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