tjh.dev
Linux kernel mirror (for testing)
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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
25enum {
26 GOLDFISH_TTY_PUT_CHAR = 0x00,
27 GOLDFISH_TTY_BYTES_READY = 0x04,
28 GOLDFISH_TTY_CMD = 0x08,
29
30 GOLDFISH_TTY_DATA_PTR = 0x10,
31 GOLDFISH_TTY_DATA_LEN = 0x14,
32
33 GOLDFISH_TTY_CMD_INT_DISABLE = 0,
34 GOLDFISH_TTY_CMD_INT_ENABLE = 1,
35 GOLDFISH_TTY_CMD_WRITE_BUFFER = 2,
36 GOLDFISH_TTY_CMD_READ_BUFFER = 3,
37};
38
39struct goldfish_tty {
40 struct tty_port port;
41 spinlock_t lock;
42 void __iomem *base;
43 u32 irq;
44 int opencount;
45 struct console console;
46};
47
48static DEFINE_MUTEX(goldfish_tty_lock);
49static struct tty_driver *goldfish_tty_driver;
50static u32 goldfish_tty_line_count = 8;
51static u32 goldfish_tty_current_line_count;
52static struct goldfish_tty *goldfish_ttys;
53
54static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
55{
56 unsigned long irq_flags;
57 struct goldfish_tty *qtty = &goldfish_ttys[line];
58 void __iomem *base = qtty->base;
59 spin_lock_irqsave(&qtty->lock, irq_flags);
60 writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
61 writel(count, base + GOLDFISH_TTY_DATA_LEN);
62 writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
63 spin_unlock_irqrestore(&qtty->lock, irq_flags);
64}
65
66static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
67{
68 struct platform_device *pdev = dev_id;
69 struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
70 void __iomem *base = qtty->base;
71 unsigned long irq_flags;
72 unsigned char *buf;
73 u32 count;
74
75 count = readl(base + GOLDFISH_TTY_BYTES_READY);
76 if(count == 0)
77 return IRQ_NONE;
78
79 count = tty_prepare_flip_string(&qtty->port, &buf, count);
80 spin_lock_irqsave(&qtty->lock, irq_flags);
81 writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
82 writel(count, base + GOLDFISH_TTY_DATA_LEN);
83 writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
84 spin_unlock_irqrestore(&qtty->lock, irq_flags);
85 tty_schedule_flip(&qtty->port);
86 return IRQ_HANDLED;
87}
88
89static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
90{
91 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
92 writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
93 return 0;
94}
95
96static void goldfish_tty_shutdown(struct tty_port *port)
97{
98 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
99 writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
100}
101
102static int goldfish_tty_open(struct tty_struct * tty, struct file * filp)
103{
104 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
105 return tty_port_open(&qtty->port, tty, filp);
106}
107
108static void goldfish_tty_close(struct tty_struct * tty, struct file * filp)
109{
110 tty_port_close(tty->port, tty, filp);
111}
112
113static void goldfish_tty_hangup(struct tty_struct *tty)
114{
115 tty_port_hangup(tty->port);
116}
117
118static int goldfish_tty_write(struct tty_struct * tty, const unsigned char *buf, int count)
119{
120 goldfish_tty_do_write(tty->index, buf, count);
121 return count;
122}
123
124static int goldfish_tty_write_room(struct tty_struct *tty)
125{
126 return 0x10000;
127}
128
129static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
130{
131 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
132 void __iomem *base = qtty->base;
133 return readl(base + GOLDFISH_TTY_BYTES_READY);
134}
135
136static void goldfish_tty_console_write(struct console *co, const char *b, unsigned count)
137{
138 goldfish_tty_do_write(co->index, b, count);
139}
140
141static struct tty_driver *goldfish_tty_console_device(struct console *c, int *index)
142{
143 *index = c->index;
144 return goldfish_tty_driver;
145}
146
147static int goldfish_tty_console_setup(struct console *co, char *options)
148{
149 if((unsigned)co->index > goldfish_tty_line_count)
150 return -ENODEV;
151 if(goldfish_ttys[co->index].base == 0)
152 return -ENODEV;
153 return 0;
154}
155
156static struct tty_port_operations goldfish_port_ops = {
157 .activate = goldfish_tty_activate,
158 .shutdown = goldfish_tty_shutdown
159};
160
161static struct tty_operations goldfish_tty_ops = {
162 .open = goldfish_tty_open,
163 .close = goldfish_tty_close,
164 .hangup = goldfish_tty_hangup,
165 .write = goldfish_tty_write,
166 .write_room = goldfish_tty_write_room,
167 .chars_in_buffer = goldfish_tty_chars_in_buffer,
168};
169
170static int goldfish_tty_create_driver(void)
171{
172 int ret;
173 struct tty_driver *tty;
174
175 goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) * goldfish_tty_line_count, GFP_KERNEL);
176 if(goldfish_ttys == NULL) {
177 ret = -ENOMEM;
178 goto err_alloc_goldfish_ttys_failed;
179 }
180 tty = alloc_tty_driver(goldfish_tty_line_count);
181 if(tty == NULL) {
182 ret = -ENOMEM;
183 goto err_alloc_tty_driver_failed;
184 }
185 tty->driver_name = "goldfish";
186 tty->name = "ttyGF";
187 tty->type = TTY_DRIVER_TYPE_SERIAL;
188 tty->subtype = SERIAL_TYPE_NORMAL;
189 tty->init_termios = tty_std_termios;
190 tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
191 tty_set_operations(tty, &goldfish_tty_ops);
192 ret = tty_register_driver(tty);
193 if(ret)
194 goto err_tty_register_driver_failed;
195
196 goldfish_tty_driver = tty;
197 return 0;
198
199err_tty_register_driver_failed:
200 put_tty_driver(tty);
201err_alloc_tty_driver_failed:
202 kfree(goldfish_ttys);
203 goldfish_ttys = NULL;
204err_alloc_goldfish_ttys_failed:
205 return ret;
206}
207
208static void goldfish_tty_delete_driver(void)
209{
210 tty_unregister_driver(goldfish_tty_driver);
211 put_tty_driver(goldfish_tty_driver);
212 goldfish_tty_driver = NULL;
213 kfree(goldfish_ttys);
214 goldfish_ttys = NULL;
215}
216
217static int goldfish_tty_probe(struct platform_device *pdev)
218{
219 struct goldfish_tty *qtty;
220 int ret = -EINVAL;
221 int i;
222 struct resource *r;
223 struct device *ttydev;
224 void __iomem *base;
225 u32 irq;
226
227 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
228 if(r == NULL)
229 return -EINVAL;
230
231 base = ioremap(r->start, 0x1000);
232 if (base == NULL)
233 pr_err("goldfish_tty: unable to remap base\n");
234
235 r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
236 if(r == NULL)
237 goto err_unmap;
238
239 irq = r->start;
240
241 if(pdev->id >= goldfish_tty_line_count)
242 goto err_unmap;
243
244 mutex_lock(&goldfish_tty_lock);
245 if(goldfish_tty_current_line_count == 0) {
246 ret = goldfish_tty_create_driver();
247 if(ret)
248 goto err_create_driver_failed;
249 }
250 goldfish_tty_current_line_count++;
251
252 qtty = &goldfish_ttys[pdev->id];
253 spin_lock_init(&qtty->lock);
254 tty_port_init(&qtty->port);
255 qtty->port.ops = &goldfish_port_ops;
256 qtty->base = base;
257 qtty->irq = irq;
258
259 writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
260
261 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, "goldfish_tty", pdev);
262 if(ret)
263 goto err_request_irq_failed;
264
265
266 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
267 pdev->id, &pdev->dev);
268 if(IS_ERR(ttydev)) {
269 ret = PTR_ERR(ttydev);
270 goto err_tty_register_device_failed;
271 }
272
273 strcpy(qtty->console.name, "ttyGF");
274 qtty->console.write = goldfish_tty_console_write;
275 qtty->console.device = goldfish_tty_console_device;
276 qtty->console.setup = goldfish_tty_console_setup;
277 qtty->console.flags = CON_PRINTBUFFER;
278 qtty->console.index = pdev->id;
279 register_console(&qtty->console);
280
281 mutex_unlock(&goldfish_tty_lock);
282 return 0;
283
284 tty_unregister_device(goldfish_tty_driver, i);
285err_tty_register_device_failed:
286 free_irq(irq, pdev);
287err_request_irq_failed:
288 goldfish_tty_current_line_count--;
289 if(goldfish_tty_current_line_count == 0)
290 goldfish_tty_delete_driver();
291err_create_driver_failed:
292 mutex_unlock(&goldfish_tty_lock);
293err_unmap:
294 iounmap(base);
295 return ret;
296}
297
298static int goldfish_tty_remove(struct platform_device *pdev)
299{
300 struct goldfish_tty *qtty;
301
302 mutex_lock(&goldfish_tty_lock);
303
304 qtty = &goldfish_ttys[pdev->id];
305 unregister_console(&qtty->console);
306 tty_unregister_device(goldfish_tty_driver, pdev->id);
307 iounmap(qtty->base);
308 qtty->base = 0;
309 free_irq(qtty->irq, pdev);
310 goldfish_tty_current_line_count--;
311 if(goldfish_tty_current_line_count == 0)
312 goldfish_tty_delete_driver();
313 mutex_unlock(&goldfish_tty_lock);
314 return 0;
315}
316
317static struct platform_driver goldfish_tty_platform_driver = {
318 .probe = goldfish_tty_probe,
319 .remove = goldfish_tty_remove,
320 .driver = {
321 .name = "goldfish_tty"
322 }
323};
324
325module_platform_driver(goldfish_tty_platform_driver);
326
327MODULE_LICENSE("GPL v2");