Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 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 | |
Joe Perches | b9075fa | 2011-10-31 17:11:33 -0700 | [diff] [blame] | 35 | static __printf(2, 3) |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 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 | { |
Stefan Richter | f30e6d3 | 2011-04-22 15:13:54 +0200 | [diff] [blame] | 51 | __be32 old_arg, buffer[2]; |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 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 | |
Clemens Ladisch | 1b70485 | 2011-09-04 22:17:38 +0200 | [diff] [blame^] | 59 | err = snd_fw_transaction( |
| 60 | c->resources.unit, TCODE_LOCK_COMPARE_SWAP, |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 61 | CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index), |
Clemens Ladisch | 1b70485 | 2011-09-04 22:17:38 +0200 | [diff] [blame^] | 62 | buffer, 8, |
| 63 | FW_FIXED_GENERATION | c->resources.generation); |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 64 | |
Clemens Ladisch | 1b70485 | 2011-09-04 22:17:38 +0200 | [diff] [blame^] | 65 | if (err < 0) { |
| 66 | if (err == -EAGAIN && |
| 67 | bus_reset_handling == SUCCEED_ON_BUS_RESET) |
| 68 | err = 0; |
| 69 | return err; |
| 70 | } |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 71 | |
Clemens Ladisch | 1b70485 | 2011-09-04 22:17:38 +0200 | [diff] [blame^] | 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 | } |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 80 | } |
| 81 | c->last_pcr_value = buffer[1]; |
| 82 | |
| 83 | return 0; |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 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 | */ |
| 93 | int 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, |
Clemens Ladisch | 1b70485 | 2011-09-04 22:17:38 +0200 | [diff] [blame^] | 103 | &impr_be, 4, 0); |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 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 | |
Clemens Ladisch | 5b2599a | 2011-03-15 07:55:50 +0100 | [diff] [blame] | 111 | err = fw_iso_resources_init(&c->resources, unit); |
| 112 | if (err < 0) |
| 113 | return err; |
| 114 | |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 115 | c->connected = false; |
| 116 | mutex_init(&c->mutex); |
Clemens Ladisch | 31ef913 | 2011-03-15 07:53:21 +0100 | [diff] [blame] | 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 | } |
| 125 | EXPORT_SYMBOL(cmp_connection_init); |
| 126 | |
| 127 | /** |
| 128 | * cmp_connection_destroy - free connection manager resources |
| 129 | * @c: the connection manager |
| 130 | */ |
| 131 | void 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 | } |
| 137 | EXPORT_SYMBOL(cmp_connection_destroy); |
| 138 | |
| 139 | |
| 140 | static __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 | |
| 151 | static 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 | */ |
| 177 | int 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 | |
| 190 | retry_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 | |
| 211 | err_resources: |
| 212 | fw_iso_resources_free(&c->resources); |
| 213 | err_mutex: |
| 214 | mutex_unlock(&c->mutex); |
| 215 | |
| 216 | return err; |
| 217 | } |
| 218 | EXPORT_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 | */ |
| 230 | int 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 | |
| 254 | err_resources: |
| 255 | fw_iso_resources_free(&c->resources); |
| 256 | err_unconnect: |
| 257 | c->connected = false; |
| 258 | mutex_unlock(&c->mutex); |
| 259 | |
| 260 | return err; |
| 261 | } |
| 262 | EXPORT_SYMBOL(cmp_connection_update); |
| 263 | |
| 264 | |
| 265 | static __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 | */ |
| 278 | void 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 | } |
| 299 | EXPORT_SYMBOL(cmp_connection_break); |