include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[linux-2.6.git] / drivers / char / bfin_jtag_comm.c
1 /*
2  * TTY over Blackfin JTAG Communication
3  *
4  * Copyright 2008-2009 Analog Devices Inc.
5  *
6  * Enter bugs at http://blackfin.uclinux.org/
7  *
8  * Licensed under the GPL-2 or later.
9  */
10
11 #define DRV_NAME "bfin-jtag-comm"
12 #define DEV_NAME "ttyBFJC"
13 #define pr_fmt(fmt) DRV_NAME ": " fmt
14
15 #include <linux/circ_buf.h>
16 #include <linux/console.h>
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/kernel.h>
20 #include <linux/kthread.h>
21 #include <linux/module.h>
22 #include <linux/mutex.h>
23 #include <linux/sched.h>
24 #include <linux/slab.h>
25 #include <linux/tty.h>
26 #include <linux/tty_driver.h>
27 #include <linux/tty_flip.h>
28 #include <asm/atomic.h>
29
30 #define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
31
32 /* See the Debug/Emulation chapter in the HRM */
33 #define EMUDOF   0x00000001     /* EMUDAT_OUT full & valid */
34 #define EMUDIF   0x00000002     /* EMUDAT_IN full & valid */
35 #define EMUDOOVF 0x00000004     /* EMUDAT_OUT overflow */
36 #define EMUDIOVF 0x00000008     /* EMUDAT_IN overflow */
37
38 static inline uint32_t bfin_write_emudat(uint32_t emudat)
39 {
40         __asm__ __volatile__("emudat = %0;" : : "d"(emudat));
41         return emudat;
42 }
43
44 static inline uint32_t bfin_read_emudat(void)
45 {
46         uint32_t emudat;
47         __asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
48         return emudat;
49 }
50
51 static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d)
52 {
53         return bfin_write_emudat((a << 0) | (b << 8) | (c << 16) | (d << 24));
54 }
55
56 #define CIRC_SIZE 2048  /* see comment in tty_io.c:do_tty_write() */
57 #define CIRC_MASK (CIRC_SIZE - 1)
58 #define circ_empty(circ)     ((circ)->head == (circ)->tail)
59 #define circ_free(circ)      CIRC_SPACE((circ)->head, (circ)->tail, CIRC_SIZE)
60 #define circ_cnt(circ)       CIRC_CNT((circ)->head, (circ)->tail, CIRC_SIZE)
61 #define circ_byte(circ, idx) ((circ)->buf[(idx) & CIRC_MASK])
62
63 static struct tty_driver *bfin_jc_driver;
64 static struct task_struct *bfin_jc_kthread;
65 static struct tty_struct * volatile bfin_jc_tty;
66 static unsigned long bfin_jc_count;
67 static DEFINE_MUTEX(bfin_jc_tty_mutex);
68 static volatile struct circ_buf bfin_jc_write_buf;
69
70 static int
71 bfin_jc_emudat_manager(void *arg)
72 {
73         uint32_t inbound_len = 0, outbound_len = 0;
74
75         while (!kthread_should_stop()) {
76                 /* no one left to give data to, so sleep */
77                 if (bfin_jc_tty == NULL && circ_empty(&bfin_jc_write_buf)) {
78                         pr_debug("waiting for readers\n");
79                         __set_current_state(TASK_UNINTERRUPTIBLE);
80                         schedule();
81                         __set_current_state(TASK_RUNNING);
82                 }
83
84                 /* no data available, so just chill */
85                 if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) {
86                         pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n",
87                                 inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head);
88                         if (inbound_len)
89                                 schedule();
90                         else
91                                 schedule_timeout_interruptible(HZ);
92                         continue;
93                 }
94
95                 /* if incoming data is ready, eat it */
96                 if (bfin_read_DBGSTAT() & EMUDIF) {
97                         struct tty_struct *tty;
98                         mutex_lock(&bfin_jc_tty_mutex);
99                         tty = (struct tty_struct *)bfin_jc_tty;
100                         if (tty != NULL) {
101                                 uint32_t emudat = bfin_read_emudat();
102                                 if (inbound_len == 0) {
103                                         pr_debug("incoming length: 0x%08x\n", emudat);
104                                         inbound_len = emudat;
105                                 } else {
106                                         size_t num_chars = (4 <= inbound_len ? 4 : inbound_len);
107                                         pr_debug("  incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars);
108                                         inbound_len -= num_chars;
109                                         tty_insert_flip_string(tty, (unsigned char *)&emudat, num_chars);
110                                         tty_flip_buffer_push(tty);
111                                 }
112                         }
113                         mutex_unlock(&bfin_jc_tty_mutex);
114                 }
115
116                 /* if outgoing data is ready, post it */
117                 if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) {
118                         if (outbound_len == 0) {
119                                 outbound_len = circ_cnt(&bfin_jc_write_buf);
120                                 bfin_write_emudat(outbound_len);
121                                 pr_debug("outgoing length: 0x%08x\n", outbound_len);
122                         } else {
123                                 struct tty_struct *tty;
124                                 int tail = bfin_jc_write_buf.tail;
125                                 size_t ate = (4 <= outbound_len ? 4 : outbound_len);
126                                 uint32_t emudat =
127                                 bfin_write_emudat_chars(
128                                         circ_byte(&bfin_jc_write_buf, tail + 0),
129                                         circ_byte(&bfin_jc_write_buf, tail + 1),
130                                         circ_byte(&bfin_jc_write_buf, tail + 2),
131                                         circ_byte(&bfin_jc_write_buf, tail + 3)
132                                 );
133                                 bfin_jc_write_buf.tail += ate;
134                                 outbound_len -= ate;
135                                 mutex_lock(&bfin_jc_tty_mutex);
136                                 tty = (struct tty_struct *)bfin_jc_tty;
137                                 if (tty)
138                                         tty_wakeup(tty);
139                                 mutex_unlock(&bfin_jc_tty_mutex);
140                                 pr_debug("  outgoing data: 0x%08x (pushing %zu)\n", emudat, ate);
141                         }
142                 }
143         }
144
145         __set_current_state(TASK_RUNNING);
146         return 0;
147 }
148
149 static int
150 bfin_jc_open(struct tty_struct *tty, struct file *filp)
151 {
152         mutex_lock(&bfin_jc_tty_mutex);
153         pr_debug("open %lu\n", bfin_jc_count);
154         ++bfin_jc_count;
155         bfin_jc_tty = tty;
156         wake_up_process(bfin_jc_kthread);
157         mutex_unlock(&bfin_jc_tty_mutex);
158         return 0;
159 }
160
161 static void
162 bfin_jc_close(struct tty_struct *tty, struct file *filp)
163 {
164         mutex_lock(&bfin_jc_tty_mutex);
165         pr_debug("close %lu\n", bfin_jc_count);
166         if (--bfin_jc_count == 0)
167                 bfin_jc_tty = NULL;
168         wake_up_process(bfin_jc_kthread);
169         mutex_unlock(&bfin_jc_tty_mutex);
170 }
171
172 /* XXX: we dont handle the put_char() case where we must handle count = 1 */
173 static int
174 bfin_jc_circ_write(const unsigned char *buf, int count)
175 {
176         int i;
177         count = min(count, circ_free(&bfin_jc_write_buf));
178         pr_debug("going to write chunk of %i bytes\n", count);
179         for (i = 0; i < count; ++i)
180                 circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i];
181         bfin_jc_write_buf.head += i;
182         return i;
183 }
184
185 #ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE
186 # define acquire_console_sem()
187 # define release_console_sem()
188 #endif
189 static int
190 bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count)
191 {
192         int i;
193         acquire_console_sem();
194         i = bfin_jc_circ_write(buf, count);
195         release_console_sem();
196         wake_up_process(bfin_jc_kthread);
197         return i;
198 }
199
200 static void
201 bfin_jc_flush_chars(struct tty_struct *tty)
202 {
203         wake_up_process(bfin_jc_kthread);
204 }
205
206 static int
207 bfin_jc_write_room(struct tty_struct *tty)
208 {
209         return circ_free(&bfin_jc_write_buf);
210 }
211
212 static int
213 bfin_jc_chars_in_buffer(struct tty_struct *tty)
214 {
215         return circ_cnt(&bfin_jc_write_buf);
216 }
217
218 static void
219 bfin_jc_wait_until_sent(struct tty_struct *tty, int timeout)
220 {
221         unsigned long expire = jiffies + timeout;
222         while (!circ_empty(&bfin_jc_write_buf)) {
223                 if (signal_pending(current))
224                         break;
225                 if (time_after(jiffies, expire))
226                         break;
227         }
228 }
229
230 static const struct tty_operations bfin_jc_ops = {
231         .open            = bfin_jc_open,
232         .close           = bfin_jc_close,
233         .write           = bfin_jc_write,
234         /*.put_char        = bfin_jc_put_char,*/
235         .flush_chars     = bfin_jc_flush_chars,
236         .write_room      = bfin_jc_write_room,
237         .chars_in_buffer = bfin_jc_chars_in_buffer,
238         .wait_until_sent = bfin_jc_wait_until_sent,
239 };
240
241 static int __init bfin_jc_init(void)
242 {
243         int ret;
244
245         bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME);
246         if (IS_ERR(bfin_jc_kthread))
247                 return PTR_ERR(bfin_jc_kthread);
248
249         ret = -ENOMEM;
250
251         bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0;
252         bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL);
253         if (!bfin_jc_write_buf.buf)
254                 goto err;
255
256         bfin_jc_driver = alloc_tty_driver(1);
257         if (!bfin_jc_driver)
258                 goto err;
259
260         bfin_jc_driver->owner        = THIS_MODULE;
261         bfin_jc_driver->driver_name  = DRV_NAME;
262         bfin_jc_driver->name         = DEV_NAME;
263         bfin_jc_driver->type         = TTY_DRIVER_TYPE_SERIAL;
264         bfin_jc_driver->subtype      = SERIAL_TYPE_NORMAL;
265         bfin_jc_driver->init_termios = tty_std_termios;
266         tty_set_operations(bfin_jc_driver, &bfin_jc_ops);
267
268         ret = tty_register_driver(bfin_jc_driver);
269         if (ret)
270                 goto err;
271
272         pr_init(KERN_INFO DRV_NAME ": initialized\n");
273
274         return 0;
275
276  err:
277         put_tty_driver(bfin_jc_driver);
278         kfree(bfin_jc_write_buf.buf);
279         kthread_stop(bfin_jc_kthread);
280         return ret;
281 }
282 module_init(bfin_jc_init);
283
284 static void __exit bfin_jc_exit(void)
285 {
286         kthread_stop(bfin_jc_kthread);
287         kfree(bfin_jc_write_buf.buf);
288         tty_unregister_driver(bfin_jc_driver);
289         put_tty_driver(bfin_jc_driver);
290 }
291 module_exit(bfin_jc_exit);
292
293 #if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
294 static void
295 bfin_jc_straight_buffer_write(const char *buf, unsigned count)
296 {
297         unsigned ate = 0;
298         while (bfin_read_DBGSTAT() & EMUDOF)
299                 continue;
300         bfin_write_emudat(count);
301         while (ate < count) {
302                 while (bfin_read_DBGSTAT() & EMUDOF)
303                         continue;
304                 bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]);
305                 ate += 4;
306         }
307 }
308 #endif
309
310 #ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE
311 static void
312 bfin_jc_console_write(struct console *co, const char *buf, unsigned count)
313 {
314         if (bfin_jc_kthread == NULL)
315                 bfin_jc_straight_buffer_write(buf, count);
316         else
317                 bfin_jc_circ_write(buf, count);
318 }
319
320 static struct tty_driver *
321 bfin_jc_console_device(struct console *co, int *index)
322 {
323         *index = co->index;
324         return bfin_jc_driver;
325 }
326
327 static struct console bfin_jc_console = {
328         .name    = DEV_NAME,
329         .write   = bfin_jc_console_write,
330         .device  = bfin_jc_console_device,
331         .flags   = CON_ANYTIME | CON_PRINTBUFFER,
332         .index   = -1,
333 };
334
335 static int __init bfin_jc_console_init(void)
336 {
337         register_console(&bfin_jc_console);
338         return 0;
339 }
340 console_initcall(bfin_jc_console_init);
341 #endif
342
343 #ifdef CONFIG_EARLY_PRINTK
344 static void __init
345 bfin_jc_early_write(struct console *co, const char *buf, unsigned int count)
346 {
347         bfin_jc_straight_buffer_write(buf, count);
348 }
349
350 static struct __initdata console bfin_jc_early_console = {
351         .name   = "early_BFJC",
352         .write   = bfin_jc_early_write,
353         .flags   = CON_ANYTIME | CON_PRINTBUFFER,
354         .index   = -1,
355 };
356
357 struct console * __init
358 bfin_jc_early_init(unsigned int port, unsigned int cflag)
359 {
360         return &bfin_jc_early_console;
361 }
362 #endif
363
364 MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
365 MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication");
366 MODULE_LICENSE("GPL");