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![Clemens Ladisch](/assets/img/avatar_default.png)
There is nothing audio-specific about the rcode_string() helper, so move it from snd-firewire-lib into firewire-core to allow other code to use it. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (fixed sound/firewire/cmp.c)
307 lines
7.2 KiB
C
307 lines
7.2 KiB
C
/*
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* Connection Management Procedures (IEC 61883-1) helper functions
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*
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* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
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* Licensed under the terms of the GNU General Public License, version 2.
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*/
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#include <linux/device.h>
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#include <linux/firewire.h>
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#include <linux/firewire-constants.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include "lib.h"
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#include "iso-resources.h"
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#include "cmp.h"
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#define IMPR_SPEED_MASK 0xc0000000
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#define IMPR_SPEED_SHIFT 30
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#define IMPR_XSPEED_MASK 0x00000060
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#define IMPR_XSPEED_SHIFT 5
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#define IMPR_PLUGS_MASK 0x0000001f
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#define IPCR_ONLINE 0x80000000
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#define IPCR_BCAST_CONN 0x40000000
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#define IPCR_P2P_CONN_MASK 0x3f000000
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#define IPCR_P2P_CONN_SHIFT 24
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#define IPCR_CHANNEL_MASK 0x003f0000
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#define IPCR_CHANNEL_SHIFT 16
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enum bus_reset_handling {
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ABORT_ON_BUS_RESET,
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SUCCEED_ON_BUS_RESET,
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};
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static __printf(2, 3)
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void cmp_error(struct cmp_connection *c, const char *fmt, ...)
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{
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va_list va;
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va_start(va, fmt);
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dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
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'i', c->pcr_index, &(struct va_format){ fmt, &va });
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va_end(va);
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}
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static int pcr_modify(struct cmp_connection *c,
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__be32 (*modify)(struct cmp_connection *c, __be32 old),
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int (*check)(struct cmp_connection *c, __be32 pcr),
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enum bus_reset_handling bus_reset_handling)
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{
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struct fw_device *device = fw_parent_device(c->resources.unit);
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int generation = c->resources.generation;
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int rcode, errors = 0;
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__be32 old_arg, buffer[2];
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int err;
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buffer[0] = c->last_pcr_value;
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for (;;) {
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old_arg = buffer[0];
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buffer[1] = modify(c, buffer[0]);
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rcode = fw_run_transaction(
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device->card, TCODE_LOCK_COMPARE_SWAP,
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device->node_id, generation, device->max_speed,
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CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
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buffer, 8);
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if (rcode == RCODE_COMPLETE) {
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if (buffer[0] == old_arg) /* success? */
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break;
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if (check) {
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err = check(c, buffer[0]);
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if (err < 0)
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return err;
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}
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} else if (rcode == RCODE_GENERATION)
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goto bus_reset;
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else if (rcode_is_permanent_error(rcode) || ++errors >= 3)
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goto io_error;
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}
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c->last_pcr_value = buffer[1];
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return 0;
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io_error:
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cmp_error(c, "transaction failed: %s\n", fw_rcode_string(rcode));
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return -EIO;
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bus_reset:
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return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 0;
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}
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/**
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* cmp_connection_init - initializes a connection manager
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* @c: the connection manager to initialize
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* @unit: a unit of the target device
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* @ipcr_index: the index of the iPCR on the target device
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*/
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int cmp_connection_init(struct cmp_connection *c,
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struct fw_unit *unit,
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unsigned int ipcr_index)
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{
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__be32 impr_be;
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u32 impr;
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int err;
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err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
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CSR_REGISTER_BASE + CSR_IMPR,
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&impr_be, 4);
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if (err < 0)
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return err;
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impr = be32_to_cpu(impr_be);
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if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
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return -EINVAL;
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err = fw_iso_resources_init(&c->resources, unit);
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if (err < 0)
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return err;
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c->connected = false;
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mutex_init(&c->mutex);
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c->last_pcr_value = cpu_to_be32(0x80000000);
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c->pcr_index = ipcr_index;
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c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;
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if (c->max_speed == SCODE_BETA)
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c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT;
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return 0;
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}
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EXPORT_SYMBOL(cmp_connection_init);
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/**
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* cmp_connection_destroy - free connection manager resources
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* @c: the connection manager
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*/
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void cmp_connection_destroy(struct cmp_connection *c)
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{
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WARN_ON(c->connected);
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mutex_destroy(&c->mutex);
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fw_iso_resources_destroy(&c->resources);
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}
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EXPORT_SYMBOL(cmp_connection_destroy);
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static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
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{
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ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN |
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IPCR_P2P_CONN_MASK |
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IPCR_CHANNEL_MASK);
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ipcr |= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT);
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ipcr |= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT);
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return ipcr;
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}
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static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr)
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{
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if (ipcr & cpu_to_be32(IPCR_BCAST_CONN |
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IPCR_P2P_CONN_MASK)) {
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cmp_error(c, "plug is already in use\n");
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return -EBUSY;
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}
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if (!(ipcr & cpu_to_be32(IPCR_ONLINE))) {
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cmp_error(c, "plug is not on-line\n");
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return -ECONNREFUSED;
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}
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return 0;
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}
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/**
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* cmp_connection_establish - establish a connection to the target
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* @c: the connection manager
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* @max_payload_bytes: the amount of data (including CIP headers) per packet
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*
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* This function establishes a point-to-point connection from the local
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* computer to the target by allocating isochronous resources (channel and
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* bandwidth) and setting the target's input plug control register. When this
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* function succeeds, the caller is responsible for starting transmitting
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* packets.
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*/
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int cmp_connection_establish(struct cmp_connection *c,
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unsigned int max_payload_bytes)
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{
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int err;
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if (WARN_ON(c->connected))
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return -EISCONN;
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c->speed = min(c->max_speed,
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fw_parent_device(c->resources.unit)->max_speed);
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mutex_lock(&c->mutex);
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retry_after_bus_reset:
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err = fw_iso_resources_allocate(&c->resources,
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max_payload_bytes, c->speed);
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if (err < 0)
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goto err_mutex;
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err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
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ABORT_ON_BUS_RESET);
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if (err == -EAGAIN) {
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fw_iso_resources_free(&c->resources);
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goto retry_after_bus_reset;
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}
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if (err < 0)
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goto err_resources;
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c->connected = true;
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mutex_unlock(&c->mutex);
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return 0;
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err_resources:
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fw_iso_resources_free(&c->resources);
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err_mutex:
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mutex_unlock(&c->mutex);
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return err;
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}
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EXPORT_SYMBOL(cmp_connection_establish);
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/**
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* cmp_connection_update - update the connection after a bus reset
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* @c: the connection manager
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*
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* This function must be called from the driver's .update handler to reestablish
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* any connection that might have been active.
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*
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* Returns zero on success, or a negative error code. On an error, the
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* connection is broken and the caller must stop transmitting iso packets.
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*/
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int cmp_connection_update(struct cmp_connection *c)
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{
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int err;
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mutex_lock(&c->mutex);
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if (!c->connected) {
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mutex_unlock(&c->mutex);
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return 0;
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}
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err = fw_iso_resources_update(&c->resources);
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if (err < 0)
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goto err_unconnect;
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err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
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SUCCEED_ON_BUS_RESET);
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if (err < 0)
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goto err_resources;
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mutex_unlock(&c->mutex);
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return 0;
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err_resources:
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fw_iso_resources_free(&c->resources);
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err_unconnect:
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c->connected = false;
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mutex_unlock(&c->mutex);
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return err;
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}
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EXPORT_SYMBOL(cmp_connection_update);
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static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr)
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{
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return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN | IPCR_P2P_CONN_MASK);
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}
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/**
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* cmp_connection_break - break the connection to the target
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* @c: the connection manager
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*
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* This function deactives the connection in the target's input plug control
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* register, and frees the isochronous resources of the connection. Before
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* calling this function, the caller should cease transmitting packets.
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*/
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void cmp_connection_break(struct cmp_connection *c)
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{
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int err;
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mutex_lock(&c->mutex);
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if (!c->connected) {
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mutex_unlock(&c->mutex);
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return;
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}
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err = pcr_modify(c, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
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if (err < 0)
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cmp_error(c, "plug is still connected\n");
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fw_iso_resources_free(&c->resources);
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c->connected = false;
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mutex_unlock(&c->mutex);
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}
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EXPORT_SYMBOL(cmp_connection_break);
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