| /* |
| * Connection Management Procedures (IEC 61883-1) helper functions |
| * |
| * Copyright (c) Clemens Ladisch <clemens@ladisch.de> |
| * Licensed under the terms of the GNU General Public License, version 2. |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/firewire.h> |
| #include <linux/firewire-constants.h> |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include "lib.h" |
| #include "iso-resources.h" |
| #include "cmp.h" |
| |
| #define IMPR_SPEED_MASK 0xc0000000 |
| #define IMPR_SPEED_SHIFT 30 |
| #define IMPR_XSPEED_MASK 0x00000060 |
| #define IMPR_XSPEED_SHIFT 5 |
| #define IMPR_PLUGS_MASK 0x0000001f |
| |
| #define IPCR_ONLINE 0x80000000 |
| #define IPCR_BCAST_CONN 0x40000000 |
| #define IPCR_P2P_CONN_MASK 0x3f000000 |
| #define IPCR_P2P_CONN_SHIFT 24 |
| #define IPCR_CHANNEL_MASK 0x003f0000 |
| #define IPCR_CHANNEL_SHIFT 16 |
| |
| enum bus_reset_handling { |
| ABORT_ON_BUS_RESET, |
| SUCCEED_ON_BUS_RESET, |
| }; |
| |
| static __attribute__((format(printf, 2, 3))) |
| void cmp_error(struct cmp_connection *c, const char *fmt, ...) |
| { |
| va_list va; |
| |
| va_start(va, fmt); |
| dev_err(&c->resources.unit->device, "%cPCR%u: %pV", |
| 'i', c->pcr_index, &(struct va_format){ fmt, &va }); |
| va_end(va); |
| } |
| |
| static int pcr_modify(struct cmp_connection *c, |
| __be32 (*modify)(struct cmp_connection *c, __be32 old), |
| int (*check)(struct cmp_connection *c, __be32 pcr), |
| enum bus_reset_handling bus_reset_handling) |
| { |
| struct fw_device *device = fw_parent_device(c->resources.unit); |
| __be32 *buffer = c->resources.buffer; |
| int generation = c->resources.generation; |
| int rcode, errors = 0; |
| __be32 old_arg; |
| int err; |
| |
| buffer[0] = c->last_pcr_value; |
| for (;;) { |
| old_arg = buffer[0]; |
| buffer[1] = modify(c, buffer[0]); |
| |
| rcode = fw_run_transaction( |
| device->card, TCODE_LOCK_COMPARE_SWAP, |
| device->node_id, generation, device->max_speed, |
| CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index), |
| buffer, 8); |
| |
| if (rcode == RCODE_COMPLETE) { |
| if (buffer[0] == old_arg) /* success? */ |
| break; |
| |
| if (check) { |
| err = check(c, buffer[0]); |
| if (err < 0) |
| return err; |
| } |
| } else if (rcode == RCODE_GENERATION) |
| goto bus_reset; |
| else if (rcode_is_permanent_error(rcode) || ++errors >= 3) |
| goto io_error; |
| } |
| c->last_pcr_value = buffer[1]; |
| |
| return 0; |
| |
| io_error: |
| cmp_error(c, "transaction failed: %s\n", rcode_string(rcode)); |
| return -EIO; |
| |
| bus_reset: |
| return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 0; |
| } |
| |
| |
| /** |
| * cmp_connection_init - initializes a connection manager |
| * @c: the connection manager to initialize |
| * @unit: a unit of the target device |
| * @ipcr_index: the index of the iPCR on the target device |
| */ |
| int cmp_connection_init(struct cmp_connection *c, |
| struct fw_unit *unit, |
| unsigned int ipcr_index) |
| { |
| __be32 impr_be; |
| u32 impr; |
| int err; |
| |
| err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST, |
| CSR_REGISTER_BASE + CSR_IMPR, |
| &impr_be, 4); |
| if (err < 0) |
| return err; |
| impr = be32_to_cpu(impr_be); |
| |
| if (ipcr_index >= (impr & IMPR_PLUGS_MASK)) |
| return -EINVAL; |
| |
| c->connected = false; |
| mutex_init(&c->mutex); |
| fw_iso_resources_init(&c->resources, unit); |
| c->last_pcr_value = cpu_to_be32(0x80000000); |
| c->pcr_index = ipcr_index; |
| c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT; |
| if (c->max_speed == SCODE_BETA) |
| c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(cmp_connection_init); |
| |
| /** |
| * cmp_connection_destroy - free connection manager resources |
| * @c: the connection manager |
| */ |
| void cmp_connection_destroy(struct cmp_connection *c) |
| { |
| WARN_ON(c->connected); |
| mutex_destroy(&c->mutex); |
| fw_iso_resources_destroy(&c->resources); |
| } |
| EXPORT_SYMBOL(cmp_connection_destroy); |
| |
| |
| static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr) |
| { |
| ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN | |
| IPCR_P2P_CONN_MASK | |
| IPCR_CHANNEL_MASK); |
| ipcr |= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT); |
| ipcr |= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT); |
| |
| return ipcr; |
| } |
| |
| static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr) |
| { |
| if (ipcr & cpu_to_be32(IPCR_BCAST_CONN | |
| IPCR_P2P_CONN_MASK)) { |
| cmp_error(c, "plug is already in use\n"); |
| return -EBUSY; |
| } |
| if (!(ipcr & cpu_to_be32(IPCR_ONLINE))) { |
| cmp_error(c, "plug is not on-line\n"); |
| return -ECONNREFUSED; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * cmp_connection_establish - establish a connection to the target |
| * @c: the connection manager |
| * @max_payload_bytes: the amount of data (including CIP headers) per packet |
| * |
| * This function establishes a point-to-point connection from the local |
| * computer to the target by allocating isochronous resources (channel and |
| * bandwidth) and setting the target's input plug control register. When this |
| * function succeeds, the caller is responsible for starting transmitting |
| * packets. |
| */ |
| int cmp_connection_establish(struct cmp_connection *c, |
| unsigned int max_payload_bytes) |
| { |
| int err; |
| |
| if (WARN_ON(c->connected)) |
| return -EISCONN; |
| |
| c->speed = min(c->max_speed, |
| fw_parent_device(c->resources.unit)->max_speed); |
| |
| mutex_lock(&c->mutex); |
| |
| retry_after_bus_reset: |
| err = fw_iso_resources_allocate(&c->resources, |
| max_payload_bytes, c->speed); |
| if (err < 0) |
| goto err_mutex; |
| |
| err = pcr_modify(c, ipcr_set_modify, ipcr_set_check, |
| ABORT_ON_BUS_RESET); |
| if (err == -EAGAIN) { |
| fw_iso_resources_free(&c->resources); |
| goto retry_after_bus_reset; |
| } |
| if (err < 0) |
| goto err_resources; |
| |
| c->connected = true; |
| |
| mutex_unlock(&c->mutex); |
| |
| return 0; |
| |
| err_resources: |
| fw_iso_resources_free(&c->resources); |
| err_mutex: |
| mutex_unlock(&c->mutex); |
| |
| return err; |
| } |
| EXPORT_SYMBOL(cmp_connection_establish); |
| |
| /** |
| * cmp_connection_update - update the connection after a bus reset |
| * @c: the connection manager |
| * |
| * This function must be called from the driver's .update handler to reestablish |
| * any connection that might have been active. |
| * |
| * Returns zero on success, or a negative error code. On an error, the |
| * connection is broken and the caller must stop transmitting iso packets. |
| */ |
| int cmp_connection_update(struct cmp_connection *c) |
| { |
| int err; |
| |
| mutex_lock(&c->mutex); |
| |
| if (!c->connected) { |
| mutex_unlock(&c->mutex); |
| return 0; |
| } |
| |
| err = fw_iso_resources_update(&c->resources); |
| if (err < 0) |
| goto err_unconnect; |
| |
| err = pcr_modify(c, ipcr_set_modify, ipcr_set_check, |
| SUCCEED_ON_BUS_RESET); |
| if (err < 0) |
| goto err_resources; |
| |
| mutex_unlock(&c->mutex); |
| |
| return 0; |
| |
| err_resources: |
| fw_iso_resources_free(&c->resources); |
| err_unconnect: |
| c->connected = false; |
| mutex_unlock(&c->mutex); |
| |
| return err; |
| } |
| EXPORT_SYMBOL(cmp_connection_update); |
| |
| |
| static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr) |
| { |
| return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN | IPCR_P2P_CONN_MASK); |
| } |
| |
| /** |
| * cmp_connection_break - break the connection to the target |
| * @c: the connection manager |
| * |
| * This function deactives the connection in the target's input plug control |
| * register, and frees the isochronous resources of the connection. Before |
| * calling this function, the caller should cease transmitting packets. |
| */ |
| void cmp_connection_break(struct cmp_connection *c) |
| { |
| int err; |
| |
| mutex_lock(&c->mutex); |
| |
| if (!c->connected) { |
| mutex_unlock(&c->mutex); |
| return; |
| } |
| |
| err = pcr_modify(c, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET); |
| if (err < 0) |
| cmp_error(c, "plug is still connected\n"); |
| |
| fw_iso_resources_free(&c->resources); |
| |
| c->connected = false; |
| |
| mutex_unlock(&c->mutex); |
| } |
| EXPORT_SYMBOL(cmp_connection_break); |