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 #define IMPR_SPEED_MASK 0xc0000000
18 #define IMPR_SPEED_SHIFT 30
19 #define IMPR_XSPEED_MASK 0x00000060
20 #define IMPR_XSPEED_SHIFT 5
21 #define IMPR_PLUGS_MASK 0x0000001f
23 #define IPCR_ONLINE 0x80000000
24 #define IPCR_BCAST_CONN 0x40000000
25 #define IPCR_P2P_CONN_MASK 0x3f000000
26 #define IPCR_P2P_CONN_SHIFT 24
27 #define IPCR_CHANNEL_MASK 0x003f0000
28 #define IPCR_CHANNEL_SHIFT 16
30 enum bus_reset_handling {
35 static __attribute__((format(printf, 2, 3)))
36 void cmp_error(struct cmp_connection *c, const char *fmt, ...)
41 dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
42 'i', c->pcr_index, &(struct va_format){ fmt, &va });
46 static int pcr_modify(struct cmp_connection *c,
47 __be32 (*modify)(struct cmp_connection *c, __be32 old),
48 int (*check)(struct cmp_connection *c, __be32 pcr),
49 enum bus_reset_handling bus_reset_handling)
51 struct fw_device *device = fw_parent_device(c->resources.unit);
52 __be32 *buffer = c->resources.buffer;
53 int generation = c->resources.generation;
54 int rcode, errors = 0;
58 buffer[0] = c->last_pcr_value;
61 buffer[1] = modify(c, buffer[0]);
63 rcode = fw_run_transaction(
64 device->card, TCODE_LOCK_COMPARE_SWAP,
65 device->node_id, generation, device->max_speed,
66 CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
69 if (rcode == RCODE_COMPLETE) {
70 if (buffer[0] == old_arg) /* success? */
74 err = check(c, buffer[0]);
78 } else if (rcode == RCODE_GENERATION)
80 else if (rcode_is_permanent_error(rcode) || ++errors >= 3)
83 c->last_pcr_value = buffer[1];
88 cmp_error(c, "transaction failed: %s\n", rcode_string(rcode));
92 return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 0;
97 * cmp_connection_init - initializes a connection manager
98 * @c: the connection manager to initialize
99 * @unit: a unit of the target device
100 * @ipcr_index: the index of the iPCR on the target device
102 int cmp_connection_init(struct cmp_connection *c,
103 struct fw_unit *unit,
104 unsigned int ipcr_index)
110 err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
111 CSR_REGISTER_BASE + CSR_IMPR,
115 impr = be32_to_cpu(impr_be);
117 if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
120 err = fw_iso_resources_init(&c->resources, unit);
124 c->connected = false;
125 mutex_init(&c->mutex);
126 c->last_pcr_value = cpu_to_be32(0x80000000);
127 c->pcr_index = ipcr_index;
128 c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;
129 if (c->max_speed == SCODE_BETA)
130 c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT;
134 EXPORT_SYMBOL(cmp_connection_init);
137 * cmp_connection_destroy - free connection manager resources
138 * @c: the connection manager
140 void cmp_connection_destroy(struct cmp_connection *c)
142 WARN_ON(c->connected);
143 mutex_destroy(&c->mutex);
144 fw_iso_resources_destroy(&c->resources);
146 EXPORT_SYMBOL(cmp_connection_destroy);
149 static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
151 ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN |
154 ipcr |= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT);
155 ipcr |= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT);
160 static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr)
162 if (ipcr & cpu_to_be32(IPCR_BCAST_CONN |
163 IPCR_P2P_CONN_MASK)) {
164 cmp_error(c, "plug is already in use\n");
167 if (!(ipcr & cpu_to_be32(IPCR_ONLINE))) {
168 cmp_error(c, "plug is not on-line\n");
169 return -ECONNREFUSED;
176 * cmp_connection_establish - establish a connection to the target
177 * @c: the connection manager
178 * @max_payload_bytes: the amount of data (including CIP headers) per packet
180 * This function establishes a point-to-point connection from the local
181 * computer to the target by allocating isochronous resources (channel and
182 * bandwidth) and setting the target's input plug control register. When this
183 * function succeeds, the caller is responsible for starting transmitting
186 int cmp_connection_establish(struct cmp_connection *c,
187 unsigned int max_payload_bytes)
191 if (WARN_ON(c->connected))
194 c->speed = min(c->max_speed,
195 fw_parent_device(c->resources.unit)->max_speed);
197 mutex_lock(&c->mutex);
199 retry_after_bus_reset:
200 err = fw_iso_resources_allocate(&c->resources,
201 max_payload_bytes, c->speed);
205 err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
207 if (err == -EAGAIN) {
208 fw_iso_resources_free(&c->resources);
209 goto retry_after_bus_reset;
216 mutex_unlock(&c->mutex);
221 fw_iso_resources_free(&c->resources);
223 mutex_unlock(&c->mutex);
227 EXPORT_SYMBOL(cmp_connection_establish);
230 * cmp_connection_update - update the connection after a bus reset
231 * @c: the connection manager
233 * This function must be called from the driver's .update handler to reestablish
234 * any connection that might have been active.
236 * Returns zero on success, or a negative error code. On an error, the
237 * connection is broken and the caller must stop transmitting iso packets.
239 int cmp_connection_update(struct cmp_connection *c)
243 mutex_lock(&c->mutex);
246 mutex_unlock(&c->mutex);
250 err = fw_iso_resources_update(&c->resources);
254 err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
255 SUCCEED_ON_BUS_RESET);
259 mutex_unlock(&c->mutex);
264 fw_iso_resources_free(&c->resources);
266 c->connected = false;
267 mutex_unlock(&c->mutex);
271 EXPORT_SYMBOL(cmp_connection_update);
274 static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr)
276 return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN | IPCR_P2P_CONN_MASK);
280 * cmp_connection_break - break the connection to the target
281 * @c: the connection manager
283 * This function deactives the connection in the target's input plug control
284 * register, and frees the isochronous resources of the connection. Before
285 * calling this function, the caller should cease transmitting packets.
287 void cmp_connection_break(struct cmp_connection *c)
291 mutex_lock(&c->mutex);
294 mutex_unlock(&c->mutex);
298 err = pcr_modify(c, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
300 cmp_error(c, "plug is still connected\n");
302 fw_iso_resources_free(&c->resources);
304 c->connected = false;
306 mutex_unlock(&c->mutex);
308 EXPORT_SYMBOL(cmp_connection_break);