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1/*
2 * Connection Management Procedures (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/module.h>
12#include <linux/sched.h>
13#include "lib.h"
14#include "iso-resources.h"
15#include "cmp.h"
16
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
22
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
29
30enum bus_reset_handling {
31 ABORT_ON_BUS_RESET,
32 SUCCEED_ON_BUS_RESET,
33};
34
35static __printf(2, 3)
36void cmp_error(struct cmp_connection *c, const char *fmt, ...)
37{
38 va_list va;
39
40 va_start(va, fmt);
41 dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
42 'i', c->pcr_index, &(struct va_format){ fmt, &va });
43 va_end(va);
44}
45
46static 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)
50{
51 __be32 old_arg, buffer[2];
52 int err;
53
54 buffer[0] = c->last_pcr_value;
55 for (;;) {
56 old_arg = buffer[0];
57 buffer[1] = modify(c, buffer[0]);
58
59 err = snd_fw_transaction(
60 c->resources.unit, TCODE_LOCK_COMPARE_SWAP,
61 CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
62 buffer, 8,
63 FW_FIXED_GENERATION | c->resources.generation);
64
65 if (err < 0) {
66 if (err == -EAGAIN &&
67 bus_reset_handling == SUCCEED_ON_BUS_RESET)
68 err = 0;
69 return err;
70 }
71
72 if (buffer[0] == old_arg) /* success? */
73 break;
74
75 if (check) {
76 err = check(c, buffer[0]);
77 if (err < 0)
78 return err;
79 }
80 }
81 c->last_pcr_value = buffer[1];
82
83 return 0;
84}
85
86
87/**
88 * cmp_connection_init - initializes a connection manager
89 * @c: the connection manager to initialize
90 * @unit: a unit of the target device
91 * @ipcr_index: the index of the iPCR on the target device
92 */
93int cmp_connection_init(struct cmp_connection *c,
94 struct fw_unit *unit,
95 unsigned int ipcr_index)
96{
97 __be32 impr_be;
98 u32 impr;
99 int err;
100
101 err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
102 CSR_REGISTER_BASE + CSR_IMPR,
103 &impr_be, 4, 0);
104 if (err < 0)
105 return err;
106 impr = be32_to_cpu(impr_be);
107
108 if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
109 return -EINVAL;
110
111 err = fw_iso_resources_init(&c->resources, unit);
112 if (err < 0)
113 return err;
114
115 c->connected = false;
116 mutex_init(&c->mutex);
117 c->last_pcr_value = cpu_to_be32(0x80000000);
118 c->pcr_index = ipcr_index;
119 c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;
120 if (c->max_speed == SCODE_BETA)
121 c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT;
122
123 return 0;
124}
125EXPORT_SYMBOL(cmp_connection_init);
126
127/**
128 * cmp_connection_destroy - free connection manager resources
129 * @c: the connection manager
130 */
131void cmp_connection_destroy(struct cmp_connection *c)
132{
133 WARN_ON(c->connected);
134 mutex_destroy(&c->mutex);
135 fw_iso_resources_destroy(&c->resources);
136}
137EXPORT_SYMBOL(cmp_connection_destroy);
138
139
140static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
141{
142 ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN |
143 IPCR_P2P_CONN_MASK |
144 IPCR_CHANNEL_MASK);
145 ipcr |= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT);
146 ipcr |= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT);
147
148 return ipcr;
149}
150
151static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr)
152{
153 if (ipcr & cpu_to_be32(IPCR_BCAST_CONN |
154 IPCR_P2P_CONN_MASK)) {
155 cmp_error(c, "plug is already in use\n");
156 return -EBUSY;
157 }
158 if (!(ipcr & cpu_to_be32(IPCR_ONLINE))) {
159 cmp_error(c, "plug is not on-line\n");
160 return -ECONNREFUSED;
161 }
162
163 return 0;
164}
165
166/**
167 * cmp_connection_establish - establish a connection to the target
168 * @c: the connection manager
169 * @max_payload_bytes: the amount of data (including CIP headers) per packet
170 *
171 * This function establishes a point-to-point connection from the local
172 * computer to the target by allocating isochronous resources (channel and
173 * bandwidth) and setting the target's input plug control register. When this
174 * function succeeds, the caller is responsible for starting transmitting
175 * packets.
176 */
177int cmp_connection_establish(struct cmp_connection *c,
178 unsigned int max_payload_bytes)
179{
180 int err;
181
182 if (WARN_ON(c->connected))
183 return -EISCONN;
184
185 c->speed = min(c->max_speed,
186 fw_parent_device(c->resources.unit)->max_speed);
187
188 mutex_lock(&c->mutex);
189
190retry_after_bus_reset:
191 err = fw_iso_resources_allocate(&c->resources,
192 max_payload_bytes, c->speed);
193 if (err < 0)
194 goto err_mutex;
195
196 err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
197 ABORT_ON_BUS_RESET);
198 if (err == -EAGAIN) {
199 fw_iso_resources_free(&c->resources);
200 goto retry_after_bus_reset;
201 }
202 if (err < 0)
203 goto err_resources;
204
205 c->connected = true;
206
207 mutex_unlock(&c->mutex);
208
209 return 0;
210
211err_resources:
212 fw_iso_resources_free(&c->resources);
213err_mutex:
214 mutex_unlock(&c->mutex);
215
216 return err;
217}
218EXPORT_SYMBOL(cmp_connection_establish);
219
220/**
221 * cmp_connection_update - update the connection after a bus reset
222 * @c: the connection manager
223 *
224 * This function must be called from the driver's .update handler to reestablish
225 * any connection that might have been active.
226 *
227 * Returns zero on success, or a negative error code. On an error, the
228 * connection is broken and the caller must stop transmitting iso packets.
229 */
230int cmp_connection_update(struct cmp_connection *c)
231{
232 int err;
233
234 mutex_lock(&c->mutex);
235
236 if (!c->connected) {
237 mutex_unlock(&c->mutex);
238 return 0;
239 }
240
241 err = fw_iso_resources_update(&c->resources);
242 if (err < 0)
243 goto err_unconnect;
244
245 err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
246 SUCCEED_ON_BUS_RESET);
247 if (err < 0)
248 goto err_resources;
249
250 mutex_unlock(&c->mutex);
251
252 return 0;
253
254err_resources:
255 fw_iso_resources_free(&c->resources);
256err_unconnect:
257 c->connected = false;
258 mutex_unlock(&c->mutex);
259
260 return err;
261}
262EXPORT_SYMBOL(cmp_connection_update);
263
264
265static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr)
266{
267 return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN | IPCR_P2P_CONN_MASK);
268}
269
270/**
271 * cmp_connection_break - break the connection to the target
272 * @c: the connection manager
273 *
274 * This function deactives the connection in the target's input plug control
275 * register, and frees the isochronous resources of the connection. Before
276 * calling this function, the caller should cease transmitting packets.
277 */
278void cmp_connection_break(struct cmp_connection *c)
279{
280 int err;
281
282 mutex_lock(&c->mutex);
283
284 if (!c->connected) {
285 mutex_unlock(&c->mutex);
286 return;
287 }
288
289 err = pcr_modify(c, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
290 if (err < 0)
291 cmp_error(c, "plug is still connected\n");
292
293 fw_iso_resources_free(&c->resources);
294
295 c->connected = false;
296
297 mutex_unlock(&c->mutex);
298}
299EXPORT_SYMBOL(cmp_connection_break);
1/*
2 * Connection Management Procedures (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/module.h>
12#include <linux/sched.h>
13#include "lib.h"
14#include "iso-resources.h"
15#include "cmp.h"
16
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
22
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
29
30enum bus_reset_handling {
31 ABORT_ON_BUS_RESET,
32 SUCCEED_ON_BUS_RESET,
33};
34
35static __printf(2, 3)
36void cmp_error(struct cmp_connection *c, const char *fmt, ...)
37{
38 va_list va;
39
40 va_start(va, fmt);
41 dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
42 'i', c->pcr_index, &(struct va_format){ fmt, &va });
43 va_end(va);
44}
45
46static 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)
50{
51 struct fw_device *device = fw_parent_device(c->resources.unit);
52 int generation = c->resources.generation;
53 int rcode, errors = 0;
54 __be32 old_arg, buffer[2];
55 int err;
56
57 buffer[0] = c->last_pcr_value;
58 for (;;) {
59 old_arg = buffer[0];
60 buffer[1] = modify(c, buffer[0]);
61
62 rcode = fw_run_transaction(
63 device->card, TCODE_LOCK_COMPARE_SWAP,
64 device->node_id, generation, device->max_speed,
65 CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
66 buffer, 8);
67
68 if (rcode == RCODE_COMPLETE) {
69 if (buffer[0] == old_arg) /* success? */
70 break;
71
72 if (check) {
73 err = check(c, buffer[0]);
74 if (err < 0)
75 return err;
76 }
77 } else if (rcode == RCODE_GENERATION)
78 goto bus_reset;
79 else if (rcode_is_permanent_error(rcode) || ++errors >= 3)
80 goto io_error;
81 }
82 c->last_pcr_value = buffer[1];
83
84 return 0;
85
86io_error:
87 cmp_error(c, "transaction failed: %s\n", fw_rcode_string(rcode));
88 return -EIO;
89
90bus_reset:
91 return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 0;
92}
93
94
95/**
96 * cmp_connection_init - initializes a connection manager
97 * @c: the connection manager to initialize
98 * @unit: a unit of the target device
99 * @ipcr_index: the index of the iPCR on the target device
100 */
101int cmp_connection_init(struct cmp_connection *c,
102 struct fw_unit *unit,
103 unsigned int ipcr_index)
104{
105 __be32 impr_be;
106 u32 impr;
107 int err;
108
109 err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
110 CSR_REGISTER_BASE + CSR_IMPR,
111 &impr_be, 4);
112 if (err < 0)
113 return err;
114 impr = be32_to_cpu(impr_be);
115
116 if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
117 return -EINVAL;
118
119 err = fw_iso_resources_init(&c->resources, unit);
120 if (err < 0)
121 return err;
122
123 c->connected = false;
124 mutex_init(&c->mutex);
125 c->last_pcr_value = cpu_to_be32(0x80000000);
126 c->pcr_index = ipcr_index;
127 c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;
128 if (c->max_speed == SCODE_BETA)
129 c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT;
130
131 return 0;
132}
133EXPORT_SYMBOL(cmp_connection_init);
134
135/**
136 * cmp_connection_destroy - free connection manager resources
137 * @c: the connection manager
138 */
139void cmp_connection_destroy(struct cmp_connection *c)
140{
141 WARN_ON(c->connected);
142 mutex_destroy(&c->mutex);
143 fw_iso_resources_destroy(&c->resources);
144}
145EXPORT_SYMBOL(cmp_connection_destroy);
146
147
148static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
149{
150 ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN |
151 IPCR_P2P_CONN_MASK |
152 IPCR_CHANNEL_MASK);
153 ipcr |= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT);
154 ipcr |= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT);
155
156 return ipcr;
157}
158
159static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr)
160{
161 if (ipcr & cpu_to_be32(IPCR_BCAST_CONN |
162 IPCR_P2P_CONN_MASK)) {
163 cmp_error(c, "plug is already in use\n");
164 return -EBUSY;
165 }
166 if (!(ipcr & cpu_to_be32(IPCR_ONLINE))) {
167 cmp_error(c, "plug is not on-line\n");
168 return -ECONNREFUSED;
169 }
170
171 return 0;
172}
173
174/**
175 * cmp_connection_establish - establish a connection to the target
176 * @c: the connection manager
177 * @max_payload_bytes: the amount of data (including CIP headers) per packet
178 *
179 * This function establishes a point-to-point connection from the local
180 * computer to the target by allocating isochronous resources (channel and
181 * bandwidth) and setting the target's input plug control register. When this
182 * function succeeds, the caller is responsible for starting transmitting
183 * packets.
184 */
185int cmp_connection_establish(struct cmp_connection *c,
186 unsigned int max_payload_bytes)
187{
188 int err;
189
190 if (WARN_ON(c->connected))
191 return -EISCONN;
192
193 c->speed = min(c->max_speed,
194 fw_parent_device(c->resources.unit)->max_speed);
195
196 mutex_lock(&c->mutex);
197
198retry_after_bus_reset:
199 err = fw_iso_resources_allocate(&c->resources,
200 max_payload_bytes, c->speed);
201 if (err < 0)
202 goto err_mutex;
203
204 err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
205 ABORT_ON_BUS_RESET);
206 if (err == -EAGAIN) {
207 fw_iso_resources_free(&c->resources);
208 goto retry_after_bus_reset;
209 }
210 if (err < 0)
211 goto err_resources;
212
213 c->connected = true;
214
215 mutex_unlock(&c->mutex);
216
217 return 0;
218
219err_resources:
220 fw_iso_resources_free(&c->resources);
221err_mutex:
222 mutex_unlock(&c->mutex);
223
224 return err;
225}
226EXPORT_SYMBOL(cmp_connection_establish);
227
228/**
229 * cmp_connection_update - update the connection after a bus reset
230 * @c: the connection manager
231 *
232 * This function must be called from the driver's .update handler to reestablish
233 * any connection that might have been active.
234 *
235 * Returns zero on success, or a negative error code. On an error, the
236 * connection is broken and the caller must stop transmitting iso packets.
237 */
238int cmp_connection_update(struct cmp_connection *c)
239{
240 int err;
241
242 mutex_lock(&c->mutex);
243
244 if (!c->connected) {
245 mutex_unlock(&c->mutex);
246 return 0;
247 }
248
249 err = fw_iso_resources_update(&c->resources);
250 if (err < 0)
251 goto err_unconnect;
252
253 err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
254 SUCCEED_ON_BUS_RESET);
255 if (err < 0)
256 goto err_resources;
257
258 mutex_unlock(&c->mutex);
259
260 return 0;
261
262err_resources:
263 fw_iso_resources_free(&c->resources);
264err_unconnect:
265 c->connected = false;
266 mutex_unlock(&c->mutex);
267
268 return err;
269}
270EXPORT_SYMBOL(cmp_connection_update);
271
272
273static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr)
274{
275 return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN | IPCR_P2P_CONN_MASK);
276}
277
278/**
279 * cmp_connection_break - break the connection to the target
280 * @c: the connection manager
281 *
282 * This function deactives the connection in the target's input plug control
283 * register, and frees the isochronous resources of the connection. Before
284 * calling this function, the caller should cease transmitting packets.
285 */
286void cmp_connection_break(struct cmp_connection *c)
287{
288 int err;
289
290 mutex_lock(&c->mutex);
291
292 if (!c->connected) {
293 mutex_unlock(&c->mutex);
294 return;
295 }
296
297 err = pcr_modify(c, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
298 if (err < 0)
299 cmp_error(c, "plug is still connected\n");
300
301 fw_iso_resources_free(&c->resources);
302
303 c->connected = false;
304
305 mutex_unlock(&c->mutex);
306}
307EXPORT_SYMBOL(cmp_connection_break);