[GSoC '24]: wip: virtio_audio: initial basic driver.

This commit in no form is intended to provide a working/functional
driver, but rather as a starting base and minimal code contribution
for GSoC.

This driver can only identify if the current device is a Sound
VirtIO device.

Change-Id: I718bb87c768dd84ff2be77a14e839f94955671fc
Signed-off-by: Diego Roux <diegoroux04@protonmail.com>
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7557
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>

headers/private/virtio/virtio.h

@@ -25,6 +25,7 @@
 #define VIRTIO_DEVICE_ID_INPUT		18
 #define VIRTIO_DEVICE_ID_VSOCK		19
 #define VIRTIO_DEVICE_ID_CRYPTO		20
+#define VIRTIO_DEVICE_ID_SOUND		25
 
 #define VIRTIO_FEATURE_TRANSPORT_MASK	((1ULL << 28) - 1)
 

src/add-ons/kernel/drivers/audio/virtio/Jamfile

@@ -0,0 +1,8 @@
+SubDir HAIKU_TOP src add-ons kernel drivers audio virtio ;
+
+UsePrivateKernelHeaders ;
+UsePrivateHeaders drivers virtio ;
+
+KernelAddon virtio_audio :
+	virtio_audio.cpp
+;

src/add-ons/kernel/drivers/audio/virtio/virtio_sound.cpp

@@ -0,0 +1,122 @@
+/*
+ *  Copyright 2024, Diego Roux, diegoroux04 at proton dot me
+ *  Distributed under the terms of the MIT License.
+ */
+
+#include <fs/devfs.h>
+#include <virtio.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+#define VIRTIO_SOUND_DRIVER_MODULE_NAME 	"drivers/audio/virtio/driver_v1"
+#define VIRTIO_SOUND_DEVICE_MODULE_NAME 	"drivers/audio/virtio/device_v1"
+#define VIRTIO_SOUND_DEVICE_ID_GEN 			"virtio_sound/device_id"
+
+
+struct {
+	device_node* 				node;
+	::virtio_device 			virtio_dev;
+	virtio_device_interface*	iface;
+	uint32						features;
+} VirtIOSoundDriverInfo;
+
+typedef struct {
+    VirtIOSoundDriverInfo*		info;
+} VirtIOSoundHandle;
+
+static device_manager_info*		sDeviceManager;
+
+
+const char*
+get_feature_name(uint32 feature)
+{
+	// TODO: Implement this.
+	return NULL;
+}
+
+
+static float
+SupportsDevice(device_node* parent)
+{
+	uint16 deviceType;
+	char* bus;
+
+	if (sDeviceManager->get_attr_string(parent, B_DEVICE_BUS, &bus, false) != B_OK
+		|| sDeviceManager->get_attr_uint16(parent, VIRTIO_DEVICE_TYPE_ITEM,
+			&deviceType, true) != B_OK) {
+		return 0.0f;
+	}
+
+	if (strcmp(bus, "virtio") != 0)
+		return 0.0f;
+
+	if (deviceType != VIRTIO_DEVICE_ID_SOUND)
+		return 0.0f;
+
+	return 1.0f;
+}
+
+
+static status_t
+InitDriver(device_node* node, void** cookie)
+{
+	VirtIOSoundDriverInfo* info = (VirtIOSoundDriverInfo*)malloc(sizeof(VirtIOSoundDriverInfo));
+
+	if (info == NULL)
+		return B_NO_MEMORY;
+
+	info->node = node;
+	*cookie = info;
+
+	return B_OK;
+}
+
+
+static status_t
+UninitDriver(void* cookie)
+{
+	free(cookie);
+	return B_OK;
+}
+
+
+struct driver_module_info sVirtioSoundDriver = {
+	{
+		VIRTIO_SOUND_DRIVER_MODULE_NAME,
+		0,
+		NULL
+	},
+
+	.supports_device = SupportsDevice,
+
+	.init_driver = InitDriver,
+	.uninit_driver = UninitDriver,
+};
+
+
+struct device_module_info sVirtioSoundDevice = {
+	{
+		VIRTIO_SOUND_DEVICE_MODULE_NAME,
+		0,
+		NULL
+	},
+};
+
+
+module_info* modules[] = {
+	(module_info*)&sVirtioSoundDriver,
+	(module_info*)&sVirtioSoundDevice,
+	NULL
+};
+
+
+module_dependency module_dependencies[] = {
+	{
+		B_DEVICE_MANAGER_MODULE_NAME,
+		(module_info**)&sDeviceManager
+	},
+	{}
+};