1 /*
2 * Function Control Protocol (IEC 61883-1) helper functions
3 *
4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
5 * Licensed under the terms of the GNU General Public License, version 2.
6 */
7
8 #include <linux/device.h>
9 #include <linux/firewire.h>
10 #include <linux/firewire-constants.h>
11 #include <linux/list.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/spinlock.h>
16 #include <linux/wait.h>
17 #include <linux/delay.h>
18 #include "fcp.h"
19 #include "lib.h"
20 #include "amdtp.h"
21
22 #define CTS_AVC 0x00
23
24 #define ERROR_RETRIES 3
25 #define ERROR_DELAY_MS 5
26 #define FCP_TIMEOUT_MS 125
27
avc_general_set_sig_fmt(struct fw_unit * unit,unsigned int rate,enum avc_general_plug_dir dir,unsigned short pid)28 int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
29 enum avc_general_plug_dir dir,
30 unsigned short pid)
31 {
32 unsigned int sfc;
33 u8 *buf;
34 bool flag;
35 int err;
36
37 flag = false;
38 for (sfc = 0; sfc < CIP_SFC_COUNT; sfc++) {
39 if (amdtp_rate_table[sfc] == rate) {
40 flag = true;
41 break;
42 }
43 }
44 if (!flag)
45 return -EINVAL;
46
47 buf = kzalloc(8, GFP_KERNEL);
48 if (buf == NULL)
49 return -ENOMEM;
50
51 buf[0] = 0x00; /* AV/C CONTROL */
52 buf[1] = 0xff; /* UNIT */
53 if (dir == AVC_GENERAL_PLUG_DIR_IN)
54 buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */
55 else
56 buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */
57 buf[3] = 0xff & pid; /* plug id */
58 buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */
59 buf[5] = 0x07 & sfc; /* FDF-hi. AM824, frequency */
60 buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used)*/
61 buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */
62
63 /* do transaction and check buf[1-5] are the same against command */
64 err = fcp_avc_transaction(unit, buf, 8, buf, 8,
65 BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5));
66 if (err >= 0 && err < 8)
67 err = -EIO;
68 else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
69 err = -ENOSYS;
70 else if (buf[0] == 0x0a) /* REJECTED */
71 err = -EINVAL;
72 if (err < 0)
73 goto end;
74
75 err = 0;
76 end:
77 kfree(buf);
78 return err;
79 }
80 EXPORT_SYMBOL(avc_general_set_sig_fmt);
81
avc_general_get_sig_fmt(struct fw_unit * unit,unsigned int * rate,enum avc_general_plug_dir dir,unsigned short pid)82 int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate,
83 enum avc_general_plug_dir dir,
84 unsigned short pid)
85 {
86 unsigned int sfc;
87 u8 *buf;
88 int err;
89
90 buf = kzalloc(8, GFP_KERNEL);
91 if (buf == NULL)
92 return -ENOMEM;
93
94 buf[0] = 0x01; /* AV/C STATUS */
95 buf[1] = 0xff; /* Unit */
96 if (dir == AVC_GENERAL_PLUG_DIR_IN)
97 buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */
98 else
99 buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */
100 buf[3] = 0xff & pid; /* plug id */
101 buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */
102 buf[5] = 0xff; /* FDF-hi. AM824, frequency */
103 buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used) */
104 buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */
105
106 /* do transaction and check buf[1-4] are the same against command */
107 err = fcp_avc_transaction(unit, buf, 8, buf, 8,
108 BIT(1) | BIT(2) | BIT(3) | BIT(4));
109 if (err >= 0 && err < 8)
110 err = -EIO;
111 else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
112 err = -ENOSYS;
113 else if (buf[0] == 0x0a) /* REJECTED */
114 err = -EINVAL;
115 else if (buf[0] == 0x0b) /* IN TRANSITION */
116 err = -EAGAIN;
117 if (err < 0)
118 goto end;
119
120 /* check sfc field and pick up rate */
121 sfc = 0x07 & buf[5];
122 if (sfc >= CIP_SFC_COUNT) {
123 err = -EAGAIN; /* also in transition */
124 goto end;
125 }
126
127 *rate = amdtp_rate_table[sfc];
128 err = 0;
129 end:
130 kfree(buf);
131 return err;
132 }
133 EXPORT_SYMBOL(avc_general_get_sig_fmt);
134
avc_general_get_plug_info(struct fw_unit * unit,unsigned int subunit_type,unsigned int subunit_id,unsigned int subfunction,u8 info[AVC_PLUG_INFO_BUF_BYTES])135 int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
136 unsigned int subunit_id, unsigned int subfunction,
137 u8 info[AVC_PLUG_INFO_BUF_BYTES])
138 {
139 u8 *buf;
140 int err;
141
142 /* extended subunit in spec.4.2 is not supported */
143 if ((subunit_type == 0x1E) || (subunit_id == 5))
144 return -EINVAL;
145
146 buf = kzalloc(8, GFP_KERNEL);
147 if (buf == NULL)
148 return -ENOMEM;
149
150 buf[0] = 0x01; /* AV/C STATUS */
151 /* UNIT or Subunit, Functionblock */
152 buf[1] = ((subunit_type & 0x1f) << 3) | (subunit_id & 0x7);
153 buf[2] = 0x02; /* PLUG INFO */
154 buf[3] = 0xff & subfunction;
155
156 err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2));
157 if (err >= 0 && err < 8)
158 err = -EIO;
159 else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
160 err = -ENOSYS;
161 else if (buf[0] == 0x0a) /* REJECTED */
162 err = -EINVAL;
163 else if (buf[0] == 0x0b) /* IN TRANSITION */
164 err = -EAGAIN;
165 if (err < 0)
166 goto end;
167
168 info[0] = buf[4];
169 info[1] = buf[5];
170 info[2] = buf[6];
171 info[3] = buf[7];
172
173 err = 0;
174 end:
175 kfree(buf);
176 return err;
177 }
178 EXPORT_SYMBOL(avc_general_get_plug_info);
179
180 static DEFINE_SPINLOCK(transactions_lock);
181 static LIST_HEAD(transactions);
182
183 enum fcp_state {
184 STATE_PENDING,
185 STATE_BUS_RESET,
186 STATE_COMPLETE,
187 STATE_DEFERRED,
188 };
189
190 struct fcp_transaction {
191 struct list_head list;
192 struct fw_unit *unit;
193 void *response_buffer;
194 unsigned int response_size;
195 unsigned int response_match_bytes;
196 enum fcp_state state;
197 wait_queue_head_t wait;
198 bool deferrable;
199 };
200
201 /**
202 * fcp_avc_transaction - send an AV/C command and wait for its response
203 * @unit: a unit on the target device
204 * @command: a buffer containing the command frame; must be DMA-able
205 * @command_size: the size of @command
206 * @response: a buffer for the response frame
207 * @response_size: the maximum size of @response
208 * @response_match_bytes: a bitmap specifying the bytes used to detect the
209 * correct response frame
210 *
211 * This function sends a FCP command frame to the target and waits for the
212 * corresponding response frame to be returned.
213 *
214 * Because it is possible for multiple FCP transactions to be active at the
215 * same time, the correct response frame is detected by the value of certain
216 * bytes. These bytes must be set in @response before calling this function,
217 * and the corresponding bits must be set in @response_match_bytes.
218 *
219 * @command and @response can point to the same buffer.
220 *
221 * Returns the actual size of the response frame, or a negative error code.
222 */
fcp_avc_transaction(struct fw_unit * unit,const void * command,unsigned int command_size,void * response,unsigned int response_size,unsigned int response_match_bytes)223 int fcp_avc_transaction(struct fw_unit *unit,
224 const void *command, unsigned int command_size,
225 void *response, unsigned int response_size,
226 unsigned int response_match_bytes)
227 {
228 struct fcp_transaction t;
229 int tcode, ret, tries = 0;
230
231 t.unit = unit;
232 t.response_buffer = response;
233 t.response_size = response_size;
234 t.response_match_bytes = response_match_bytes;
235 t.state = STATE_PENDING;
236 init_waitqueue_head(&t.wait);
237
238 if (*(const u8 *)command == 0x00 || *(const u8 *)command == 0x03)
239 t.deferrable = true;
240
241 spin_lock_irq(&transactions_lock);
242 list_add_tail(&t.list, &transactions);
243 spin_unlock_irq(&transactions_lock);
244
245 for (;;) {
246 tcode = command_size == 4 ? TCODE_WRITE_QUADLET_REQUEST
247 : TCODE_WRITE_BLOCK_REQUEST;
248 ret = snd_fw_transaction(t.unit, tcode,
249 CSR_REGISTER_BASE + CSR_FCP_COMMAND,
250 (void *)command, command_size, 0);
251 if (ret < 0)
252 break;
253 deferred:
254 wait_event_timeout(t.wait, t.state != STATE_PENDING,
255 msecs_to_jiffies(FCP_TIMEOUT_MS));
256
257 if (t.state == STATE_DEFERRED) {
258 /*
259 * 'AV/C General Specification' define no time limit
260 * on command completion once an INTERIM response has
261 * been sent. but we promise to finish this function
262 * for a caller. Here we use FCP_TIMEOUT_MS for next
263 * interval. This is not in the specification.
264 */
265 t.state = STATE_PENDING;
266 goto deferred;
267 } else if (t.state == STATE_COMPLETE) {
268 ret = t.response_size;
269 break;
270 } else if (t.state == STATE_BUS_RESET) {
271 msleep(ERROR_DELAY_MS);
272 } else if (++tries >= ERROR_RETRIES) {
273 dev_err(&t.unit->device, "FCP command timed out\n");
274 ret = -EIO;
275 break;
276 }
277 }
278
279 spin_lock_irq(&transactions_lock);
280 list_del(&t.list);
281 spin_unlock_irq(&transactions_lock);
282
283 return ret;
284 }
285 EXPORT_SYMBOL(fcp_avc_transaction);
286
287 /**
288 * fcp_bus_reset - inform the target handler about a bus reset
289 * @unit: the unit that might be used by fcp_avc_transaction()
290 *
291 * This function must be called from the driver's .update handler to inform
292 * the FCP transaction handler that a bus reset has happened. Any pending FCP
293 * transactions are retried.
294 */
fcp_bus_reset(struct fw_unit * unit)295 void fcp_bus_reset(struct fw_unit *unit)
296 {
297 struct fcp_transaction *t;
298
299 spin_lock_irq(&transactions_lock);
300 list_for_each_entry(t, &transactions, list) {
301 if (t->unit == unit &&
302 (t->state == STATE_PENDING ||
303 t->state == STATE_DEFERRED)) {
304 t->state = STATE_BUS_RESET;
305 wake_up(&t->wait);
306 }
307 }
308 spin_unlock_irq(&transactions_lock);
309 }
310 EXPORT_SYMBOL(fcp_bus_reset);
311
312 /* checks whether the response matches the masked bytes in response_buffer */
is_matching_response(struct fcp_transaction * transaction,const void * response,size_t length)313 static bool is_matching_response(struct fcp_transaction *transaction,
314 const void *response, size_t length)
315 {
316 const u8 *p1, *p2;
317 unsigned int mask, i;
318
319 p1 = response;
320 p2 = transaction->response_buffer;
321 mask = transaction->response_match_bytes;
322
323 for (i = 0; ; ++i) {
324 if ((mask & 1) && p1[i] != p2[i])
325 return false;
326 mask >>= 1;
327 if (!mask)
328 return true;
329 if (--length == 0)
330 return false;
331 }
332 }
333
fcp_response(struct fw_card * card,struct fw_request * request,int tcode,int destination,int source,int generation,unsigned long long offset,void * data,size_t length,void * callback_data)334 static void fcp_response(struct fw_card *card, struct fw_request *request,
335 int tcode, int destination, int source,
336 int generation, unsigned long long offset,
337 void *data, size_t length, void *callback_data)
338 {
339 struct fcp_transaction *t;
340 unsigned long flags;
341
342 if (length < 1 || (*(const u8 *)data & 0xf0) != CTS_AVC)
343 return;
344
345 spin_lock_irqsave(&transactions_lock, flags);
346 list_for_each_entry(t, &transactions, list) {
347 struct fw_device *device = fw_parent_device(t->unit);
348 if (device->card != card ||
349 device->generation != generation)
350 continue;
351 smp_rmb(); /* node_id vs. generation */
352 if (device->node_id != source)
353 continue;
354
355 if (t->state == STATE_PENDING &&
356 is_matching_response(t, data, length)) {
357 if (t->deferrable && *(const u8 *)data == 0x0f) {
358 t->state = STATE_DEFERRED;
359 } else {
360 t->state = STATE_COMPLETE;
361 t->response_size = min_t(unsigned int, length,
362 t->response_size);
363 memcpy(t->response_buffer, data,
364 t->response_size);
365 }
366 wake_up(&t->wait);
367 }
368 }
369 spin_unlock_irqrestore(&transactions_lock, flags);
370 }
371
372 static struct fw_address_handler response_register_handler = {
373 .length = 0x200,
374 .address_callback = fcp_response,
375 };
376
fcp_module_init(void)377 static int __init fcp_module_init(void)
378 {
379 static const struct fw_address_region response_register_region = {
380 .start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE,
381 .end = CSR_REGISTER_BASE + CSR_FCP_END,
382 };
383
384 fw_core_add_address_handler(&response_register_handler,
385 &response_register_region);
386
387 return 0;
388 }
389
fcp_module_exit(void)390 static void __exit fcp_module_exit(void)
391 {
392 WARN_ON(!list_empty(&transactions));
393 fw_core_remove_address_handler(&response_register_handler);
394 }
395
396 module_init(fcp_module_init);
397 module_exit(fcp_module_exit);
398