/*
* Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
* Copyright (C) 2009, 2010 Red Hat, Inc.
*
* 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
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/virtio.h>
#include <linux/virtio_console.h>
#include <linux/workqueue.h>
#include "hvc_console.h"
/*
* This is a global struct for storing common data for all the devices
* this driver handles.
*
* Mainly, it has a linked list for all the consoles in one place so
* that callbacks from hvc for get_chars(), put_chars() work properly
* across multiple devices and multiple ports per device.
*/
struct ports_driver_data {
/*
* This is used to keep track of the number of hvc consoles
* spawned by this driver. This number is given as the first
* argument to hvc_alloc(). To correctly map an initial
* console spawned via hvc_instantiate to the console being
* hooked up via hvc_alloc, we need to pass the same vtermno.
*
* We also just assume the first console being initialised was
* the first one that got used as the initial console.
*/
unsigned int next_vtermno;
/* All the console devices handled by this driver */
struct list_head consoles;
};
static struct ports_driver_data pdrvdata;
DEFINE_SPINLOCK(pdrvdata_lock);
/* This struct holds information that's relevant only for console ports */
struct console {
/* We'll place all consoles in a list in the pdrvdata struct */
struct list_head list;
/* The hvc device associated with this console port */
struct hvc_struct *hvc;
/*
* This number identifies the number that we used to register
* with hvc in hvc_instantiate() and hvc_alloc(); this is the
* number passed on by the hvc callbacks to us to
* differentiate between the other console ports handled by
* this driver
*/
u32 vtermno;
};
struct port_buffer {
char *buf;
/* size of the buffer in *buf above */
size_t size;
/* used length of the buffer */
size_t len;
/* offset in the buf from which to consume data */
size_t offset;
};
/*
* This is a per-device struct that stores data common to all the
* ports for that device (vdev->priv).
*/
struct ports_device {
/*
* Workqueue handlers where we process deferred work after
* notification
*/
struct work_struct control_work;
struct list_head ports;
/* To protect the list of ports */
spinlock_t ports_lock;
/* To protect the vq operations for the control channel */
spinlock_t cvq_lock;
/* The current config space is stored here */
struct virtio_console_config config;
/* The virtio device we're associated with */
struct virtio_device *vdev;
/*
* A couple of virtqueues for the control channel: one for
* guest->host transfers, one for host->guest transfers
*/
struct virtqueue *c_ivq, *c_ovq;
/* Array of per-port IO virtqueues */
struct virtqueue **in_vqs, **out_vqs;
};
/* This struct holds the per-port data */
struct port {
/* Next port in the list, head is in the ports_device */
struct list_head list;
/* Pointer to the parent virtio_console device */
struct ports_device *portdev;
/* The current buffer from which data has to be fed to readers */
struct port_buffer *inbuf;
/*
* To protect the operations on the in_vq associated with this
* port. Has to be a spinlock because it can be called from
* interrupt context (get_char()).
*/
spinlock_t inbuf_lock;
/* The IO vqs for this port */
struct virtqueue *in_vq, *out_vq;
/*
* The entries in this struct will be valid if this port is
* hooked up to an hvc console
*/
struct console cons;
/* The 'id' to identify the port with the Host */
u32 id;
};
/* This is the very early arch-specified put chars function. */
static int (*early_put_chars)(u32, const char *, int);
static struct port *find_port_by_vtermno(u32 vtermno)
{
struct port *port;
struct console *cons;
unsigned long flags;
spin_lock_irqsave(&pdrvdata_lock, flags);
list_for_each_entry(cons, &pdrvdata.consoles, list) {
if (cons->vtermno == vtermno) {
port = container_of(cons, struct port, cons);
goto out;
}
}
port = NULL;
out:
spin_unlock_irqrestore(&pdrvdata_lock, flags);
return port;
}
static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
{
struct port *port;
unsigned long flags;
spin_lock_irqsave(&portdev->ports_lock, flags);
list_for_each_entry(port, &portdev->ports, list)
if (port->id == id)
goto out;
port = NULL;
out:
spin_unlock_irqrestore(&portdev->ports_lock, flags);
return port;
}
static struct port *find_port_by_vq(struct ports_device *portdev,
struct virtqueue *vq)
{
struct port *port;
unsigned long flags;
spin_lock_irqsave(&portdev->ports_lock, flags);
list_for_each_entry(port, &portdev->ports, list)
if (port->in_vq == vq || port->out_vq == vq)
goto out;
port = NULL;
out:
spin_unlock_irqrestore(&portdev->ports_lock, flags);
return port;
}
static bool is_console_port(struct port *port)
{
if (port->cons.hvc)
return true;
return false;
}
static inline bool use_multiport(struct ports_device *portdev)
{
/*
* This condition can be true when put_chars is called from
* early_init
*/
if (!portdev->vdev)
return 0;
return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
}
static void free_buf(struct port_buffer *buf)
{
kfree(buf->buf);
kfree(buf);
}
static struct port_buffer *alloc_buf(size_t buf_size)
{
struct port_buffer *buf;
buf = kmalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
goto fail;
buf->buf = kzalloc(buf_size, GFP_KERNEL);
if (!buf->buf)
goto free_buf;
buf->len = 0;
buf->offset = 0;
buf->size = buf_size;
return buf;
free_buf:
kfree(buf);
fail:
return NULL;
}
/* Callers should take appropriate locks */
static void *get_inbuf(struct port *port)
{
struct port_buffer *buf;
struct virtqueue *vq;
unsigned int len;
vq = port->in_vq;
buf = vq->vq_ops->get_buf(vq, &len);
if (buf) {
buf->len = len;
buf->offset = 0;
}
return buf;
}
/*
* Create a scatter-gather list representing our input buffer and put
* it in the queue.
*
* Callers should take appropriate locks.
*/
static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
{
struct scatterlist sg[1];
int ret;
sg_init_one(sg, buf->buf, buf->size);
ret = vq->vq_ops->add_buf(vq, sg, 0, 1, buf);
vq->vq_ops->kick(vq);
return ret;
}
static bool port_has_data(struct port *port)
{
unsigned long flags;
bool ret;
ret = false;
spin_lock_irqsave(&port->inbuf_lock, flags);
if (port->inbuf)
ret = true;
spin_unlock_irqrestore(&port->inbuf_lock, flags);
return ret;
}
static ssize_t send_control_msg(struct port *port, unsigned int event,
unsigned int value)
{
struct scatterlist sg[1];
struct virtio_console_control cpkt;
struct virtqueue *vq;
int len;
if (!use_multiport(port->portdev))
return 0;
cpkt.id = port->id;
cpkt.event = event;
cpkt.value = value;
vq = port->portdev->c_ovq;
sg_init_one(sg, &cpkt, sizeof(cpkt));
if (vq->vq_ops->add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
vq->vq_ops->kick(vq);
while (!vq->vq_ops->get_buf(vq, &len))
cpu_relax();
}
return 0;
}
static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count)
{
struct scatterlist sg[1];
struct virtqueue *out_vq;
ssize_t ret;
unsigned int len;
out_vq = port->out_vq;
sg_init_one(sg, in_buf, in_count);
ret = out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, in_buf);
/* Tell Host to go! */
out_vq->vq_ops->kick(out_vq);
if (ret < 0) {
len = 0;
goto fail;
}
/*
* Wait till the host acknowledges it pushed out the data we
* sent. Also ensure we return to userspace the number of
* bytes that were successfully consumed by the host.
*/
while (!out_vq->vq_ops->get_buf(out_vq, &len))
cpu_relax();
fail:
/* We're expected to return the amount of data we wrote */
return len;
}
/*
* Give out the data that's requested from the buffer that we have
* queued up.
*/
static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count)
{
struct port_buffer *buf;
unsigned long flags;
if (!out_count || !port_has_data(port))
return 0;
buf = port->inbuf;
if (out_count > buf->len - buf->offset)
out_count = buf->len - buf->offset;
memcpy(out_buf, buf->buf + buf->offset, out_count);
/* Return the number of bytes actually copied */
buf->offset += out_count;
if (buf->offset == buf->len) {
/*
* We're done using all the data in this buffer.
* Re-queue so that the Host can send us more data.
*/
spin_lock_irqsave(&port->inbuf_lock, flags);
port->inbuf = NULL;
if (add_inbuf(port->in_vq, buf) < 0)
dev_warn(&port->portdev->vdev->dev, "failed add_buf\n");
spin_unlock_irqrestore(&port->inbuf_lock, flags);
}
return out_count;
}
/*
* 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).
*/
static int put_chars(u32 vtermno, const char *buf, int count)
{
struct port *port;
port = find_port_by_vtermno(vtermno);
if (!port)
return 0;
if (unlikely(early_put_chars))
return early_put_chars(vtermno, buf, count);
return send_buf(port, (void *)buf, count);
}
/*
* get_chars() is the callback from the hvc_console infrastructure
* when an interrupt is received.
*
* We call out to fill_readbuf that gets us the required data from the
* buffers that are queued up.
*/
static int get_chars(u32 vtermno, char *buf, int count)
{
struct port *port;
port = find_port_by_vtermno(vtermno);
if (!port)
return 0;
/* If we don't have an input queue yet, we can't get input. */
BUG_ON(!port->in_vq);
return fill_readbuf(port, buf, count);
}
static void resize_console(struct port *port)
{
struct virtio_device *vdev;
struct winsize ws;
vdev = port->portdev->vdev;
if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) {
vdev->config->get(vdev,
offsetof(struct virtio_console_config, cols),
&ws.ws_col, sizeof(u16));
vdev->config->get(vdev,
offsetof(struct virtio_console_config, rows),
&ws.ws_row, sizeof(u16));
hvc_resize(port->cons.hvc, ws);
}
}
static void virtcons_apply_config(struct virtio_device *vdev)
{
resize_console(find_port_by_vtermno(0));
}
/* We set the configuration at this point, since we now have a tty */
static int notifier_add_vio(struct hvc_struct *hp, int data)
{
struct port *port;
port = find_port_by_vtermno(hp->vtermno);
if (!port)
return -EINVAL;
hp->irq_requested = 1;
resize_console(port);
return 0;
}
static void notifier_del_vio(struct hvc_struct *hp, int data)
{
hp->irq_requested = 0;
}
/* The operations for console ports. */
static const struct hv_ops hv_ops = {
.get_chars = get_chars,
.put_chars = put_chars,
.notifier_add = notifier_add_vio,
.notifier_del = notifier_del_vio,
.notifier_hangup = notifier_del_vio,
};
/*
* 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.
*/
int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
{
early_put_chars = put_chars;
return hvc_instantiate(0, 0, &hv_ops);
}
int init_port_console(struct port *port)
{
int ret;
/*
* The Host's telling us this port is a console port. Hook it
* up with an hvc console.
*
* To set up and manage our virtual console, we call
* hvc_alloc().
*
* The first argument of hvc_alloc() is the virtual console
* number. 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.
*/
port->cons.vtermno = pdrvdata.next_vtermno;
port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
if (IS_ERR(port->cons.hvc)) {
ret = PTR_ERR(port->cons.hvc);
port->cons.hvc = NULL;
return ret;
}
spin_lock_irq(&pdrvdata_lock);
pdrvdata.next_vtermno++;
list_add_tail(&port->cons.list, &pdrvdata.consoles);
spin_unlock_irq(&pdrvdata_lock);
return 0;
}
/* Any private messages that the Host and Guest want to share */
static void handle_control_message(struct ports_device *portdev,
struct port_buffer *buf)
{
struct virtio_console_control *cpkt;
struct port *port;
cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
port = find_port_by_id(portdev, cpkt->id);
if (!port) {
/* No valid header at start of buffer. Drop it. */
dev_dbg(&portdev->vdev->dev,
"Invalid index %u in control packet\n", cpkt->id);
return;
}
switch (cpkt->event) {
case VIRTIO_CONSOLE_CONSOLE_PORT:
if (!cpkt->value)
break;
if (is_console_port(port))
break;
init_port_console(port);
/*
* Could remove the port here in case init fails - but
* have to notify the host first.
*/
break;
case VIRTIO_CONSOLE_RESIZE:
if (!is_console_port(port))
break;
port->cons.hvc->irq_requested = 1;
resize_console(port);
break;
}
}
static void control_work_handler(struct work_struct *work)
{
struct ports_device *portdev;
struct virtqueue *vq;
struct port_buffer *buf;
unsigned int len;
portdev = container_of(work, struct ports_device, control_work);
vq = portdev->c_ivq;
spin_lock(&portdev->cvq_lock);
while ((buf = vq->vq_ops->get_buf(vq, &len))) {
spin_unlock(&portdev->cvq_lock);
buf->len = len;
buf->offset = 0;
handle_control_message(portdev, buf);
spin_lock(&portdev->cvq_lock);
if (add_inbuf(portdev->c_ivq, buf) < 0) {
dev_warn(&portdev->vdev->dev,
"Error adding buffer to queue\n");
free_buf(buf);
}
}
spin_unlock(&portdev->cvq_lock);
}
static void in_intr(struct virtqueue *vq)
{
struct port *port;
unsigned long flags;
port = find_port_by_vq(vq->vdev->priv, vq);
if (!port)
return;
spin_lock_irqsave(&port->inbuf_lock, flags);
port->inbuf = get_inbuf(port);
spin_unlock_irqrestore(&port->inbuf_lock, flags);
if (is_console_port(port) && hvc_poll(port->cons.hvc))
hvc_kick();
}
static void control_intr(struct virtqueue *vq)
{
struct ports_device *portdev;
portdev = vq->vdev->priv;
schedule_work(&portdev->control_work);
}
static void fill_queue(struct virtqueue *vq, spinlock_t *lock)
{
struct port_buffer *buf;
int ret;
do {
buf = alloc_buf(PAGE_SIZE);
if (!buf)
break;
spin_lock_irq(lock);
ret = add_inbuf(vq, buf);
if (ret < 0) {
spin_unlock_irq(lock);
free_buf(buf);
break;
}
spin_unlock_irq(lock);
} while (ret > 0);
}
static int add_port(struct ports_device *portdev, u32 id)
{
struct port *port;
struct port_buffer *inbuf;
int err;
port = kmalloc(sizeof(*port), GFP_KERNEL);
if (!port) {
err = -ENOMEM;
goto fail;
}
port->portdev = portdev;
port->id = id;
port->inbuf = NULL;
port->cons.hvc = NULL;
port->in_vq = portdev->in_vqs[port->id];
port->out_vq = portdev->out_vqs[port->id];
spin_lock_init(&port->inbuf_lock);
inbuf = alloc_buf(PAGE_SIZE);
if (!inbuf) {
err = -ENOMEM;
goto free_port;
}
/* Register the input buffer the first time. */
add_inbuf(port->in_vq, inbuf);
/*
* If we're not using multiport support, this has to be a console port
*/
if (!use_multiport(port->portdev)) {
err = init_port_console(port);
if (err)
goto free_inbuf;
}
spin_lock_irq(&portdev->ports_lock);
list_add_tail(&port->list, &port->portdev->ports);
spin_unlock_irq(&portdev->ports_lock);
/*
* Tell the Host we're set so that it can send us various
* configuration parameters for this port (eg, port name,
* caching, whether this is a console port, etc.)
*/
send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
return 0;
free_inbuf:
free_buf(inbuf);
free_port:
kfree(port);
fail:
return err;
}
static int init_vqs(struct ports_device *portdev)
{
vq_callback_t **io_callbacks;
char **io_names;
struct virtqueue **vqs;
u32 i, j, nr_ports, nr_queues;
int err;
nr_ports = portdev->config.max_nr_ports;
nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
if (!vqs) {
err = -ENOMEM;
goto fail;
}
io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
if (!io_callbacks) {
err = -ENOMEM;
goto free_vqs;
}
io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
if (!io_names) {
err = -ENOMEM;
goto free_callbacks;
}
portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
GFP_KERNEL);
if (!portdev->in_vqs) {
err = -ENOMEM;
goto free_names;
}
portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
GFP_KERNEL);
if (!portdev->out_vqs) {
err = -ENOMEM;
goto free_invqs;
}
/*
* For backward compat (newer host but older guest), the host
* spawns a console port first and also inits the vqs for port
* 0 before others.
*/
j = 0;
io_callbacks[j] = in_intr;
io_callbacks[j + 1] = NULL;
io_names[j] = "input";
io_names[j + 1] = "output";
j += 2;
if (use_multiport(portdev)) {
io_callbacks[j] = control_intr;
io_callbacks[j + 1] = NULL;
io_names[j] = "control-i";
io_names[j + 1] = "control-o";
for (i = 1; i < nr_ports; i++) {
j += 2;
io_callbacks[j] = in_intr;
io_callbacks[j + 1] = NULL;
io_names[j] = "input";
io_names[j + 1] = "output";
}
}
/* Find the queues. */
err = portdev->vdev->config->find_vqs(portdev->vdev, nr_queues, vqs,
io_callbacks,
(const char **)io_names);
if (err)
goto free_outvqs;
j = 0;
portdev->in_vqs[0] = vqs[0];
portdev->out_vqs[0] = vqs[1];
j += 2;
if (use_multiport(portdev)) {
portdev->c_ivq = vqs[j];
portdev->c_ovq = vqs[j + 1];
for (i = 1; i < nr_ports; i++) {
j += 2;
portdev->in_vqs[i] = vqs[j];
portdev->out_vqs[i] = vqs[j + 1];
}
}
kfree(io_callbacks);
kfree(io_names);
kfree(vqs);
return 0;
free_names:
kfree(io_names);
free_callbacks:
kfree(io_callbacks);
free_outvqs:
kfree(portdev->out_vqs);
free_invqs:
kfree(portdev->in_vqs);
free_vqs:
kfree(vqs);
fail:
return err;
}
/*
* Once we're further in boot, we get probed like any other virtio
* device.
*
* If the host also supports multiple console ports, we check the
* config space to see how many ports the host has spawned. We
* initialize each port found.
*/
static int __devinit virtcons_probe(struct virtio_device *vdev)
{
struct ports_device *portdev;
u32 i;
int err;
bool multiport;
portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
if (!portdev) {
err = -ENOMEM;
goto fail;
}
/* Attach this portdev to this virtio_device, and vice-versa. */
portdev->vdev = vdev;
vdev->priv = portdev;
multiport = false;
portdev->config.nr_ports = 1;
portdev->config.max_nr_ports = 1;
if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
multiport = true;
vdev->features[0] |= 1 << VIRTIO_CONSOLE_F_MULTIPORT;
vdev->config->get(vdev, offsetof(struct virtio_console_config,
nr_ports),
&portdev->config.nr_ports,
sizeof(portdev->config.nr_ports));
vdev->config->get(vdev, offsetof(struct virtio_console_config,
max_nr_ports),
&portdev->config.max_nr_ports,
sizeof(portdev->config.max_nr_ports));
if (portdev->config.nr_ports > portdev->config.max_nr_ports) {
dev_warn(&vdev->dev,
"More ports (%u) specified than allowed (%u). Will init %u ports.",
portdev->config.nr_ports,
portdev->config.max_nr_ports,
portdev->config.max_nr_ports);
portdev->config.nr_ports = portdev->config.max_nr_ports;
}
}
/* Let the Host know we support multiple ports.*/
vdev->config->finalize_features(vdev);
err = init_vqs(portdev);
if (err < 0) {
dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
goto free;
}
spin_lock_init(&portdev->ports_lock);
INIT_LIST_HEAD(&portdev->ports);
if (multiport) {
spin_lock_init(&portdev->cvq_lock);
INIT_WORK(&portdev->control_work, &control_work_handler);
fill_queue(portdev->c_ivq, &portdev->cvq_lock);
}
for (i = 0; i < portdev->config.nr_ports; i++)
add_port(portdev, i);
/* Start using the new console output. */
early_put_chars = NULL;
return 0;
free_vqs:
vdev->config->del_vqs(vdev);
kfree(portdev->in_vqs);
kfree(portdev->out_vqs);
free:
kfree(portdev);
fail:
return err;
}
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
{ 0 },
};
static unsigned int features[] = {
VIRTIO_CONSOLE_F_SIZE,
VIRTIO_CONSOLE_F_MULTIPORT,
};
static struct virtio_driver virtio_console = {
.feature_table = features,
.feature_table_size = ARRAY_SIZE(features),
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
.probe = virtcons_probe,
.config_changed = virtcons_apply_config,
};
static int __init init(void)
{
INIT_LIST_HEAD(&pdrvdata.consoles);
return register_virtio_driver(&virtio_console);
}
module_init(init);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio console driver");
MODULE_LICENSE("GPL");
