1/*
2 * fireworks_transaction.c - a part of driver for Fireworks based devices
3 *
4 * Copyright (c) 2013-2014 Takashi Sakamoto
5 *
6 * Licensed under the terms of the GNU General Public License, version 2.
7 */
8
9/*
10 * Fireworks have its own transaction. The transaction can be delivered by AV/C
11 * Vendor Specific command frame or usual asynchronous transaction. At least,
12 * Windows driver and firmware version 5.5 or later don't use AV/C command.
13 *
14 * Transaction substance:
15 *  At first, 6 data exist. Following to the data, parameters for each command
16 *  exist. All of the parameters are 32 bit aligned to big endian.
17 *   data[0]:	Length of transaction substance
18 *   data[1]:	Transaction version
19 *   data[2]:	Sequence number. This is incremented by the device
20 *   data[3]:	Transaction category
21 *   data[4]:	Transaction command
22 *   data[5]:	Return value in response.
23 *   data[6-]:	Parameters
24 *
25 * Transaction address:
26 *  command:	0xecc000000000
27 *  response:	0xecc080000000 (default)
28 *
29 * I note that the address for response can be changed by command. But this
30 * module uses the default address.
31 */
32#include "./fireworks.h"
33
34#define MEMORY_SPACE_EFW_COMMAND	0xecc000000000ULL
35#define MEMORY_SPACE_EFW_RESPONSE	0xecc080000000ULL
36
37#define ERROR_RETRIES 3
38#define ERROR_DELAY_MS 5
39#define EFC_TIMEOUT_MS 125
40
41static DEFINE_SPINLOCK(instances_lock);
42static struct snd_efw *instances[SNDRV_CARDS] = SNDRV_DEFAULT_PTR;
43
44static DEFINE_SPINLOCK(transaction_queues_lock);
45static LIST_HEAD(transaction_queues);
46
47enum transaction_queue_state {
48	STATE_PENDING,
49	STATE_BUS_RESET,
50	STATE_COMPLETE
51};
52
53struct transaction_queue {
54	struct list_head list;
55	struct fw_unit *unit;
56	void *buf;
57	unsigned int size;
58	u32 seqnum;
59	enum transaction_queue_state state;
60	wait_queue_head_t wait;
61};
62
63int snd_efw_transaction_cmd(struct fw_unit *unit,
64			    const void *cmd, unsigned int size)
65{
66	return snd_fw_transaction(unit, TCODE_WRITE_BLOCK_REQUEST,
67				  MEMORY_SPACE_EFW_COMMAND,
68				  (void *)cmd, size, 0);
69}
70
71int snd_efw_transaction_run(struct fw_unit *unit,
72			    const void *cmd, unsigned int cmd_size,
73			    void *resp, unsigned int resp_size)
74{
75	struct transaction_queue t;
76	unsigned int tries;
77	int ret;
78
79	t.unit = unit;
80	t.buf = resp;
81	t.size = resp_size;
82	t.seqnum = be32_to_cpu(((struct snd_efw_transaction *)cmd)->seqnum) + 1;
83	t.state = STATE_PENDING;
84	init_waitqueue_head(&t.wait);
85
86	spin_lock_irq(&transaction_queues_lock);
87	list_add_tail(&t.list, &transaction_queues);
88	spin_unlock_irq(&transaction_queues_lock);
89
90	tries = 0;
91	do {
92		ret = snd_efw_transaction_cmd(t.unit, (void *)cmd, cmd_size);
93		if (ret < 0)
94			break;
95
96		wait_event_timeout(t.wait, t.state != STATE_PENDING,
97				   msecs_to_jiffies(EFC_TIMEOUT_MS));
98
99		if (t.state == STATE_COMPLETE) {
100			ret = t.size;
101			break;
102		} else if (t.state == STATE_BUS_RESET) {
103			msleep(ERROR_DELAY_MS);
104		} else if (++tries >= ERROR_RETRIES) {
105			dev_err(&t.unit->device, "EFW transaction timed out\n");
106			ret = -EIO;
107			break;
108		}
109	} while (1);
110
111	spin_lock_irq(&transaction_queues_lock);
112	list_del(&t.list);
113	spin_unlock_irq(&transaction_queues_lock);
114
115	return ret;
116}
117
118static void
119copy_resp_to_buf(struct snd_efw *efw, void *data, size_t length, int *rcode)
120{
121	size_t capacity, till_end;
122	struct snd_efw_transaction *t;
123
124	spin_lock_irq(&efw->lock);
125
126	t = (struct snd_efw_transaction *)data;
127	length = min_t(size_t, be32_to_cpu(t->length) * sizeof(u32), length);
128
129	if (efw->push_ptr < efw->pull_ptr)
130		capacity = (unsigned int)(efw->pull_ptr - efw->push_ptr);
131	else
132		capacity = snd_efw_resp_buf_size -
133			   (unsigned int)(efw->push_ptr - efw->pull_ptr);
134
135	/* confirm enough space for this response */
136	if (capacity < length) {
137		*rcode = RCODE_CONFLICT_ERROR;
138		goto end;
139	}
140
141	/* copy to ring buffer */
142	while (length > 0) {
143		till_end = snd_efw_resp_buf_size -
144			   (unsigned int)(efw->push_ptr - efw->resp_buf);
145		till_end = min_t(unsigned int, length, till_end);
146
147		memcpy(efw->push_ptr, data, till_end);
148
149		efw->push_ptr += till_end;
150		if (efw->push_ptr >= efw->resp_buf + snd_efw_resp_buf_size)
151			efw->push_ptr -= snd_efw_resp_buf_size;
152
153		length -= till_end;
154		data += till_end;
155	}
156
157	/* for hwdep */
158	efw->resp_queues++;
159	wake_up(&efw->hwdep_wait);
160
161	*rcode = RCODE_COMPLETE;
162end:
163	spin_unlock_irq(&efw->lock);
164}
165
166static void
167handle_resp_for_user(struct fw_card *card, int generation, int source,
168		     void *data, size_t length, int *rcode)
169{
170	struct fw_device *device;
171	struct snd_efw *efw;
172	unsigned int i;
173
174	spin_lock_irq(&instances_lock);
175
176	for (i = 0; i < SNDRV_CARDS; i++) {
177		efw = instances[i];
178		if (efw == NULL)
179			continue;
180		device = fw_parent_device(efw->unit);
181		if ((device->card != card) ||
182		    (device->generation != generation))
183			continue;
184		smp_rmb();	/* node id vs. generation */
185		if (device->node_id != source)
186			continue;
187
188		break;
189	}
190	if (i == SNDRV_CARDS)
191		goto end;
192
193	copy_resp_to_buf(efw, data, length, rcode);
194end:
195	spin_unlock_irq(&instances_lock);
196}
197
198static void
199handle_resp_for_kernel(struct fw_card *card, int generation, int source,
200		       void *data, size_t length, int *rcode, u32 seqnum)
201{
202	struct fw_device *device;
203	struct transaction_queue *t;
204	unsigned long flags;
205
206	spin_lock_irqsave(&transaction_queues_lock, flags);
207	list_for_each_entry(t, &transaction_queues, list) {
208		device = fw_parent_device(t->unit);
209		if ((device->card != card) ||
210		    (device->generation != generation))
211			continue;
212		smp_rmb();	/* node_id vs. generation */
213		if (device->node_id != source)
214			continue;
215
216		if ((t->state == STATE_PENDING) && (t->seqnum == seqnum)) {
217			t->state = STATE_COMPLETE;
218			t->size = min_t(unsigned int, length, t->size);
219			memcpy(t->buf, data, t->size);
220			wake_up(&t->wait);
221			*rcode = RCODE_COMPLETE;
222		}
223	}
224	spin_unlock_irqrestore(&transaction_queues_lock, flags);
225}
226
227static void
228efw_response(struct fw_card *card, struct fw_request *request,
229	     int tcode, int destination, int source,
230	     int generation, unsigned long long offset,
231	     void *data, size_t length, void *callback_data)
232{
233	int rcode, dummy;
234	u32 seqnum;
235
236	rcode = RCODE_TYPE_ERROR;
237	if (length < sizeof(struct snd_efw_transaction)) {
238		rcode = RCODE_DATA_ERROR;
239		goto end;
240	} else if (offset != MEMORY_SPACE_EFW_RESPONSE) {
241		rcode = RCODE_ADDRESS_ERROR;
242		goto end;
243	}
244
245	seqnum = be32_to_cpu(((struct snd_efw_transaction *)data)->seqnum);
246	if (seqnum > SND_EFW_TRANSACTION_USER_SEQNUM_MAX + 1) {
247		handle_resp_for_kernel(card, generation, source,
248				       data, length, &rcode, seqnum);
249		if (snd_efw_resp_buf_debug)
250			handle_resp_for_user(card, generation, source,
251					     data, length, &dummy);
252	} else {
253		handle_resp_for_user(card, generation, source,
254				     data, length, &rcode);
255	}
256end:
257	fw_send_response(card, request, rcode);
258}
259
260void snd_efw_transaction_add_instance(struct snd_efw *efw)
261{
262	unsigned int i;
263
264	spin_lock_irq(&instances_lock);
265
266	for (i = 0; i < SNDRV_CARDS; i++) {
267		if (instances[i] != NULL)
268			continue;
269		instances[i] = efw;
270		break;
271	}
272
273	spin_unlock_irq(&instances_lock);
274}
275
276void snd_efw_transaction_remove_instance(struct snd_efw *efw)
277{
278	unsigned int i;
279
280	spin_lock_irq(&instances_lock);
281
282	for (i = 0; i < SNDRV_CARDS; i++) {
283		if (instances[i] != efw)
284			continue;
285		instances[i] = NULL;
286	}
287
288	spin_unlock_irq(&instances_lock);
289}
290
291void snd_efw_transaction_bus_reset(struct fw_unit *unit)
292{
293	struct transaction_queue *t;
294
295	spin_lock_irq(&transaction_queues_lock);
296	list_for_each_entry(t, &transaction_queues, list) {
297		if ((t->unit == unit) &&
298		    (t->state == STATE_PENDING)) {
299			t->state = STATE_BUS_RESET;
300			wake_up(&t->wait);
301		}
302	}
303	spin_unlock_irq(&transaction_queues_lock);
304}
305
306static struct fw_address_handler resp_register_handler = {
307	.length = SND_EFW_RESPONSE_MAXIMUM_BYTES,
308	.address_callback = efw_response
309};
310
311int snd_efw_transaction_register(void)
312{
313	static const struct fw_address_region resp_register_region = {
314		.start	= MEMORY_SPACE_EFW_RESPONSE,
315		.end	= MEMORY_SPACE_EFW_RESPONSE +
316			  SND_EFW_RESPONSE_MAXIMUM_BYTES
317	};
318	return fw_core_add_address_handler(&resp_register_handler,
319					   &resp_register_region);
320}
321
322void snd_efw_transaction_unregister(void)
323{
324	WARN_ON(!list_empty(&transaction_queues));
325	fw_core_remove_address_handler(&resp_register_handler);
326}
327