[linux.git] / sound / firewire / fcp.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Function Control Protocol (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/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include "fcp.h"
#include "lib.h"
#include "amdtp-stream.h"

#define CTS_AVC 0x00

#define ERROR_RETRIES	3
#define ERROR_DELAY_MS	5
#define FCP_TIMEOUT_MS	125

int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
			    enum avc_general_plug_dir dir,
			    unsigned short pid)
{
	unsigned int sfc;
	u8 *buf;
	bool flag;
	int err;

	flag = false;
	for (sfc = 0; sfc < CIP_SFC_COUNT; sfc++) {
		if (amdtp_rate_table[sfc] == rate) {
			flag = true;
			break;
		}
	}
	if (!flag)
		return -EINVAL;

	buf = kzalloc(8, GFP_KERNEL);
	if (buf == NULL)
		return -ENOMEM;

	buf[0] = 0x00;		/* AV/C CONTROL */
	buf[1] = 0xff;		/* UNIT */
	if (dir == AVC_GENERAL_PLUG_DIR_IN)
		buf[2] = 0x19;	/* INPUT PLUG SIGNAL FORMAT */
	else
		buf[2] = 0x18;	/* OUTPUT PLUG SIGNAL FORMAT */
	buf[3] = 0xff & pid;	/* plug id */
	buf[4] = 0x90;		/* EOH_1, Form_1, FMT. AM824 */
	buf[5] = 0x07 & sfc;	/* FDF-hi. AM824, frequency */
	buf[6] = 0xff;		/* FDF-mid. AM824, SYT hi (not used)*/
	buf[7] = 0xff;		/* FDF-low. AM824, SYT lo (not used) */

	/* do transaction and check buf[1-5] are the same against command */
	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5));
	if (err < 0)
		;
	else if (err < 8)
		err = -EIO;
	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
		err = -ENOSYS;
	else if (buf[0] == 0x0a) /* REJECTED */
		err = -EINVAL;
	if (err < 0)
		goto end;

	err = 0;
end:
	kfree(buf);
	return err;
}
EXPORT_SYMBOL(avc_general_set_sig_fmt);

int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate,
			    enum avc_general_plug_dir dir,
			    unsigned short pid)
{
	unsigned int sfc;
	u8 *buf;
	int err;

	buf = kzalloc(8, GFP_KERNEL);
	if (buf == NULL)
		return -ENOMEM;

	buf[0] = 0x01;		/* AV/C STATUS */
	buf[1] = 0xff;		/* Unit */
	if (dir == AVC_GENERAL_PLUG_DIR_IN)
		buf[2] = 0x19;	/* INPUT PLUG SIGNAL FORMAT */
	else
		buf[2] = 0x18;	/* OUTPUT PLUG SIGNAL FORMAT */
	buf[3] = 0xff & pid;	/* plug id */
	buf[4] = 0x90;		/* EOH_1, Form_1, FMT. AM824 */
	buf[5] = 0xff;		/* FDF-hi. AM824, frequency */
	buf[6] = 0xff;		/* FDF-mid. AM824, SYT hi (not used) */
	buf[7] = 0xff;		/* FDF-low. AM824, SYT lo (not used) */

	/* do transaction and check buf[1-4] are the same against command */
	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
				  BIT(1) | BIT(2) | BIT(3) | BIT(4));
	if (err < 0)
		;
	else if (err < 8)
		err = -EIO;
	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
		err = -ENOSYS;
	else if (buf[0] == 0x0a) /* REJECTED */
		err = -EINVAL;
	else if (buf[0] == 0x0b) /* IN TRANSITION */
		err = -EAGAIN;
	if (err < 0)
		goto end;

	/* check sfc field and pick up rate */
	sfc = 0x07 & buf[5];
	if (sfc >= CIP_SFC_COUNT) {
		err = -EAGAIN;	/* also in transition */
		goto end;
	}

	*rate = amdtp_rate_table[sfc];
	err = 0;
end:
	kfree(buf);
	return err;
}
EXPORT_SYMBOL(avc_general_get_sig_fmt);

int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
			      unsigned int subunit_id, unsigned int subfunction,
			      u8 info[AVC_PLUG_INFO_BUF_BYTES])
{
	u8 *buf;
	int err;

	/* extended subunit in spec.4.2 is not supported */
	if ((subunit_type == 0x1E) || (subunit_id == 5))
		return -EINVAL;

	buf = kzalloc(8, GFP_KERNEL);
	if (buf == NULL)
		return -ENOMEM;

	buf[0] = 0x01;	/* AV/C STATUS */
	/* UNIT or Subunit, Functionblock */
	buf[1] = ((subunit_type & 0x1f) << 3) | (subunit_id & 0x7);
	buf[2] = 0x02;	/* PLUG INFO */
	buf[3] = 0xff & subfunction;

	err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2));
	if (err < 0)
		;
	else if (err < 8)
		err = -EIO;
	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
		err = -ENOSYS;
	else if (buf[0] == 0x0a) /* REJECTED */
		err = -EINVAL;
	else if (buf[0] == 0x0b) /* IN TRANSITION */
		err = -EAGAIN;
	if (err < 0)
		goto end;

	info[0] = buf[4];
	info[1] = buf[5];
	info[2] = buf[6];
	info[3] = buf[7];

	err = 0;
end:
	kfree(buf);
	return err;
}
EXPORT_SYMBOL(avc_general_get_plug_info);

static DEFINE_SPINLOCK(transactions_lock);
static LIST_HEAD(transactions);

enum fcp_state {
	STATE_PENDING,
	STATE_BUS_RESET,
	STATE_COMPLETE,
	STATE_DEFERRED,
};

struct fcp_transaction {
	struct list_head list;
	struct fw_unit *unit;
	void *response_buffer;
	unsigned int response_size;
	unsigned int response_match_bytes;
	enum fcp_state state;
	wait_queue_head_t wait;
	bool deferrable;
};

/**
 * fcp_avc_transaction - send an AV/C command and wait for its response
 * @unit: a unit on the target device
 * @command: a buffer containing the command frame; must be DMA-able
 * @command_size: the size of @command
 * @response: a buffer for the response frame
 * @response_size: the maximum size of @response
 * @response_match_bytes: a bitmap specifying the bytes used to detect the
 *                        correct response frame
 *
 * This function sends a FCP command frame to the target and waits for the
 * corresponding response frame to be returned.
 *
 * Because it is possible for multiple FCP transactions to be active at the
 * same time, the correct response frame is detected by the value of certain
 * bytes.  These bytes must be set in @response before calling this function,
 * and the corresponding bits must be set in @response_match_bytes.
 *
 * @command and @response can point to the same buffer.
 *
 * Returns the actual size of the response frame, or a negative error code.
 */
int fcp_avc_transaction(struct fw_unit *unit,
			const void *command, unsigned int command_size,
			void *response, unsigned int response_size,
			unsigned int response_match_bytes)
{
	struct fcp_transaction t;
	int tcode, ret, tries = 0;

	t.unit = unit;
	t.response_buffer = response;
	t.response_size = response_size;
	t.response_match_bytes = response_match_bytes;
	t.state = STATE_PENDING;
	init_waitqueue_head(&t.wait);

	if (*(const u8 *)command == 0x00 || *(const u8 *)command == 0x03)
		t.deferrable = true;

	spin_lock_irq(&transactions_lock);
	list_add_tail(&t.list, &transactions);
	spin_unlock_irq(&transactions_lock);

	for (;;) {
		tcode = command_size == 4 ? TCODE_WRITE_QUADLET_REQUEST
					  : TCODE_WRITE_BLOCK_REQUEST;
		ret = snd_fw_transaction(t.unit, tcode,
					 CSR_REGISTER_BASE + CSR_FCP_COMMAND,
					 (void *)command, command_size, 0);
		if (ret < 0)
			break;
deferred:
		wait_event_timeout(t.wait, t.state != STATE_PENDING,
				   msecs_to_jiffies(FCP_TIMEOUT_MS));

		if (t.state == STATE_DEFERRED) {
			/*
			 * 'AV/C General Specification' define no time limit
			 * on command completion once an INTERIM response has
			 * been sent. but we promise to finish this function
			 * for a caller. Here we use FCP_TIMEOUT_MS for next
			 * interval. This is not in the specification.
			 */
			t.state = STATE_PENDING;
			goto deferred;
		} else if (t.state == STATE_COMPLETE) {
			ret = t.response_size;
			break;
		} else if (t.state == STATE_BUS_RESET) {
			msleep(ERROR_DELAY_MS);
		} else if (++tries >= ERROR_RETRIES) {
			dev_err(&t.unit->device, "FCP command timed out\n");
			ret = -EIO;
			break;
		}
	}

	spin_lock_irq(&transactions_lock);
	list_del(&t.list);
	spin_unlock_irq(&transactions_lock);

	return ret;
}
EXPORT_SYMBOL(fcp_avc_transaction);

/**
 * fcp_bus_reset - inform the target handler about a bus reset
 * @unit: the unit that might be used by fcp_avc_transaction()
 *
 * This function must be called from the driver's .update handler to inform
 * the FCP transaction handler that a bus reset has happened.  Any pending FCP
 * transactions are retried.
 */
void fcp_bus_reset(struct fw_unit *unit)
{
	struct fcp_transaction *t;

	spin_lock_irq(&transactions_lock);
	list_for_each_entry(t, &transactions, list) {
		if (t->unit == unit &&
		    (t->state == STATE_PENDING ||
		     t->state == STATE_DEFERRED)) {
			t->state = STATE_BUS_RESET;
			wake_up(&t->wait);
		}
	}
	spin_unlock_irq(&transactions_lock);
}
EXPORT_SYMBOL(fcp_bus_reset);

/* checks whether the response matches the masked bytes in response_buffer */
static bool is_matching_response(struct fcp_transaction *transaction,
				 const void *response, size_t length)
{
	const u8 *p1, *p2;
	unsigned int mask, i;

	p1 = response;
	p2 = transaction->response_buffer;
	mask = transaction->response_match_bytes;

	for (i = 0; ; ++i) {
		if ((mask & 1) && p1[i] != p2[i])
			return false;
		mask >>= 1;
		if (!mask)
			return true;
		if (--length == 0)
			return false;
	}
}

static void fcp_response(struct fw_card *card, struct fw_request *request,
			 int tcode, int destination, int source,
			 int generation, unsigned long long offset,
			 void *data, size_t length, void *callback_data)
{
	struct fcp_transaction *t;
	unsigned long flags;

	if (length < 1 || (*(const u8 *)data & 0xf0) != CTS_AVC)
		return;

	spin_lock_irqsave(&transactions_lock, flags);
	list_for_each_entry(t, &transactions, list) {
		struct fw_device *device = fw_parent_device(t->unit);
		if (device->card != card ||
		    device->generation != generation)
			continue;
		smp_rmb(); /* node_id vs. generation */
		if (device->node_id != source)
			continue;

		if (t->state == STATE_PENDING &&
		    is_matching_response(t, data, length)) {
			if (t->deferrable && *(const u8 *)data == 0x0f) {
				t->state = STATE_DEFERRED;
			} else {
				t->state = STATE_COMPLETE;
				t->response_size = min_t(unsigned int, length,
							 t->response_size);
				memcpy(t->response_buffer, data,
				       t->response_size);
			}
			wake_up(&t->wait);
		}
	}
	spin_unlock_irqrestore(&transactions_lock, flags);
}

static struct fw_address_handler response_register_handler = {
	.length = 0x200,
	.address_callback = fcp_response,
};

static int __init fcp_module_init(void)
{
	static const struct fw_address_region response_register_region = {
		.start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE,
		.end = CSR_REGISTER_BASE + CSR_FCP_END,
	};

	fw_core_add_address_handler(&response_register_handler,
				    &response_register_region);

	return 0;
}

static void __exit fcp_module_exit(void)
{
	WARN_ON(!list_empty(&transactions));
	fw_core_remove_address_handler(&response_register_handler);
}

module_init(fcp_module_init);
module_exit(fcp_module_exit);
Commit	Line	Data
da607e19	1	// SPDX-License-Identifier: GPL-2.0-only
31ef9134 CL	2	/*
	3	* Function Control Protocol (IEC 61883-1) helper functions
	4	*
	5	* Copyright (c) Clemens Ladisch <[email protected]>
31ef9134 CL	6	*/
	7
	8	#include <linux/device.h>
	9	#include <linux/firewire.h>
	10	#include <linux/firewire-constants.h>
	11	#include <linux/list.h>
	12	#include <linux/module.h>
1017abed	13	#include <linux/slab.h>
31ef9134 CL	14	#include <linux/sched.h>
	15	#include <linux/spinlock.h>
	16	#include <linux/wait.h>
5de0ee57	17	#include <linux/delay.h>
31ef9134 CL	18	#include "fcp.h"
31ef9134 CL	19	#include "lib.h"
d67c46b9	20	#include "amdtp-stream.h"
31ef9134 CL	21
	22	#define CTS_AVC 0x00
	23
	24	#define ERROR_RETRIES 3
	25	#define ERROR_DELAY_MS 5
	26	#define FCP_TIMEOUT_MS 125
	27
1017abed TS	28	int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
	29	enum avc_general_plug_dir dir,
	30	unsigned short pid)
	31	{
	32	unsigned int sfc;
	33	u8 *buf;
	34	bool flag;
	35	int err;
	36
	37	flag = false;
	38	for (sfc = 0; sfc < CIP_SFC_COUNT; sfc++) {
	39	if (amdtp_rate_table[sfc] == rate) {
	40	flag = true;
	41	break;
	42	}
	43	}
	44	if (!flag)
	45	return -EINVAL;
	46
	47	buf = kzalloc(8, GFP_KERNEL);
	48	if (buf == NULL)
	49	return -ENOMEM;
	50
	51	buf[0] = 0x00; /* AV/C CONTROL */
	52	buf[1] = 0xff; /* UNIT */
	53	if (dir == AVC_GENERAL_PLUG_DIR_IN)
	54	buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */
	55	else
	56	buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */
	57	buf[3] = 0xff & pid; /* plug id */
	58	buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */
	59	buf[5] = 0x07 & sfc; /* FDF-hi. AM824, frequency */
	60	buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used)*/
	61	buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */
	62
	63	/* do transaction and check buf[1-5] are the same against command */
	64	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
	65	BIT(1) \| BIT(2) \| BIT(3) \| BIT(4) \| BIT(5));
7e1621de TS	66	if (err < 0)
	67	;
	68	else if (err < 8)
1017abed TS	69	err = -EIO;
	70	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
	71	err = -ENOSYS;
	72	else if (buf[0] == 0x0a) /* REJECTED */
	73	err = -EINVAL;
	74	if (err < 0)
	75	goto end;
	76
	77	err = 0;
	78	end:
	79	kfree(buf);
	80	return err;
	81	}
	82	EXPORT_SYMBOL(avc_general_set_sig_fmt);
	83
	84	int avc_general_get_sig_fmt(struct fw_unit unit, unsigned int rate,
	85	enum avc_general_plug_dir dir,
	86	unsigned short pid)
	87	{
	88	unsigned int sfc;
	89	u8 *buf;
	90	int err;
	91
	92	buf = kzalloc(8, GFP_KERNEL);
	93	if (buf == NULL)
	94	return -ENOMEM;
	95
	96	buf[0] = 0x01; /* AV/C STATUS */
	97	buf[1] = 0xff; /* Unit */
	98	if (dir == AVC_GENERAL_PLUG_DIR_IN)
	99	buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */
	100	else
	101	buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */
	102	buf[3] = 0xff & pid; /* plug id */
	103	buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */
	104	buf[5] = 0xff; /* FDF-hi. AM824, frequency */
	105	buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used) */
	106	buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */
	107
	108	/* do transaction and check buf[1-4] are the same against command */
	109	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
	110	BIT(1) \| BIT(2) \| BIT(3) \| BIT(4));
7e1621de TS	111	if (err < 0)
	112	;
	113	else if (err < 8)
1017abed TS	114	err = -EIO;
	115	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
	116	err = -ENOSYS;
	117	else if (buf[0] == 0x0a) /* REJECTED */
	118	err = -EINVAL;
	119	else if (buf[0] == 0x0b) /* IN TRANSITION */
	120	err = -EAGAIN;
	121	if (err < 0)
	122	goto end;
	123
	124	/* check sfc field and pick up rate */
	125	sfc = 0x07 & buf[5];
	126	if (sfc >= CIP_SFC_COUNT) {
	127	err = -EAGAIN; /* also in transition */
	128	goto end;
	129	}
	130
	131	*rate = amdtp_rate_table[sfc];
	132	err = 0;
	133	end:
	134	kfree(buf);
	135	return err;
	136	}
	137	EXPORT_SYMBOL(avc_general_get_sig_fmt);
	138
	139	int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
	140	unsigned int subunit_id, unsigned int subfunction,
	141	u8 info[AVC_PLUG_INFO_BUF_BYTES])
	142	{
	143	u8 *buf;
	144	int err;
	145
	146	/* extended subunit in spec.4.2 is not supported */
	147	if ((subunit_type == 0x1E) \|\| (subunit_id == 5))
	148	return -EINVAL;
	149
	150	buf = kzalloc(8, GFP_KERNEL);
	151	if (buf == NULL)
	152	return -ENOMEM;
	153
	154	buf[0] = 0x01; /* AV/C STATUS */
	155	/* UNIT or Subunit, Functionblock */
	156	buf[1] = ((subunit_type & 0x1f) << 3) \| (subunit_id & 0x7);
	157	buf[2] = 0x02; /* PLUG INFO */
	158	buf[3] = 0xff & subfunction;
	159
	160	err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) \| BIT(2));
7e1621de TS	161	if (err < 0)
	162	;
	163	else if (err < 8)
1017abed TS	164	err = -EIO;
	165	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
	166	err = -ENOSYS;
	167	else if (buf[0] == 0x0a) /* REJECTED */
	168	err = -EINVAL;
	169	else if (buf[0] == 0x0b) /* IN TRANSITION */
	170	err = -EAGAIN;
	171	if (err < 0)
	172	goto end;
	173
	174	info[0] = buf[4];
	175	info[1] = buf[5];
	176	info[2] = buf[6];
	177	info[3] = buf[7];
	178
	179	err = 0;
	180	end:
	181	kfree(buf);
	182	return err;
	183	}
	184	EXPORT_SYMBOL(avc_general_get_plug_info);
	185
31ef9134 CL	186	static DEFINE_SPINLOCK(transactions_lock);
	187	static LIST_HEAD(transactions);
	188
	189	enum fcp_state {
	190	STATE_PENDING,
	191	STATE_BUS_RESET,
	192	STATE_COMPLETE,
00a7bb81	193	STATE_DEFERRED,
31ef9134 CL	194	};
	195
	196	struct fcp_transaction {
	197	struct list_head list;
	198	struct fw_unit *unit;
	199	void *response_buffer;
	200	unsigned int response_size;
	201	unsigned int response_match_bytes;
	202	enum fcp_state state;
	203	wait_queue_head_t wait;
00a7bb81	204	bool deferrable;
31ef9134 CL	205	};
	206
	207	/**
	208	* fcp_avc_transaction - send an AV/C command and wait for its response
	209	* @unit: a unit on the target device
	210	* @command: a buffer containing the command frame; must be DMA-able
	211	* @command_size: the size of @command
	212	* @response: a buffer for the response frame
	213	* @response_size: the maximum size of @response
	214	* @response_match_bytes: a bitmap specifying the bytes used to detect the
	215	* correct response frame
	216	*
	217	* This function sends a FCP command frame to the target and waits for the
	218	* corresponding response frame to be returned.
	219	*
	220	* Because it is possible for multiple FCP transactions to be active at the
	221	* same time, the correct response frame is detected by the value of certain
	222	* bytes. These bytes must be set in @response before calling this function,
	223	* and the corresponding bits must be set in @response_match_bytes.
	224	*
	225	* @command and @response can point to the same buffer.
	226	*
31ef9134 CL	227	* Returns the actual size of the response frame, or a negative error code.
	228	*/
	229	int fcp_avc_transaction(struct fw_unit *unit,
	230	const void *command, unsigned int command_size,
	231	void *response, unsigned int response_size,
	232	unsigned int response_match_bytes)
	233	{
	234	struct fcp_transaction t;
	235	int tcode, ret, tries = 0;
	236
	237	t.unit = unit;
	238	t.response_buffer = response;
	239	t.response_size = response_size;
	240	t.response_match_bytes = response_match_bytes;
	241	t.state = STATE_PENDING;
	242	init_waitqueue_head(&t.wait);
	243
00a7bb81 TS	244	if ((const u8 )command == 0x00 \|\| (const u8 )command == 0x03)
	245	t.deferrable = true;
	246
31ef9134 CL	247	spin_lock_irq(&transactions_lock);
	248	list_add_tail(&t.list, &transactions);
	249	spin_unlock_irq(&transactions_lock);
	250
	251	for (;;) {
	252	tcode = command_size == 4 ? TCODE_WRITE_QUADLET_REQUEST
	253	: TCODE_WRITE_BLOCK_REQUEST;
	254	ret = snd_fw_transaction(t.unit, tcode,
	255	CSR_REGISTER_BASE + CSR_FCP_COMMAND,
1b70485f	256	(void *)command, command_size, 0);
31ef9134 CL	257	if (ret < 0)
31ef9134 CL	258	break;
00a7bb81	259	deferred:
31ef9134 CL	260	wait_event_timeout(t.wait, t.state != STATE_PENDING,
	261	msecs_to_jiffies(FCP_TIMEOUT_MS));
	262
00a7bb81 TS	263	if (t.state == STATE_DEFERRED) {
	264	/*
	265	* 'AV/C General Specification' define no time limit
	266	* on command completion once an INTERIM response has
	267	* been sent. but we promise to finish this function
	268	* for a caller. Here we use FCP_TIMEOUT_MS for next
	269	* interval. This is not in the specification.
	270	*/
	271	t.state = STATE_PENDING;
	272	goto deferred;
	273	} else if (t.state == STATE_COMPLETE) {
31ef9134 CL	274	ret = t.response_size;
	275	break;
	276	} else if (t.state == STATE_BUS_RESET) {
	277	msleep(ERROR_DELAY_MS);
	278	} else if (++tries >= ERROR_RETRIES) {
	279	dev_err(&t.unit->device, "FCP command timed out\n");
	280	ret = -EIO;
	281	break;
	282	}
	283	}
	284
	285	spin_lock_irq(&transactions_lock);
	286	list_del(&t.list);
	287	spin_unlock_irq(&transactions_lock);
	288
	289	return ret;
	290	}
	291	EXPORT_SYMBOL(fcp_avc_transaction);
	292
	293	/**
	294	* fcp_bus_reset - inform the target handler about a bus reset
	295	* @unit: the unit that might be used by fcp_avc_transaction()
	296	*
	297	* This function must be called from the driver's .update handler to inform
	298	* the FCP transaction handler that a bus reset has happened. Any pending FCP
	299	* transactions are retried.
	300	*/
	301	void fcp_bus_reset(struct fw_unit *unit)
	302	{
	303	struct fcp_transaction *t;
	304
	305	spin_lock_irq(&transactions_lock);
	306	list_for_each_entry(t, &transactions, list) {
	307	if (t->unit == unit &&
00a7bb81 TS	308	(t->state == STATE_PENDING \|\|
00a7bb81 TS	309	t->state == STATE_DEFERRED)) {
31ef9134 CL	310	t->state = STATE_BUS_RESET;
	311	wake_up(&t->wait);
	312	}
	313	}
	314	spin_unlock_irq(&transactions_lock);
	315	}
	316	EXPORT_SYMBOL(fcp_bus_reset);
	317
	318	/* checks whether the response matches the masked bytes in response_buffer */
	319	static bool is_matching_response(struct fcp_transaction *transaction,
	320	const void *response, size_t length)
	321	{
	322	const u8 p1, p2;
	323	unsigned int mask, i;
	324
	325	p1 = response;
	326	p2 = transaction->response_buffer;
	327	mask = transaction->response_match_bytes;
	328
	329	for (i = 0; ; ++i) {
	330	if ((mask & 1) && p1[i] != p2[i])
	331	return false;
	332	mask >>= 1;
	333	if (!mask)
	334	return true;
	335	if (--length == 0)
	336	return false;
	337	}
	338	}
	339
	340	static void fcp_response(struct fw_card card, struct fw_request request,
	341	int tcode, int destination, int source,
	342	int generation, unsigned long long offset,
	343	void data, size_t length, void callback_data)
	344	{
	345	struct fcp_transaction *t;
	346	unsigned long flags;
	347
	348	if (length < 1 \|\| ((const u8 )data & 0xf0) != CTS_AVC)
	349	return;
	350
	351	spin_lock_irqsave(&transactions_lock, flags);
	352	list_for_each_entry(t, &transactions, list) {
	353	struct fw_device *device = fw_parent_device(t->unit);
	354	if (device->card != card \|\|
	355	device->generation != generation)
	356	continue;
	357	smp_rmb(); /* node_id vs. generation */
	358	if (device->node_id != source)
	359	continue;
	360
	361	if (t->state == STATE_PENDING &&
	362	is_matching_response(t, data, length)) {
00a7bb81 TS	363	if (t->deferrable && (const u8 )data == 0x0f) {
	364	t->state = STATE_DEFERRED;
	365	} else {
	366	t->state = STATE_COMPLETE;
	367	t->response_size = min_t(unsigned int, length,
	368	t->response_size);
	369	memcpy(t->response_buffer, data,
	370	t->response_size);
	371	}
31ef9134 CL	372	wake_up(&t->wait);
	373	}
	374	}
	375	spin_unlock_irqrestore(&transactions_lock, flags);
	376	}
	377
	378	static struct fw_address_handler response_register_handler = {
	379	.length = 0x200,
	380	.address_callback = fcp_response,
	381	};
	382
	383	static int __init fcp_module_init(void)
	384	{
	385	static const struct fw_address_region response_register_region = {
	386	.start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE,
	387	.end = CSR_REGISTER_BASE + CSR_FCP_END,
	388	};
	389
	390	fw_core_add_address_handler(&response_register_handler,
	391	&response_register_region);
	392
	393	return 0;
	394	}
	395
	396	static void __exit fcp_module_exit(void)
	397	{
	398	WARN_ON(!list_empty(&transactions));
	399	fw_core_remove_address_handler(&response_register_handler);
	400	}
	401
	402	module_init(fcp_module_init);
	403	module_exit(fcp_module_exit);