linux-sg2042/sound/firewire/cmp.c

308 lines
7.2 KiB
C

/*
* 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)
{
struct fw_device *device = fw_parent_device(c->resources.unit);
int generation = c->resources.generation;
int rcode, errors = 0;
__be32 old_arg, buffer[2];
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;
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);