virtio_console: use virtqueue notification for hvc_console (91fcad19) · Commits · 戴 / test

drivers/char/virtio_console.c

+33 −7

Original line number	Diff line number	Diff line
		@@ -46,6 +46,9 @@ static char in, inbuf;
		/* The operations for our console. */
		static struct hv_ops virtio_cons;

		/* The hvc device */
		static struct hvc_struct *hvc;

		/*D:310 The put_chars() callback is pretty straightforward.
		*
		* We turn the characters into a scatter-gather list, add it to the output
		@@ -134,6 +137,27 @@ int __init virtio_cons_early_init(int (put_chars)(u32, const char , int))
		return hvc_instantiate(0, 0, &virtio_cons);
		}

		/*
		* we support only one console, the hvc struct is a global var
		* There is no need to do anything
		*/
		static int notifier_add_vio(struct hvc_struct *hp, int data)
		{
		hp->irq_requested = 1;
		return 0;
		}

		static void notifier_del_vio(struct hvc_struct *hp, int data)
		{
		hp->irq_requested = 0;
		}

		static void hvc_handle_input(struct virtqueue *vq)
		{
		if (hvc_poll(hvc))
		hvc_kick();
		}

		/*D:370 Once we're further in boot, we get probed like any other virtio device.
		* At this stage we set up the output virtqueue.
		*
		@@ -144,7 +168,6 @@ int __init virtio_cons_early_init(int (put_chars)(u32, const char , int))
		static int __devinit virtcons_probe(struct virtio_device *dev)
		{
		int err;
		struct hvc_struct *hvc;

		vdev = dev;

		@@ -158,7 +181,7 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
		/* Find the input queue. */
		/* FIXME: This is why we want to wean off hvc: we do nothing
		* when input comes in. */
		in_vq = vdev->config->find_vq(vdev, 0, NULL);
		in_vq = vdev->config->find_vq(vdev, 0, hvc_handle_input);
		if (IS_ERR(in_vq)) {
		err = PTR_ERR(in_vq);
		goto free;
		@@ -173,15 +196,18 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
		/* Start using the new console output. */
		virtio_cons.get_chars = get_chars;
		virtio_cons.put_chars = put_chars;
		virtio_cons.notifier_add = notifier_add_vio;
		virtio_cons.notifier_del = notifier_del_vio;

		/* The first argument of hvc_alloc() is the virtual console number, so
		* we use zero. The second argument is the interrupt number; we
		* currently leave this as zero: it would be better not to use the
		* hvc mechanism and fix this (FIXME!).
		* we use zero. The second argument is the parameter for the
		* notification mechanism (like irq number). We currently leave this
		* as zero, virtqueues have implicit notifications.
		*
		* The third argument is a "struct hv_ops" containing the put_chars()
		* and get_chars() pointers. The final argument is the output buffer
		* size: we can do any size, so we put PAGE_SIZE here. */
		* get_chars(), notifier_add() and notifier_del() pointers.
		* The final argument is the output buffer size: we can do any size,
		* so we put PAGE_SIZE here. */
		hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE);
		if (IS_ERR(hvc)) {
		err = PTR_ERR(hvc);

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