */
			dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);

			addr += avail;
		}
	} else {
		/*
		 * Old style Goldfish TTY used on the Goldfish platform
		 * uses virtual addresses.
		 */
		do_rw_io(qtty, addr, count, is_write);
	}
}

static void goldfish_tty_do_write(int line, const u8 *buf, size_t count)
{
	struct goldfish_tty *qtty = &goldfish_ttys[line];

	goldfish_tty_rw(qtty, (unsigned long)buf, count, true);
}

static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
{
	struct goldfish_tty *qtty = dev_id;
	void __iomem *base = qtty->base;
	u8 *buf;
	u32 count;

	count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
	if (count == 0)
		return IRQ_NONE;

	count = tty_prepare_flip_string(&qtty->port, &buf, count);

	goldfish_tty_rw(qtty, (unsigned long)buf, count, false);

	tty_flip_buffer_push(&qtty->port);
	return IRQ_HANDLED;
}

static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
{
	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
									port);
	gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
	return 0;
}

static void goldfish_tty_shutdown(struct tty_port *port)
{
	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
									port);
	gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
}

static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
{
	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
	return tty_port_open(&qtty->port, tty, filp);
}

static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
{
	tty_port_close(tty->port, tty, filp);
}

static void goldfish_tty_hangup(struct tty_struct *tty)
{
	tty_port_hangup(tty->port);
}

static ssize_t goldfish_tty_write(struct tty_struct *tty, const u8 *buf,
				  size_t count)
{
	goldfish_tty_do_write(tty->index, buf, count);
	return count;
}

static unsigned int goldfish_tty_write_room(struct tty_struct *tty)
{
	return 0x10000;
}

static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
{
	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
	void __iomem *base = qtty->base;
	return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
}

static void goldfish_tty_console_write(struct console *co, const char *b,
								unsigned count)
{
	goldfish_tty_do_write(co->index, b, count);
}

static struct tty_driver *goldfish_tty_console_device(struct console *c,
								int *index)
{
	*index = c->index;
	return goldfish_tty_driver;
}

static int goldfish_tty_console_setup(struct console *co, char *options)
{
	if ((unsigned)co->index >= goldfish_tty_line_count)
		return -ENODEV;
	if (!goldfish_ttys[co->index].base)
		return -ENODEV;
	return 0;
}

static const struct tty_port_operations goldfish_port_ops = {
	.activate = goldfish_tty_activate,
	.shutdown = goldfish_tty_shutdown
};

static const struct tty_operations goldfish_tty_ops = {
	.open = goldfish_tty_open,
	.close = goldfish_tty_close,
	.hangup = goldfish_tty_hangup,
	.write = goldfish_tty_write,
	.write_room = goldfish_tty_write_room,
	.chars_in_buffer = goldfish_tty_chars_in_buffer,
};

static int goldfish_tty_create_driver(void)
{
	int ret;
	struct tty_driver *tty;

	goldfish_ttys = kcalloc(goldfish_tty_line_count,
				sizeof(*goldfish_ttys),
				GFP_KERNEL);
	if (goldfish_ttys == NULL) {
		ret = -ENOMEM;
		goto err_alloc_goldfish_ttys_failed;
	}
	tty = tty_alloc_driver(goldfish_tty_line_count,
			TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
			TTY_DRIVER_DYNAMIC_DEV);
	if (IS_ERR(tty)) {
		ret = PTR_ERR(tty);
		goto err_tty_alloc_driver_failed;
	}
	tty->driver_name = "goldfish";
	tty->name = "ttyGF";
	tty->type = TTY_DRIVER_TYPE_SERIAL;
	tty->subtype = SERIAL_TYPE_NORMAL;
	tty->init_termios = tty_std_termios;
	tty_set_operations(tty, &goldfish_tty_ops);
	ret = tty_register_driver(tty);
	if (ret)
		goto err_tty_register_driver_failed;

	goldfish_tty_driver = tty;
	return 0;

err_tty_register_driver_failed:
	tty_driver_kref_put(tty);
err_tty_alloc_driver_failed:
	kfree(goldfish_ttys);
	goldfish_ttys = NULL;
err_alloc_goldfish_ttys_failed:
	return ret;
}

static void goldfish_tty_delete_driver(void)
{
	tty_unregister_driver(goldfish_tty_driver);
	tty_driver_kref_put(goldfish_tty_driver);
	goldfish_tty_driver = NULL;
	kfree(goldfish_ttys);
	goldfish_ttys = NULL;
}

static int goldfish_tty_probe(struct platform_device *pdev)
{
	struct goldfish_tty *qtty;
	int ret = -ENODEV;
	struct resource *r;
	struct device *ttydev;
	void __iomem *base;
	int irq;
	unsigned int line;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
		pr_err("goldfish_tty: No MEM resource available!\n");
		return -ENOMEM;
	}

	base = ioremap(r->start, 0x1000);
	if (!base) {
		pr_err("goldfish_tty: Unable to ioremap base!\n");
		return -ENOMEM;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		ret = irq;
		goto err_unmap;
	}

	mutex_lock(&goldfish_tty_lock);

	if (pdev->id == PLATFORM_DEVID_NONE)
		line = goldfish_tty_current_line_count;
	else
		line = pdev->id;

	if (line >= goldfish_tty_line_count) {
		pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
		       goldfish_tty_current_line_count);
		ret = -ENOMEM;
		goto err_unlock;
	}

	if (goldfish_tty_current_line_count == 0) {
		ret = goldfish_tty_create_driver();
		if (ret)
			goto err_unlock;
	}
	goldfish_tty_current_line_count++;

	qtty = &goldfish_ttys[line];
	spin_lock_init(&qtty->lock);
	tty_port_init(&qtty->port);
	qtty->port.ops = &goldfish_port_ops;
	qtty->base = base;
	qtty->irq = irq;
	qtty->dev = &pdev->dev;

	/*
	 * Goldfish TTY device used by the Goldfish emulator
	 * should identify itself with 0, forcing the driver
	 * to use virtual addresses. Goldfish TTY device
	 * on Ranchu emulator (qemu2) returns 1 here and
	 * driver will use physical addresses.
	 */
	qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION);

	/*
	 * Goldfish TTY device on Ranchu emulator (qemu2)
	 * will use DMA for read/write IO operations.
	 */
	if (qtty->version > 0) {
		/*
		 * Initialize dma_mask to 32-bits.
		 */
		if (!pdev->dev.dma_mask)
			pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
		ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
		if (ret) {
			dev_err(&pdev->dev, "No suitable DMA available.\n");
			goto err_dec_line_count;
		}
	}

	gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);

	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
			  "goldfish_tty", qtty);
	if (ret) {
		pr_err("goldfish_tty: No IRQ available!\n");
		goto err_dec_line_count;
	}

	ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
					  line, &pdev->dev);
	if (IS_ERR(ttydev)) {
		ret = PTR_ERR(ttydev);
		goto err_tty_register_device_failed;
	}

	strcpy(qtty->console.name, "ttyGF");
	qtty->console.write = goldfish_tty_console_write;
	qtty->console.device = goldfish_tty_console_device;
	qtty->console.setup = goldfish_tty_console_setup;
	qtty->console.flags = CON_PRINTBUFFER;
	qtty->console.index = line;
	register_console(&qtty->console);
	platform_set_drvdata(pdev, qtty);

	mutex_unlock(&goldfish_tty_lock);
	return 0;

err_tty_register_device_failed:
	free_irq(irq, qtty);
err_dec_line_count:
	tty_port_destroy(&qtty->port);
	goldfish_tty_current_line_count--;
	if (goldfish_tty_current_line_count == 0)
		goldfish_tty_delete_driver();
err_unlock:
	mutex_unlock(&goldfish_tty_lock);
err_unmap:
	iounmap(base);
	return ret;
}

static int goldfish_tty_remove(struct platform_device *pdev)
{
	struct goldfish_tty *qtty = platform_get_drvdata(pdev);

	mutex_lock(&goldfish_tty_lock);

	unregister_console(&qtty->console);
	tty_unregister_device(goldfish_tty_driver, qtty->console.index);
	iounmap(qtty->base);
	qtty->base = NULL;
	free_irq(qtty->irq, qtty);
	tty_port_destroy(&qtty->port);
	goldfish_tty_current_line_count--;
	if (goldfish_tty_current_line_count == 0)
		goldfish_tty_delete_driver();
	mutex_unlock(&goldfish_tty_lock);
	return 0;
}

#ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
{
	gf_iowrite32(ch, port->membase);
}

static void gf_early_write(struct console *con, const char *s, unsigned int n)
{
	struct earlycon_device *dev = con->data;

	uart_console_write(&dev->port, s, n, gf_early_console_putchar);
}

static int __init gf_earlycon_setup(struct earlycon_device *device,
				    const char *opt)
{
	if (!device->port.membase)
		return -ENODEV;

	device->con->write = gf_early_write;
	return 0;
}

OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
#endif

static const struct of_device_id goldfish_tty_of_match[] = {
	{ .compatible = "google,goldfish-tty", },
	{},
};

MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);

static struct platform_driver goldfish_tty_platform_driver = {
	.probe = goldfish_tty_probe,
	.remove = goldfish_tty_remove,
	.driver = {
		.name = "goldfish_tty",
		.of_match_table = goldfish_tty_of_match,
	}
};

module_platform_driver(goldfish_tty_platform_driver);

MODULE_LICENSE("GPL v2");