// SPDX-License-Identifier: GPL-2.0-only
/*
* Connection Management Procedures (IEC 61883-1) helper functions
*
* Copyright (c) Clemens Ladisch <[email protected]>
*/
#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"
/* MPR common fields */
#define MPR_SPEED_MASK 0xc0000000
#define MPR_SPEED_SHIFT 30
#define MPR_XSPEED_MASK 0x00000060
#define MPR_XSPEED_SHIFT 5
#define MPR_PLUGS_MASK 0x0000001f
/* PCR common fields */
#define PCR_ONLINE 0x80000000
#define PCR_BCAST_CONN 0x40000000
#define PCR_P2P_CONN_MASK 0x3f000000
#define PCR_P2P_CONN_SHIFT 24
#define PCR_CHANNEL_MASK 0x003f0000
#define PCR_CHANNEL_SHIFT 16
/* oPCR specific fields */
#define OPCR_XSPEED_MASK 0x00C00000
#define OPCR_XSPEED_SHIFT 22
#define OPCR_SPEED_MASK 0x0000C000
#define OPCR_SPEED_SHIFT 14
#define OPCR_OVERHEAD_ID_MASK 0x00003C00
#define OPCR_OVERHEAD_ID_SHIFT 10
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",
(c->direction == CMP_INPUT) ? 'i' : 'o',
c->pcr_index, &(struct va_format){ fmt, &va });
va_end(va);
}
static u64 mpr_address(struct cmp_connection *c)
{
if (c->direction == CMP_INPUT)
return CSR_REGISTER_BASE + CSR_IMPR;
else
return CSR_REGISTER_BASE + CSR_OMPR;
}
static u64 pcr_address(struct cmp_connection *c)
{
if (c->direction == CMP_INPUT)
return CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index);
else
return CSR_REGISTER_BASE + CSR_OPCR(c->pcr_index);
}
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,
pcr_address(c), 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
* @direction: input or output
* @pcr_index: the index of the iPCR/oPCR on the target device
*/
int cmp_connection_init(struct cmp_connection *c,
struct fw_unit *unit,
enum cmp_direction direction,
unsigned int pcr_index)
{
__be32 mpr_be;
u32 mpr;
int err;
c->direction = direction;
err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
mpr_address(c), &mpr_be, 4, 0);
if (err < 0)
return err;
mpr = be32_to_cpu(mpr_be);
if (pcr_index >= (mpr & MPR_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 = pcr_index;
c->max_speed = (mpr & MPR_SPEED_MASK) >> MPR_SPEED_SHIFT;
if (c->max_speed == SCODE_BETA)
c->max_speed += (mpr & MPR_XSPEED_MASK) >> MPR_XSPEED_SHIFT;
return 0;
}
EXPORT_SYMBOL(cmp_connection_init);
/**
* cmp_connection_check_used - check connection is already esablished or not
* @c: the connection manager to be checked
* @used: the pointer to store the result of checking the connection
*/
int cmp_connection_check_used(struct cmp_connection *c, bool *used)
{
__be32 pcr;
int err;
err = snd_fw_transaction(
c->resources.unit, TCODE_READ_QUADLET_REQUEST,
pcr_address(c), &pcr, 4, 0);
if (err >= 0)
*used = !!(pcr & cpu_to_be32(PCR_BCAST_CONN |
PCR_P2P_CONN_MASK));
return err;
}
EXPORT_SYMBOL(cmp_connection_check_used);
/**
* 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);
int cmp_connection_reserve(struct cmp_connection *c,
unsigned int max_payload_bytes)
{
int err;
mutex_lock(&c->mutex);
if (WARN_ON(c->resources.allocated)) {
err = -EBUSY;
goto end;
}
c->speed = min(c->max_speed,
fw_parent_device(c->resources.unit)->max_speed);
err = fw_iso_resources_allocate(&c->resources, max_payload_bytes,
c->speed);
end:
mutex_unlock(&c->mutex);
return err;
}
EXPORT_SYMBOL(cmp_connection_reserve);
void cmp_connection_release(struct cmp_connection *c)
{
mutex_lock(&c->mutex);
fw_iso_resources_free(&c->resources);
mutex_unlock(&c->mutex);
}
EXPORT_SYMBOL(cmp_connection_release);
static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
{
ipcr &= ~cpu_to_be32(PCR_BCAST_CONN |
PCR_P2P_CONN_MASK |
PCR_CHANNEL_MASK);
ipcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
ipcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
return ipcr;
}
static int get_overhead_id(struct cmp_connection *c)
{
int id;
/*
* apply "oPCR overhead ID encoding"
* the encoding table can convert up to 512.
* here the value over 512 is converted as the same way as 512.
*/
for (id = 1; id < 16; id++) {
if (c->resources.bandwidth_overhead < (id << 5))
break;
}
if (id == 16)
id = 0;
return id;
}
static __be32 opcr_set_modify(struct cmp_connection *c, __be32 opcr)
{
unsigned int spd, xspd;
/* generate speed and extended speed field value */
if (c->speed > SCODE_400) {
spd = SCODE_800;
xspd = c->speed - SCODE_800;
} else {
spd = c->speed;
xspd = 0;
}
opcr &= ~cpu_to_be32(PCR_BCAST_CONN |
PCR_P2P_CONN_MASK |
OPCR_XSPEED_MASK |
PCR_CHANNEL_MASK |
OPCR_SPEED_MASK |
OPCR_OVERHEAD_ID_MASK);
opcr |= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
opcr |= cpu_to_be32(xspd << OPCR_XSPEED_SHIFT);
opcr |= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
opcr |= cpu_to_be32(spd << OPCR_SPEED_SHIFT);
opcr |= cpu_to_be32(get_overhead_id(c) << OPCR_OVERHEAD_ID_SHIFT);
return opcr;
}
static int pcr_set_check(struct cmp_connection *c, __be32 pcr)
{
if (pcr & cpu_to_be32(PCR_BCAST_CONN |
PCR_P2P_CONN_MASK)) {
cmp_error(c, "plug is already in use\n");
return -EBUSY;
}
if (!(pcr & cpu_to_be32(PCR_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
*
* 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/output plug control register.
* When this function succeeds, the caller is responsible for starting
* transmitting packets.
*/
int cmp_connection_establish(struct cmp_connection *c)
{
int err;
mutex_lock(&c->mutex);
if (WARN_ON(c->connected)) {
mutex_unlock(&c->mutex);
return -EISCONN;
}
retry_after_bus_reset:
if (c->direction == CMP_OUTPUT)
err = pcr_modify(c, opcr_set_modify, pcr_set_check,
ABORT_ON_BUS_RESET);
else
err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
ABORT_ON_BUS_RESET);
if (err == -EAGAIN) {
err = fw_iso_resources_update(&c->resources);
if (err >= 0)
goto retry_after_bus_reset;
}
if (err >= 0)
c->connected = true;
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;
if (c->direction == CMP_OUTPUT)
err = pcr_modify(c, opcr_set_modify, pcr_set_check,
SUCCEED_ON_BUS_RESET);
else
err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
SUCCEED_ON_BUS_RESET);
if (err < 0)
goto err_unconnect;
mutex_unlock(&c->mutex);
return 0;
err_unconnect:
c->connected = false;
mutex_unlock(&c->mutex);
return err;
}
EXPORT_SYMBOL(cmp_connection_update);
static __be32 pcr_break_modify(struct cmp_connection *c, __be32 pcr)
{
return pcr & ~cpu_to_be32(PCR_BCAST_CONN | PCR_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/output 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, pcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
if (err < 0)
cmp_error(c, "plug is still connected\n");
c->connected = false;
mutex_unlock(&c->mutex);
}
EXPORT_SYMBOL(cmp_connection_break);
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