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0b914218 MF |
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 | ||
56578abf MF |
11 | #define DRV_NAME "bfin-jtag-comm" |
12 | #define DEV_NAME "ttyBFJC" | |
13 | #define pr_fmt(fmt) DRV_NAME ": " fmt | |
14 | ||
0b914218 MF |
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> | |
5a0e3ad6 | 24 | #include <linux/slab.h> |
0b914218 MF |
25 | #include <linux/tty.h> |
26 | #include <linux/tty_driver.h> | |
27 | #include <linux/tty_flip.h> | |
60063497 | 28 | #include <linux/atomic.h> |
0b914218 | 29 | |
56578abf MF |
30 | #define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); }) |
31 | ||
0b914218 MF |
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 | ||
0b914218 MF |
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; | |
560460b8 | 65 | static struct tty_port port; |
0b914218 MF |
66 | static volatile struct circ_buf bfin_jc_write_buf; |
67 | ||
68 | static int | |
69 | bfin_jc_emudat_manager(void *arg) | |
70 | { | |
71 | uint32_t inbound_len = 0, outbound_len = 0; | |
72 | ||
73 | while (!kthread_should_stop()) { | |
e63f9f74 | 74 | struct tty_struct *tty = tty_port_tty_get(&port); |
0b914218 | 75 | /* no one left to give data to, so sleep */ |
e63f9f74 | 76 | if (tty == NULL && circ_empty(&bfin_jc_write_buf)) { |
56578abf | 77 | pr_debug("waiting for readers\n"); |
0b914218 MF |
78 | __set_current_state(TASK_UNINTERRUPTIBLE); |
79 | schedule(); | |
e63f9f74 | 80 | continue; |
0b914218 MF |
81 | } |
82 | ||
83 | /* no data available, so just chill */ | |
84 | if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) { | |
56578abf | 85 | pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n", |
0b914218 | 86 | inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head); |
e63f9f74 | 87 | tty_kref_put(tty); |
0b914218 MF |
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) { | |
2e124b4a JS |
97 | uint32_t emudat = bfin_read_emudat(); |
98 | if (inbound_len == 0) { | |
99 | pr_debug("incoming length: 0x%08x\n", emudat); | |
100 | inbound_len = emudat; | |
101 | } else { | |
102 | size_t num_chars = (4 <= inbound_len ? 4 : inbound_len); | |
103 | pr_debug(" incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars); | |
104 | inbound_len -= num_chars; | |
105 | tty_insert_flip_string(&port, (unsigned char *)&emudat, num_chars); | |
106 | tty_flip_buffer_push(&port); | |
0b914218 | 107 | } |
0b914218 MF |
108 | } |
109 | ||
110 | /* if outgoing data is ready, post it */ | |
111 | if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) { | |
112 | if (outbound_len == 0) { | |
113 | outbound_len = circ_cnt(&bfin_jc_write_buf); | |
114 | bfin_write_emudat(outbound_len); | |
56578abf | 115 | pr_debug("outgoing length: 0x%08x\n", outbound_len); |
0b914218 | 116 | } else { |
0b914218 MF |
117 | int tail = bfin_jc_write_buf.tail; |
118 | size_t ate = (4 <= outbound_len ? 4 : outbound_len); | |
119 | uint32_t emudat = | |
120 | bfin_write_emudat_chars( | |
121 | circ_byte(&bfin_jc_write_buf, tail + 0), | |
122 | circ_byte(&bfin_jc_write_buf, tail + 1), | |
123 | circ_byte(&bfin_jc_write_buf, tail + 2), | |
124 | circ_byte(&bfin_jc_write_buf, tail + 3) | |
125 | ); | |
126 | bfin_jc_write_buf.tail += ate; | |
127 | outbound_len -= ate; | |
0b914218 MF |
128 | if (tty) |
129 | tty_wakeup(tty); | |
56578abf | 130 | pr_debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate); |
0b914218 MF |
131 | } |
132 | } | |
e63f9f74 | 133 | tty_kref_put(tty); |
0b914218 MF |
134 | } |
135 | ||
136 | __set_current_state(TASK_RUNNING); | |
137 | return 0; | |
138 | } | |
139 | ||
140 | static int | |
141 | bfin_jc_open(struct tty_struct *tty, struct file *filp) | |
142 | { | |
e63f9f74 JS |
143 | unsigned long flags; |
144 | ||
145 | spin_lock_irqsave(&port.lock, flags); | |
560460b8 | 146 | port.count++; |
e63f9f74 JS |
147 | spin_unlock_irqrestore(&port.lock, flags); |
148 | tty_port_tty_set(&port, tty); | |
0b914218 | 149 | wake_up_process(bfin_jc_kthread); |
0b914218 MF |
150 | return 0; |
151 | } | |
152 | ||
153 | static void | |
154 | bfin_jc_close(struct tty_struct *tty, struct file *filp) | |
155 | { | |
e63f9f74 JS |
156 | unsigned long flags; |
157 | bool last; | |
158 | ||
159 | spin_lock_irqsave(&port.lock, flags); | |
160 | last = --port.count == 0; | |
161 | spin_unlock_irqrestore(&port.lock, flags); | |
162 | if (last) | |
163 | tty_port_tty_set(&port, NULL); | |
0b914218 | 164 | wake_up_process(bfin_jc_kthread); |
0b914218 MF |
165 | } |
166 | ||
167 | /* XXX: we dont handle the put_char() case where we must handle count = 1 */ | |
168 | static int | |
169 | bfin_jc_circ_write(const unsigned char *buf, int count) | |
170 | { | |
171 | int i; | |
172 | count = min(count, circ_free(&bfin_jc_write_buf)); | |
56578abf | 173 | pr_debug("going to write chunk of %i bytes\n", count); |
0b914218 MF |
174 | for (i = 0; i < count; ++i) |
175 | circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i]; | |
176 | bfin_jc_write_buf.head += i; | |
177 | return i; | |
178 | } | |
179 | ||
180 | #ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE | |
ac751efa TH |
181 | # define console_lock() |
182 | # define console_unlock() | |
0b914218 MF |
183 | #endif |
184 | static int | |
185 | bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
186 | { | |
187 | int i; | |
ac751efa | 188 | console_lock(); |
0b914218 | 189 | i = bfin_jc_circ_write(buf, count); |
ac751efa | 190 | console_unlock(); |
0b914218 MF |
191 | wake_up_process(bfin_jc_kthread); |
192 | return i; | |
193 | } | |
194 | ||
195 | static void | |
196 | bfin_jc_flush_chars(struct tty_struct *tty) | |
197 | { | |
198 | wake_up_process(bfin_jc_kthread); | |
199 | } | |
200 | ||
201 | static int | |
202 | bfin_jc_write_room(struct tty_struct *tty) | |
203 | { | |
204 | return circ_free(&bfin_jc_write_buf); | |
205 | } | |
206 | ||
207 | static int | |
208 | bfin_jc_chars_in_buffer(struct tty_struct *tty) | |
209 | { | |
210 | return circ_cnt(&bfin_jc_write_buf); | |
211 | } | |
212 | ||
1cceefd3 | 213 | static const struct tty_operations bfin_jc_ops = { |
0b914218 MF |
214 | .open = bfin_jc_open, |
215 | .close = bfin_jc_close, | |
216 | .write = bfin_jc_write, | |
217 | /*.put_char = bfin_jc_put_char,*/ | |
218 | .flush_chars = bfin_jc_flush_chars, | |
219 | .write_room = bfin_jc_write_room, | |
220 | .chars_in_buffer = bfin_jc_chars_in_buffer, | |
0b914218 MF |
221 | }; |
222 | ||
223 | static int __init bfin_jc_init(void) | |
224 | { | |
225 | int ret; | |
226 | ||
227 | bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME); | |
228 | if (IS_ERR(bfin_jc_kthread)) | |
229 | return PTR_ERR(bfin_jc_kthread); | |
230 | ||
231 | ret = -ENOMEM; | |
232 | ||
233 | bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0; | |
234 | bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL); | |
235 | if (!bfin_jc_write_buf.buf) | |
d9d691f5 | 236 | goto err_buf; |
0b914218 MF |
237 | |
238 | bfin_jc_driver = alloc_tty_driver(1); | |
239 | if (!bfin_jc_driver) | |
d9d691f5 | 240 | goto err_driver; |
0b914218 | 241 | |
191c5f10 JS |
242 | tty_port_init(&port); |
243 | ||
0b914218 MF |
244 | bfin_jc_driver->driver_name = DRV_NAME; |
245 | bfin_jc_driver->name = DEV_NAME; | |
246 | bfin_jc_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
247 | bfin_jc_driver->subtype = SERIAL_TYPE_NORMAL; | |
248 | bfin_jc_driver->init_termios = tty_std_termios; | |
249 | tty_set_operations(bfin_jc_driver, &bfin_jc_ops); | |
b19e2ca7 | 250 | tty_port_link_device(&port, bfin_jc_driver, 0); |
0b914218 MF |
251 | |
252 | ret = tty_register_driver(bfin_jc_driver); | |
253 | if (ret) | |
254 | goto err; | |
255 | ||
256 | pr_init(KERN_INFO DRV_NAME ": initialized\n"); | |
257 | ||
258 | return 0; | |
259 | ||
260 | err: | |
191c5f10 | 261 | tty_port_destroy(&port); |
0b914218 | 262 | put_tty_driver(bfin_jc_driver); |
d9d691f5 | 263 | err_driver: |
0b914218 | 264 | kfree(bfin_jc_write_buf.buf); |
d9d691f5 | 265 | err_buf: |
0b914218 MF |
266 | kthread_stop(bfin_jc_kthread); |
267 | return ret; | |
268 | } | |
269 | module_init(bfin_jc_init); | |
270 | ||
271 | static void __exit bfin_jc_exit(void) | |
272 | { | |
273 | kthread_stop(bfin_jc_kthread); | |
274 | kfree(bfin_jc_write_buf.buf); | |
275 | tty_unregister_driver(bfin_jc_driver); | |
276 | put_tty_driver(bfin_jc_driver); | |
191c5f10 | 277 | tty_port_destroy(&port); |
0b914218 MF |
278 | } |
279 | module_exit(bfin_jc_exit); | |
280 | ||
281 | #if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK) | |
282 | static void | |
283 | bfin_jc_straight_buffer_write(const char *buf, unsigned count) | |
284 | { | |
285 | unsigned ate = 0; | |
286 | while (bfin_read_DBGSTAT() & EMUDOF) | |
287 | continue; | |
288 | bfin_write_emudat(count); | |
289 | while (ate < count) { | |
290 | while (bfin_read_DBGSTAT() & EMUDOF) | |
291 | continue; | |
292 | bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]); | |
293 | ate += 4; | |
294 | } | |
295 | } | |
296 | #endif | |
297 | ||
298 | #ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE | |
299 | static void | |
300 | bfin_jc_console_write(struct console *co, const char *buf, unsigned count) | |
301 | { | |
302 | if (bfin_jc_kthread == NULL) | |
303 | bfin_jc_straight_buffer_write(buf, count); | |
304 | else | |
305 | bfin_jc_circ_write(buf, count); | |
306 | } | |
307 | ||
308 | static struct tty_driver * | |
309 | bfin_jc_console_device(struct console *co, int *index) | |
310 | { | |
311 | *index = co->index; | |
312 | return bfin_jc_driver; | |
313 | } | |
314 | ||
315 | static struct console bfin_jc_console = { | |
316 | .name = DEV_NAME, | |
317 | .write = bfin_jc_console_write, | |
318 | .device = bfin_jc_console_device, | |
319 | .flags = CON_ANYTIME | CON_PRINTBUFFER, | |
320 | .index = -1, | |
321 | }; | |
322 | ||
323 | static int __init bfin_jc_console_init(void) | |
324 | { | |
325 | register_console(&bfin_jc_console); | |
326 | return 0; | |
327 | } | |
328 | console_initcall(bfin_jc_console_init); | |
329 | #endif | |
330 | ||
331 | #ifdef CONFIG_EARLY_PRINTK | |
332 | static void __init | |
333 | bfin_jc_early_write(struct console *co, const char *buf, unsigned int count) | |
334 | { | |
335 | bfin_jc_straight_buffer_write(buf, count); | |
336 | } | |
337 | ||
f8294523 | 338 | static struct console bfin_jc_early_console __initdata = { |
0b914218 MF |
339 | .name = "early_BFJC", |
340 | .write = bfin_jc_early_write, | |
341 | .flags = CON_ANYTIME | CON_PRINTBUFFER, | |
342 | .index = -1, | |
343 | }; | |
344 | ||
345 | struct console * __init | |
346 | bfin_jc_early_init(unsigned int port, unsigned int cflag) | |
347 | { | |
348 | return &bfin_jc_early_console; | |
349 | } | |
350 | #endif | |
351 | ||
352 | MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); | |
353 | MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication"); | |
354 | MODULE_LICENSE("GPL"); |