Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / sound / firewire / cmp.c
blobae3bc1940efa6811b3bb5ec28d7a5999e1263b89
1 /*
2 * Connection Management Procedures (IEC 61883-1) helper functions
4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
5 * Licensed under the terms of the GNU General Public License, version 2.
6 */
8 #include <linux/device.h>
9 #include <linux/firewire.h>
10 #include <linux/firewire-constants.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include "lib.h"
14 #include "iso-resources.h"
15 #include "cmp.h"
17 /* MPR common fields */
18 #define MPR_SPEED_MASK 0xc0000000
19 #define MPR_SPEED_SHIFT 30
20 #define MPR_XSPEED_MASK 0x00000060
21 #define MPR_XSPEED_SHIFT 5
22 #define MPR_PLUGS_MASK 0x0000001f
24 /* PCR common fields */
25 #define PCR_ONLINE 0x80000000
26 #define PCR_BCAST_CONN 0x40000000
27 #define PCR_P2P_CONN_MASK 0x3f000000
28 #define PCR_P2P_CONN_SHIFT 24
29 #define PCR_CHANNEL_MASK 0x003f0000
30 #define PCR_CHANNEL_SHIFT 16
32 /* oPCR specific fields */
33 #define OPCR_XSPEED_MASK 0x00C00000
34 #define OPCR_XSPEED_SHIFT 22
35 #define OPCR_SPEED_MASK 0x0000C000
36 #define OPCR_SPEED_SHIFT 14
37 #define OPCR_OVERHEAD_ID_MASK 0x00003C00
38 #define OPCR_OVERHEAD_ID_SHIFT 10
40 enum bus_reset_handling {
41 ABORT_ON_BUS_RESET,
42 SUCCEED_ON_BUS_RESET,
45 static __printf(2, 3)
46 void cmp_error(struct cmp_connection *c, const char *fmt, ...)
48 va_list va;
50 va_start(va, fmt);
51 dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
52 (c->direction == CMP_INPUT) ? 'i' : 'o',
53 c->pcr_index, &(struct va_format){ fmt, &va });
54 va_end(va);
57 static u64 mpr_address(struct cmp_connection *c)
59 if (c->direction == CMP_INPUT)
60 return CSR_REGISTER_BASE + CSR_IMPR;
61 else
62 return CSR_REGISTER_BASE + CSR_OMPR;
65 static u64 pcr_address(struct cmp_connection *c)
67 if (c->direction == CMP_INPUT)
68 return CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index);
69 else
70 return CSR_REGISTER_BASE + CSR_OPCR(c->pcr_index);
73 static int pcr_modify(struct cmp_connection *c,
74 __be32 (*modify)(struct cmp_connection *c, __be32 old),
75 int (*check)(struct cmp_connection *c, __be32 pcr),
76 enum bus_reset_handling bus_reset_handling)
78 __be32 old_arg, buffer[2];
79 int err;
81 buffer[0] = c->last_pcr_value;
82 for (;;) {
83 old_arg = buffer[0];
84 buffer[1] = modify(c, buffer[0]);
86 err = snd_fw_transaction(
87 c->resources.unit, TCODE_LOCK_COMPARE_SWAP,
88 pcr_address(c), buffer, 8,
89 FW_FIXED_GENERATION | c->resources.generation);
91 if (err < 0) {
92 if (err == -EAGAIN &&
93 bus_reset_handling == SUCCEED_ON_BUS_RESET)
94 err = 0;
95 return err;
98 if (buffer[0] == old_arg) /* success? */
99 break;
101 if (check) {
102 err = check(c, buffer[0]);
103 if (err < 0)
104 return err;
107 c->last_pcr_value = buffer[1];
109 return 0;
114 * cmp_connection_init - initializes a connection manager
115 * @c: the connection manager to initialize
116 * @unit: a unit of the target device
117 * @direction: input or output
118 * @pcr_index: the index of the iPCR/oPCR on the target device
120 int cmp_connection_init(struct cmp_connection *c,
121 struct fw_unit *unit,
122 enum cmp_direction direction,
123 unsigned int pcr_index)
125 __be32 mpr_be;
126 u32 mpr;
127 int err;
129 c->direction = direction;
130 err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
131 mpr_address(c), &mpr_be, 4, 0);
132 if (err < 0)
133 return err;
134 mpr = be32_to_cpu(mpr_be);
136 if (pcr_index >= (mpr & MPR_PLUGS_MASK))
137 return -EINVAL;
139 err = fw_iso_resources_init(&c->resources, unit);
140 if (err < 0)
141 return err;
143 c->connected = false;
144 mutex_init(&c->mutex);
145 c->last_pcr_value = cpu_to_be32(0x80000000);
146 c->pcr_index = pcr_index;
147 c->max_speed = (mpr & MPR_SPEED_MASK) >> MPR_SPEED_SHIFT;
148 if (c->max_speed == SCODE_BETA)
149 c->max_speed += (mpr & MPR_XSPEED_MASK) >> MPR_XSPEED_SHIFT;
151 return 0;
153 EXPORT_SYMBOL(cmp_connection_init);
156 * cmp_connection_check_used - check connection is already esablished or not
157 * @c: the connection manager to be checked
158 * @used: the pointer to store the result of checking the connection
160 int cmp_connection_check_used(struct cmp_connection *c, bool *used)
162 __be32 pcr;
163 int err;
165 err = snd_fw_transaction(
166 c->resources.unit, TCODE_READ_QUADLET_REQUEST,
167 pcr_address(c), &pcr, 4, 0);
168 if (err >= 0)
169 *used = !!(pcr & cpu_to_be32(PCR_BCAST_CONN |
170 PCR_P2P_CONN_MASK));
172 return err;
174 EXPORT_SYMBOL(cmp_connection_check_used);
177 * cmp_connection_destroy - free connection manager resources
178 * @c: the connection manager
180 void cmp_connection_destroy(struct cmp_connection *c)
182 WARN_ON(c->connected);
183 mutex_destroy(&c->mutex);
184 fw_iso_resources_destroy(&c->resources);
186 EXPORT_SYMBOL(cmp_connection_destroy);
189 static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
191 ipcr &= ~cpu_to_be32(PCR_BCAST_CONN |
192 PCR_P2P_CONN_MASK |
193 PCR_CHANNEL_MASK);
194 ipcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
195 ipcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
197 return ipcr;
200 static int get_overhead_id(struct cmp_connection *c)
202 int id;
205 * apply "oPCR overhead ID encoding"
206 * the encoding table can convert up to 512.
207 * here the value over 512 is converted as the same way as 512.
209 for (id = 1; id < 16; id++) {
210 if (c->resources.bandwidth_overhead < (id << 5))
211 break;
213 if (id == 16)
214 id = 0;
216 return id;
219 static __be32 opcr_set_modify(struct cmp_connection *c, __be32 opcr)
221 unsigned int spd, xspd;
223 /* generate speed and extended speed field value */
224 if (c->speed > SCODE_400) {
225 spd = SCODE_800;
226 xspd = c->speed - SCODE_800;
227 } else {
228 spd = c->speed;
229 xspd = 0;
232 opcr &= ~cpu_to_be32(PCR_BCAST_CONN |
233 PCR_P2P_CONN_MASK |
234 OPCR_XSPEED_MASK |
235 PCR_CHANNEL_MASK |
236 OPCR_SPEED_MASK |
237 OPCR_OVERHEAD_ID_MASK);
238 opcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
239 opcr |= cpu_to_be32(xspd << OPCR_XSPEED_SHIFT);
240 opcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
241 opcr |= cpu_to_be32(spd << OPCR_SPEED_SHIFT);
242 opcr |= cpu_to_be32(get_overhead_id(c) << OPCR_OVERHEAD_ID_SHIFT);
244 return opcr;
247 static int pcr_set_check(struct cmp_connection *c, __be32 pcr)
249 if (pcr & cpu_to_be32(PCR_BCAST_CONN |
250 PCR_P2P_CONN_MASK)) {
251 cmp_error(c, "plug is already in use\n");
252 return -EBUSY;
254 if (!(pcr & cpu_to_be32(PCR_ONLINE))) {
255 cmp_error(c, "plug is not on-line\n");
256 return -ECONNREFUSED;
259 return 0;
263 * cmp_connection_establish - establish a connection to the target
264 * @c: the connection manager
265 * @max_payload_bytes: the amount of data (including CIP headers) per packet
267 * This function establishes a point-to-point connection from the local
268 * computer to the target by allocating isochronous resources (channel and
269 * bandwidth) and setting the target's input/output plug control register.
270 * When this function succeeds, the caller is responsible for starting
271 * transmitting packets.
273 int cmp_connection_establish(struct cmp_connection *c,
274 unsigned int max_payload_bytes)
276 int err;
278 if (WARN_ON(c->connected))
279 return -EISCONN;
281 c->speed = min(c->max_speed,
282 fw_parent_device(c->resources.unit)->max_speed);
284 mutex_lock(&c->mutex);
286 retry_after_bus_reset:
287 err = fw_iso_resources_allocate(&c->resources,
288 max_payload_bytes, c->speed);
289 if (err < 0)
290 goto err_mutex;
292 if (c->direction == CMP_OUTPUT)
293 err = pcr_modify(c, opcr_set_modify, pcr_set_check,
294 ABORT_ON_BUS_RESET);
295 else
296 err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
297 ABORT_ON_BUS_RESET);
299 if (err == -EAGAIN) {
300 fw_iso_resources_free(&c->resources);
301 goto retry_after_bus_reset;
303 if (err < 0)
304 goto err_resources;
306 c->connected = true;
308 mutex_unlock(&c->mutex);
310 return 0;
312 err_resources:
313 fw_iso_resources_free(&c->resources);
314 err_mutex:
315 mutex_unlock(&c->mutex);
317 return err;
319 EXPORT_SYMBOL(cmp_connection_establish);
322 * cmp_connection_update - update the connection after a bus reset
323 * @c: the connection manager
325 * This function must be called from the driver's .update handler to
326 * reestablish any connection that might have been active.
328 * Returns zero on success, or a negative error code. On an error, the
329 * connection is broken and the caller must stop transmitting iso packets.
331 int cmp_connection_update(struct cmp_connection *c)
333 int err;
335 mutex_lock(&c->mutex);
337 if (!c->connected) {
338 mutex_unlock(&c->mutex);
339 return 0;
342 err = fw_iso_resources_update(&c->resources);
343 if (err < 0)
344 goto err_unconnect;
346 if (c->direction == CMP_OUTPUT)
347 err = pcr_modify(c, opcr_set_modify, pcr_set_check,
348 SUCCEED_ON_BUS_RESET);
349 else
350 err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
351 SUCCEED_ON_BUS_RESET);
353 if (err < 0)
354 goto err_resources;
356 mutex_unlock(&c->mutex);
358 return 0;
360 err_resources:
361 fw_iso_resources_free(&c->resources);
362 err_unconnect:
363 c->connected = false;
364 mutex_unlock(&c->mutex);
366 return err;
368 EXPORT_SYMBOL(cmp_connection_update);
370 static __be32 pcr_break_modify(struct cmp_connection *c, __be32 pcr)
372 return pcr & ~cpu_to_be32(PCR_BCAST_CONN | PCR_P2P_CONN_MASK);
376 * cmp_connection_break - break the connection to the target
377 * @c: the connection manager
379 * This function deactives the connection in the target's input/output plug
380 * control register, and frees the isochronous resources of the connection.
381 * Before calling this function, the caller should cease transmitting packets.
383 void cmp_connection_break(struct cmp_connection *c)
385 int err;
387 mutex_lock(&c->mutex);
389 if (!c->connected) {
390 mutex_unlock(&c->mutex);
391 return;
394 err = pcr_modify(c, pcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
395 if (err < 0)
396 cmp_error(c, "plug is still connected\n");
398 fw_iso_resources_free(&c->resources);
400 c->connected = false;
402 mutex_unlock(&c->mutex);
404 EXPORT_SYMBOL(cmp_connection_break);