[mirror_ubuntu-bionic-kernel.git] / sound / firewire / cmp.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"

/* 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);


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
 * @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/output 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;

	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) {
		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;

	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_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 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");

	fw_iso_resources_free(&c->resources);

	c->connected = false;

	mutex_unlock(&c->mutex);
}
EXPORT_SYMBOL(cmp_connection_break);
Commit	Line	Data
31ef9134 CL	1	/*
	2	* Connection Management Procedures (IEC 61883-1) helper functions
	3	*
	4	* Copyright (c) Clemens Ladisch <clemens@ladisch.de>
	5	* Licensed under the terms of the GNU General Public License, version 2.
	6	*/
	7
	8	#include <linux/device.h>
	9	#include <linux/firewire.h>
	10	#include <linux/firewire-constants.h>
	11	#include <linux/module.h>
	12	#include <linux/sched.h>
	13	#include "lib.h"
	14	#include "iso-resources.h"
	15	#include "cmp.h"
	16
a7fa0d04 TS	17	/* MPR common fields */
	18	#define MPR_SPEED_MASK 0xc0000000
	19	#define MPR_SPEED_SHIFT 30
	20	#define MPR_XSPEED_MASK 0x00000060
	21	#define MPR_XSPEED_SHIFT 5
	22	#define MPR_PLUGS_MASK 0x0000001f
	23
	24	/* PCR common fields */
	25	#define PCR_ONLINE 0x80000000
	26	#define PCR_BCAST_CONN 0x40000000
	27	#define PCR_P2P_CONN_MASK 0x3f000000
	28	#define PCR_P2P_CONN_SHIFT 24
	29	#define PCR_CHANNEL_MASK 0x003f0000
	30	#define PCR_CHANNEL_SHIFT 16
31ef9134	31
44aff698 TS	32	/* oPCR specific fields */
	33	#define OPCR_XSPEED_MASK 0x00C00000
	34	#define OPCR_XSPEED_SHIFT 22
	35	#define OPCR_SPEED_MASK 0x0000C000
	36	#define OPCR_SPEED_SHIFT 14
	37	#define OPCR_OVERHEAD_ID_MASK 0x00003C00
	38	#define OPCR_OVERHEAD_ID_SHIFT 10
	39
31ef9134 CL	40	enum bus_reset_handling {
	41	ABORT_ON_BUS_RESET,
	42	SUCCEED_ON_BUS_RESET,
	43	};
	44
b9075fa9	45	static __printf(2, 3)
31ef9134 CL	46	void cmp_error(struct cmp_connection c, const char fmt, ...)
	47	{
	48	va_list va;
	49
	50	va_start(va, fmt);
	51	dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
44aff698 TS	52	(c->direction == CMP_INPUT) ? 'i' : 'o',
44aff698 TS	53	c->pcr_index, &(struct va_format){ fmt, &va });
31ef9134 CL	54	va_end(va);
	55	}
	56
44aff698 TS	57	static u64 mpr_address(struct cmp_connection *c)
	58	{
	59	if (c->direction == CMP_INPUT)
	60	return CSR_REGISTER_BASE + CSR_IMPR;
	61	else
	62	return CSR_REGISTER_BASE + CSR_OMPR;
	63	}
	64
	65	static u64 pcr_address(struct cmp_connection *c)
	66	{
	67	if (c->direction == CMP_INPUT)
	68	return CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index);
	69	else
	70	return CSR_REGISTER_BASE + CSR_OPCR(c->pcr_index);
	71	}
	72
31ef9134 CL	73	static int pcr_modify(struct cmp_connection *c,
	74	__be32 (modify)(struct cmp_connection c, __be32 old),
	75	int (check)(struct cmp_connection c, __be32 pcr),
	76	enum bus_reset_handling bus_reset_handling)
	77	{
f30e6d3e	78	__be32 old_arg, buffer[2];
31ef9134 CL	79	int err;
	80
	81	buffer[0] = c->last_pcr_value;
	82	for (;;) {
	83	old_arg = buffer[0];
	84	buffer[1] = modify(c, buffer[0]);
	85
1b70485f CL	86	err = snd_fw_transaction(
1b70485f CL	87	c->resources.unit, TCODE_LOCK_COMPARE_SWAP,
44aff698	88	pcr_address(c), buffer, 8,
1b70485f CL	89	FW_FIXED_GENERATION \| c->resources.generation);
	90
	91	if (err < 0) {
	92	if (err == -EAGAIN &&
	93	bus_reset_handling == SUCCEED_ON_BUS_RESET)
	94	err = 0;
	95	return err;
	96	}
	97
	98	if (buffer[0] == old_arg) /* success? */
	99	break;
	100
	101	if (check) {
	102	err = check(c, buffer[0]);
	103	if (err < 0)
	104	return err;
	105	}
31ef9134 CL	106	}
	107	c->last_pcr_value = buffer[1];
	108
	109	return 0;
31ef9134 CL	110	}
	111
	112
	113	/**
	114	* cmp_connection_init - initializes a connection manager
	115	* @c: the connection manager to initialize
	116	* @unit: a unit of the target device
5f217f90	117	* @direction: input or output
a7fa0d04	118	* @pcr_index: the index of the iPCR/oPCR on the target device
31ef9134 CL	119	*/
	120	int cmp_connection_init(struct cmp_connection *c,
	121	struct fw_unit *unit,
c68a1c65	122	enum cmp_direction direction,
a7fa0d04	123	unsigned int pcr_index)
31ef9134	124	{
a7fa0d04 TS	125	__be32 mpr_be;
a7fa0d04 TS	126	u32 mpr;
31ef9134 CL	127	int err;
31ef9134 CL	128
44aff698	129	c->direction = direction;
31ef9134	130	err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
44aff698	131	mpr_address(c), &mpr_be, 4, 0);
31ef9134 CL	132	if (err < 0)
31ef9134 CL	133	return err;
a7fa0d04	134	mpr = be32_to_cpu(mpr_be);
31ef9134	135
a7fa0d04	136	if (pcr_index >= (mpr & MPR_PLUGS_MASK))
31ef9134 CL	137	return -EINVAL;
31ef9134 CL	138
5b2599a0 CL	139	err = fw_iso_resources_init(&c->resources, unit);
	140	if (err < 0)
	141	return err;
	142
31ef9134 CL	143	c->connected = false;
31ef9134 CL	144	mutex_init(&c->mutex);
31ef9134	145	c->last_pcr_value = cpu_to_be32(0x80000000);
a7fa0d04 TS	146	c->pcr_index = pcr_index;
a7fa0d04 TS	147	c->max_speed = (mpr & MPR_SPEED_MASK) >> MPR_SPEED_SHIFT;
31ef9134	148	if (c->max_speed == SCODE_BETA)
a7fa0d04	149	c->max_speed += (mpr & MPR_XSPEED_MASK) >> MPR_XSPEED_SHIFT;
31ef9134 CL	150
	151	return 0;
	152	}
	153	EXPORT_SYMBOL(cmp_connection_init);
	154
b04479fb TS	155	/**
	156	* cmp_connection_check_used - check connection is already esablished or not
	157	* @c: the connection manager to be checked
5f217f90	158	* @used: the pointer to store the result of checking the connection
b04479fb TS	159	*/
	160	int cmp_connection_check_used(struct cmp_connection c, bool used)
	161	{
	162	__be32 pcr;
	163	int err;
	164
	165	err = snd_fw_transaction(
	166	c->resources.unit, TCODE_READ_QUADLET_REQUEST,
	167	pcr_address(c), &pcr, 4, 0);
	168	if (err >= 0)
51212eea TS	169	*used = !!(pcr & cpu_to_be32(PCR_BCAST_CONN \|
	170	PCR_P2P_CONN_MASK));
	171
b04479fb TS	172	return err;
	173	}
	174	EXPORT_SYMBOL(cmp_connection_check_used);
	175
31ef9134 CL	176	/**
	177	* cmp_connection_destroy - free connection manager resources
	178	* @c: the connection manager
	179	*/
	180	void cmp_connection_destroy(struct cmp_connection *c)
	181	{
	182	WARN_ON(c->connected);
	183	mutex_destroy(&c->mutex);
	184	fw_iso_resources_destroy(&c->resources);
	185	}
	186	EXPORT_SYMBOL(cmp_connection_destroy);
	187
	188
	189	static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
	190	{
a7fa0d04 TS	191	ipcr &= ~cpu_to_be32(PCR_BCAST_CONN \|
	192	PCR_P2P_CONN_MASK \|
	193	PCR_CHANNEL_MASK);
	194	ipcr \|= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
	195	ipcr \|= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
31ef9134 CL	196
	197	return ipcr;
	198	}
	199
44aff698 TS	200	static int get_overhead_id(struct cmp_connection *c)
	201	{
	202	int id;
	203
	204	/*
	205	* apply "oPCR overhead ID encoding"
	206	* the encoding table can convert up to 512.
	207	* here the value over 512 is converted as the same way as 512.
	208	*/
	209	for (id = 1; id < 16; id++) {
	210	if (c->resources.bandwidth_overhead < (id << 5))
	211	break;
	212	}
	213	if (id == 16)
	214	id = 0;
	215
	216	return id;
	217	}
	218
	219	static __be32 opcr_set_modify(struct cmp_connection *c, __be32 opcr)
	220	{
	221	unsigned int spd, xspd;
	222
	223	/* generate speed and extended speed field value */
	224	if (c->speed > SCODE_400) {
	225	spd = SCODE_800;
	226	xspd = c->speed - SCODE_800;
	227	} else {
	228	spd = c->speed;
	229	xspd = 0;
	230	}
	231
	232	opcr &= ~cpu_to_be32(PCR_BCAST_CONN \|
	233	PCR_P2P_CONN_MASK \|
	234	OPCR_XSPEED_MASK \|
	235	PCR_CHANNEL_MASK \|
	236	OPCR_SPEED_MASK \|
	237	OPCR_OVERHEAD_ID_MASK);
	238	opcr \|= cpu_to_be32(1 << PCR_P2P_CONN_SHIFT);
	239	opcr \|= cpu_to_be32(xspd << OPCR_XSPEED_SHIFT);
	240	opcr \|= cpu_to_be32(c->resources.channel << PCR_CHANNEL_SHIFT);
	241	opcr \|= cpu_to_be32(spd << OPCR_SPEED_SHIFT);
	242	opcr \|= cpu_to_be32(get_overhead_id(c) << OPCR_OVERHEAD_ID_SHIFT);
	243
	244	return opcr;
	245	}
	246
a7fa0d04	247	static int pcr_set_check(struct cmp_connection *c, __be32 pcr)
31ef9134	248	{
a7fa0d04 TS	249	if (pcr & cpu_to_be32(PCR_BCAST_CONN \|
a7fa0d04 TS	250	PCR_P2P_CONN_MASK)) {
31ef9134 CL	251	cmp_error(c, "plug is already in use\n");
	252	return -EBUSY;
	253	}
a7fa0d04	254	if (!(pcr & cpu_to_be32(PCR_ONLINE))) {
31ef9134 CL	255	cmp_error(c, "plug is not on-line\n");
	256	return -ECONNREFUSED;
	257	}
	258
	259	return 0;
	260	}
	261
	262	/**
	263	* cmp_connection_establish - establish a connection to the target
	264	* @c: the connection manager
	265	* @max_payload_bytes: the amount of data (including CIP headers) per packet
	266	*
	267	* This function establishes a point-to-point connection from the local
	268	* computer to the target by allocating isochronous resources (channel and
a7fa0d04 TS	269	* bandwidth) and setting the target's input/output plug control register.
	270	* When this function succeeds, the caller is responsible for starting
	271	* transmitting packets.
31ef9134 CL	272	*/
	273	int cmp_connection_establish(struct cmp_connection *c,
	274	unsigned int max_payload_bytes)
	275	{
	276	int err;
	277
	278	if (WARN_ON(c->connected))
	279	return -EISCONN;
	280
	281	c->speed = min(c->max_speed,
	282	fw_parent_device(c->resources.unit)->max_speed);
	283
	284	mutex_lock(&c->mutex);
	285
	286	retry_after_bus_reset:
	287	err = fw_iso_resources_allocate(&c->resources,
	288	max_payload_bytes, c->speed);
	289	if (err < 0)
	290	goto err_mutex;
	291
44aff698 TS	292	if (c->direction == CMP_OUTPUT)
	293	err = pcr_modify(c, opcr_set_modify, pcr_set_check,
	294	ABORT_ON_BUS_RESET);
	295	else
	296	err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
	297	ABORT_ON_BUS_RESET);
	298
31ef9134 CL	299	if (err == -EAGAIN) {
	300	fw_iso_resources_free(&c->resources);
	301	goto retry_after_bus_reset;
	302	}
	303	if (err < 0)
	304	goto err_resources;
	305
	306	c->connected = true;
	307
	308	mutex_unlock(&c->mutex);
	309
	310	return 0;
	311
	312	err_resources:
	313	fw_iso_resources_free(&c->resources);
	314	err_mutex:
	315	mutex_unlock(&c->mutex);
	316
	317	return err;
	318	}
	319	EXPORT_SYMBOL(cmp_connection_establish);
	320
	321	/**
	322	* cmp_connection_update - update the connection after a bus reset
	323	* @c: the connection manager
	324	*
a7fa0d04 TS	325	* This function must be called from the driver's .update handler to
a7fa0d04 TS	326	* reestablish any connection that might have been active.
31ef9134 CL	327	*
	328	* Returns zero on success, or a negative error code. On an error, the
	329	* connection is broken and the caller must stop transmitting iso packets.
	330	*/
	331	int cmp_connection_update(struct cmp_connection *c)
	332	{
	333	int err;
	334
	335	mutex_lock(&c->mutex);
	336
	337	if (!c->connected) {
	338	mutex_unlock(&c->mutex);
	339	return 0;
	340	}
	341
	342	err = fw_iso_resources_update(&c->resources);
	343	if (err < 0)
	344	goto err_unconnect;
	345
44aff698 TS	346	if (c->direction == CMP_OUTPUT)
	347	err = pcr_modify(c, opcr_set_modify, pcr_set_check,
	348	SUCCEED_ON_BUS_RESET);
	349	else
	350	err = pcr_modify(c, ipcr_set_modify, pcr_set_check,
	351	SUCCEED_ON_BUS_RESET);
	352
31ef9134 CL	353	if (err < 0)
	354	goto err_resources;
	355
	356	mutex_unlock(&c->mutex);
	357
	358	return 0;
	359
	360	err_resources:
	361	fw_iso_resources_free(&c->resources);
	362	err_unconnect:
	363	c->connected = false;
	364	mutex_unlock(&c->mutex);
	365
	366	return err;
	367	}
	368	EXPORT_SYMBOL(cmp_connection_update);
	369
a7fa0d04	370	static __be32 pcr_break_modify(struct cmp_connection *c, __be32 pcr)
31ef9134	371	{
a7fa0d04	372	return pcr & ~cpu_to_be32(PCR_BCAST_CONN \| PCR_P2P_CONN_MASK);
31ef9134 CL	373	}
	374
	375	/**
	376	* cmp_connection_break - break the connection to the target
	377	* @c: the connection manager
	378	*
a7fa0d04 TS	379	* This function deactives the connection in the target's input/output plug
	380	* control register, and frees the isochronous resources of the connection.
	381	* Before calling this function, the caller should cease transmitting packets.
31ef9134 CL	382	*/
	383	void cmp_connection_break(struct cmp_connection *c)
	384	{
	385	int err;
	386
	387	mutex_lock(&c->mutex);
	388
	389	if (!c->connected) {
	390	mutex_unlock(&c->mutex);
	391	return;
	392	}
	393
a7fa0d04	394	err = pcr_modify(c, pcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
31ef9134 CL	395	if (err < 0)
	396	cmp_error(c, "plug is still connected\n");
	397
	398	fw_iso_resources_free(&c->resources);
	399
	400	c->connected = false;
	401
	402	mutex_unlock(&c->mutex);
	403	}
	404	EXPORT_SYMBOL(cmp_connection_break);