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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
0b914218 MF |
2 | /* |
3 | * TTY over Blackfin JTAG Communication | |
4 | * | |
5 | * Copyright 2008-2009 Analog Devices Inc. | |
6 | * | |
7 | * Enter bugs at http://blackfin.uclinux.org/ | |
0b914218 MF |
8 | */ |
9 | ||
56578abf MF |
10 | #define DRV_NAME "bfin-jtag-comm" |
11 | #define DEV_NAME "ttyBFJC" | |
12 | #define pr_fmt(fmt) DRV_NAME ": " fmt | |
13 | ||
0b914218 MF |
14 | #include <linux/circ_buf.h> |
15 | #include <linux/console.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/kthread.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/mutex.h> | |
22 | #include <linux/sched.h> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
0b914218 MF |
24 | #include <linux/tty.h> |
25 | #include <linux/tty_driver.h> | |
26 | #include <linux/tty_flip.h> | |
60063497 | 27 | #include <linux/atomic.h> |
0b914218 | 28 | |
56578abf MF |
29 | #define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); }) |
30 | ||
0b914218 MF |
31 | /* See the Debug/Emulation chapter in the HRM */ |
32 | #define EMUDOF 0x00000001 /* EMUDAT_OUT full & valid */ | |
33 | #define EMUDIF 0x00000002 /* EMUDAT_IN full & valid */ | |
34 | #define EMUDOOVF 0x00000004 /* EMUDAT_OUT overflow */ | |
35 | #define EMUDIOVF 0x00000008 /* EMUDAT_IN overflow */ | |
36 | ||
0b914218 MF |
37 | static inline uint32_t bfin_write_emudat(uint32_t emudat) |
38 | { | |
39 | __asm__ __volatile__("emudat = %0;" : : "d"(emudat)); | |
40 | return emudat; | |
41 | } | |
42 | ||
43 | static inline uint32_t bfin_read_emudat(void) | |
44 | { | |
45 | uint32_t emudat; | |
46 | __asm__ __volatile__("%0 = emudat;" : "=d"(emudat)); | |
47 | return emudat; | |
48 | } | |
49 | ||
50 | static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d) | |
51 | { | |
52 | return bfin_write_emudat((a << 0) | (b << 8) | (c << 16) | (d << 24)); | |
53 | } | |
54 | ||
55 | #define CIRC_SIZE 2048 /* see comment in tty_io.c:do_tty_write() */ | |
56 | #define CIRC_MASK (CIRC_SIZE - 1) | |
57 | #define circ_empty(circ) ((circ)->head == (circ)->tail) | |
58 | #define circ_free(circ) CIRC_SPACE((circ)->head, (circ)->tail, CIRC_SIZE) | |
59 | #define circ_cnt(circ) CIRC_CNT((circ)->head, (circ)->tail, CIRC_SIZE) | |
60 | #define circ_byte(circ, idx) ((circ)->buf[(idx) & CIRC_MASK]) | |
61 | ||
62 | static struct tty_driver *bfin_jc_driver; | |
63 | static struct task_struct *bfin_jc_kthread; | |
560460b8 | 64 | static struct tty_port port; |
0b914218 MF |
65 | static volatile struct circ_buf bfin_jc_write_buf; |
66 | ||
67 | static int | |
68 | bfin_jc_emudat_manager(void *arg) | |
69 | { | |
70 | uint32_t inbound_len = 0, outbound_len = 0; | |
71 | ||
72 | while (!kthread_should_stop()) { | |
e63f9f74 | 73 | struct tty_struct *tty = tty_port_tty_get(&port); |
0b914218 | 74 | /* no one left to give data to, so sleep */ |
e63f9f74 | 75 | if (tty == NULL && circ_empty(&bfin_jc_write_buf)) { |
56578abf | 76 | pr_debug("waiting for readers\n"); |
0b914218 MF |
77 | __set_current_state(TASK_UNINTERRUPTIBLE); |
78 | schedule(); | |
e63f9f74 | 79 | continue; |
0b914218 MF |
80 | } |
81 | ||
82 | /* no data available, so just chill */ | |
83 | if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) { | |
56578abf | 84 | pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n", |
0b914218 | 85 | inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head); |
e63f9f74 | 86 | tty_kref_put(tty); |
0b914218 MF |
87 | if (inbound_len) |
88 | schedule(); | |
89 | else | |
90 | schedule_timeout_interruptible(HZ); | |
91 | continue; | |
92 | } | |
93 | ||
94 | /* if incoming data is ready, eat it */ | |
95 | if (bfin_read_DBGSTAT() & EMUDIF) { | |
2e124b4a JS |
96 | uint32_t emudat = bfin_read_emudat(); |
97 | if (inbound_len == 0) { | |
98 | pr_debug("incoming length: 0x%08x\n", emudat); | |
99 | inbound_len = emudat; | |
100 | } else { | |
101 | size_t num_chars = (4 <= inbound_len ? 4 : inbound_len); | |
102 | pr_debug(" incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars); | |
103 | inbound_len -= num_chars; | |
104 | tty_insert_flip_string(&port, (unsigned char *)&emudat, num_chars); | |
105 | tty_flip_buffer_push(&port); | |
0b914218 | 106 | } |
0b914218 MF |
107 | } |
108 | ||
109 | /* if outgoing data is ready, post it */ | |
110 | if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) { | |
111 | if (outbound_len == 0) { | |
112 | outbound_len = circ_cnt(&bfin_jc_write_buf); | |
113 | bfin_write_emudat(outbound_len); | |
56578abf | 114 | pr_debug("outgoing length: 0x%08x\n", outbound_len); |
0b914218 | 115 | } else { |
0b914218 MF |
116 | int tail = bfin_jc_write_buf.tail; |
117 | size_t ate = (4 <= outbound_len ? 4 : outbound_len); | |
118 | uint32_t emudat = | |
119 | bfin_write_emudat_chars( | |
120 | circ_byte(&bfin_jc_write_buf, tail + 0), | |
121 | circ_byte(&bfin_jc_write_buf, tail + 1), | |
122 | circ_byte(&bfin_jc_write_buf, tail + 2), | |
123 | circ_byte(&bfin_jc_write_buf, tail + 3) | |
124 | ); | |
125 | bfin_jc_write_buf.tail += ate; | |
126 | outbound_len -= ate; | |
0b914218 MF |
127 | if (tty) |
128 | tty_wakeup(tty); | |
56578abf | 129 | pr_debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate); |
0b914218 MF |
130 | } |
131 | } | |
e63f9f74 | 132 | tty_kref_put(tty); |
0b914218 MF |
133 | } |
134 | ||
135 | __set_current_state(TASK_RUNNING); | |
136 | return 0; | |
137 | } | |
138 | ||
139 | static int | |
140 | bfin_jc_open(struct tty_struct *tty, struct file *filp) | |
141 | { | |
e63f9f74 JS |
142 | unsigned long flags; |
143 | ||
144 | spin_lock_irqsave(&port.lock, flags); | |
560460b8 | 145 | port.count++; |
e63f9f74 JS |
146 | spin_unlock_irqrestore(&port.lock, flags); |
147 | tty_port_tty_set(&port, tty); | |
0b914218 | 148 | wake_up_process(bfin_jc_kthread); |
0b914218 MF |
149 | return 0; |
150 | } | |
151 | ||
152 | static void | |
153 | bfin_jc_close(struct tty_struct *tty, struct file *filp) | |
154 | { | |
e63f9f74 JS |
155 | unsigned long flags; |
156 | bool last; | |
157 | ||
158 | spin_lock_irqsave(&port.lock, flags); | |
159 | last = --port.count == 0; | |
160 | spin_unlock_irqrestore(&port.lock, flags); | |
161 | if (last) | |
162 | tty_port_tty_set(&port, NULL); | |
0b914218 | 163 | wake_up_process(bfin_jc_kthread); |
0b914218 MF |
164 | } |
165 | ||
166 | /* XXX: we dont handle the put_char() case where we must handle count = 1 */ | |
167 | static int | |
168 | bfin_jc_circ_write(const unsigned char *buf, int count) | |
169 | { | |
170 | int i; | |
171 | count = min(count, circ_free(&bfin_jc_write_buf)); | |
56578abf | 172 | pr_debug("going to write chunk of %i bytes\n", count); |
0b914218 MF |
173 | for (i = 0; i < count; ++i) |
174 | circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i]; | |
175 | bfin_jc_write_buf.head += i; | |
176 | return i; | |
177 | } | |
178 | ||
179 | #ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE | |
ac751efa TH |
180 | # define console_lock() |
181 | # define console_unlock() | |
0b914218 MF |
182 | #endif |
183 | static int | |
184 | bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count) | |
185 | { | |
186 | int i; | |
ac751efa | 187 | console_lock(); |
0b914218 | 188 | i = bfin_jc_circ_write(buf, count); |
ac751efa | 189 | console_unlock(); |
0b914218 MF |
190 | wake_up_process(bfin_jc_kthread); |
191 | return i; | |
192 | } | |
193 | ||
194 | static void | |
195 | bfin_jc_flush_chars(struct tty_struct *tty) | |
196 | { | |
197 | wake_up_process(bfin_jc_kthread); | |
198 | } | |
199 | ||
200 | static int | |
201 | bfin_jc_write_room(struct tty_struct *tty) | |
202 | { | |
203 | return circ_free(&bfin_jc_write_buf); | |
204 | } | |
205 | ||
206 | static int | |
207 | bfin_jc_chars_in_buffer(struct tty_struct *tty) | |
208 | { | |
209 | return circ_cnt(&bfin_jc_write_buf); | |
210 | } | |
211 | ||
1cceefd3 | 212 | static const struct tty_operations bfin_jc_ops = { |
0b914218 MF |
213 | .open = bfin_jc_open, |
214 | .close = bfin_jc_close, | |
215 | .write = bfin_jc_write, | |
216 | /*.put_char = bfin_jc_put_char,*/ | |
217 | .flush_chars = bfin_jc_flush_chars, | |
218 | .write_room = bfin_jc_write_room, | |
219 | .chars_in_buffer = bfin_jc_chars_in_buffer, | |
0b914218 MF |
220 | }; |
221 | ||
222 | static int __init bfin_jc_init(void) | |
223 | { | |
224 | int ret; | |
225 | ||
226 | bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME); | |
227 | if (IS_ERR(bfin_jc_kthread)) | |
228 | return PTR_ERR(bfin_jc_kthread); | |
229 | ||
230 | ret = -ENOMEM; | |
231 | ||
232 | bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0; | |
233 | bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL); | |
234 | if (!bfin_jc_write_buf.buf) | |
d9d691f5 | 235 | goto err_buf; |
0b914218 MF |
236 | |
237 | bfin_jc_driver = alloc_tty_driver(1); | |
238 | if (!bfin_jc_driver) | |
d9d691f5 | 239 | goto err_driver; |
0b914218 | 240 | |
191c5f10 JS |
241 | tty_port_init(&port); |
242 | ||
0b914218 MF |
243 | bfin_jc_driver->driver_name = DRV_NAME; |
244 | bfin_jc_driver->name = DEV_NAME; | |
245 | bfin_jc_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
246 | bfin_jc_driver->subtype = SERIAL_TYPE_NORMAL; | |
247 | bfin_jc_driver->init_termios = tty_std_termios; | |
248 | tty_set_operations(bfin_jc_driver, &bfin_jc_ops); | |
b19e2ca7 | 249 | tty_port_link_device(&port, bfin_jc_driver, 0); |
0b914218 MF |
250 | |
251 | ret = tty_register_driver(bfin_jc_driver); | |
252 | if (ret) | |
253 | goto err; | |
254 | ||
255 | pr_init(KERN_INFO DRV_NAME ": initialized\n"); | |
256 | ||
257 | return 0; | |
258 | ||
259 | err: | |
191c5f10 | 260 | tty_port_destroy(&port); |
0b914218 | 261 | put_tty_driver(bfin_jc_driver); |
d9d691f5 | 262 | err_driver: |
0b914218 | 263 | kfree(bfin_jc_write_buf.buf); |
d9d691f5 | 264 | err_buf: |
0b914218 MF |
265 | kthread_stop(bfin_jc_kthread); |
266 | return ret; | |
267 | } | |
268 | module_init(bfin_jc_init); | |
269 | ||
270 | static void __exit bfin_jc_exit(void) | |
271 | { | |
272 | kthread_stop(bfin_jc_kthread); | |
273 | kfree(bfin_jc_write_buf.buf); | |
274 | tty_unregister_driver(bfin_jc_driver); | |
275 | put_tty_driver(bfin_jc_driver); | |
191c5f10 | 276 | tty_port_destroy(&port); |
0b914218 MF |
277 | } |
278 | module_exit(bfin_jc_exit); | |
279 | ||
280 | #if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK) | |
281 | static void | |
282 | bfin_jc_straight_buffer_write(const char *buf, unsigned count) | |
283 | { | |
284 | unsigned ate = 0; | |
285 | while (bfin_read_DBGSTAT() & EMUDOF) | |
286 | continue; | |
287 | bfin_write_emudat(count); | |
288 | while (ate < count) { | |
289 | while (bfin_read_DBGSTAT() & EMUDOF) | |
290 | continue; | |
291 | bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]); | |
292 | ate += 4; | |
293 | } | |
294 | } | |
295 | #endif | |
296 | ||
297 | #ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE | |
298 | static void | |
299 | bfin_jc_console_write(struct console *co, const char *buf, unsigned count) | |
300 | { | |
301 | if (bfin_jc_kthread == NULL) | |
302 | bfin_jc_straight_buffer_write(buf, count); | |
303 | else | |
304 | bfin_jc_circ_write(buf, count); | |
305 | } | |
306 | ||
307 | static struct tty_driver * | |
308 | bfin_jc_console_device(struct console *co, int *index) | |
309 | { | |
310 | *index = co->index; | |
311 | return bfin_jc_driver; | |
312 | } | |
313 | ||
314 | static struct console bfin_jc_console = { | |
315 | .name = DEV_NAME, | |
316 | .write = bfin_jc_console_write, | |
317 | .device = bfin_jc_console_device, | |
318 | .flags = CON_ANYTIME | CON_PRINTBUFFER, | |
319 | .index = -1, | |
320 | }; | |
321 | ||
322 | static int __init bfin_jc_console_init(void) | |
323 | { | |
324 | register_console(&bfin_jc_console); | |
325 | return 0; | |
326 | } | |
327 | console_initcall(bfin_jc_console_init); | |
328 | #endif | |
329 | ||
330 | #ifdef CONFIG_EARLY_PRINTK | |
331 | static void __init | |
332 | bfin_jc_early_write(struct console *co, const char *buf, unsigned int count) | |
333 | { | |
334 | bfin_jc_straight_buffer_write(buf, count); | |
335 | } | |
336 | ||
f8294523 | 337 | static struct console bfin_jc_early_console __initdata = { |
0b914218 MF |
338 | .name = "early_BFJC", |
339 | .write = bfin_jc_early_write, | |
340 | .flags = CON_ANYTIME | CON_PRINTBUFFER, | |
341 | .index = -1, | |
342 | }; | |
343 | ||
344 | struct console * __init | |
345 | bfin_jc_early_init(unsigned int port, unsigned int cflag) | |
346 | { | |
347 | return &bfin_jc_early_console; | |
348 | } | |
349 | #endif | |
350 | ||
351 | MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); | |
352 | MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication"); | |
353 | MODULE_LICENSE("GPL"); |