Root/drivers/tty/goldfish.c

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/init.h>
18#include <linux/interrupt.h>
19#include <linux/platform_device.h>
20#include <linux/tty.h>
21#include <linux/tty_flip.h>
22#include <linux/slab.h>
23#include <linux/io.h>
24#include <linux/module.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
34    GOLDFISH_TTY_CMD_INT_DISABLE = 0,
35    GOLDFISH_TTY_CMD_INT_ENABLE = 1,
36    GOLDFISH_TTY_CMD_WRITE_BUFFER = 2,
37    GOLDFISH_TTY_CMD_READ_BUFFER = 3,
38};
39
40struct goldfish_tty {
41    struct tty_port port;
42    spinlock_t lock;
43    void __iomem *base;
44    u32 irq;
45    int opencount;
46    struct console console;
47};
48
49static DEFINE_MUTEX(goldfish_tty_lock);
50static struct tty_driver *goldfish_tty_driver;
51static u32 goldfish_tty_line_count = 8;
52static u32 goldfish_tty_current_line_count;
53static struct goldfish_tty *goldfish_ttys;
54
55static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
56{
57    unsigned long irq_flags;
58    struct goldfish_tty *qtty = &goldfish_ttys[line];
59    void __iomem *base = qtty->base;
60    spin_lock_irqsave(&qtty->lock, irq_flags);
61    writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
62    writel(count, base + GOLDFISH_TTY_DATA_LEN);
63    writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
64    spin_unlock_irqrestore(&qtty->lock, irq_flags);
65}
66
67static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
68{
69    struct platform_device *pdev = dev_id;
70    struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
71    void __iomem *base = qtty->base;
72    unsigned long irq_flags;
73    unsigned char *buf;
74    u32 count;
75
76    count = readl(base + GOLDFISH_TTY_BYTES_READY);
77    if(count == 0)
78        return IRQ_NONE;
79
80    count = tty_prepare_flip_string(&qtty->port, &buf, count);
81    spin_lock_irqsave(&qtty->lock, irq_flags);
82    writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
83    writel(count, base + GOLDFISH_TTY_DATA_LEN);
84    writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
85    spin_unlock_irqrestore(&qtty->lock, irq_flags);
86    tty_schedule_flip(&qtty->port);
87    return IRQ_HANDLED;
88}
89
90static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
91{
92    struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
93    writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
94    return 0;
95}
96
97static void goldfish_tty_shutdown(struct tty_port *port)
98{
99    struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
100    writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
101}
102
103static int goldfish_tty_open(struct tty_struct * tty, struct file * filp)
104{
105    struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
106    return tty_port_open(&qtty->port, tty, filp);
107}
108
109static void goldfish_tty_close(struct tty_struct * tty, struct file * filp)
110{
111    tty_port_close(tty->port, tty, filp);
112}
113
114static void goldfish_tty_hangup(struct tty_struct *tty)
115{
116    tty_port_hangup(tty->port);
117}
118
119static int goldfish_tty_write(struct tty_struct * tty, const unsigned char *buf, int count)
120{
121    goldfish_tty_do_write(tty->index, buf, count);
122    return count;
123}
124
125static int goldfish_tty_write_room(struct tty_struct *tty)
126{
127    return 0x10000;
128}
129
130static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
131{
132    struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
133    void __iomem *base = qtty->base;
134    return readl(base + GOLDFISH_TTY_BYTES_READY);
135}
136
137static void goldfish_tty_console_write(struct console *co, const char *b, unsigned count)
138{
139    goldfish_tty_do_write(co->index, b, count);
140}
141
142static struct tty_driver *goldfish_tty_console_device(struct console *c, int *index)
143{
144    *index = c->index;
145    return goldfish_tty_driver;
146}
147
148static int goldfish_tty_console_setup(struct console *co, char *options)
149{
150    if((unsigned)co->index > goldfish_tty_line_count)
151        return -ENODEV;
152    if(goldfish_ttys[co->index].base == 0)
153        return -ENODEV;
154    return 0;
155}
156
157static struct tty_port_operations goldfish_port_ops = {
158    .activate = goldfish_tty_activate,
159    .shutdown = goldfish_tty_shutdown
160};
161
162static struct tty_operations goldfish_tty_ops = {
163    .open = goldfish_tty_open,
164    .close = goldfish_tty_close,
165    .hangup = goldfish_tty_hangup,
166    .write = goldfish_tty_write,
167    .write_room = goldfish_tty_write_room,
168    .chars_in_buffer = goldfish_tty_chars_in_buffer,
169};
170
171static int goldfish_tty_create_driver(void)
172{
173    int ret;
174    struct tty_driver *tty;
175
176    goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) * goldfish_tty_line_count, GFP_KERNEL);
177    if(goldfish_ttys == NULL) {
178        ret = -ENOMEM;
179        goto err_alloc_goldfish_ttys_failed;
180    }
181    tty = alloc_tty_driver(goldfish_tty_line_count);
182    if(tty == NULL) {
183        ret = -ENOMEM;
184        goto err_alloc_tty_driver_failed;
185    }
186    tty->driver_name = "goldfish";
187    tty->name = "ttyGF";
188    tty->type = TTY_DRIVER_TYPE_SERIAL;
189    tty->subtype = SERIAL_TYPE_NORMAL;
190    tty->init_termios = tty_std_termios;
191    tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
192    tty_set_operations(tty, &goldfish_tty_ops);
193    ret = tty_register_driver(tty);
194    if(ret)
195        goto err_tty_register_driver_failed;
196
197    goldfish_tty_driver = tty;
198    return 0;
199
200err_tty_register_driver_failed:
201    put_tty_driver(tty);
202err_alloc_tty_driver_failed:
203    kfree(goldfish_ttys);
204    goldfish_ttys = NULL;
205err_alloc_goldfish_ttys_failed:
206    return ret;
207}
208
209static void goldfish_tty_delete_driver(void)
210{
211    tty_unregister_driver(goldfish_tty_driver);
212    put_tty_driver(goldfish_tty_driver);
213    goldfish_tty_driver = NULL;
214    kfree(goldfish_ttys);
215    goldfish_ttys = NULL;
216}
217
218static int goldfish_tty_probe(struct platform_device *pdev)
219{
220    struct goldfish_tty *qtty;
221    int ret = -EINVAL;
222    int i;
223    struct resource *r;
224    struct device *ttydev;
225    void __iomem *base;
226    u32 irq;
227
228    r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
229    if(r == NULL)
230        return -EINVAL;
231
232    base = ioremap(r->start, 0x1000);
233    if (base == NULL)
234        pr_err("goldfish_tty: unable to remap base\n");
235
236    r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
237    if(r == NULL)
238        goto err_unmap;
239
240    irq = r->start;
241
242    if(pdev->id >= goldfish_tty_line_count)
243        goto err_unmap;
244
245    mutex_lock(&goldfish_tty_lock);
246    if(goldfish_tty_current_line_count == 0) {
247        ret = goldfish_tty_create_driver();
248        if(ret)
249            goto err_create_driver_failed;
250    }
251    goldfish_tty_current_line_count++;
252
253    qtty = &goldfish_ttys[pdev->id];
254    spin_lock_init(&qtty->lock);
255    tty_port_init(&qtty->port);
256    qtty->port.ops = &goldfish_port_ops;
257    qtty->base = base;
258    qtty->irq = irq;
259
260    writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
261
262    ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, "goldfish_tty", pdev);
263    if(ret)
264        goto err_request_irq_failed;
265
266
267    ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
268                            pdev->id, &pdev->dev);
269    if(IS_ERR(ttydev)) {
270        ret = PTR_ERR(ttydev);
271        goto err_tty_register_device_failed;
272    }
273
274    strcpy(qtty->console.name, "ttyGF");
275    qtty->console.write = goldfish_tty_console_write;
276    qtty->console.device = goldfish_tty_console_device;
277    qtty->console.setup = goldfish_tty_console_setup;
278    qtty->console.flags = CON_PRINTBUFFER;
279    qtty->console.index = pdev->id;
280    register_console(&qtty->console);
281
282    mutex_unlock(&goldfish_tty_lock);
283    return 0;
284
285    tty_unregister_device(goldfish_tty_driver, i);
286err_tty_register_device_failed:
287    free_irq(irq, pdev);
288err_request_irq_failed:
289    goldfish_tty_current_line_count--;
290    if(goldfish_tty_current_line_count == 0)
291        goldfish_tty_delete_driver();
292err_create_driver_failed:
293    mutex_unlock(&goldfish_tty_lock);
294err_unmap:
295    iounmap(base);
296    return ret;
297}
298
299static int goldfish_tty_remove(struct platform_device *pdev)
300{
301    struct goldfish_tty *qtty;
302
303    mutex_lock(&goldfish_tty_lock);
304
305    qtty = &goldfish_ttys[pdev->id];
306    unregister_console(&qtty->console);
307    tty_unregister_device(goldfish_tty_driver, pdev->id);
308    iounmap(qtty->base);
309    qtty->base = 0;
310    free_irq(qtty->irq, pdev);
311    goldfish_tty_current_line_count--;
312    if(goldfish_tty_current_line_count == 0)
313        goldfish_tty_delete_driver();
314    mutex_unlock(&goldfish_tty_lock);
315    return 0;
316}
317
318static struct platform_driver goldfish_tty_platform_driver = {
319    .probe = goldfish_tty_probe,
320    .remove = goldfish_tty_remove,
321    .driver = {
322        .name = "goldfish_tty"
323    }
324};
325
326module_platform_driver(goldfish_tty_platform_driver);
327
328MODULE_LICENSE("GPL v2");
329

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