ALSA: dice: Split transaction functionality into a file

This commit adds a file with some helper functions for transaction, and move
some codes into the file with some arrangements.

For Dice chipset, well-known FCP or AV/C commands are not used to control
devices. It's achieved by read/write transactions into specific addresses.

Dice's address area is split into 5 areas. Each area has its own role. The
offset for each area can be got by reading head of the address area. By
reading these areas, drivers can get to know device status. By writing these
areas, drivers can change device status.

Dice has a specific mechanism called as 'notification'. When device status is
changed, Dice devices tells the event by sending transaction. This notification
is sent to an address which drivers register in advance. But this causes an
issue to drivers.

To handle the notification, drivers need to allocate its own callback function
to the address region in host controller. This region is exclusive. For the
other applications, drivers must give a mechanism to read the received
notification. For this purpose, Dice driver already implements hwdep interface.

Dice chipset doesn't allow drivers to register several addresses. In this
reason, when this driver is applied to a device, the other drivers should
_not_ try to register its own address to the device.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/dice/Makefile

-snd-dice-objs := dice.o
+snd-dice-objs := dice-transaction.o dice.o
 obj-m += snd-dice.o

sound/firewire/dice/dice-transaction.c

+/*
+ * dice_transaction.c - a part of driver for Dice based devices
+ *
+ * Copyright (c) Clemens Ladisch
+ * Copyright (c) 2014 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include "dice.h"
+
+#define NOTIFICATION_TIMEOUT_MS	100
+
+static u64 get_subaddr(struct snd_dice *dice, enum snd_dice_addr_type type,
+		       u64 offset)
+{
+	switch (type) {
+	case SND_DICE_ADDR_TYPE_TX:
+		offset += dice->tx_offset;
+		break;
+	case SND_DICE_ADDR_TYPE_RX:
+		offset += dice->rx_offset;
+		break;
+	case SND_DICE_ADDR_TYPE_SYNC:
+		offset += dice->sync_offset;
+		break;
+	case SND_DICE_ADDR_TYPE_RSRV:
+		offset += dice->rsrv_offset;
+		break;
+	case SND_DICE_ADDR_TYPE_GLOBAL:
+	default:
+		offset += dice->global_offset;
+		break;
+	};
+	offset += DICE_PRIVATE_SPACE;
+	return offset;
+}
+
+int snd_dice_transaction_write(struct snd_dice *dice,
+			       enum snd_dice_addr_type type,
+			       unsigned int offset, void *buf, unsigned int len)
+{
+	return snd_fw_transaction(dice->unit,
+				  (len == 4) ? TCODE_WRITE_QUADLET_REQUEST :
+					       TCODE_WRITE_BLOCK_REQUEST,
+				  get_subaddr(dice, type, offset), buf, len, 0);
+}
+
+int snd_dice_transaction_read(struct snd_dice *dice,
+			      enum snd_dice_addr_type type, unsigned int offset,
+			      void *buf, unsigned int len)
+{
+	return snd_fw_transaction(dice->unit,
+				  (len == 4) ? TCODE_READ_QUADLET_REQUEST :
+					       TCODE_READ_BLOCK_REQUEST,
+				  get_subaddr(dice, type, offset), buf, len, 0);
+}
+
+static unsigned int get_clock_info(struct snd_dice *dice, __be32 *info)
+{
+	return snd_dice_transaction_read_global(dice, GLOBAL_CLOCK_SELECT,
+						info, 4);
+}
+
+static int set_clock_info(struct snd_dice *dice,
+			  unsigned int rate, unsigned int source)
+{
+	unsigned int retries = 3;
+	unsigned int i;
+	__be32 info;
+	u32 mask;
+	u32 clock;
+	int err;
+retry:
+	err = get_clock_info(dice, &info);
+	if (err < 0)
+		goto end;
+
+	clock = be32_to_cpu(info);
+	if (source != UINT_MAX) {
+		mask = CLOCK_SOURCE_MASK;
+		clock &= ~mask;
+		clock |= source;
+	}
+	if (rate != UINT_MAX) {
+		for (i = 0; i < ARRAY_SIZE(snd_dice_rates); i++) {
+			if (snd_dice_rates[i] == rate)
+				break;
+		}
+		if (i == ARRAY_SIZE(snd_dice_rates)) {
+			err = -EINVAL;
+			goto end;
+		}
+
+		mask = CLOCK_RATE_MASK;
+		clock &= ~mask;
+		clock |= i << CLOCK_RATE_SHIFT;
+	}
+	info = cpu_to_be32(clock);
+
+	if (completion_done(&dice->clock_accepted))
+		reinit_completion(&dice->clock_accepted);
+
+	err = snd_dice_transaction_write_global(dice, GLOBAL_CLOCK_SELECT,
+						&info, 4);
+	if (err < 0)
+		goto end;
+
+	/* Timeout means it's invalid request, probably bus reset occurred. */
+	if (wait_for_completion_timeout(&dice->clock_accepted,
+			msecs_to_jiffies(NOTIFICATION_TIMEOUT_MS)) == 0) {
+		if (retries-- == 0) {
+			err = -ETIMEDOUT;
+			goto end;
+		}
+
+		err = snd_dice_transaction_reinit(dice);
+		if (err < 0)
+			goto end;
+
+		msleep(500);	/* arbitrary */
+		goto retry;
+	}
+end:
+	return err;
+}
+
+int snd_dice_transaction_get_clock_source(struct snd_dice *dice,
+					  unsigned int *source)
+{
+	__be32 info;
+	int err;
+
+	err = get_clock_info(dice, &info);
+	if (err >= 0)
+		*source = be32_to_cpu(info) & CLOCK_SOURCE_MASK;
+
+	return err;
+}
+int snd_dice_transaction_set_clock_source(struct snd_dice *dice,
+					  unsigned int source)
+{
+	return set_clock_info(dice, UINT_MAX, source);
+}
+
+int snd_dice_transaction_get_rate(struct snd_dice *dice, unsigned int *rate)
+{
+	__be32 info;
+	unsigned int index;
+	int err;
+
+	err = get_clock_info(dice, &info);
+	if (err < 0)
+		goto end;
+
+	index = (be32_to_cpu(info) & CLOCK_RATE_MASK) >> CLOCK_RATE_SHIFT;
+	if (index >= SND_DICE_RATES_COUNT) {
+		err = -ENOSYS;
+		goto end;
+	}
+
+	*rate = snd_dice_rates[index];
+end:
+	return err;
+}
+int snd_dice_transaction_set_rate(struct snd_dice *dice, unsigned int rate)
+{
+	return set_clock_info(dice, rate, UINT_MAX);
+}
+
+int snd_dice_transaction_set_enable(struct snd_dice *dice)
+{
+	__be32 value;
+	int err = 0;
+
+	if (dice->global_enabled)
+		goto end;
+
+	value = cpu_to_be32(1);
+	err = snd_fw_transaction(dice->unit, TCODE_WRITE_QUADLET_REQUEST,
+				 get_subaddr(dice, SND_DICE_ADDR_TYPE_GLOBAL,
+					     GLOBAL_ENABLE),
+				 &value, 4,
+				 FW_FIXED_GENERATION | dice->owner_generation);
+	if (err < 0)
+		goto end;
+
+	dice->global_enabled = true;
+end:
+	return err;
+}
+
+void snd_dice_transaction_clear_enable(struct snd_dice *dice)
+{
+	__be32 value;
+
+	value = 0;
+	snd_fw_transaction(dice->unit, TCODE_WRITE_QUADLET_REQUEST,
+			   get_subaddr(dice, SND_DICE_ADDR_TYPE_GLOBAL,
+				       GLOBAL_ENABLE),
+			   &value, 4, FW_QUIET |
+			   FW_FIXED_GENERATION | dice->owner_generation);
+
+	dice->global_enabled = false;
+}
+
+static void dice_notification(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 snd_dice *dice = callback_data;
+	u32 bits;
+	unsigned long flags;
+
+	if (tcode != TCODE_WRITE_QUADLET_REQUEST) {
+		fw_send_response(card, request, RCODE_TYPE_ERROR);
+		return;
+	}
+	if ((offset & 3) != 0) {
+		fw_send_response(card, request, RCODE_ADDRESS_ERROR);
+		return;
+	}
+
+	bits = be32_to_cpup(data);
+
+	spin_lock_irqsave(&dice->lock, flags);
+	dice->notification_bits |= bits;
+	spin_unlock_irqrestore(&dice->lock, flags);
+
+	fw_send_response(card, request, RCODE_COMPLETE);
+
+	if (bits & NOTIFY_CLOCK_ACCEPTED)
+		complete(&dice->clock_accepted);
+	wake_up(&dice->hwdep_wait);
+}
+
+static int register_notification_address(struct snd_dice *dice, bool retry)
+{
+	struct fw_device *device = fw_parent_device(dice->unit);
+	__be64 *buffer;
+	unsigned int retries;
+	int err;
+
+	retries = (retry) ? 3 : 0;
+
+	buffer = kmalloc(2 * 8, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	for (;;) {
+		buffer[0] = cpu_to_be64(OWNER_NO_OWNER);
+		buffer[1] = cpu_to_be64(
+			((u64)device->card->node_id << OWNER_NODE_SHIFT) |
+			dice->notification_handler.offset);
+
+		dice->owner_generation = device->generation;
+		smp_rmb(); /* node_id vs. generation */
+		err = snd_fw_transaction(dice->unit, TCODE_LOCK_COMPARE_SWAP,
+					 get_subaddr(dice,
+						     SND_DICE_ADDR_TYPE_GLOBAL,
+						     GLOBAL_OWNER),
+					 buffer, 2 * 8,
+					 FW_FIXED_GENERATION |
+							dice->owner_generation);
+		if (err == 0) {
+			/* success */
+			if (buffer[0] == cpu_to_be64(OWNER_NO_OWNER))
+				break;
+			/* The address seems to be already registered. */
+			if (buffer[0] == buffer[1])
+				break;
+
+			dev_err(&dice->unit->device,
+				"device is already in use\n");
+			err = -EBUSY;
+		}
+		if (err != -EAGAIN || retries-- > 0)
+			break;
+
+		msleep(20);
+	}
+
+	kfree(buffer);
+
+	if (err < 0)
+		dice->owner_generation = -1;
+
+	return err;
+}
+
+static void unregister_notification_address(struct snd_dice *dice)
+{
+	struct fw_device *device = fw_parent_device(dice->unit);
+	__be64 *buffer;
+
+	buffer = kmalloc(2 * 8, GFP_KERNEL);
+	if (buffer == NULL)
+		return;
+
+	buffer[0] = cpu_to_be64(
+		((u64)device->card->node_id << OWNER_NODE_SHIFT) |
+		dice->notification_handler.offset);
+	buffer[1] = cpu_to_be64(OWNER_NO_OWNER);
+	snd_fw_transaction(dice->unit, TCODE_LOCK_COMPARE_SWAP,
+			   get_subaddr(dice, SND_DICE_ADDR_TYPE_GLOBAL,
+				       GLOBAL_OWNER),
+			   buffer, 2 * 8, FW_QUIET |
+			   FW_FIXED_GENERATION | dice->owner_generation);
+
+	kfree(buffer);
+
+	dice->owner_generation = -1;
+}
+
+void snd_dice_transaction_destroy(struct snd_dice *dice)
+{
+	struct fw_address_handler *handler = &dice->notification_handler;
+
+	if (handler->callback_data == NULL)
+		return;
+
+	unregister_notification_address(dice);
+
+	fw_core_remove_address_handler(handler);
+	handler->callback_data = NULL;
+}
+
+int snd_dice_transaction_reinit(struct snd_dice *dice)
+{
+	struct fw_address_handler *handler = &dice->notification_handler;
+
+	if (handler->callback_data == NULL)
+		return -EINVAL;
+
+	return register_notification_address(dice, false);
+}
+
+int snd_dice_transaction_init(struct snd_dice *dice)
+{
+	struct fw_address_handler *handler = &dice->notification_handler;
+	__be32 *pointers;
+	int err;
+
+	/* Use the same way which dice_interface_check() does. */
+	pointers = kmalloc(sizeof(__be32) * 10, GFP_KERNEL);
+	if (pointers == NULL)
+		return -ENOMEM;
+
+	/* Get offsets for sub-addresses */
+	err = snd_fw_transaction(dice->unit, TCODE_READ_BLOCK_REQUEST,
+				 DICE_PRIVATE_SPACE,
+				 pointers, sizeof(__be32) * 10, 0);
+	if (err < 0)
+		goto end;
+
+	/* Allocation callback in address space over host controller */
+	handler->length = 4;
+	handler->address_callback = dice_notification;
+	handler->callback_data = dice;
+	err = fw_core_add_address_handler(handler, &fw_high_memory_region);
+	if (err < 0) {
+		handler->callback_data = NULL;
+		goto end;
+	}
+
+	/* Register the address space */
+	err = register_notification_address(dice, true);
+	if (err < 0) {
+		fw_core_remove_address_handler(handler);
+		handler->callback_data = NULL;
+		goto end;
+	}
+
+	dice->global_offset = be32_to_cpu(pointers[0]) * 4;
+	dice->tx_offset = be32_to_cpu(pointers[2]) * 4;
+	dice->rx_offset = be32_to_cpu(pointers[4]) * 4;
+	dice->sync_offset = be32_to_cpu(pointers[6]) * 4;
+	dice->rsrv_offset = be32_to_cpu(pointers[8]) * 4;
+
+	/* Set up later. */
+	if (be32_to_cpu(pointers[1]) * 4 >= GLOBAL_CLOCK_CAPABILITIES + 4)
+		dice->clock_caps = 1;
+end:
+	kfree(pointers);
+	return err;
+}

sound/firewire/dice/dice.h

+/*
+ * dice.h - a part of driver for Dice based devices
+ *
+ * Copyright (c) Clemens Ladisch
+ * Copyright (c) 2014 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#ifndef SOUND_DICE_H_INCLUDED
+#define SOUND_DICE_H_INCLUDED
+
+#include <linux/compat.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/firewire.h>
+#include <sound/hwdep.h>
+#include <sound/info.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "../amdtp.h"
+#include "../iso-resources.h"
+#include "../lib.h"
+#include "dice-interface.h"
+
+struct snd_dice {
+	struct snd_card *card;
+	struct fw_unit *unit;
+	spinlock_t lock;
+	struct mutex mutex;
+
+	/* Offsets for sub-addresses */
+	unsigned int global_offset;
+	unsigned int rx_offset;
+	unsigned int tx_offset;
+	unsigned int sync_offset;
+	unsigned int rsrv_offset;
+
+	unsigned int clock_caps;
+	unsigned int rx_channels[3];
+	unsigned int rx_midi_ports[3];
+	struct fw_address_handler notification_handler;
+	int owner_generation;
+	int dev_lock_count; /* > 0 driver, < 0 userspace */
+	bool dev_lock_changed;
+	bool global_enabled;
+	struct completion clock_accepted;
+	wait_queue_head_t hwdep_wait;
+	u32 notification_bits;
+	struct fw_iso_resources rx_resources;
+	struct amdtp_stream rx_stream;
+};
+
+enum snd_dice_addr_type {
+	SND_DICE_ADDR_TYPE_PRIVATE,
+	SND_DICE_ADDR_TYPE_GLOBAL,
+	SND_DICE_ADDR_TYPE_TX,
+	SND_DICE_ADDR_TYPE_RX,
+	SND_DICE_ADDR_TYPE_SYNC,
+	SND_DICE_ADDR_TYPE_RSRV,
+};
+
+int snd_dice_transaction_write(struct snd_dice *dice,
+			       enum snd_dice_addr_type type,
+			       unsigned int offset,
+			       void *buf, unsigned int len);
+int snd_dice_transaction_read(struct snd_dice *dice,
+			      enum snd_dice_addr_type type, unsigned int offset,
+			      void *buf, unsigned int len);
+
+static inline int snd_dice_transaction_write_global(struct snd_dice *dice,
+						    unsigned int offset,
+						    void *buf, unsigned int len)
+{
+	return snd_dice_transaction_write(dice,
+					  SND_DICE_ADDR_TYPE_GLOBAL, offset,
+					  buf, len);
+}
+static inline int snd_dice_transaction_read_global(struct snd_dice *dice,
+						   unsigned int offset,
+						   void *buf, unsigned int len)
+{
+	return snd_dice_transaction_read(dice,
+					 SND_DICE_ADDR_TYPE_GLOBAL, offset,
+					 buf, len);
+}
+static inline int snd_dice_transaction_write_tx(struct snd_dice *dice,
+						unsigned int offset,
+						void *buf, unsigned int len)
+{
+	return snd_dice_transaction_write(dice, SND_DICE_ADDR_TYPE_TX, offset,
+					  buf, len);
+}
+static inline int snd_dice_transaction_read_tx(struct snd_dice *dice,
+					       unsigned int offset,
+					       void *buf, unsigned int len)
+{
+	return snd_dice_transaction_read(dice, SND_DICE_ADDR_TYPE_TX, offset,
+					 buf, len);
+}
+static inline int snd_dice_transaction_write_rx(struct snd_dice *dice,
+						unsigned int offset,
+						void *buf, unsigned int len)
+{
+	return snd_dice_transaction_write(dice, SND_DICE_ADDR_TYPE_RX, offset,
+					  buf, len);
+}
+static inline int snd_dice_transaction_read_rx(struct snd_dice *dice,
+					       unsigned int offset,
+					       void *buf, unsigned int len)
+{
+	return snd_dice_transaction_read(dice, SND_DICE_ADDR_TYPE_RX, offset,
+					 buf, len);
+}
+static inline int snd_dice_transaction_write_sync(struct snd_dice *dice,
+						  unsigned int offset,
+						  void *buf, unsigned int len)
+{
+	return snd_dice_transaction_write(dice, SND_DICE_ADDR_TYPE_SYNC, offset,
+					  buf, len);
+}
+static inline int snd_dice_transaction_read_sync(struct snd_dice *dice,
+						 unsigned int offset,
+						 void *buf, unsigned int len)
+{
+	return snd_dice_transaction_read(dice, SND_DICE_ADDR_TYPE_SYNC, offset,
+					 buf, len);
+}
+
+int snd_dice_transaction_set_clock_source(struct snd_dice *dice,
+					  unsigned int source);
+int snd_dice_transaction_get_clock_source(struct snd_dice *dice,
+					  unsigned int *source);
+int snd_dice_transaction_set_rate(struct snd_dice *dice, unsigned int rate);
+int snd_dice_transaction_get_rate(struct snd_dice *dice, unsigned int *rate);
+int snd_dice_transaction_set_enable(struct snd_dice *dice);
+void snd_dice_transaction_clear_enable(struct snd_dice *dice);
+int snd_dice_transaction_init(struct snd_dice *dice);
+int snd_dice_transaction_reinit(struct snd_dice *dice);
+void snd_dice_transaction_destroy(struct snd_dice *dice);
+
+#define SND_DICE_RATES_COUNT	7
+extern const unsigned int snd_dice_rates[SND_DICE_RATES_COUNT];
+
+#endif