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-rw-r--r--sound/virtio/virtio_ctl_msg.c310
1 files changed, 310 insertions, 0 deletions
diff --git a/sound/virtio/virtio_ctl_msg.c b/sound/virtio/virtio_ctl_msg.c
new file mode 100644
index 000000000000..26ff7e7cc041
--- /dev/null
+++ b/sound/virtio/virtio_ctl_msg.c
@@ -0,0 +1,310 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * virtio-snd: Virtio sound device
+ * Copyright (C) 2021 OpenSynergy GmbH
+ */
+#include <linux/moduleparam.h>
+#include <linux/virtio_config.h>
+
+#include "virtio_card.h"
+
+/**
+ * struct virtio_snd_msg - Control message.
+ * @sg_request: Scattergather list containing a device request (header).
+ * @sg_response: Scattergather list containing a device response (status).
+ * @list: Pending message list entry.
+ * @notify: Request completed notification.
+ * @ref_count: Reference count used to manage a message lifetime.
+ */
+struct virtio_snd_msg {
+ struct scatterlist sg_request;
+ struct scatterlist sg_response;
+ struct list_head list;
+ struct completion notify;
+ refcount_t ref_count;
+};
+
+/**
+ * virtsnd_ctl_msg_ref() - Increment reference counter for the message.
+ * @msg: Control message.
+ *
+ * Context: Any context.
+ */
+void virtsnd_ctl_msg_ref(struct virtio_snd_msg *msg)
+{
+ refcount_inc(&msg->ref_count);
+}
+
+/**
+ * virtsnd_ctl_msg_unref() - Decrement reference counter for the message.
+ * @msg: Control message.
+ *
+ * The message will be freed when the ref_count value is 0.
+ *
+ * Context: Any context.
+ */
+void virtsnd_ctl_msg_unref(struct virtio_snd_msg *msg)
+{
+ if (refcount_dec_and_test(&msg->ref_count))
+ kfree(msg);
+}
+
+/**
+ * virtsnd_ctl_msg_request() - Get a pointer to the request header.
+ * @msg: Control message.
+ *
+ * Context: Any context.
+ */
+void *virtsnd_ctl_msg_request(struct virtio_snd_msg *msg)
+{
+ return sg_virt(&msg->sg_request);
+}
+
+/**
+ * virtsnd_ctl_msg_request() - Get a pointer to the response header.
+ * @msg: Control message.
+ *
+ * Context: Any context.
+ */
+void *virtsnd_ctl_msg_response(struct virtio_snd_msg *msg)
+{
+ return sg_virt(&msg->sg_response);
+}
+
+/**
+ * virtsnd_ctl_msg_alloc() - Allocate and initialize a control message.
+ * @request_size: Size of request header.
+ * @response_size: Size of response header.
+ * @gfp: Kernel flags for memory allocation.
+ *
+ * The message will be automatically freed when the ref_count value is 0.
+ *
+ * Context: Any context. May sleep if @gfp flags permit.
+ * Return: Allocated message on success, NULL on failure.
+ */
+struct virtio_snd_msg *virtsnd_ctl_msg_alloc(size_t request_size,
+ size_t response_size, gfp_t gfp)
+{
+ struct virtio_snd_msg *msg;
+
+ if (!request_size || !response_size)
+ return NULL;
+
+ msg = kzalloc(sizeof(*msg) + request_size + response_size, gfp);
+ if (!msg)
+ return NULL;
+
+ sg_init_one(&msg->sg_request, (u8 *)msg + sizeof(*msg), request_size);
+ sg_init_one(&msg->sg_response, (u8 *)msg + sizeof(*msg) + request_size,
+ response_size);
+
+ INIT_LIST_HEAD(&msg->list);
+ init_completion(&msg->notify);
+ /* This reference is dropped in virtsnd_ctl_msg_complete(). */
+ refcount_set(&msg->ref_count, 1);
+
+ return msg;
+}
+
+/**
+ * virtsnd_ctl_msg_send() - Send a control message.
+ * @snd: VirtIO sound device.
+ * @msg: Control message.
+ * @out_sgs: Additional sg-list to attach to the request header (may be NULL).
+ * @in_sgs: Additional sg-list to attach to the response header (may be NULL).
+ * @nowait: Flag indicating whether to wait for completion.
+ *
+ * Context: Any context. Takes and releases the control queue spinlock.
+ * May sleep if @nowait is false.
+ * Return: 0 on success, -errno on failure.
+ */
+int virtsnd_ctl_msg_send(struct virtio_snd *snd, struct virtio_snd_msg *msg,
+ struct scatterlist *out_sgs,
+ struct scatterlist *in_sgs, bool nowait)
+{
+ struct virtio_device *vdev = snd->vdev;
+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
+ unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
+ struct virtio_snd_hdr *request = virtsnd_ctl_msg_request(msg);
+ struct virtio_snd_hdr *response = virtsnd_ctl_msg_response(msg);
+ unsigned int nouts = 0;
+ unsigned int nins = 0;
+ struct scatterlist *psgs[4];
+ bool notify = false;
+ unsigned long flags;
+ int rc;
+
+ virtsnd_ctl_msg_ref(msg);
+
+ /* Set the default status in case the message was canceled. */
+ response->code = cpu_to_le32(VIRTIO_SND_S_IO_ERR);
+
+ psgs[nouts++] = &msg->sg_request;
+ if (out_sgs)
+ psgs[nouts++] = out_sgs;
+
+ psgs[nouts + nins++] = &msg->sg_response;
+ if (in_sgs)
+ psgs[nouts + nins++] = in_sgs;
+
+ spin_lock_irqsave(&queue->lock, flags);
+ rc = virtqueue_add_sgs(queue->vqueue, psgs, nouts, nins, msg,
+ GFP_ATOMIC);
+ if (!rc) {
+ notify = virtqueue_kick_prepare(queue->vqueue);
+
+ list_add_tail(&msg->list, &snd->ctl_msgs);
+ }
+ spin_unlock_irqrestore(&queue->lock, flags);
+
+ if (rc) {
+ dev_err(&vdev->dev, "failed to send control message (0x%08x)\n",
+ le32_to_cpu(request->code));
+
+ /*
+ * Since in this case virtsnd_ctl_msg_complete() will not be
+ * called, it is necessary to decrement the reference count.
+ */
+ virtsnd_ctl_msg_unref(msg);
+
+ goto on_exit;
+ }
+
+ if (notify)
+ virtqueue_notify(queue->vqueue);
+
+ if (nowait)
+ goto on_exit;
+
+ rc = wait_for_completion_interruptible_timeout(&msg->notify, js);
+ if (rc <= 0) {
+ if (!rc) {
+ dev_err(&vdev->dev,
+ "control message (0x%08x) timeout\n",
+ le32_to_cpu(request->code));
+ rc = -ETIMEDOUT;
+ }
+
+ goto on_exit;
+ }
+
+ switch (le32_to_cpu(response->code)) {
+ case VIRTIO_SND_S_OK:
+ rc = 0;
+ break;
+ case VIRTIO_SND_S_NOT_SUPP:
+ rc = -EOPNOTSUPP;
+ break;
+ case VIRTIO_SND_S_IO_ERR:
+ rc = -EIO;
+ break;
+ default:
+ rc = -EINVAL;
+ break;
+ }
+
+on_exit:
+ virtsnd_ctl_msg_unref(msg);
+
+ return rc;
+}
+
+/**
+ * virtsnd_ctl_msg_complete() - Complete a control message.
+ * @msg: Control message.
+ *
+ * Context: Any context. Expects the control queue spinlock to be held by
+ * caller.
+ */
+void virtsnd_ctl_msg_complete(struct virtio_snd_msg *msg)
+{
+ list_del(&msg->list);
+ complete(&msg->notify);
+
+ virtsnd_ctl_msg_unref(msg);
+}
+
+/**
+ * virtsnd_ctl_msg_cancel_all() - Cancel all pending control messages.
+ * @snd: VirtIO sound device.
+ *
+ * Context: Any context.
+ */
+void virtsnd_ctl_msg_cancel_all(struct virtio_snd *snd)
+{
+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->lock, flags);
+ while (!list_empty(&snd->ctl_msgs)) {
+ struct virtio_snd_msg *msg =
+ list_first_entry(&snd->ctl_msgs, struct virtio_snd_msg,
+ list);
+
+ virtsnd_ctl_msg_complete(msg);
+ }
+ spin_unlock_irqrestore(&queue->lock, flags);
+}
+
+/**
+ * virtsnd_ctl_query_info() - Query the item configuration from the device.
+ * @snd: VirtIO sound device.
+ * @command: Control request code (VIRTIO_SND_R_XXX_INFO).
+ * @start_id: Item start identifier.
+ * @count: Item count to query.
+ * @size: Item information size in bytes.
+ * @info: Buffer for storing item information.
+ *
+ * Context: Any context that permits to sleep.
+ * Return: 0 on success, -errno on failure.
+ */
+int virtsnd_ctl_query_info(struct virtio_snd *snd, int command, int start_id,
+ int count, size_t size, void *info)
+{
+ struct virtio_snd_msg *msg;
+ struct virtio_snd_query_info *query;
+ struct scatterlist sg;
+
+ msg = virtsnd_ctl_msg_alloc(sizeof(*query),
+ sizeof(struct virtio_snd_hdr), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ query = virtsnd_ctl_msg_request(msg);
+ query->hdr.code = cpu_to_le32(command);
+ query->start_id = cpu_to_le32(start_id);
+ query->count = cpu_to_le32(count);
+ query->size = cpu_to_le32(size);
+
+ sg_init_one(&sg, info, count * size);
+
+ return virtsnd_ctl_msg_send(snd, msg, NULL, &sg, false);
+}
+
+/**
+ * virtsnd_ctl_notify_cb() - Process all completed control messages.
+ * @vqueue: Underlying control virtqueue.
+ *
+ * This callback function is called upon a vring interrupt request from the
+ * device.
+ *
+ * Context: Interrupt context. Takes and releases the control queue spinlock.
+ */
+void virtsnd_ctl_notify_cb(struct virtqueue *vqueue)
+{
+ struct virtio_snd *snd = vqueue->vdev->priv;
+ struct virtio_snd_queue *queue = virtsnd_control_queue(snd);
+ struct virtio_snd_msg *msg;
+ u32 length;
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->lock, flags);
+ do {
+ virtqueue_disable_cb(vqueue);
+ while ((msg = virtqueue_get_buf(vqueue, &length)))
+ virtsnd_ctl_msg_complete(msg);
+ if (unlikely(virtqueue_is_broken(vqueue)))
+ break;
+ } while (!virtqueue_enable_cb(vqueue));
+ spin_unlock_irqrestore(&queue->lock, flags);
+}