/* * 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 __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) { __be32 old_arg, buffer[2]; int err; buffer[0] = c->last_pcr_value; for (;;) { old_arg = buffer[0]; buffer[1] = modify(c, buffer[0]); err = snd_fw_transaction( c->resources.unit, TCODE_LOCK_COMPARE_SWAP, CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index), buffer, 8, FW_FIXED_GENERATION | c->resources.generation); if (err < 0) { if (err == -EAGAIN && bus_reset_handling == SUCCEED_ON_BUS_RESET) err = 0; return err; } if (buffer[0] == old_arg) /* success? */ break; if (check) { err = check(c, buffer[0]); if (err < 0) return err; } } c->last_pcr_value = buffer[1]; return 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, 0); if (err < 0) return err; impr = be32_to_cpu(impr_be); if (ipcr_index >= (impr & IMPR_PLUGS_MASK)) return -EINVAL; err = fw_iso_resources_init(&c->resources, unit); if (err < 0) return err; c->connected = false; mutex_init(&c->mutex); 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);