ALSA: add LaCie FireWire Speakers/Griffin FireWave Surround driver

Add a driver for two playback-only FireWire devices based on the OXFW970
chip.

v2: better AMDTP API abstraction; fix fw_unit leak; small fixes
v3: cache the iPCR value
v4: FireWave constraints; fix fw_device reference counting;
    fix PCR caching; small changes and fixes
v5: volume/mute support; fix crashing due to pcm stop races
v6: fix build; one-channel volume for LaCie
v7: use signed values to make volume (range checks) work; fix function
    block IDs for volume/mute; always use channel 0 for LaCie volume

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Jay Fenlason <fenlason@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

drivers/firewire/core-iso.c

@@ -362,3 +362,4 @@ void fw_iso_resource_manage(struct fw_card *card, int generation,
 		*channel = ret;
 	}
 }
+EXPORT_SYMBOL(fw_iso_resource_manage);

drivers/firewire/core.h

@@ -147,9 +147,6 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event);
 /* -iso */
 
 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma);
-void fw_iso_resource_manage(struct fw_card *card, int generation,
-			    u64 channels_mask, int *channel, int *bandwidth,
-			    bool allocate, __be32 buffer[2]);
 
 
 /* -topology */

include/linux/firewire.h

@@ -42,6 +42,10 @@
 #define CSR_BROADCAST_CHANNEL		0x234
 #define CSR_CONFIG_ROM			0x400
 #define CSR_CONFIG_ROM_END		0x800
+#define CSR_OMPR			0x900
+#define CSR_OPCR(i)			(0x904 + (i) * 4)
+#define CSR_IMPR			0x980
+#define CSR_IPCR(i)			(0x984 + (i) * 4)
 #define CSR_FCP_COMMAND			0xB00
 #define CSR_FCP_RESPONSE		0xD00
 #define CSR_FCP_END			0xF00
@@ -441,5 +445,8 @@ int fw_iso_context_start(struct fw_iso_context *ctx,
 			 int cycle, int sync, int tags);
 int fw_iso_context_stop(struct fw_iso_context *ctx);
 void fw_iso_context_destroy(struct fw_iso_context *ctx);
+void fw_iso_resource_manage(struct fw_card *card, int generation,
+			    u64 channels_mask, int *channel, int *bandwidth,
+			    bool allocate, __be32 buffer[2]);
 
 #endif /* _LINUX_FIREWIRE_H */

sound/Kconfig

@@ -97,6 +97,8 @@ source "sound/sh/Kconfig"
 # here assuming USB is defined before ALSA
 source "sound/usb/Kconfig"
 
+source "sound/firewire/Kconfig"
+
 # the following will depend on the order of config.
 # here assuming PCMCIA is defined before ALSA
 source "sound/pcmcia/Kconfig"

sound/Makefile

@@ -6,7 +6,7 @@ obj-$(CONFIG_SOUND_PRIME) += sound_firmware.o
 obj-$(CONFIG_SOUND_PRIME) += oss/
 obj-$(CONFIG_DMASOUND) += oss/
 obj-$(CONFIG_SND) += core/ i2c/ drivers/ isa/ pci/ ppc/ arm/ sh/ synth/ usb/ \
-	sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/
+	firewire/ sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/
 obj-$(CONFIG_SND_AOA) += aoa/
 
 # This one must be compilable even if sound is configured out

sound/firewire/Kconfig

@@ -0,0 +1,25 @@
+menuconfig SND_FIREWIRE
+	bool "FireWire sound devices"
+	depends on FIREWIRE
+	default y
+	help
+	  Support for IEEE-1394/FireWire/iLink sound devices.
+
+if SND_FIREWIRE && FIREWIRE
+
+config SND_FIREWIRE_LIB
+	tristate
+	depends on SND_PCM
+
+config SND_FIREWIRE_SPEAKERS
+	tristate "FireWire speakers"
+	select SND_PCM
+	select SND_FIREWIRE_LIB
+	help
+	  Say Y here to include support for the Griffin FireWave Surround
+	  and the LaCie FireWire Speakers.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-firewire-speakers.
+
+endif # SND_FIREWIRE

sound/firewire/Makefile

@@ -0,0 +1,6 @@
+snd-firewire-lib-objs := lib.o iso-resources.o packets-buffer.o \
+			 fcp.o cmp.o amdtp.o
+snd-firewire-speakers-objs := speakers.o
+
+obj-$(CONFIG_SND_FIREWIRE_LIB) += snd-firewire-lib.o
+obj-$(CONFIG_SND_FIREWIRE_SPEAKERS) += snd-firewire-speakers.o

sound/firewire/amdtp.h

@@ -0,0 +1,157 @@
+#ifndef SOUND_FIREWIRE_AMDTP_H_INCLUDED
+#define SOUND_FIREWIRE_AMDTP_H_INCLUDED
+
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include "packets-buffer.h"
+
+/**
+ * enum cip_out_flags - describes details of the streaming protocol
+ * @CIP_NONBLOCKING: In non-blocking mode, each packet contains
+ *	sample_rate/8000 samples, with rounding up or down to adjust
+ *	for clock skew and left-over fractional samples.  This should
+ *	be used if supported by the device.
+ */
+enum cip_out_flags {
+	CIP_NONBLOCKING = 0,
+};
+
+/**
+ * enum cip_sfc - a stream's sample rate
+ */
+enum cip_sfc {
+	CIP_SFC_32000  = 0,
+	CIP_SFC_44100  = 1,
+	CIP_SFC_48000  = 2,
+	CIP_SFC_88200  = 3,
+	CIP_SFC_96000  = 4,
+	CIP_SFC_176400 = 5,
+	CIP_SFC_192000 = 6,
+};
+
+#define AMDTP_OUT_PCM_FORMAT_BITS	(SNDRV_PCM_FMTBIT_S16 | \
+					 SNDRV_PCM_FMTBIT_S32)
+
+struct fw_unit;
+struct fw_iso_context;
+struct snd_pcm_substream;
+
+struct amdtp_out_stream {
+	struct fw_unit *unit;
+	enum cip_out_flags flags;
+	struct fw_iso_context *context;
+	struct mutex mutex;
+
+	enum cip_sfc sfc;
+	unsigned int data_block_quadlets;
+	unsigned int pcm_channels;
+	unsigned int midi_ports;
+	void (*transfer_samples)(struct amdtp_out_stream *s,
+				 struct snd_pcm_substream *pcm,
+				 __be32 *buffer, unsigned int frames);
+
+	unsigned int syt_interval;
+	unsigned int source_node_id_field;
+	struct iso_packets_buffer buffer;
+
+	struct snd_pcm_substream *pcm;
+
+	unsigned int packet_counter;
+	unsigned int data_block_counter;
+
+	unsigned int data_block_state;
+
+	unsigned int last_syt_offset;
+	unsigned int syt_offset_state;
+
+	unsigned int pcm_buffer_pointer;
+	unsigned int pcm_period_pointer;
+};
+
+int amdtp_out_stream_init(struct amdtp_out_stream *s, struct fw_unit *unit,
+			  enum cip_out_flags flags);
+void amdtp_out_stream_destroy(struct amdtp_out_stream *s);
+
+void amdtp_out_stream_set_rate(struct amdtp_out_stream *s, unsigned int rate);
+unsigned int amdtp_out_stream_get_max_payload(struct amdtp_out_stream *s);
+
+int amdtp_out_stream_start(struct amdtp_out_stream *s, int channel, int speed);
+void amdtp_out_stream_update(struct amdtp_out_stream *s);
+void amdtp_out_stream_stop(struct amdtp_out_stream *s);
+
+void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
+				     snd_pcm_format_t format);
+void amdtp_out_stream_pcm_abort(struct amdtp_out_stream *s);
+
+/**
+ * amdtp_out_stream_set_pcm - configure format of PCM samples
+ * @s: the AMDTP output stream to be configured
+ * @pcm_channels: the number of PCM samples in each data block, to be encoded
+ *                as AM824 multi-bit linear audio
+ *
+ * This function must not be called while the stream is running.
+ */
+static inline void amdtp_out_stream_set_pcm(struct amdtp_out_stream *s,
+					    unsigned int pcm_channels)
+{
+	s->pcm_channels = pcm_channels;
+}
+
+/**
+ * amdtp_out_stream_set_midi - configure format of MIDI data
+ * @s: the AMDTP output stream to be configured
+ * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
+ *
+ * This function must not be called while the stream is running.
+ */
+static inline void amdtp_out_stream_set_midi(struct amdtp_out_stream *s,
+					     unsigned int midi_ports)
+{
+	s->midi_ports = midi_ports;
+}
+
+/**
+ * amdtp_out_stream_pcm_prepare - prepare PCM device for running
+ * @s: the AMDTP output stream
+ *
+ * This function should be called from the PCM device's .prepare callback.
+ */
+static inline void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s)
+{
+	s->pcm_buffer_pointer = 0;
+	s->pcm_period_pointer = 0;
+}
+
+/**
+ * amdtp_out_stream_pcm_trigger - start/stop playback from a PCM device
+ * @s: the AMDTP output stream
+ * @pcm: the PCM device to be started, or %NULL to stop the current device
+ *
+ * Call this function on a running isochronous stream to enable the actual
+ * transmission of PCM data.  This function should be called from the PCM
+ * device's .trigger callback.
+ */
+static inline void amdtp_out_stream_pcm_trigger(struct amdtp_out_stream *s,
+						struct snd_pcm_substream *pcm)
+{
+	ACCESS_ONCE(s->pcm) = pcm;
+}
+
+/**
+ * amdtp_out_stream_pcm_pointer - get the PCM buffer position
+ * @s: the AMDTP output stream that transports the PCM data
+ *
+ * Returns the current buffer position, in frames.
+ */
+static inline unsigned long
+amdtp_out_stream_pcm_pointer(struct amdtp_out_stream *s)
+{
+	return ACCESS_ONCE(s->pcm_buffer_pointer);
+}
+
+static inline bool cip_sfc_is_base_44100(enum cip_sfc sfc)
+{
+	return sfc & 1;
+}
+
+#endif

sound/firewire/cmp.c

@@ -0,0 +1,305 @@
+/*
+ * 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 __attribute__((format(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)
+{
+	struct fw_device *device = fw_parent_device(c->resources.unit);
+	__be32 *buffer = c->resources.buffer;
+	int generation = c->resources.generation;
+	int rcode, errors = 0;
+	__be32 old_arg;
+	int err;
+
+	buffer[0] = c->last_pcr_value;
+	for (;;) {
+		old_arg = buffer[0];
+		buffer[1] = modify(c, buffer[0]);
+
+		rcode = fw_run_transaction(
+				device->card, TCODE_LOCK_COMPARE_SWAP,
+				device->node_id, generation, device->max_speed,
+				CSR_REGISTER_BASE + CSR_IPCR(c->pcr_index),
+				buffer, 8);
+
+		if (rcode == RCODE_COMPLETE) {
+			if (buffer[0] == old_arg) /* success? */
+				break;
+
+			if (check) {
+				err = check(c, buffer[0]);
+				if (err < 0)
+					return err;
+			}
+		} else if (rcode == RCODE_GENERATION)
+			goto bus_reset;
+		else if (rcode_is_permanent_error(rcode) || ++errors >= 3)
+			goto io_error;
+	}
+	c->last_pcr_value = buffer[1];
+
+	return 0;
+
+io_error:
+	cmp_error(c, "transaction failed: %s\n", rcode_string(rcode));
+	return -EIO;
+
+bus_reset:
+	return bus_reset_handling == ABORT_ON_BUS_RESET ? -EAGAIN : 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);
+	if (err < 0)
+		return err;
+	impr = be32_to_cpu(impr_be);
+
+	if (ipcr_index >= (impr & IMPR_PLUGS_MASK))
+		return -EINVAL;
+
+	c->connected = false;
+	mutex_init(&c->mutex);
+	fw_iso_resources_init(&c->resources, unit);
+	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);

sound/firewire/cmp.h

@@ -0,0 +1,41 @@
+#ifndef SOUND_FIREWIRE_CMP_H_INCLUDED
+#define SOUND_FIREWIRE_CMP_H_INCLUDED
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include "iso-resources.h"
+
+struct fw_unit;
+
+/**
+ * struct cmp_connection - manages an isochronous connection to a device
+ * @speed: the connection's actual speed
+ *
+ * This structure manages (using CMP) an isochronous stream from the local
+ * computer to a device's input plug (iPCR).
+ *
+ * There is no corresponding oPCR created on the local computer, so it is not
+ * possible to overlay connections on top of this one.
+ */
+struct cmp_connection {
+	int speed;
+	/* private: */
+	bool connected;
+	struct mutex mutex;
+	struct fw_iso_resources resources;
+	__be32 last_pcr_value;
+	unsigned int pcr_index;
+	unsigned int max_speed;
+};
+
+int cmp_connection_init(struct cmp_connection *connection,
+			struct fw_unit *unit,
+			unsigned int ipcr_index);
+void cmp_connection_destroy(struct cmp_connection *connection);
+
+int cmp_connection_establish(struct cmp_connection *connection,
+			     unsigned int max_payload);
+int cmp_connection_update(struct cmp_connection *connection);
+void cmp_connection_break(struct cmp_connection *connection);
+
+#endif

sound/firewire/fcp.c

@@ -0,0 +1,223 @@
+/*
+ * Function Control Protocol (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/list.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include "fcp.h"
+#include "lib.h"
+
+#define CTS_AVC 0x00
+
+#define ERROR_RETRIES	3
+#define ERROR_DELAY_MS	5
+#define FCP_TIMEOUT_MS	125
+
+static DEFINE_SPINLOCK(transactions_lock);
+static LIST_HEAD(transactions);
+
+enum fcp_state {
+	STATE_PENDING,
+	STATE_BUS_RESET,
+	STATE_COMPLETE,
+};
+
+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;
+};
+
+/**
+ * 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.
+ *
+ * Asynchronous operation (INTERIM, NOTIFY) is not supported at the moment.
+ *
+ * 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);
+
+	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);
+		if (ret < 0)
+			break;
+
+		wait_event_timeout(t.wait, t.state != STATE_PENDING,
+				   msecs_to_jiffies(FCP_TIMEOUT_MS));
+
+		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_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)) {
+			t->state = STATE_COMPLETE;
+			t->response_size = min((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);

sound/firewire/fcp.h

@@ -0,0 +1,12 @@
+#ifndef SOUND_FIREWIRE_FCP_H_INCLUDED
+#define SOUND_FIREWIRE_FCP_H_INCLUDED
+
+struct fw_unit;
+
+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);
+void fcp_bus_reset(struct fw_unit *unit);
+
+#endif

sound/firewire/iso-resources.c

@@ -0,0 +1,224 @@
+/*
+ * isochronous resources 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/jiffies.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include "iso-resources.h"
+
+/**
+ * fw_iso_resources_init - initializes a &struct fw_iso_resources
+ * @r: the resource manager to initialize
+ * @unit: the device unit for which the resources will be needed
+ *
+ * If the device does not support all channel numbers, change @r->channels_mask
+ * after calling this function.
+ */
+void fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit)
+{
+	r->channels_mask = ~0uLL;
+	r->unit = fw_unit_get(unit);
+	mutex_init(&r->mutex);
+	r->allocated = false;
+}
+
+/**
+ * fw_iso_resources_destroy - destroy a resource manager
+ * @r: the resource manager that is no longer needed
+ */
+void fw_iso_resources_destroy(struct fw_iso_resources *r)
+{
+	WARN_ON(r->allocated);
+	mutex_destroy(&r->mutex);
+	fw_unit_put(r->unit);
+}
+
+static unsigned int packet_bandwidth(unsigned int max_payload_bytes, int speed)
+{
+	unsigned int bytes, s400_bytes;
+
+	/* iso packets have three header quadlets and quadlet-aligned payload */
+	bytes = 3 * 4 + ALIGN(max_payload_bytes, 4);
+
+	/* convert to bandwidth units (quadlets at S1600 = bytes at S400) */
+	if (speed <= SCODE_400)
+		s400_bytes = bytes * (1 << (SCODE_400 - speed));
+	else
+		s400_bytes = DIV_ROUND_UP(bytes, 1 << (speed - SCODE_400));
+
+	return s400_bytes;
+}
+
+static int current_bandwidth_overhead(struct fw_card *card)
+{
+	/*
+	 * Under the usual pessimistic assumption (cable length 4.5 m), the
+	 * isochronous overhead for N cables is 1.797 µs + N * 0.494 µs, or
+	 * 88.3 + N * 24.3 in bandwidth units.
+	 *
+	 * The calculation below tries to deduce N from the current gap count.
+	 * If the gap count has been optimized by measuring the actual packet
+	 * transmission time, this derived overhead should be near the actual
+	 * overhead as well.
+	 */
+	return card->gap_count < 63 ? card->gap_count * 97 / 10 + 89 : 512;
+}
+
+static int wait_isoch_resource_delay_after_bus_reset(struct fw_card *card)
+{
+	for (;;) {
+		s64 delay = (card->reset_jiffies + HZ) - get_jiffies_64();
+		if (delay <= 0)
+			return 0;
+		if (schedule_timeout_interruptible(delay) > 0)
+			return -ERESTARTSYS;
+	}
+}
+
+/**
+ * fw_iso_resources_allocate - allocate isochronous channel and bandwidth
+ * @r: the resource manager
+ * @max_payload_bytes: the amount of data (including CIP headers) per packet
+ * @speed: the speed (e.g., SCODE_400) at which the packets will be sent
+ *
+ * This function allocates one isochronous channel and enough bandwidth for the
+ * specified packet size.
+ *
+ * Returns the channel number that the caller must use for streaming, or
+ * a negative error code.  Due to potentionally long delays, this function is
+ * interruptible and can return -ERESTARTSYS.  On success, the caller is
+ * responsible for calling fw_iso_resources_update() on bus resets, and
+ * fw_iso_resources_free() when the resources are not longer needed.
+ */
+int fw_iso_resources_allocate(struct fw_iso_resources *r,
+			      unsigned int max_payload_bytes, int speed)
+{
+	struct fw_card *card = fw_parent_device(r->unit)->card;
+	int bandwidth, channel, err;
+
+	if (WARN_ON(r->allocated))
+		return -EBADFD;
+
+	r->bandwidth = packet_bandwidth(max_payload_bytes, speed);
+
+retry_after_bus_reset:
+	spin_lock_irq(&card->lock);
+	r->generation = card->generation;
+	r->bandwidth_overhead = current_bandwidth_overhead(card);
+	spin_unlock_irq(&card->lock);
+
+	err = wait_isoch_resource_delay_after_bus_reset(card);
+	if (err < 0)
+		return err;
+
+	mutex_lock(&r->mutex);
+
+	bandwidth = r->bandwidth + r->bandwidth_overhead;
+	fw_iso_resource_manage(card, r->generation, r->channels_mask,
+			       &channel, &bandwidth, true, r->buffer);
+	if (channel == -EAGAIN) {
+		mutex_unlock(&r->mutex);
+		goto retry_after_bus_reset;
+	}
+	if (channel >= 0) {
+		r->channel = channel;
+		r->allocated = true;
+	} else {
+		if (channel == -EBUSY)
+			dev_err(&r->unit->device,
+				"isochronous resources exhausted\n");
+		else
+			dev_err(&r->unit->device,
+				"isochronous resource allocation failed\n");
+	}
+
+	mutex_unlock(&r->mutex);
+
+	return channel;
+}
+
+/**
+ * fw_iso_resources_update - update resource allocations after a bus reset
+ * @r: the resource manager
+ *
+ * This function must be called from the driver's .update handler to reallocate
+ * any resources that were allocated before the bus reset.  It is safe to call
+ * this function if no resources are currently allocated.
+ *
+ * Returns a negative error code on failure.  If this happens, the caller must
+ * stop streaming.
+ */
+int fw_iso_resources_update(struct fw_iso_resources *r)
+{
+	struct fw_card *card = fw_parent_device(r->unit)->card;
+	int bandwidth, channel;
+
+	mutex_lock(&r->mutex);
+
+	if (!r->allocated) {
+		mutex_unlock(&r->mutex);
+		return 0;
+	}
+
+	spin_lock_irq(&card->lock);
+	r->generation = card->generation;
+	r->bandwidth_overhead = current_bandwidth_overhead(card);
+	spin_unlock_irq(&card->lock);
+
+	bandwidth = r->bandwidth + r->bandwidth_overhead;
+
+	fw_iso_resource_manage(card, r->generation, 1uLL << r->channel,
+			       &channel, &bandwidth, true, r->buffer);
+	/*
+	 * When another bus reset happens, pretend that the allocation
+	 * succeeded; we will try again for the new generation later.
+	 */
+	if (channel < 0 && channel != -EAGAIN) {
+		r->allocated = false;
+		if (channel == -EBUSY)
+			dev_err(&r->unit->device,
+				"isochronous resources exhausted\n");
+		else
+			dev_err(&r->unit->device,
+				"isochronous resource allocation failed\n");
+	}
+
+	mutex_unlock(&r->mutex);
+
+	return channel;
+}
+
+/**
+ * fw_iso_resources_free - frees allocated resources
+ * @r: the resource manager
+ *
+ * This function deallocates the channel and bandwidth, if allocated.
+ */
+void fw_iso_resources_free(struct fw_iso_resources *r)
+{
+	struct fw_card *card = fw_parent_device(r->unit)->card;
+	int bandwidth, channel;
+
+	mutex_lock(&r->mutex);
+
+	if (r->allocated) {
+		bandwidth = r->bandwidth + r->bandwidth_overhead;
+		fw_iso_resource_manage(card, r->generation, 1uLL << r->channel,
+				       &channel, &bandwidth, false, r->buffer);
+		if (channel < 0)
+			dev_err(&r->unit->device,
+				"isochronous resource deallocation failed\n");
+
+		r->allocated = false;
+	}
+
+	mutex_unlock(&r->mutex);
+}

sound/firewire/iso-resources.h

@@ -0,0 +1,39 @@
+#ifndef SOUND_FIREWIRE_ISO_RESOURCES_H_INCLUDED
+#define SOUND_FIREWIRE_ISO_RESOURCES_H_INCLUDED
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+struct fw_unit;
+
+/**
+ * struct fw_iso_resources - manages channel/bandwidth allocation
+ * @channels_mask: if the device does not support all channel numbers, set this
+ *                 bit mask to something else than the default (all ones)
+ *
+ * This structure manages (de)allocation of isochronous resources (channel and
+ * bandwidth) for one isochronous stream.
+ */
+struct fw_iso_resources {
+	u64 channels_mask;
+	/* private: */
+	struct fw_unit *unit;
+	struct mutex mutex;
+	unsigned int channel;
+	unsigned int bandwidth; /* in bandwidth units, without overhead */
+	unsigned int bandwidth_overhead;
+	int generation; /* in which allocation is valid */
+	bool allocated;
+	__be32 buffer[2];
+};
+
+void fw_iso_resources_init(struct fw_iso_resources *r,
+			   struct fw_unit *unit);
+void fw_iso_resources_destroy(struct fw_iso_resources *r);
+
+int fw_iso_resources_allocate(struct fw_iso_resources *r,
+			      unsigned int max_payload_bytes, int speed);
+int fw_iso_resources_update(struct fw_iso_resources *r);
+void fw_iso_resources_free(struct fw_iso_resources *r);
+
+#endif

sound/firewire/lib.c

@@ -0,0 +1,85 @@
+/*
+ * miscellaneous helper functions
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/module.h>
+#include "lib.h"
+
+#define ERROR_RETRY_DELAY_MS	5
+
+/**
+ * rcode_string - convert a firewire result code to a string
+ * @rcode: the result
+ */
+const char *rcode_string(unsigned int rcode)
+{
+	static const char *const names[] = {
+		[RCODE_COMPLETE]	= "complete",
+		[RCODE_CONFLICT_ERROR]	= "conflict error",
+		[RCODE_DATA_ERROR]	= "data error",
+		[RCODE_TYPE_ERROR]	= "type error",
+		[RCODE_ADDRESS_ERROR]	= "address error",
+		[RCODE_SEND_ERROR]	= "send error",
+		[RCODE_CANCELLED]	= "cancelled",
+		[RCODE_BUSY]		= "busy",
+		[RCODE_GENERATION]	= "generation",
+		[RCODE_NO_ACK]		= "no ack",
+	};
+
+	if (rcode < ARRAY_SIZE(names) && names[rcode])
+		return names[rcode];
+	else
+		return "unknown";
+}
+EXPORT_SYMBOL(rcode_string);
+
+/**
+ * snd_fw_transaction - send a request and wait for its completion
+ * @unit: the driver's unit on the target device
+ * @tcode: the transaction code
+ * @offset: the address in the target's address space
+ * @buffer: input/output data
+ * @length: length of @buffer
+ *
+ * Submits an asynchronous request to the target device, and waits for the
+ * response.  The node ID and the current generation are derived from @unit.
+ * On a bus reset or an error, the transaction is retried a few times.
+ * Returns zero on success, or a negative error code.
+ */
+int snd_fw_transaction(struct fw_unit *unit, int tcode,
+		       u64 offset, void *buffer, size_t length)
+{
+	struct fw_device *device = fw_parent_device(unit);
+	int generation, rcode, tries = 0;
+
+	for (;;) {
+		generation = device->generation;
+		smp_rmb(); /* node_id vs. generation */
+		rcode = fw_run_transaction(device->card, tcode,
+					   device->node_id, generation,
+					   device->max_speed, offset,
+					   buffer, length);
+
+		if (rcode == RCODE_COMPLETE)
+			return 0;
+
+		if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
+			dev_err(&unit->device, "transaction failed: %s\n",
+				rcode_string(rcode));
+			return -EIO;
+		}
+
+		msleep(ERROR_RETRY_DELAY_MS);
+	}
+}
+EXPORT_SYMBOL(snd_fw_transaction);
+
+MODULE_DESCRIPTION("FireWire audio helper functions");
+MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
+MODULE_LICENSE("GPL v2");

sound/firewire/lib.h

@@ -0,0 +1,19 @@
+#ifndef SOUND_FIREWIRE_LIB_H_INCLUDED
+#define SOUND_FIREWIRE_LIB_H_INCLUDED
+
+#include <linux/firewire-constants.h>
+#include <linux/types.h>
+
+struct fw_unit;
+
+int snd_fw_transaction(struct fw_unit *unit, int tcode,
+		       u64 offset, void *buffer, size_t length);
+const char *rcode_string(unsigned int rcode);
+
+/* returns true if retrying the transaction would not make sense */
+static inline bool rcode_is_permanent_error(int rcode)
+{
+	return rcode == RCODE_TYPE_ERROR || rcode == RCODE_ADDRESS_ERROR;
+}
+
+#endif

sound/firewire/packets-buffer.c

@@ -0,0 +1,74 @@
+/*
+ * helpers for managing a buffer for many packets
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include <linux/firewire.h>
+#include <linux/slab.h>
+#include "packets-buffer.h"
+
+/**
+ * iso_packets_buffer_init - allocates the memory for packets
+ * @b: the buffer structure to initialize
+ * @unit: the device at the other end of the stream
+ * @count: the number of packets
+ * @packet_size: the (maximum) size of a packet, in bytes
+ * @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE
+ */
+int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
+			    unsigned int count, unsigned int packet_size,
+			    enum dma_data_direction direction)
+{
+	unsigned int packets_per_page, pages;
+	unsigned int i, page_index, offset_in_page;
+	void *p;
+	int err;
+
+	b->packets = kmalloc(count * sizeof(*b->packets), GFP_KERNEL);
+	if (!b->packets) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	packet_size = L1_CACHE_ALIGN(packet_size);
+	packets_per_page = PAGE_SIZE / packet_size;
+	if (WARN_ON(!packets_per_page)) {
+		err = -EINVAL;
+		goto error;
+	}
+	pages = DIV_ROUND_UP(count, packets_per_page);
+
+	err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card,
+				 pages, direction);
+	if (err < 0)
+		goto err_packets;
+
+	for (i = 0; i < count; ++i) {
+		page_index = i / packets_per_page;
+		p = page_address(b->iso_buffer.pages[page_index]);
+		offset_in_page = (i % packets_per_page) * packet_size;
+		b->packets[i].buffer = p + offset_in_page;
+		b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page;
+	}
+
+	return 0;
+
+err_packets:
+	kfree(b->packets);
+error:
+	return err;
+}
+
+/**
+ * iso_packets_buffer_destroy - frees packet buffer resources
+ * @b: the buffer structure to free
+ * @unit: the device at the other end of the stream
+ */
+void iso_packets_buffer_destroy(struct iso_packets_buffer *b,
+				struct fw_unit *unit)
+{
+	fw_iso_buffer_destroy(&b->iso_buffer, fw_parent_device(unit)->card);
+	kfree(b->packets);
+}

sound/firewire/packets-buffer.h

@@ -0,0 +1,26 @@
+#ifndef SOUND_FIREWIRE_PACKETS_BUFFER_H_INCLUDED
+#define SOUND_FIREWIRE_PACKETS_BUFFER_H_INCLUDED
+
+#include <linux/dma-mapping.h>
+#include <linux/firewire.h>
+
+/**
+ * struct iso_packets_buffer - manages a buffer for many packets
+ * @iso_buffer: the memory containing the packets
+ * @packets: an array, with each element pointing to one packet
+ */
+struct iso_packets_buffer {
+	struct fw_iso_buffer iso_buffer;
+	struct {
+		void *buffer;
+		unsigned int offset;
+	} *packets;
+};
+
+int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
+			    unsigned int count, unsigned int packet_size,
+			    enum dma_data_direction direction);
+void iso_packets_buffer_destroy(struct iso_packets_buffer *b,
+				struct fw_unit *unit);
+
+#endif