// SPDX-License-Identifier: GPL-2.0-only/* * Connection Management Procedures (IEC 61883-1) helper functions * * Copyright (c) Clemens Ladisch <clemens@ladisch.de> */ #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){	guard(mutex)(&c->mutex); 	if (WARN_ON(c->resources.allocated))		return -EBUSY; 	c->speed = min(c->max_speed,		       fw_parent_device(c->resources.unit)->max_speed); 	return fw_iso_resources_allocate(&c->resources, max_payload_bytes,					 c->speed);}EXPORT_SYMBOL(cmp_connection_reserve); void cmp_connection_release(struct cmp_connection *c){	guard(mutex)(&c->mutex);	fw_iso_resources_free(&c->resources);}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; 	guard(mutex)(&c->mutex); 	if (WARN_ON(c->connected))		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; 	return err;}EXPORT_SYMBOL(cmp_connection_establish); 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; 	guard(mutex)(&c->mutex); 	if (!c->connected)		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;}EXPORT_SYMBOL(cmp_connection_break);