sound/hda/core/bus.c

Source file repositories/reference/linux-study-clean/sound/hda/core/bus.c

File Facts

System
Linux kernel
Corpus path
sound/hda/core/bus.c
Extension
.c
Size
7554 bytes
Lines
287
Domain
Driver Families
Bucket
sound/hda
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * HD-audio core bus driver
 */

#include <linux/init.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/export.h>
#include <sound/hdaudio.h>
#include "local.h"
#include "trace.h"

static void snd_hdac_bus_process_unsol_events(struct work_struct *work);

static const struct hdac_bus_ops default_ops = {
	.command = snd_hdac_bus_send_cmd,
	.get_response = snd_hdac_bus_get_response,
	.link_power = snd_hdac_bus_link_power,
};

/**
 * snd_hdac_bus_init - initialize a HD-audio bas bus
 * @bus: the pointer to bus object
 * @dev: device pointer
 * @ops: bus verb operators
 *
 * Returns 0 if successful, or a negative error code.
 */
int snd_hdac_bus_init(struct hdac_bus *bus, struct device *dev,
		      const struct hdac_bus_ops *ops)
{
	memset(bus, 0, sizeof(*bus));
	bus->dev = dev;
	if (ops)
		bus->ops = ops;
	else
		bus->ops = &default_ops;
	bus->dma_type = SNDRV_DMA_TYPE_DEV;
	INIT_LIST_HEAD(&bus->stream_list);
	INIT_LIST_HEAD(&bus->codec_list);
	INIT_WORK(&bus->unsol_work, snd_hdac_bus_process_unsol_events);
	spin_lock_init(&bus->reg_lock);
	mutex_init(&bus->cmd_mutex);
	mutex_init(&bus->lock);
	INIT_LIST_HEAD(&bus->hlink_list);
	init_waitqueue_head(&bus->rirb_wq);
	bus->irq = -1;
	bus->addr_offset = 0;

	/*
	 * Default value of '8' is as per the HD audio specification (Rev 1.0a).
	 * Following relation is used to derive STRIPE control value.
	 *  For sample rate <= 48K:
	 *   { ((num_channels * bits_per_sample) / number of SDOs) >= 8 }
	 *  For sample rate > 48K:
	 *   { ((num_channels * bits_per_sample * rate/48000) /
	 *	number of SDOs) >= 8 }
	 */
	bus->sdo_limit = 8;

	return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_init);

/**
 * snd_hdac_bus_exit - clean up a HD-audio bas bus
 * @bus: the pointer to bus object
 */
void snd_hdac_bus_exit(struct hdac_bus *bus)
{
	WARN_ON(!list_empty(&bus->stream_list));
	WARN_ON(!list_empty(&bus->codec_list));
	cancel_work_sync(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exit);

/**
 * snd_hdac_bus_exec_verb - execute a HD-audio verb on the given bus
 * @bus: bus object
 * @addr: the HDAC device address
 * @cmd: HD-audio encoded verb
 * @res: pointer to store the response, NULL if performing asynchronously
 *
 * Returns 0 if successful, or a negative error code.
 */
int snd_hdac_bus_exec_verb(struct hdac_bus *bus, unsigned int addr,
			   unsigned int cmd, unsigned int *res)
{

Annotation

Implementation Notes