[linux-2.6-block.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"

#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)
{
	__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,
				CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
				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
 * @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, 0);
	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);
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
	17	#define IMPR_SPEED_MASK 0xc0000000
	18	#define IMPR_SPEED_SHIFT 30
	19	#define IMPR_XSPEED_MASK 0x00000060
	20	#define IMPR_XSPEED_SHIFT 5
	21	#define IMPR_PLUGS_MASK 0x0000001f
	22
	23	#define IPCR_ONLINE 0x80000000
	24	#define IPCR_BCAST_CONN 0x40000000
	25	#define IPCR_P2P_CONN_MASK 0x3f000000
	26	#define IPCR_P2P_CONN_SHIFT 24
	27	#define IPCR_CHANNEL_MASK 0x003f0000
	28	#define IPCR_CHANNEL_SHIFT 16
	29
	30	enum bus_reset_handling {
	31	ABORT_ON_BUS_RESET,
	32	SUCCEED_ON_BUS_RESET,
	33	};
	34
b9075fa9	35	static __printf(2, 3)
31ef9134 CL	36	void cmp_error(struct cmp_connection c, const char fmt, ...)
	37	{
	38	va_list va;
	39
	40	va_start(va, fmt);
	41	dev_err(&c->resources.unit->device, "%cPCR%u: %pV",
	42	'i', c->pcr_index, &(struct va_format){ fmt, &va });
	43	va_end(va);
	44	}
	45
	46	static int pcr_modify(struct cmp_connection *c,
	47	__be32 (modify)(struct cmp_connection c, __be32 old),
	48	int (check)(struct cmp_connection c, __be32 pcr),
	49	enum bus_reset_handling bus_reset_handling)
	50	{
f30e6d3e	51	__be32 old_arg, buffer[2];
31ef9134 CL	52	int err;
	53
	54	buffer[0] = c->last_pcr_value;
	55	for (;;) {
	56	old_arg = buffer[0];
	57	buffer[1] = modify(c, buffer[0]);
	58
1b70485f CL	59	err = snd_fw_transaction(
1b70485f CL	60	c->resources.unit, TCODE_LOCK_COMPARE_SWAP,
31ef9134	61	CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
1b70485f CL	62	buffer, 8,
	63	FW_FIXED_GENERATION \| c->resources.generation);
	64
	65	if (err < 0) {
	66	if (err == -EAGAIN &&
	67	bus_reset_handling == SUCCEED_ON_BUS_RESET)
	68	err = 0;
	69	return err;
	70	}
	71
	72	if (buffer[0] == old_arg) /* success? */
	73	break;
	74
	75	if (check) {
	76	err = check(c, buffer[0]);
	77	if (err < 0)
	78	return err;
	79	}
31ef9134 CL	80	}
	81	c->last_pcr_value = buffer[1];
	82
	83	return 0;
31ef9134 CL	84	}
	85
	86
	87	/**
	88	* cmp_connection_init - initializes a connection manager
	89	* @c: the connection manager to initialize
	90	* @unit: a unit of the target device
	91	* @ipcr_index: the index of the iPCR on the target device
	92	*/
	93	int cmp_connection_init(struct cmp_connection *c,
	94	struct fw_unit *unit,
	95	unsigned int ipcr_index)
	96	{
	97	__be32 impr_be;
	98	u32 impr;
	99	int err;
	100
	101	err = snd_fw_transaction(unit, TCODE_READ_QUADLET_REQUEST,
	102	CSR_REGISTER_BASE + CSR_IMPR,
1b70485f	103	&impr_be, 4, 0);
31ef9134 CL	104	if (err < 0)
	105	return err;
	106	impr = be32_to_cpu(impr_be);
	107
	108	if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
	109	return -EINVAL;
	110
5b2599a0 CL	111	err = fw_iso_resources_init(&c->resources, unit);
	112	if (err < 0)
	113	return err;
	114
31ef9134 CL	115	c->connected = false;
31ef9134 CL	116	mutex_init(&c->mutex);
31ef9134 CL	117	c->last_pcr_value = cpu_to_be32(0x80000000);
	118	c->pcr_index = ipcr_index;
	119	c->max_speed = (impr & IMPR_SPEED_MASK) >> IMPR_SPEED_SHIFT;
	120	if (c->max_speed == SCODE_BETA)
	121	c->max_speed += (impr & IMPR_XSPEED_MASK) >> IMPR_XSPEED_SHIFT;
	122
	123	return 0;
	124	}
	125	EXPORT_SYMBOL(cmp_connection_init);
	126
	127	/**
	128	* cmp_connection_destroy - free connection manager resources
	129	* @c: the connection manager
	130	*/
	131	void cmp_connection_destroy(struct cmp_connection *c)
	132	{
	133	WARN_ON(c->connected);
	134	mutex_destroy(&c->mutex);
	135	fw_iso_resources_destroy(&c->resources);
	136	}
	137	EXPORT_SYMBOL(cmp_connection_destroy);
	138
	139
	140	static __be32 ipcr_set_modify(struct cmp_connection *c, __be32 ipcr)
	141	{
	142	ipcr &= ~cpu_to_be32(IPCR_BCAST_CONN \|
	143	IPCR_P2P_CONN_MASK \|
	144	IPCR_CHANNEL_MASK);
	145	ipcr \|= cpu_to_be32(1 << IPCR_P2P_CONN_SHIFT);
	146	ipcr \|= cpu_to_be32(c->resources.channel << IPCR_CHANNEL_SHIFT);
	147
	148	return ipcr;
	149	}
	150
	151	static int ipcr_set_check(struct cmp_connection *c, __be32 ipcr)
	152	{
	153	if (ipcr & cpu_to_be32(IPCR_BCAST_CONN \|
	154	IPCR_P2P_CONN_MASK)) {
	155	cmp_error(c, "plug is already in use\n");
	156	return -EBUSY;
	157	}
	158	if (!(ipcr & cpu_to_be32(IPCR_ONLINE))) {
	159	cmp_error(c, "plug is not on-line\n");
	160	return -ECONNREFUSED;
	161	}
	162
	163	return 0;
	164	}
	165
	166	/**
	167	* cmp_connection_establish - establish a connection to the target
	168	* @c: the connection manager
	169	* @max_payload_bytes: the amount of data (including CIP headers) per packet
	170	*
	171	* This function establishes a point-to-point connection from the local
	172	* computer to the target by allocating isochronous resources (channel and
	173	* bandwidth) and setting the target's input plug control register. When this
	174	* function succeeds, the caller is responsible for starting transmitting
	175	* packets.
	176	*/
	177	int cmp_connection_establish(struct cmp_connection *c,
	178	unsigned int max_payload_bytes)
	179	{
	180	int err;
181
182	if (WARN_ON(c->connected))
183	return -EISCONN;
184
185	c->speed = min(c->max_speed,
186	fw_parent_device(c->resources.unit)->max_speed);
187
188	mutex_lock(&c->mutex);
189
190	retry_after_bus_reset:
191	err = fw_iso_resources_allocate(&c->resources,
192	max_payload_bytes, c->speed);
193	if (err < 0)
194	goto err_mutex;
195
196	err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
197	ABORT_ON_BUS_RESET);
198	if (err == -EAGAIN) {
199	fw_iso_resources_free(&c->resources);
200	goto retry_after_bus_reset;
201	}
202	if (err < 0)
203	goto err_resources;
204
205	c->connected = true;
206
207	mutex_unlock(&c->mutex);
208
209	return 0;
210
211	err_resources:
212	fw_iso_resources_free(&c->resources);
213	err_mutex:
214	mutex_unlock(&c->mutex);
215
216	return err;
217	}
218	EXPORT_SYMBOL(cmp_connection_establish);
219
220	/**
221	* cmp_connection_update - update the connection after a bus reset
222	* @c: the connection manager
223	*
224	* This function must be called from the driver's .update handler to reestablish
225	* any connection that might have been active.
226	*
227	* Returns zero on success, or a negative error code. On an error, the
228	* connection is broken and the caller must stop transmitting iso packets.
229	*/
230	int cmp_connection_update(struct cmp_connection *c)
231	{
232	int err;
233
234	mutex_lock(&c->mutex);
235
236	if (!c->connected) {
237	mutex_unlock(&c->mutex);
238	return 0;
239	}
240
241	err = fw_iso_resources_update(&c->resources);
242	if (err < 0)
243	goto err_unconnect;
244
245	err = pcr_modify(c, ipcr_set_modify, ipcr_set_check,
246	SUCCEED_ON_BUS_RESET);
247	if (err < 0)
248	goto err_resources;
249
250	mutex_unlock(&c->mutex);
251
252	return 0;
253
254	err_resources:
255	fw_iso_resources_free(&c->resources);
256	err_unconnect:
257	c->connected = false;
258	mutex_unlock(&c->mutex);
259
260	return err;
261	}
262	EXPORT_SYMBOL(cmp_connection_update);
263
264
265	static __be32 ipcr_break_modify(struct cmp_connection *c, __be32 ipcr)
266	{
267	return ipcr & ~cpu_to_be32(IPCR_BCAST_CONN \| IPCR_P2P_CONN_MASK);
268	}
269
270	/**
271	* cmp_connection_break - break the connection to the target
272	* @c: the connection manager
273	*
274	* This function deactives the connection in the target's input plug control
275	* register, and frees the isochronous resources of the connection. Before
276	* calling this function, the caller should cease transmitting packets.
277	*/
278	void cmp_connection_break(struct cmp_connection *c)
279	{
280	int err;
281
282	mutex_lock(&c->mutex);
283
284	if (!c->connected) {
285	mutex_unlock(&c->mutex);
286	return;
287	}
288
289	err = pcr_modify(c, ipcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
290	if (err < 0)
291	cmp_error(c, "plug is still connected\n");
292
293	fw_iso_resources_free(&c->resources);
294
295	c->connected = false;
296
297	mutex_unlock(&c->mutex);
298	}
299	EXPORT_SYMBOL(cmp_connection_break);