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 30 enum bus_reset_handling { 31 ABORT_ON_BUS_RESET, 32 SUCCEED_ON_BUS_RESET, 33 }; 34 35 static __attribute__((format(printf, 2, 3))) 36 void 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 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) 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 86 io_error: 87 cmp_error(c, "transaction failed: %s\n", rcode_string(rcode)); 88 return -EIO; 89 90 bus_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 */ 101 int 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 } 133 EXPORT_SYMBOL(cmp_connection_init); 134 135 /** 136 * cmp_connection_destroy - free connection manager resources 137 * @c: the connection manager 138 */ 139 void 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 } 145 EXPORT_SYMBOL(cmp_connection_destroy); 146 147 148 static __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 } 158 159 static 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 */ 185 int 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); 197 198 retry_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; 218 219 err_resources: 220 fw_iso_resources_free(&c->resources); 221 err_mutex: 222 mutex_unlock(&c->mutex); 223 224 return err; 225 } 226 EXPORT_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 */ 238 int 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; 261 262 err_resources: 263 fw_iso_resources_free(&c->resources); 264 err_unconnect: 265 c->connected = false; 266 mutex_unlock(&c->mutex); 267 268 return err; 269 } 270 EXPORT_SYMBOL(cmp_connection_update); 271 272 273 static __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 */ 286 void 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 } 307 EXPORT_SYMBOL(cmp_connection_break); 308