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.
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>
14 #include "iso-resources.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 {
46 void cmp_error(struct cmp_connection *c, const char *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 });
57 static u64 mpr_address(struct cmp_connection *c)
59 if (c->direction == CMP_INPUT)
60 return CSR_REGISTER_BASE + CSR_IMPR;
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);
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];
81 buffer[0] = c->last_pcr_value;
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);
93 bus_reset_handling == SUCCEED_ON_BUS_RESET)
98 if (buffer[0] == old_arg) /* success? */
102 err = check(c, buffer[0]);
107 c->last_pcr_value = buffer[1];
114 * cmp_connection_init - initializes a connection manager
115 * @c: the connection manager to initialize
116 * @unit: a unit of the target device
117 * @pcr_index: the index of the iPCR/oPCR on the target device
119 int cmp_connection_init(struct cmp_connection *c,
120 struct fw_unit *unit,
121 enum cmp_direction direction,
122 unsigned int pcr_index)
128 c->direction = direction;
129 err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
130 mpr_address(c), &mpr_be, 4, 0);
133 mpr = be32_to_cpu(mpr_be);
135 if (pcr_index >= (mpr & MPR_PLUGS_MASK))
138 err = fw_iso_resources_init(&c->resources, unit);
142 c->connected = false;
143 mutex_init(&c->mutex);
144 c->last_pcr_value = cpu_to_be32(0x80000000);
145 c->pcr_index = pcr_index;
146 c->max_speed = (mpr & MPR_SPEED_MASK) >> MPR_SPEED_SHIFT;
147 if (c->max_speed == SCODE_BETA)
148 c->max_speed += (mpr & MPR_XSPEED_MASK) >> MPR_XSPEED_SHIFT;
152 EXPORT_SYMBOL(cmp_connection_init);
155 * cmp_connection_check_used - check connection is already esablished or not
156 * @c: the connection manager to be checked
158 int cmp_connection_check_used(struct cmp_connection *c, bool *used)
163 err = snd_fw_transaction(
164 c->resources.unit, TCODE_READ_QUADLET_REQUEST,
165 pcr_address(c), &pcr, 4, 0);
167 *used = !!(pcr & cpu_to_be32(PCR_BCAST_CONN |
172 EXPORT_SYMBOL(cmp_connection_check_used);
175 * cmp_connection_destroy - free connection manager resources
176 * @c: the connection manager
178 void cmp_connection_destroy(struct cmp_connection *c)
180 WARN_ON(c->connected);
181 mutex_destroy(&c->mutex);
182 fw_iso_resources_destroy(&c->resources);
184 EXPORT_SYMBOL(cmp_connection_destroy);
187 static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
189 ipcr &= ~cpu_to_be32(PCR_BCAST_CONN |
192 ipcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
193 ipcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
198 static int get_overhead_id(struct cmp_connection *c)
203 * apply "oPCR overhead ID encoding"
204 * the encoding table can convert up to 512.
205 * here the value over 512 is converted as the same way as 512.
207 for (id = 1; id < 16; id++) {
208 if (c->resources.bandwidth_overhead < (id << 5))
217 static __be32 opcr_set_modify(struct cmp_connection *c, __be32 opcr)
219 unsigned int spd, xspd;
221 /* generate speed and extended speed field value */
222 if (c->speed > SCODE_400) {
224 xspd = c->speed - SCODE_800;
230 opcr &= ~cpu_to_be32(PCR_BCAST_CONN |
235 OPCR_OVERHEAD_ID_MASK);
236 opcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
237 opcr |= cpu_to_be32(xspd << OPCR_XSPEED_SHIFT);
238 opcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
239 opcr |= cpu_to_be32(spd << OPCR_SPEED_SHIFT);
240 opcr |= cpu_to_be32(get_overhead_id(c) << OPCR_OVERHEAD_ID_SHIFT);
245 static int pcr_set_check(struct cmp_connection *c, __be32 pcr)
247 if (pcr & cpu_to_be32(PCR_BCAST_CONN |
248 PCR_P2P_CONN_MASK)) {
249 cmp_error(c, "plug is already in use\n");
252 if (!(pcr & cpu_to_be32(PCR_ONLINE))) {
253 cmp_error(c, "plug is not on-line\n");
254 return -ECONNREFUSED;
261 * cmp_connection_establish - establish a connection to the target
262 * @c: the connection manager
263 * @max_payload_bytes: the amount of data (including CIP headers) per packet
265 * This function establishes a point-to-point connection from the local
266 * computer to the target by allocating isochronous resources (channel and
267 * bandwidth) and setting the target's input/output plug control register.
268 * When this function succeeds, the caller is responsible for starting
269 * transmitting packets.
271 int cmp_connection_establish(struct cmp_connection *c,
272 unsigned int max_payload_bytes)
276 if (WARN_ON(c->connected))
279 c->speed = min(c->max_speed,
280 fw_parent_device(c->resources.unit)->max_speed);
282 mutex_lock(&c->mutex);
284 retry_after_bus_reset:
285 err = fw_iso_resources_allocate(&c->resources,
286 max_payload_bytes, c->speed);
290 if (c->direction == CMP_OUTPUT)
291 err = pcr_modify(c, opcr_set_modify, pcr_set_check,
294 err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
297 if (err == -EAGAIN) {
298 fw_iso_resources_free(&c->resources);
299 goto retry_after_bus_reset;
306 mutex_unlock(&c->mutex);
311 fw_iso_resources_free(&c->resources);
313 mutex_unlock(&c->mutex);
317 EXPORT_SYMBOL(cmp_connection_establish);
320 * cmp_connection_update - update the connection after a bus reset
321 * @c: the connection manager
323 * This function must be called from the driver's .update handler to
324 * reestablish any connection that might have been active.
326 * Returns zero on success, or a negative error code. On an error, the
327 * connection is broken and the caller must stop transmitting iso packets.
329 int cmp_connection_update(struct cmp_connection *c)
333 mutex_lock(&c->mutex);
336 mutex_unlock(&c->mutex);
340 err = fw_iso_resources_update(&c->resources);
344 if (c->direction == CMP_OUTPUT)
345 err = pcr_modify(c, opcr_set_modify, pcr_set_check,
346 SUCCEED_ON_BUS_RESET);
348 err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
349 SUCCEED_ON_BUS_RESET);
354 mutex_unlock(&c->mutex);
359 fw_iso_resources_free(&c->resources);
361 c->connected = false;
362 mutex_unlock(&c->mutex);
366 EXPORT_SYMBOL(cmp_connection_update);
368 static __be32 pcr_break_modify(struct cmp_connection *c, __be32 pcr)
370 return pcr & ~cpu_to_be32(PCR_BCAST_CONN | PCR_P2P_CONN_MASK);
374 * cmp_connection_break - break the connection to the target
375 * @c: the connection manager
377 * This function deactives the connection in the target's input/output plug
378 * control register, and frees the isochronous resources of the connection.
379 * Before calling this function, the caller should cease transmitting packets.
381 void cmp_connection_break(struct cmp_connection *c)
385 mutex_lock(&c->mutex);
388 mutex_unlock(&c->mutex);
392 err = pcr_modify(c, pcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
394 cmp_error(c, "plug is still connected\n");
396 fw_iso_resources_free(&c->resources);
398 c->connected = false;
400 mutex_unlock(&c->mutex);
402 EXPORT_SYMBOL(cmp_connection_break);