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virtio: console: port encapsulation
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We are heading towards a multiple-"port" system, so as part of weaning off
globals we encapsulate the information into 'struct port'.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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Rusty Russell committed Feb 24, 2010
1 parent f550804 commit 21206ed
Showing 1 changed file with 58 additions and 49 deletions.
107 changes: 58 additions & 49 deletions drivers/char/virtio_console.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,15 +21,19 @@
#include <linux/virtio_console.h>
#include "hvc_console.h"

static struct virtqueue *in_vq, *out_vq;
static struct virtio_device *vdev;

/* This is our input buffer, and how much data is left in it. */
static unsigned int in_len;
static char *in, *inbuf;
struct port {
struct virtqueue *in_vq, *out_vq;
struct virtio_device *vdev;
/* This is our input buffer, and how much data is left in it. */
char *inbuf;
unsigned int used_len, offset;

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

/* The hvc device */
static struct hvc_struct *hvc;
/* We have one port ready to go immediately, for a console. */
static struct port console;

/* This is the very early arch-specified put chars function. */
static int (*early_put_chars)(u32, const char *, int);
Expand All @@ -46,22 +50,21 @@ static int put_chars(u32 vtermno, const char *buf, int count)
{
struct scatterlist sg[1];
unsigned int len;
struct port *port;

if (unlikely(early_put_chars))
return early_put_chars(vtermno, buf, count);

port = &console;

/* This is a convenient routine to initialize a single-elem sg list */
sg_init_one(sg, buf, count);

/*
* add_buf wants a token to identify this buffer: we hand it
* any non-NULL pointer, since there's only ever one buffer.
*/
if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) >= 0) {
/* This shouldn't fail: if it does, we lose chars. */
if (port->out_vq->vq_ops->add_buf(port->out_vq, sg, 1, 0, port) >= 0) {
/* Tell Host to go! */
out_vq->vq_ops->kick(out_vq);
/* Chill out until it's done with the buffer. */
while (!out_vq->vq_ops->get_buf(out_vq, &len))
port->out_vq->vq_ops->kick(port->out_vq);
while (!port->out_vq->vq_ops->get_buf(port->out_vq, &len))
cpu_relax();
}

Expand All @@ -73,15 +76,15 @@ static int put_chars(u32 vtermno, const char *buf, int count)
* Create a scatter-gather list representing our input buffer and put
* it in the queue.
*/
static void add_inbuf(void)
static void add_inbuf(struct port *port)
{
struct scatterlist sg[1];
sg_init_one(sg, inbuf, PAGE_SIZE);
sg_init_one(sg, port->inbuf, PAGE_SIZE);

/* We should always be able to add one buffer to an empty queue. */
if (in_vq->vq_ops->add_buf(in_vq, sg, 0, 1, inbuf) < 0)
/* Should always be able to add one buffer to an empty queue. */
if (port->in_vq->vq_ops->add_buf(port->in_vq, sg, 0, 1, port) < 0)
BUG();
in_vq->vq_ops->kick(in_vq);
port->in_vq->vq_ops->kick(port->in_vq);
}

/*
Expand All @@ -94,28 +97,31 @@ static void add_inbuf(void)
*/
static int get_chars(u32 vtermno, char *buf, int count)
{
struct port *port;

port = &console;

/* If we don't have an input queue yet, we can't get input. */
BUG_ON(!in_vq);
BUG_ON(!port->in_vq);

/* No buffer? Try to get one. */
if (!in_len) {
in = in_vq->vq_ops->get_buf(in_vq, &in_len);
if (!in)
/* No more in buffer? See if they've (re)used it. */
if (port->offset == port->used_len) {
if (!port->in_vq->vq_ops->get_buf(port->in_vq, &port->used_len))
return 0;
port->offset = 0;
}

/* You want more than we have to give? Well, try wanting less! */
if (in_len < count)
count = in_len;
if (port->offset + count > port->used_len)
count = port->used_len - port->offset;

/* Copy across to their buffer and increment offset. */
memcpy(buf, in, count);
in += count;
in_len -= count;
memcpy(buf, port->inbuf + port->offset, count);
port->offset += count;

/* Finished? Re-register buffer so Host will use it again. */
if (in_len == 0)
add_inbuf();
if (port->offset == port->used_len)
add_inbuf(port);

return count;
}
Expand All @@ -135,7 +141,7 @@ static void virtcons_apply_config(struct virtio_device *dev)
dev->config->get(dev,
offsetof(struct virtio_console_config, rows),
&ws.ws_row, sizeof(u16));
hvc_resize(hvc, ws);
hvc_resize(console.hvc, ws);
}
}

Expand All @@ -146,7 +152,7 @@ static void virtcons_apply_config(struct virtio_device *dev)
static int notifier_add_vio(struct hvc_struct *hp, int data)
{
hp->irq_requested = 1;
virtcons_apply_config(vdev);
virtcons_apply_config(console.vdev);

return 0;
}
Expand All @@ -158,7 +164,7 @@ static void notifier_del_vio(struct hvc_struct *hp, int data)

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

Expand Down Expand Up @@ -197,23 +203,26 @@ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
* Finally we put our input buffer in the input queue, ready to
* receive.
*/
static int __devinit virtcons_probe(struct virtio_device *dev)
static int __devinit virtcons_probe(struct virtio_device *vdev)
{
vq_callback_t *callbacks[] = { hvc_handle_input, NULL};
const char *names[] = { "input", "output" };
struct virtqueue *vqs[2];
struct port *port;
int err;

if (vdev) {
dev_warn(&vdev->dev,
port = &console;
if (port->vdev) {
dev_warn(&port->vdev->dev,
"Multiple virtio-console devices not supported yet\n");
return -EEXIST;
}
vdev = dev;
port->vdev = vdev;

/* This is the scratch page we use to receive console input */
inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!inbuf) {
port->used_len = 0;
port->inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!port->inbuf) {
err = -ENOMEM;
goto fail;
}
Expand All @@ -223,8 +232,8 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
if (err)
goto free;

in_vq = vqs[0];
out_vq = vqs[1];
port->in_vq = vqs[0];
port->out_vq = vqs[1];

/*
* The first argument of hvc_alloc() is the virtual console
Expand All @@ -238,14 +247,14 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
* 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, &hv_ops, PAGE_SIZE);
if (IS_ERR(hvc)) {
err = PTR_ERR(hvc);
port->hvc = hvc_alloc(0, 0, &hv_ops, PAGE_SIZE);
if (IS_ERR(port->hvc)) {
err = PTR_ERR(port->hvc);
goto free_vqs;
}

/* Register the input buffer the first time. */
add_inbuf();
add_inbuf(port);

/* Start using the new console output. */
early_put_chars = NULL;
Expand All @@ -254,7 +263,7 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
free_vqs:
vdev->config->del_vqs(vdev);
free:
kfree(inbuf);
kfree(port->inbuf);
fail:
return err;
}
Expand Down

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