1/*
2 * Copyright (C) 2007 Google, Inc.
3 * Copyright (C) 2012 Intel, Inc.
4 *
5 * This software is licensed under the terms of the GNU General Public
6 * License version 2, as published by the Free Software Foundation, and
7 * may be copied, distributed, and modified under those terms.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 */
15
16#include <linux/console.h>
17#include <linux/interrupt.h>
18#include <linux/platform_device.h>
19#include <linux/tty.h>
20#include <linux/tty_flip.h>
21#include <linux/slab.h>
22#include <linux/io.h>
23#include <linux/module.h>
24#include <linux/goldfish.h>
25
26enum {
27	GOLDFISH_TTY_PUT_CHAR       = 0x00,
28	GOLDFISH_TTY_BYTES_READY    = 0x04,
29	GOLDFISH_TTY_CMD            = 0x08,
30
31	GOLDFISH_TTY_DATA_PTR       = 0x10,
32	GOLDFISH_TTY_DATA_LEN       = 0x14,
33	GOLDFISH_TTY_DATA_PTR_HIGH  = 0x18,
34
35	GOLDFISH_TTY_CMD_INT_DISABLE    = 0,
36	GOLDFISH_TTY_CMD_INT_ENABLE     = 1,
37	GOLDFISH_TTY_CMD_WRITE_BUFFER   = 2,
38	GOLDFISH_TTY_CMD_READ_BUFFER    = 3,
39};
40
41struct goldfish_tty {
42	struct tty_port port;
43	spinlock_t lock;
44	void __iomem *base;
45	u32 irq;
46	int opencount;
47	struct console console;
48};
49
50static DEFINE_MUTEX(goldfish_tty_lock);
51static struct tty_driver *goldfish_tty_driver;
52static u32 goldfish_tty_line_count = 8;
53static u32 goldfish_tty_current_line_count;
54static struct goldfish_tty *goldfish_ttys;
55
56static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
57{
58	unsigned long irq_flags;
59	struct goldfish_tty *qtty = &goldfish_ttys[line];
60	void __iomem *base = qtty->base;
61	spin_lock_irqsave(&qtty->lock, irq_flags);
62	gf_write64((u64)buf, base + GOLDFISH_TTY_DATA_PTR,
63				base + GOLDFISH_TTY_DATA_PTR_HIGH);
64	writel(count, base + GOLDFISH_TTY_DATA_LEN);
65	writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
66	spin_unlock_irqrestore(&qtty->lock, irq_flags);
67}
68
69static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
70{
71	struct platform_device *pdev = dev_id;
72	struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
73	void __iomem *base = qtty->base;
74	unsigned long irq_flags;
75	unsigned char *buf;
76	u32 count;
77
78	count = readl(base + GOLDFISH_TTY_BYTES_READY);
79	if (count == 0)
80		return IRQ_NONE;
81
82	count = tty_prepare_flip_string(&qtty->port, &buf, count);
83	spin_lock_irqsave(&qtty->lock, irq_flags);
84	gf_write64((u64)buf, base + GOLDFISH_TTY_DATA_PTR,
85				base + GOLDFISH_TTY_DATA_PTR_HIGH);
86	writel(count, base + GOLDFISH_TTY_DATA_LEN);
87	writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
88	spin_unlock_irqrestore(&qtty->lock, irq_flags);
89	tty_schedule_flip(&qtty->port);
90	return IRQ_HANDLED;
91}
92
93static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
94{
95	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
96									port);
97	writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
98	return 0;
99}
100
101static void goldfish_tty_shutdown(struct tty_port *port)
102{
103	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
104									port);
105	writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
106}
107
108static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
109{
110	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
111	return tty_port_open(&qtty->port, tty, filp);
112}
113
114static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
115{
116	tty_port_close(tty->port, tty, filp);
117}
118
119static void goldfish_tty_hangup(struct tty_struct *tty)
120{
121	tty_port_hangup(tty->port);
122}
123
124static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf,
125								int count)
126{
127	goldfish_tty_do_write(tty->index, buf, count);
128	return count;
129}
130
131static int goldfish_tty_write_room(struct tty_struct *tty)
132{
133	return 0x10000;
134}
135
136static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
137{
138	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
139	void __iomem *base = qtty->base;
140	return readl(base + GOLDFISH_TTY_BYTES_READY);
141}
142
143static void goldfish_tty_console_write(struct console *co, const char *b,
144								unsigned count)
145{
146	goldfish_tty_do_write(co->index, b, count);
147}
148
149static struct tty_driver *goldfish_tty_console_device(struct console *c,
150								int *index)
151{
152	*index = c->index;
153	return goldfish_tty_driver;
154}
155
156static int goldfish_tty_console_setup(struct console *co, char *options)
157{
158	if ((unsigned)co->index >= goldfish_tty_line_count)
159		return -ENODEV;
160	if (!goldfish_ttys[co->index].base)
161		return -ENODEV;
162	return 0;
163}
164
165static struct tty_port_operations goldfish_port_ops = {
166	.activate = goldfish_tty_activate,
167	.shutdown = goldfish_tty_shutdown
168};
169
170static const struct tty_operations goldfish_tty_ops = {
171	.open = goldfish_tty_open,
172	.close = goldfish_tty_close,
173	.hangup = goldfish_tty_hangup,
174	.write = goldfish_tty_write,
175	.write_room = goldfish_tty_write_room,
176	.chars_in_buffer = goldfish_tty_chars_in_buffer,
177};
178
179static int goldfish_tty_create_driver(void)
180{
181	int ret;
182	struct tty_driver *tty;
183
184	goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) *
185				goldfish_tty_line_count, GFP_KERNEL);
186	if (goldfish_ttys == NULL) {
187		ret = -ENOMEM;
188		goto err_alloc_goldfish_ttys_failed;
189	}
190	tty = alloc_tty_driver(goldfish_tty_line_count);
191	if (tty == NULL) {
192		ret = -ENOMEM;
193		goto err_alloc_tty_driver_failed;
194	}
195	tty->driver_name = "goldfish";
196	tty->name = "ttyGF";
197	tty->type = TTY_DRIVER_TYPE_SERIAL;
198	tty->subtype = SERIAL_TYPE_NORMAL;
199	tty->init_termios = tty_std_termios;
200	tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
201						TTY_DRIVER_DYNAMIC_DEV;
202	tty_set_operations(tty, &goldfish_tty_ops);
203	ret = tty_register_driver(tty);
204	if (ret)
205		goto err_tty_register_driver_failed;
206
207	goldfish_tty_driver = tty;
208	return 0;
209
210err_tty_register_driver_failed:
211	put_tty_driver(tty);
212err_alloc_tty_driver_failed:
213	kfree(goldfish_ttys);
214	goldfish_ttys = NULL;
215err_alloc_goldfish_ttys_failed:
216	return ret;
217}
218
219static void goldfish_tty_delete_driver(void)
220{
221	tty_unregister_driver(goldfish_tty_driver);
222	put_tty_driver(goldfish_tty_driver);
223	goldfish_tty_driver = NULL;
224	kfree(goldfish_ttys);
225	goldfish_ttys = NULL;
226}
227
228static int goldfish_tty_probe(struct platform_device *pdev)
229{
230	struct goldfish_tty *qtty;
231	int ret = -EINVAL;
232	struct resource *r;
233	struct device *ttydev;
234	void __iomem *base;
235	u32 irq;
236
237	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
238	if (r == NULL)
239		return -EINVAL;
240
241	base = ioremap(r->start, 0x1000);
242	if (base == NULL)
243		pr_err("goldfish_tty: unable to remap base\n");
244
245	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
246	if (r == NULL)
247		goto err_unmap;
248
249	irq = r->start;
250
251	if (pdev->id >= goldfish_tty_line_count)
252		goto err_unmap;
253
254	mutex_lock(&goldfish_tty_lock);
255	if (goldfish_tty_current_line_count == 0) {
256		ret = goldfish_tty_create_driver();
257		if (ret)
258			goto err_create_driver_failed;
259	}
260	goldfish_tty_current_line_count++;
261
262	qtty = &goldfish_ttys[pdev->id];
263	spin_lock_init(&qtty->lock);
264	tty_port_init(&qtty->port);
265	qtty->port.ops = &goldfish_port_ops;
266	qtty->base = base;
267	qtty->irq = irq;
268
269	writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
270
271	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
272						"goldfish_tty", pdev);
273	if (ret)
274		goto err_request_irq_failed;
275
276
277	ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
278							pdev->id, &pdev->dev);
279	if (IS_ERR(ttydev)) {
280		ret = PTR_ERR(ttydev);
281		goto err_tty_register_device_failed;
282	}
283
284	strcpy(qtty->console.name, "ttyGF");
285	qtty->console.write = goldfish_tty_console_write;
286	qtty->console.device = goldfish_tty_console_device;
287	qtty->console.setup = goldfish_tty_console_setup;
288	qtty->console.flags = CON_PRINTBUFFER;
289	qtty->console.index = pdev->id;
290	register_console(&qtty->console);
291
292	mutex_unlock(&goldfish_tty_lock);
293	return 0;
294
295err_tty_register_device_failed:
296	free_irq(irq, pdev);
297err_request_irq_failed:
298	goldfish_tty_current_line_count--;
299	if (goldfish_tty_current_line_count == 0)
300		goldfish_tty_delete_driver();
301err_create_driver_failed:
302	mutex_unlock(&goldfish_tty_lock);
303err_unmap:
304	iounmap(base);
305	return ret;
306}
307
308static int goldfish_tty_remove(struct platform_device *pdev)
309{
310	struct goldfish_tty *qtty;
311
312	mutex_lock(&goldfish_tty_lock);
313
314	qtty = &goldfish_ttys[pdev->id];
315	unregister_console(&qtty->console);
316	tty_unregister_device(goldfish_tty_driver, pdev->id);
317	iounmap(qtty->base);
318	qtty->base = NULL;
319	free_irq(qtty->irq, pdev);
320	goldfish_tty_current_line_count--;
321	if (goldfish_tty_current_line_count == 0)
322		goldfish_tty_delete_driver();
323	mutex_unlock(&goldfish_tty_lock);
324	return 0;
325}
326
327static struct platform_driver goldfish_tty_platform_driver = {
328	.probe = goldfish_tty_probe,
329	.remove = goldfish_tty_remove,
330	.driver = {
331		.name = "goldfish_tty"
332	}
333};
334
335module_platform_driver(goldfish_tty_platform_driver);
336
337MODULE_LICENSE("GPL v2");
338