virtio_console: Add support for remoteproc serial
Add a simple serial connection driver called VIRTIO_ID_RPROC_SERIAL (11) for communicating with a remote processor in an asymmetric multi-processing configuration. This implementation reuses the existing virtio_console implementation, and adds support for DMA allocation of data buffers and disables use of tty console and the virtio control queue. Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com> Acked-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Sjur Brændeland
Rusty Russell
Родитель
276a3e954c
Коммит
1b6370463e
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@ -37,8 +37,12 @@
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#include <linux/wait.h>
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#include <linux/workqueue.h>
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#include <linux/module.h>
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#include <linux/dma-mapping.h>
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#include <linux/kconfig.h>
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#include "../tty/hvc/hvc_console.h"
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#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
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/*
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* This is a global struct for storing common data for all the devices
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* this driver handles.
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@ -112,6 +116,15 @@ struct port_buffer {
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/* offset in the buf from which to consume data */
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size_t offset;
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/* DMA address of buffer */
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dma_addr_t dma;
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/* Device we got DMA memory from */
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struct device *dev;
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/* List of pending dma buffers to free */
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struct list_head list;
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/* If sgpages == 0 then buf is used */
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unsigned int sgpages;
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@ -331,6 +344,11 @@ static bool is_console_port(struct port *port)
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return false;
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}
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static bool is_rproc_serial(const struct virtio_device *vdev)
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{
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return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
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}
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static inline bool use_multiport(struct ports_device *portdev)
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{
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/*
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@ -342,11 +360,13 @@ static inline bool use_multiport(struct ports_device *portdev)
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return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
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}
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static void free_buf(struct port_buffer *buf)
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static DEFINE_SPINLOCK(dma_bufs_lock);
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static LIST_HEAD(pending_free_dma_bufs);
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static void free_buf(struct port_buffer *buf, bool can_sleep)
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{
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unsigned int i;
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kfree(buf->buf);
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for (i = 0; i < buf->sgpages; i++) {
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struct page *page = sg_page(&buf->sg[i]);
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if (!page)
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@ -354,14 +374,57 @@ static void free_buf(struct port_buffer *buf)
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put_page(page);
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}
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if (!buf->dev) {
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kfree(buf->buf);
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} else if (is_rproc_enabled) {
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unsigned long flags;
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/* dma_free_coherent requires interrupts to be enabled. */
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if (!can_sleep) {
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/* queue up dma-buffers to be freed later */
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spin_lock_irqsave(&dma_bufs_lock, flags);
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list_add_tail(&buf->list, &pending_free_dma_bufs);
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spin_unlock_irqrestore(&dma_bufs_lock, flags);
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return;
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}
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dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
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/* Release device refcnt and allow it to be freed */
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put_device(buf->dev);
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}
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kfree(buf);
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}
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static void reclaim_dma_bufs(void)
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{
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unsigned long flags;
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struct port_buffer *buf, *tmp;
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LIST_HEAD(tmp_list);
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if (list_empty(&pending_free_dma_bufs))
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return;
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/* Create a copy of the pending_free_dma_bufs while holding the lock */
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spin_lock_irqsave(&dma_bufs_lock, flags);
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list_cut_position(&tmp_list, &pending_free_dma_bufs,
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pending_free_dma_bufs.prev);
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spin_unlock_irqrestore(&dma_bufs_lock, flags);
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/* Release the dma buffers, without irqs enabled */
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list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
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list_del(&buf->list);
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free_buf(buf, true);
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}
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}
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static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
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int pages)
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{
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struct port_buffer *buf;
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reclaim_dma_bufs();
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/*
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* Allocate buffer and the sg list. The sg list array is allocated
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* directly after the port_buffer struct.
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@ -373,11 +436,34 @@ static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
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buf->sgpages = pages;
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if (pages > 0) {
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buf->dev = NULL;
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buf->buf = NULL;
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return buf;
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}
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if (is_rproc_serial(vq->vdev)) {
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/*
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* Allocate DMA memory from ancestor. When a virtio
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* device is created by remoteproc, the DMA memory is
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* associated with the grandparent device:
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* vdev => rproc => platform-dev.
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* The code here would have been less quirky if
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* DMA_MEMORY_INCLUDES_CHILDREN had been supported
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* in dma-coherent.c
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*/
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if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
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goto free_buf;
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buf->dev = vq->vdev->dev.parent->parent;
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/* Increase device refcnt to avoid freeing it */
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get_device(buf->dev);
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buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
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GFP_KERNEL);
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} else {
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buf->dev = NULL;
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buf->buf = kmalloc(buf_size, GFP_KERNEL);
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}
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if (!buf->buf)
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goto free_buf;
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buf->len = 0;
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@ -446,7 +532,7 @@ static void discard_port_data(struct port *port)
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port->stats.bytes_discarded += buf->len - buf->offset;
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if (add_inbuf(port->in_vq, buf) < 0) {
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err++;
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free_buf(buf);
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free_buf(buf, false);
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}
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port->inbuf = NULL;
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buf = get_inbuf(port);
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@ -518,7 +604,7 @@ static void reclaim_consumed_buffers(struct port *port)
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return;
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}
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while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
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free_buf(buf);
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free_buf(buf, false);
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port->outvq_full = false;
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}
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}
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@ -765,7 +851,7 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
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goto out;
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free_buf:
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free_buf(buf);
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free_buf(buf, true);
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out:
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return ret;
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}
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@ -839,6 +925,15 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
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.u.data = &sgl,
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};
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/*
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* Rproc_serial does not yet support splice. To support splice
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* pipe_to_sg() must allocate dma-buffers and copy content from
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* regular pages to dma pages. And alloc_buf and free_buf must
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* support allocating and freeing such a list of dma-buffers.
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*/
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if (is_rproc_serial(port->out_vq->vdev))
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return -EINVAL;
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ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
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if (ret < 0)
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return ret;
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@ -857,7 +952,7 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
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ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
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if (unlikely(ret <= 0))
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kfree(sgl.sg);
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free_buf(buf, true);
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return ret;
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}
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@ -906,6 +1001,7 @@ static int port_fops_release(struct inode *inode, struct file *filp)
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reclaim_consumed_buffers(port);
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spin_unlock_irq(&port->outvq_lock);
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reclaim_dma_bufs();
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/*
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* Locks aren't necessary here as a port can't be opened after
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* unplug, and if a port isn't unplugged, a kref would already
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@ -1057,7 +1153,10 @@ static void resize_console(struct port *port)
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return;
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vdev = port->portdev->vdev;
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if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
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/* Don't test F_SIZE at all if we're rproc: not a valid feature! */
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if (!is_rproc_serial(vdev) &&
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virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
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hvc_resize(port->cons.hvc, port->cons.ws);
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}
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@ -1249,7 +1348,7 @@ static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
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ret = add_inbuf(vq, buf);
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if (ret < 0) {
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spin_unlock_irq(lock);
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free_buf(buf);
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free_buf(buf, true);
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break;
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}
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nr_added_bufs++;
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@ -1337,10 +1436,18 @@ static int add_port(struct ports_device *portdev, u32 id)
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goto free_device;
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}
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if (is_rproc_serial(port->portdev->vdev))
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/*
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* If we're not using multiport support, this has to be a console port
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* For rproc_serial assume remote processor is connected.
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* rproc_serial does not want the console port, only
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* the generic port implementation.
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*/
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port->host_connected = true;
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else if (!use_multiport(port->portdev)) {
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/*
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* If we're not using multiport support,
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* this has to be a console port.
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*/
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if (!use_multiport(port->portdev)) {
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err = init_port_console(port);
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if (err)
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goto free_inbufs;
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@ -1373,7 +1480,7 @@ static int add_port(struct ports_device *portdev, u32 id)
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free_inbufs:
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while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
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free_buf(buf);
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free_buf(buf, true);
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free_device:
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device_destroy(pdrvdata.class, port->dev->devt);
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free_cdev:
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@ -1415,11 +1522,11 @@ static void remove_port_data(struct port *port)
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/* Remove buffers we queued up for the Host to send us data in. */
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while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
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free_buf(buf);
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free_buf(buf, true);
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/* Free pending buffers from the out-queue. */
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while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
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free_buf(buf);
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free_buf(buf, true);
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}
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/*
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@ -1621,7 +1728,7 @@ static void control_work_handler(struct work_struct *work)
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if (add_inbuf(portdev->c_ivq, buf) < 0) {
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dev_warn(&portdev->vdev->dev,
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"Error adding buffer to queue\n");
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free_buf(buf);
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free_buf(buf, false);
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}
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}
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spin_unlock(&portdev->cvq_lock);
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@ -1817,10 +1924,10 @@ static void remove_controlq_data(struct ports_device *portdev)
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return;
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while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
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free_buf(buf);
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free_buf(buf, true);
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while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
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free_buf(buf);
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free_buf(buf, true);
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}
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/*
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@ -1867,11 +1974,15 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
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multiport = false;
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portdev->config.max_nr_ports = 1;
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if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
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/* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
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if (!is_rproc_serial(vdev) &&
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virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
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offsetof(struct virtio_console_config,
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max_nr_ports),
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&portdev->config.max_nr_ports) == 0)
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&portdev->config.max_nr_ports) == 0) {
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multiport = true;
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}
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err = init_vqs(portdev);
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if (err < 0) {
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@ -1981,6 +2092,16 @@ static unsigned int features[] = {
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VIRTIO_CONSOLE_F_MULTIPORT,
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};
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static struct virtio_device_id rproc_serial_id_table[] = {
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#if IS_ENABLED(CONFIG_REMOTEPROC)
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{ VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
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#endif
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{ 0 },
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};
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static unsigned int rproc_serial_features[] = {
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};
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#ifdef CONFIG_PM
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static int virtcons_freeze(struct virtio_device *vdev)
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{
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@ -2065,6 +2186,20 @@ static struct virtio_driver virtio_console = {
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#endif
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};
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/*
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* virtio_rproc_serial refers to __devinit function which causes
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* section mismatch warnings. So use __refdata to silence warnings.
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*/
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static struct virtio_driver __refdata virtio_rproc_serial = {
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.feature_table = rproc_serial_features,
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.feature_table_size = ARRAY_SIZE(rproc_serial_features),
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.driver.name = "virtio_rproc_serial",
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.driver.owner = THIS_MODULE,
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.id_table = rproc_serial_id_table,
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.probe = virtcons_probe,
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.remove = virtcons_remove,
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};
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static int __init init(void)
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{
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int err;
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@ -2089,7 +2224,15 @@ static int __init init(void)
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pr_err("Error %d registering virtio driver\n", err);
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goto free;
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}
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err = register_virtio_driver(&virtio_rproc_serial);
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if (err < 0) {
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pr_err("Error %d registering virtio rproc serial driver\n",
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err);
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goto unregister;
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}
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return 0;
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unregister:
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unregister_virtio_driver(&virtio_console);
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free:
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if (pdrvdata.debugfs_dir)
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debugfs_remove_recursive(pdrvdata.debugfs_dir);
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@ -2099,7 +2242,10 @@ free:
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static void __exit fini(void)
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{
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reclaim_dma_bufs();
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unregister_virtio_driver(&virtio_console);
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unregister_virtio_driver(&virtio_rproc_serial);
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class_destroy(pdrvdata.class);
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if (pdrvdata.debugfs_dir)
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@ -37,5 +37,6 @@
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#define VIRTIO_ID_RPMSG 7 /* virtio remote processor messaging */
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#define VIRTIO_ID_SCSI 8 /* virtio scsi */
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#define VIRTIO_ID_9P 9 /* 9p virtio console */
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#define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */
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#endif /* _LINUX_VIRTIO_IDS_H */
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