virtio: console: comment cleanup
Remove old lguest-style comments. [Amit: - wingify comments acc. to kernel style - indent comments ] 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>
This commit is contained in:
parent
3b8706240e
commit
a23ea92474
|
@ -1,18 +1,5 @@
|
|||
/*D:300
|
||||
* The Guest console driver
|
||||
*
|
||||
* Writing console drivers is one of the few remaining Dark Arts in Linux.
|
||||
* Fortunately for us, the path of virtual consoles has been well-trodden by
|
||||
* the PowerPC folks, who wrote "hvc_console.c" to generically support any
|
||||
* virtual console. We use that infrastructure which only requires us to write
|
||||
* the basic put_chars and get_chars functions and call the right register
|
||||
* functions.
|
||||
:*/
|
||||
|
||||
/*M:002 The console can be flooded: while the Guest is processing input the
|
||||
* Host can send more. Buffering in the Host could alleviate this, but it is a
|
||||
* difficult problem in general. :*/
|
||||
/* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
|
||||
/*
|
||||
* Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
|
@ -34,8 +21,6 @@
|
|||
#include <linux/virtio_console.h>
|
||||
#include "hvc_console.h"
|
||||
|
||||
/*D:340 These represent our input and output console queues, and the virtio
|
||||
* operations for them. */
|
||||
static struct virtqueue *in_vq, *out_vq;
|
||||
static struct virtio_device *vdev;
|
||||
|
||||
|
@ -49,12 +34,14 @@ static struct hv_ops virtio_cons;
|
|||
/* The hvc device */
|
||||
static struct hvc_struct *hvc;
|
||||
|
||||
/*D:310 The put_chars() callback is pretty straightforward.
|
||||
/*
|
||||
* The put_chars() callback is pretty straightforward.
|
||||
*
|
||||
* We turn the characters into a scatter-gather list, add it to the output
|
||||
* queue and then kick the Host. Then we sit here waiting for it to finish:
|
||||
* inefficient in theory, but in practice implementations will do it
|
||||
* immediately (lguest's Launcher does). */
|
||||
* We turn the characters into a scatter-gather list, add it to the
|
||||
* output queue and then kick the Host. Then we sit here waiting for
|
||||
* it to finish: inefficient in theory, but in practice
|
||||
* implementations will do it immediately (lguest's Launcher does).
|
||||
*/
|
||||
static int put_chars(u32 vtermno, const char *buf, int count)
|
||||
{
|
||||
struct scatterlist sg[1];
|
||||
|
@ -63,8 +50,10 @@ static int put_chars(u32 vtermno, const char *buf, int count)
|
|||
/* 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. */
|
||||
/*
|
||||
* 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) {
|
||||
/* Tell Host to go! */
|
||||
out_vq->vq_ops->kick(out_vq);
|
||||
|
@ -77,8 +66,10 @@ static int put_chars(u32 vtermno, const char *buf, int count)
|
|||
return count;
|
||||
}
|
||||
|
||||
/* Create a scatter-gather list representing our input buffer and put it in the
|
||||
* queue. */
|
||||
/*
|
||||
* Create a scatter-gather list representing our input buffer and put
|
||||
* it in the queue.
|
||||
*/
|
||||
static void add_inbuf(void)
|
||||
{
|
||||
struct scatterlist sg[1];
|
||||
|
@ -90,12 +81,14 @@ static void add_inbuf(void)
|
|||
in_vq->vq_ops->kick(in_vq);
|
||||
}
|
||||
|
||||
/*D:350 get_chars() is the callback from the hvc_console infrastructure when
|
||||
* an interrupt is received.
|
||||
/*
|
||||
* get_chars() is the callback from the hvc_console infrastructure
|
||||
* when an interrupt is received.
|
||||
*
|
||||
* Most of the code deals with the fact that the hvc_console() infrastructure
|
||||
* only asks us for 16 bytes at a time. We keep in_offset and in_used fields
|
||||
* for partially-filled buffers. */
|
||||
* Most of the code deals with the fact that the hvc_console()
|
||||
* infrastructure only asks us for 16 bytes at a time. We keep
|
||||
* in_offset and in_used fields for partially-filled buffers.
|
||||
*/
|
||||
static int get_chars(u32 vtermno, char *buf, int count)
|
||||
{
|
||||
/* If we don't have an input queue yet, we can't get input. */
|
||||
|
@ -123,14 +116,16 @@ static int get_chars(u32 vtermno, char *buf, int count)
|
|||
|
||||
return count;
|
||||
}
|
||||
/*:*/
|
||||
|
||||
/*D:320 Console drivers are initialized very early so boot messages can go out,
|
||||
* so we do things slightly differently from the generic virtio initialization
|
||||
* of the net and block drivers.
|
||||
/*
|
||||
* Console drivers are initialized very early so boot messages can go
|
||||
* out, so we do things slightly differently from the generic virtio
|
||||
* initialization of the net and block drivers.
|
||||
*
|
||||
* At this stage, the console is output-only. It's too early to set up a
|
||||
* virtqueue, so we let the drivers do some boutique early-output thing. */
|
||||
* At this stage, the console is output-only. It's too early to set
|
||||
* up a virtqueue, so we let the drivers do some boutique early-output
|
||||
* thing.
|
||||
*/
|
||||
int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
|
||||
{
|
||||
virtio_cons.put_chars = put_chars;
|
||||
|
@ -157,8 +152,8 @@ static void virtcons_apply_config(struct virtio_device *dev)
|
|||
}
|
||||
|
||||
/*
|
||||
* we support only one console, the hvc struct is a global var
|
||||
* We set the configuration at this point, since we now have a tty
|
||||
* we support only one console, the hvc struct is a global var We set
|
||||
* the configuration at this point, since we now have a tty
|
||||
*/
|
||||
static int notifier_add_vio(struct hvc_struct *hp, int data)
|
||||
{
|
||||
|
@ -179,13 +174,17 @@ static void hvc_handle_input(struct virtqueue *vq)
|
|||
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.
|
||||
/*
|
||||
* Once we're further in boot, we get probed like any other virtio
|
||||
* device. At this stage we set up the output virtqueue.
|
||||
*
|
||||
* To set up and manage our virtual console, we call hvc_alloc(). Since we
|
||||
* never remove the console device we never need this pointer again.
|
||||
* To set up and manage our virtual console, we call hvc_alloc().
|
||||
* Since we never remove the console device we never need this pointer
|
||||
* again.
|
||||
*
|
||||
* Finally we put our input buffer in the input queue, ready to receive. */
|
||||
* Finally we put our input buffer in the input queue, ready to
|
||||
* receive.
|
||||
*/
|
||||
static int __devinit virtcons_probe(struct virtio_device *dev)
|
||||
{
|
||||
vq_callback_t *callbacks[] = { hvc_handle_input, NULL};
|
||||
|
@ -203,8 +202,6 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
|
|||
}
|
||||
|
||||
/* Find the queues. */
|
||||
/* FIXME: This is why we want to wean off hvc: we do nothing
|
||||
* when input comes in. */
|
||||
err = vdev->config->find_vqs(vdev, 2, vqs, callbacks, names);
|
||||
if (err)
|
||||
goto free;
|
||||
|
@ -219,15 +216,18 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
|
|||
virtio_cons.notifier_del = notifier_del_vio;
|
||||
virtio_cons.notifier_hangup = notifier_del_vio;
|
||||
|
||||
/* The first argument of hvc_alloc() is the virtual console number, so
|
||||
* 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 first argument of hvc_alloc() is the virtual console
|
||||
* number, so 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()
|
||||
* 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. */
|
||||
* The third argument is a "struct hv_ops" containing the
|
||||
* put_chars(), 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);
|
||||
|
|
|
@ -3,8 +3,10 @@
|
|||
#include <linux/types.h>
|
||||
#include <linux/virtio_ids.h>
|
||||
#include <linux/virtio_config.h>
|
||||
/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
|
||||
* anyone can use the definitions to implement compatible drivers/servers. */
|
||||
/*
|
||||
* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
|
||||
* anyone can use the definitions to implement compatible drivers/servers.
|
||||
*/
|
||||
|
||||
/* Feature bits */
|
||||
#define VIRTIO_CONSOLE_F_SIZE 0 /* Does host provide console size? */
|
||||
|
|
Loading…
Reference in a new issue