--- /dev/null
- * Copyright (C) 2009, 2010 Red Hat, Inc.
+ /*
+ * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
- io_callbacks[j + 1] = NULL;
++ * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
++ * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
+ *
+ * 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/cdev.h>
+ #include <linux/debugfs.h>
+ #include <linux/device.h>
+ #include <linux/err.h>
+ #include <linux/fs.h>
+ #include <linux/init.h>
+ #include <linux/list.h>
+ #include <linux/poll.h>
+ #include <linux/sched.h>
+ #include <linux/slab.h>
+ #include <linux/spinlock.h>
+ #include <linux/virtio.h>
+ #include <linux/virtio_console.h>
+ #include <linux/wait.h>
+ #include <linux/workqueue.h>
+ #include "../tty/hvc/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 {
+ /* Used for registering chardevs */
+ struct class *class;
+
+ /* Used for exporting per-port information to debugfs */
+ struct dentry *debugfs_dir;
+
+ /* List of all the devices we're handling */
+ struct list_head portdevs;
+
+ /* Number of devices this driver is handling */
+ unsigned int index;
+
+ /*
+ * 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;
+
+ /* The size of the console */
+ struct winsize ws;
+
+ /*
+ * 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 {
+ /* Next portdev in the list, head is in the pdrvdata struct */
+ struct list_head list;
+
+ /*
+ * 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;
+
+ /* Used for numbering devices for sysfs and debugfs */
+ unsigned int drv_index;
+
+ /* Major number for this device. Ports will be created as minors. */
+ int chr_major;
+ };
+
+ /* 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;
+
+ /* Protect the operations on the out_vq. */
+ spinlock_t outvq_lock;
+
+ /* The IO vqs for this port */
+ struct virtqueue *in_vq, *out_vq;
+
+ /* File in the debugfs directory that exposes this port's information */
+ struct dentry *debugfs_file;
+
+ /*
+ * The entries in this struct will be valid if this port is
+ * hooked up to an hvc console
+ */
+ struct console cons;
+
+ /* Each port associates with a separate char device */
+ struct cdev *cdev;
+ struct device *dev;
+
+ /* Reference-counting to handle port hot-unplugs and file operations */
+ struct kref kref;
+
+ /* A waitqueue for poll() or blocking read operations */
+ wait_queue_head_t waitqueue;
+
+ /* The 'name' of the port that we expose via sysfs properties */
+ char *name;
+
+ /* We can notify apps of host connect / disconnect events via SIGIO */
+ struct fasync_struct *async_queue;
+
+ /* The 'id' to identify the port with the Host */
+ u32 id;
+
+ bool outvq_full;
+
+ /* Is the host device open */
+ bool host_connected;
+
+ /* We should allow only one process to open a port */
+ bool guest_connected;
+ };
+
+ /* 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_devt_in_portdev(struct ports_device *portdev,
+ dev_t dev)
+ {
+ struct port *port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&portdev->ports_lock, flags);
+ list_for_each_entry(port, &portdev->ports, list)
+ if (port->cdev->dev == dev)
+ goto out;
+ port = NULL;
+ out:
+ spin_unlock_irqrestore(&portdev->ports_lock, flags);
+
+ return port;
+ }
+
+ static struct port *find_port_by_devt(dev_t dev)
+ {
+ struct ports_device *portdev;
+ struct port *port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pdrvdata_lock, flags);
+ list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
+ port = find_port_by_devt_in_portdev(portdev, dev);
+ if (port)
+ 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 = virtqueue_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 = virtqueue_add_buf(vq, sg, 0, 1, buf);
+ virtqueue_kick(vq);
+ return ret;
+ }
+
+ /* Discard any unread data this port has. Callers lockers. */
+ static void discard_port_data(struct port *port)
+ {
+ struct port_buffer *buf;
+ struct virtqueue *vq;
+ unsigned int len;
+ int ret;
+
+ vq = port->in_vq;
+ if (port->inbuf)
+ buf = port->inbuf;
+ else
+ buf = virtqueue_get_buf(vq, &len);
+
+ ret = 0;
+ while (buf) {
+ if (add_inbuf(vq, buf) < 0) {
+ ret++;
+ free_buf(buf);
+ }
+ buf = virtqueue_get_buf(vq, &len);
+ }
+ port->inbuf = NULL;
+ if (ret)
+ dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
+ ret);
+ }
+
+ static bool port_has_data(struct port *port)
+ {
+ unsigned long flags;
+ bool ret;
+
+ spin_lock_irqsave(&port->inbuf_lock, flags);
+ if (port->inbuf) {
+ ret = true;
+ goto out;
+ }
+ port->inbuf = get_inbuf(port);
+ if (port->inbuf) {
+ ret = true;
+ goto out;
+ }
+ ret = false;
+ out:
+ spin_unlock_irqrestore(&port->inbuf_lock, flags);
+ return ret;
+ }
+
+ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
+ unsigned int event, unsigned int value)
+ {
+ struct scatterlist sg[1];
+ struct virtio_console_control cpkt;
+ struct virtqueue *vq;
+ unsigned int len;
+
+ if (!use_multiport(portdev))
+ return 0;
+
+ cpkt.id = port_id;
+ cpkt.event = event;
+ cpkt.value = value;
+
+ vq = portdev->c_ovq;
+
+ sg_init_one(sg, &cpkt, sizeof(cpkt));
+ if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
+ virtqueue_kick(vq);
+ while (!virtqueue_get_buf(vq, &len))
+ cpu_relax();
+ }
+ return 0;
+ }
+
+ static ssize_t send_control_msg(struct port *port, unsigned int event,
+ unsigned int value)
+ {
+ /* Did the port get unplugged before userspace closed it? */
+ if (port->portdev)
+ return __send_control_msg(port->portdev, port->id, event, value);
+ return 0;
+ }
+
+ /* Callers must take the port->outvq_lock */
+ static void reclaim_consumed_buffers(struct port *port)
+ {
+ void *buf;
+ unsigned int len;
+
+ while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
+ kfree(buf);
+ port->outvq_full = false;
+ }
+ }
+
+ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
+ bool nonblock)
+ {
+ struct scatterlist sg[1];
+ struct virtqueue *out_vq;
+ ssize_t ret;
+ unsigned long flags;
+ unsigned int len;
+
+ out_vq = port->out_vq;
+
+ spin_lock_irqsave(&port->outvq_lock, flags);
+
+ reclaim_consumed_buffers(port);
+
+ sg_init_one(sg, in_buf, in_count);
+ ret = virtqueue_add_buf(out_vq, sg, 1, 0, in_buf);
+
+ /* Tell Host to go! */
+ virtqueue_kick(out_vq);
+
+ if (ret < 0) {
+ in_count = 0;
+ goto done;
+ }
+
+ if (ret == 0)
+ port->outvq_full = true;
+
+ if (nonblock)
+ goto done;
+
+ /*
+ * Wait till the host acknowledges it pushed out the data we
+ * sent. This is done for data from the hvc_console; the tty
+ * operations are performed with spinlocks held so we can't
+ * sleep here. An alternative would be to copy the data to a
+ * buffer and relax the spinning requirement. The downside is
+ * we need to kmalloc a GFP_ATOMIC buffer each time the
+ * console driver writes something out.
+ */
+ while (!virtqueue_get_buf(out_vq, &len))
+ cpu_relax();
+ done:
+ spin_unlock_irqrestore(&port->outvq_lock, flags);
+ /*
+ * We're expected to return the amount of data we wrote -- all
+ * of it
+ */
+ return in_count;
+ }
+
+ /*
+ * 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,
+ bool to_user)
+ {
+ struct port_buffer *buf;
+ unsigned long flags;
+
+ if (!out_count || !port_has_data(port))
+ return 0;
+
+ buf = port->inbuf;
+ out_count = min(out_count, buf->len - buf->offset);
+
+ if (to_user) {
+ ssize_t ret;
+
+ ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
+ if (ret)
+ return -EFAULT;
+ } else {
+ memcpy(out_buf, buf->buf + buf->offset, out_count);
+ }
+
+ 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->dev, "failed add_buf\n");
+
+ spin_unlock_irqrestore(&port->inbuf_lock, flags);
+ }
+ /* Return the number of bytes actually copied */
+ return out_count;
+ }
+
+ /* The condition that must be true for polling to end */
+ static bool will_read_block(struct port *port)
+ {
+ if (!port->guest_connected) {
+ /* Port got hot-unplugged. Let's exit. */
+ return false;
+ }
+ return !port_has_data(port) && port->host_connected;
+ }
+
+ static bool will_write_block(struct port *port)
+ {
+ bool ret;
+
+ if (!port->guest_connected) {
+ /* Port got hot-unplugged. Let's exit. */
+ return false;
+ }
+ if (!port->host_connected)
+ return true;
+
+ spin_lock_irq(&port->outvq_lock);
+ /*
+ * Check if the Host has consumed any buffers since we last
+ * sent data (this is only applicable for nonblocking ports).
+ */
+ reclaim_consumed_buffers(port);
+ ret = port->outvq_full;
+ spin_unlock_irq(&port->outvq_lock);
+
+ return ret;
+ }
+
+ static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *offp)
+ {
+ struct port *port;
+ ssize_t ret;
+
+ port = filp->private_data;
+
+ if (!port_has_data(port)) {
+ /*
+ * If nothing's connected on the host just return 0 in
+ * case of list_empty; this tells the userspace app
+ * that there's no connection
+ */
+ if (!port->host_connected)
+ return 0;
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(port->waitqueue,
+ !will_read_block(port));
+ if (ret < 0)
+ return ret;
+ }
+ /* Port got hot-unplugged. */
+ if (!port->guest_connected)
+ return -ENODEV;
+ /*
+ * We could've received a disconnection message while we were
+ * waiting for more data.
+ *
+ * This check is not clubbed in the if() statement above as we
+ * might receive some data as well as the host could get
+ * disconnected after we got woken up from our wait. So we
+ * really want to give off whatever data we have and only then
+ * check for host_connected.
+ */
+ if (!port_has_data(port) && !port->host_connected)
+ return 0;
+
+ return fill_readbuf(port, ubuf, count, true);
+ }
+
+ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
+ size_t count, loff_t *offp)
+ {
+ struct port *port;
+ char *buf;
+ ssize_t ret;
+ bool nonblock;
+
+ /* Userspace could be out to fool us */
+ if (!count)
+ return 0;
+
+ port = filp->private_data;
+
+ nonblock = filp->f_flags & O_NONBLOCK;
+
+ if (will_write_block(port)) {
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(port->waitqueue,
+ !will_write_block(port));
+ if (ret < 0)
+ return ret;
+ }
+ /* Port got hot-unplugged. */
+ if (!port->guest_connected)
+ return -ENODEV;
+
+ count = min((size_t)(32 * 1024), count);
+
+ buf = kmalloc(count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = copy_from_user(buf, ubuf, count);
+ if (ret) {
+ ret = -EFAULT;
+ goto free_buf;
+ }
+
+ /*
+ * We now ask send_buf() to not spin for generic ports -- we
+ * can re-use the same code path that non-blocking file
+ * descriptors take for blocking file descriptors since the
+ * wait is already done and we're certain the write will go
+ * through to the host.
+ */
+ nonblock = true;
+ ret = send_buf(port, buf, count, nonblock);
+
+ if (nonblock && ret > 0)
+ goto out;
+
+ free_buf:
+ kfree(buf);
+ out:
+ return ret;
+ }
+
+ static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
+ {
+ struct port *port;
+ unsigned int ret;
+
+ port = filp->private_data;
+ poll_wait(filp, &port->waitqueue, wait);
+
+ if (!port->guest_connected) {
+ /* Port got unplugged */
+ return POLLHUP;
+ }
+ ret = 0;
+ if (!will_read_block(port))
+ ret |= POLLIN | POLLRDNORM;
+ if (!will_write_block(port))
+ ret |= POLLOUT;
+ if (!port->host_connected)
+ ret |= POLLHUP;
+
+ return ret;
+ }
+
+ static void remove_port(struct kref *kref);
+
+ static int port_fops_release(struct inode *inode, struct file *filp)
+ {
+ struct port *port;
+
+ port = filp->private_data;
+
+ /* Notify host of port being closed */
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
+
+ spin_lock_irq(&port->inbuf_lock);
+ port->guest_connected = false;
+
+ discard_port_data(port);
+
+ spin_unlock_irq(&port->inbuf_lock);
+
+ spin_lock_irq(&port->outvq_lock);
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+
+ /*
+ * Locks aren't necessary here as a port can't be opened after
+ * unplug, and if a port isn't unplugged, a kref would already
+ * exist for the port. Plus, taking ports_lock here would
+ * create a dependency on other locks taken by functions
+ * inside remove_port if we're the last holder of the port,
+ * creating many problems.
+ */
+ kref_put(&port->kref, remove_port);
+
+ return 0;
+ }
+
+ static int port_fops_open(struct inode *inode, struct file *filp)
+ {
+ struct cdev *cdev = inode->i_cdev;
+ struct port *port;
+ int ret;
+
+ port = find_port_by_devt(cdev->dev);
+ filp->private_data = port;
+
+ /* Prevent against a port getting hot-unplugged at the same time */
+ spin_lock_irq(&port->portdev->ports_lock);
+ kref_get(&port->kref);
+ spin_unlock_irq(&port->portdev->ports_lock);
+
+ /*
+ * Don't allow opening of console port devices -- that's done
+ * via /dev/hvc
+ */
+ if (is_console_port(port)) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ /* Allow only one process to open a particular port at a time */
+ spin_lock_irq(&port->inbuf_lock);
+ if (port->guest_connected) {
+ spin_unlock_irq(&port->inbuf_lock);
+ ret = -EMFILE;
+ goto out;
+ }
+
+ port->guest_connected = true;
+ spin_unlock_irq(&port->inbuf_lock);
+
+ spin_lock_irq(&port->outvq_lock);
+ /*
+ * There might be a chance that we missed reclaiming a few
+ * buffers in the window of the port getting previously closed
+ * and opening now.
+ */
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+
+ nonseekable_open(inode, filp);
+
+ /* Notify host of port being opened */
+ send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
+
+ return 0;
+ out:
+ kref_put(&port->kref, remove_port);
+ return ret;
+ }
+
+ static int port_fops_fasync(int fd, struct file *filp, int mode)
+ {
+ struct port *port;
+
+ port = filp->private_data;
+ return fasync_helper(fd, filp, mode, &port->async_queue);
+ }
+
+ /*
+ * The file operations that we support: programs in the guest can open
+ * a console device, read from it, write to it, poll for data and
+ * close it. The devices are at
+ * /dev/vport<device number>p<port number>
+ */
+ static const struct file_operations port_fops = {
+ .owner = THIS_MODULE,
+ .open = port_fops_open,
+ .read = port_fops_read,
+ .write = port_fops_write,
+ .poll = port_fops_poll,
+ .release = port_fops_release,
+ .fasync = port_fops_fasync,
+ .llseek = no_llseek,
+ };
+
+ /*
+ * 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;
+
+ if (unlikely(early_put_chars))
+ return early_put_chars(vtermno, buf, count);
+
+ port = find_port_by_vtermno(vtermno);
+ if (!port)
+ return -EPIPE;
+
+ return send_buf(port, (void *)buf, count, false);
+ }
+
+ /*
+ * 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;
+
+ /* If we've not set up the port yet, we have no input to give. */
+ if (unlikely(early_put_chars))
+ return 0;
+
+ port = find_port_by_vtermno(vtermno);
+ if (!port)
+ return -EPIPE;
+
+ /* 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, false);
+ }
+
+ static void resize_console(struct port *port)
+ {
+ struct virtio_device *vdev;
+
+ /* The port could have been hot-unplugged */
+ if (!port || !is_console_port(port))
+ return;
+
+ vdev = port->portdev->vdev;
+ if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
+ hvc_resize(port->cons.hvc, port->cons.ws);
+ }
+
+ /* 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);
+ dev_err(port->dev,
+ "error %d allocating hvc for port\n", ret);
+ 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);
+ port->guest_connected = true;
+
+ /*
+ * Start using the new console output if this is the first
+ * console to come up.
+ */
+ if (early_put_chars)
+ early_put_chars = NULL;
+
+ /* Notify host of port being opened */
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
+
+ return 0;
+ }
+
+ static ssize_t show_port_name(struct device *dev,
+ struct device_attribute *attr, char *buffer)
+ {
+ struct port *port;
+
+ port = dev_get_drvdata(dev);
+
+ return sprintf(buffer, "%s\n", port->name);
+ }
+
+ static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
+
+ static struct attribute *port_sysfs_entries[] = {
+ &dev_attr_name.attr,
+ NULL
+ };
+
+ static struct attribute_group port_attribute_group = {
+ .name = NULL, /* put in device directory */
+ .attrs = port_sysfs_entries,
+ };
+
+ static int debugfs_open(struct inode *inode, struct file *filp)
+ {
+ filp->private_data = inode->i_private;
+ return 0;
+ }
+
+ static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *offp)
+ {
+ struct port *port;
+ char *buf;
+ ssize_t ret, out_offset, out_count;
+
+ out_count = 1024;
+ buf = kmalloc(out_count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ port = filp->private_data;
+ out_offset = 0;
+ out_offset += snprintf(buf + out_offset, out_count,
+ "name: %s\n", port->name ? port->name : "");
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "guest_connected: %d\n", port->guest_connected);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "host_connected: %d\n", port->host_connected);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "outvq_full: %d\n", port->outvq_full);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "is_console: %s\n",
+ is_console_port(port) ? "yes" : "no");
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "console_vtermno: %u\n", port->cons.vtermno);
+
+ ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+ kfree(buf);
+ return ret;
+ }
+
+ static const struct file_operations port_debugfs_ops = {
+ .owner = THIS_MODULE,
+ .open = debugfs_open,
+ .read = debugfs_read,
+ };
+
+ static void set_console_size(struct port *port, u16 rows, u16 cols)
+ {
+ if (!port || !is_console_port(port))
+ return;
+
+ port->cons.ws.ws_row = rows;
+ port->cons.ws.ws_col = cols;
+ }
+
+ static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
+ {
+ struct port_buffer *buf;
+ unsigned int nr_added_bufs;
+ int ret;
+
+ nr_added_bufs = 0;
+ 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;
+ }
+ nr_added_bufs++;
+ spin_unlock_irq(lock);
+ } while (ret > 0);
+
+ return nr_added_bufs;
+ }
+
+ static void send_sigio_to_port(struct port *port)
+ {
+ if (port->async_queue && port->guest_connected)
+ kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
+ }
+
+ static int add_port(struct ports_device *portdev, u32 id)
+ {
+ char debugfs_name[16];
+ struct port *port;
+ struct port_buffer *buf;
+ dev_t devt;
+ unsigned int nr_added_bufs;
+ int err;
+
+ port = kmalloc(sizeof(*port), GFP_KERNEL);
+ if (!port) {
+ err = -ENOMEM;
+ goto fail;
+ }
+ kref_init(&port->kref);
+
+ port->portdev = portdev;
+ port->id = id;
+
+ port->name = NULL;
+ port->inbuf = NULL;
+ port->cons.hvc = NULL;
+ port->async_queue = NULL;
+
+ port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
+
+ port->host_connected = port->guest_connected = false;
+
+ port->outvq_full = false;
+
+ port->in_vq = portdev->in_vqs[port->id];
+ port->out_vq = portdev->out_vqs[port->id];
+
+ port->cdev = cdev_alloc();
+ if (!port->cdev) {
+ dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
+ err = -ENOMEM;
+ goto free_port;
+ }
+ port->cdev->ops = &port_fops;
+
+ devt = MKDEV(portdev->chr_major, id);
+ err = cdev_add(port->cdev, devt, 1);
+ if (err < 0) {
+ dev_err(&port->portdev->vdev->dev,
+ "Error %d adding cdev for port %u\n", err, id);
+ goto free_cdev;
+ }
+ port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
+ devt, port, "vport%up%u",
+ port->portdev->drv_index, id);
+ if (IS_ERR(port->dev)) {
+ err = PTR_ERR(port->dev);
+ dev_err(&port->portdev->vdev->dev,
+ "Error %d creating device for port %u\n",
+ err, id);
+ goto free_cdev;
+ }
+
+ spin_lock_init(&port->inbuf_lock);
+ spin_lock_init(&port->outvq_lock);
+ init_waitqueue_head(&port->waitqueue);
+
+ /* Fill the in_vq with buffers so the host can send us data. */
+ nr_added_bufs = fill_queue(port->in_vq, &port->inbuf_lock);
+ if (!nr_added_bufs) {
+ dev_err(port->dev, "Error allocating inbufs\n");
+ err = -ENOMEM;
+ goto free_device;
+ }
+
+ /*
+ * 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_inbufs;
+ }
+
+ 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);
+
+ if (pdrvdata.debugfs_dir) {
+ /*
+ * Finally, create the debugfs file that we can use to
+ * inspect a port's state at any time
+ */
+ sprintf(debugfs_name, "vport%up%u",
+ port->portdev->drv_index, id);
+ port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
+ pdrvdata.debugfs_dir,
+ port,
+ &port_debugfs_ops);
+ }
+ return 0;
+
+ free_inbufs:
+ while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
+ free_buf(buf);
+ free_device:
+ device_destroy(pdrvdata.class, port->dev->devt);
+ free_cdev:
+ cdev_del(port->cdev);
+ free_port:
+ kfree(port);
+ fail:
+ /* The host might want to notify management sw about port add failure */
+ __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
+ return err;
+ }
+
+ /* No users remain, remove all port-specific data. */
+ static void remove_port(struct kref *kref)
+ {
+ struct port *port;
+
+ port = container_of(kref, struct port, kref);
+
+ sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
+ device_destroy(pdrvdata.class, port->dev->devt);
+ cdev_del(port->cdev);
+
+ kfree(port->name);
+
+ debugfs_remove(port->debugfs_file);
+
+ kfree(port);
+ }
+
+ /*
+ * Port got unplugged. Remove port from portdev's list and drop the
+ * kref reference. If no userspace has this port opened, it will
+ * result in immediate removal the port.
+ */
+ static void unplug_port(struct port *port)
+ {
+ struct port_buffer *buf;
+
+ spin_lock_irq(&port->portdev->ports_lock);
+ list_del(&port->list);
+ spin_unlock_irq(&port->portdev->ports_lock);
+
+ if (port->guest_connected) {
+ port->guest_connected = false;
+ port->host_connected = false;
+ wake_up_interruptible(&port->waitqueue);
+
+ /* Let the app know the port is going down. */
+ send_sigio_to_port(port);
+ }
+
+ if (is_console_port(port)) {
+ spin_lock_irq(&pdrvdata_lock);
+ list_del(&port->cons.list);
+ spin_unlock_irq(&pdrvdata_lock);
+ #if 0
+ /*
+ * hvc_remove() not called as removing one hvc port
+ * results in other hvc ports getting frozen.
+ *
+ * Once this is resolved in hvc, this functionality
+ * will be enabled. Till that is done, the -EPIPE
+ * return from get_chars() above will help
+ * hvc_console.c to clean up on ports we remove here.
+ */
+ hvc_remove(port->cons.hvc);
+ #endif
+ }
+
+ /* Remove unused data this port might have received. */
+ discard_port_data(port);
+
+ reclaim_consumed_buffers(port);
+
+ /* Remove buffers we queued up for the Host to send us data in. */
+ while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
+ free_buf(buf);
+
+ /*
+ * We should just assume the device itself has gone off --
+ * else a close on an open port later will try to send out a
+ * control message.
+ */
+ port->portdev = NULL;
+
+ /*
+ * Locks around here are not necessary - a port can't be
+ * opened after we removed the port struct from ports_list
+ * above.
+ */
+ kref_put(&port->kref, remove_port);
+ }
+
+ /* 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;
+ size_t name_size;
+ int err;
+
+ cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
+
+ port = find_port_by_id(portdev, cpkt->id);
+ if (!port && cpkt->event != VIRTIO_CONSOLE_PORT_ADD) {
+ /* 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_PORT_ADD:
+ if (port) {
+ dev_dbg(&portdev->vdev->dev,
+ "Port %u already added\n", port->id);
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+ break;
+ }
+ if (cpkt->id >= portdev->config.max_nr_ports) {
+ dev_warn(&portdev->vdev->dev,
+ "Request for adding port with out-of-bound id %u, max. supported id: %u\n",
+ cpkt->id, portdev->config.max_nr_ports - 1);
+ break;
+ }
+ add_port(portdev, cpkt->id);
+ break;
+ case VIRTIO_CONSOLE_PORT_REMOVE:
+ unplug_port(port);
+ break;
+ 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: {
+ struct {
+ __u16 rows;
+ __u16 cols;
+ } size;
+
+ if (!is_console_port(port))
+ break;
+
+ memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
+ sizeof(size));
+ set_console_size(port, size.rows, size.cols);
+
+ port->cons.hvc->irq_requested = 1;
+ resize_console(port);
+ break;
+ }
+ case VIRTIO_CONSOLE_PORT_OPEN:
+ port->host_connected = cpkt->value;
+ wake_up_interruptible(&port->waitqueue);
+ /*
+ * If the host port got closed and the host had any
+ * unconsumed buffers, we'll be able to reclaim them
+ * now.
+ */
+ spin_lock_irq(&port->outvq_lock);
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+
+ /*
+ * If the guest is connected, it'll be interested in
+ * knowing the host connection state changed.
+ */
+ send_sigio_to_port(port);
+ break;
+ case VIRTIO_CONSOLE_PORT_NAME:
+ /*
+ * Skip the size of the header and the cpkt to get the size
+ * of the name that was sent
+ */
+ name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
+
+ port->name = kmalloc(name_size, GFP_KERNEL);
+ if (!port->name) {
+ dev_err(port->dev,
+ "Not enough space to store port name\n");
+ break;
+ }
+ strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
+ name_size - 1);
+ port->name[name_size - 1] = 0;
+
+ /*
+ * Since we only have one sysfs attribute, 'name',
+ * create it only if we have a name for the port.
+ */
+ err = sysfs_create_group(&port->dev->kobj,
+ &port_attribute_group);
+ if (err) {
+ dev_err(port->dev,
+ "Error %d creating sysfs device attributes\n",
+ err);
+ } else {
+ /*
+ * Generate a udev event so that appropriate
+ * symlinks can be created based on udev
+ * rules.
+ */
+ kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
+ }
+ 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 = virtqueue_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 out_intr(struct virtqueue *vq)
++{
++ struct port *port;
++
++ port = find_port_by_vq(vq->vdev->priv, vq);
++ if (!port)
++ return;
++
++ wake_up_interruptible(&port->waitqueue);
++}
++
+ 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);
+ if (!port->inbuf)
+ port->inbuf = get_inbuf(port);
+
+ /*
+ * Don't queue up data when port is closed. This condition
+ * can be reached when a console port is not yet connected (no
+ * tty is spawned) and the host sends out data to console
+ * ports. For generic serial ports, the host won't
+ * (shouldn't) send data till the guest is connected.
+ */
+ if (!port->guest_connected)
+ discard_port_data(port);
+
+ spin_unlock_irqrestore(&port->inbuf_lock, flags);
+
+ wake_up_interruptible(&port->waitqueue);
+
+ /* Send a SIGIO indicating new data in case the process asked for it */
+ send_sigio_to_port(port);
+
+ 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 config_intr(struct virtio_device *vdev)
+ {
+ struct ports_device *portdev;
+
+ portdev = vdev->priv;
+
+ if (!use_multiport(portdev)) {
+ struct port *port;
+ u16 rows, cols;
+
+ vdev->config->get(vdev,
+ offsetof(struct virtio_console_config, cols),
+ &cols, sizeof(u16));
+ vdev->config->get(vdev,
+ offsetof(struct virtio_console_config, rows),
+ &rows, sizeof(u16));
+
+ port = find_port_by_id(portdev, 0);
+ set_console_size(port, rows, cols);
+
+ /*
+ * We'll use this way of resizing only for legacy
+ * support. For newer userspace
+ * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
+ * to indicate console size changes so that it can be
+ * done per-port.
+ */
+ resize_console(port);
+ }
+ }
+
+ 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);
+ io_callbacks = kmalloc(nr_queues * sizeof(vq_callback_t *), GFP_KERNEL);
+ io_names = kmalloc(nr_queues * sizeof(char *), GFP_KERNEL);
+ portdev->in_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
+ GFP_KERNEL);
+ portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
+ GFP_KERNEL);
+ if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
+ !portdev->out_vqs) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ /*
+ * 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_callbacks[j + 1] = out_intr;
+ 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] = out_intr;
+ 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;
+
+ 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_names);
+ kfree(io_callbacks);
+ kfree(vqs);
+
+ return 0;
+
+ free:
+ kfree(portdev->out_vqs);
+ kfree(portdev->in_vqs);
+ kfree(io_names);
+ kfree(io_callbacks);
+ kfree(vqs);
+
+ return err;
+ }
+
+ static const struct file_operations portdev_fops = {
+ .owner = THIS_MODULE,
+ };
+
+ /*
+ * 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;
+ 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;
+
+ spin_lock_irq(&pdrvdata_lock);
+ portdev->drv_index = pdrvdata.index++;
+ spin_unlock_irq(&pdrvdata_lock);
+
+ portdev->chr_major = register_chrdev(0, "virtio-portsdev",
+ &portdev_fops);
+ if (portdev->chr_major < 0) {
+ dev_err(&vdev->dev,
+ "Error %d registering chrdev for device %u\n",
+ portdev->chr_major, portdev->drv_index);
+ err = portdev->chr_major;
+ goto free;
+ }
+
+ multiport = false;
+ 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,
+ max_nr_ports),
+ &portdev->config.max_nr_ports,
+ sizeof(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_chrdev;
+ }
+
+ spin_lock_init(&portdev->ports_lock);
+ INIT_LIST_HEAD(&portdev->ports);
+
+ if (multiport) {
+ unsigned int nr_added_bufs;
+
+ spin_lock_init(&portdev->cvq_lock);
+ INIT_WORK(&portdev->control_work, &control_work_handler);
+
+ nr_added_bufs = fill_queue(portdev->c_ivq, &portdev->cvq_lock);
+ if (!nr_added_bufs) {
+ dev_err(&vdev->dev,
+ "Error allocating buffers for control queue\n");
+ err = -ENOMEM;
+ goto free_vqs;
+ }
+ } else {
+ /*
+ * For backward compatibility: Create a console port
+ * if we're running on older host.
+ */
+ add_port(portdev, 0);
+ }
+
+ spin_lock_irq(&pdrvdata_lock);
+ list_add_tail(&portdev->list, &pdrvdata.portdevs);
+ spin_unlock_irq(&pdrvdata_lock);
+
+ __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
+ VIRTIO_CONSOLE_DEVICE_READY, 1);
+ return 0;
+
+ free_vqs:
+ /* The host might want to notify mgmt sw about device add failure */
+ __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
+ VIRTIO_CONSOLE_DEVICE_READY, 0);
+ vdev->config->del_vqs(vdev);
+ kfree(portdev->in_vqs);
+ kfree(portdev->out_vqs);
+ free_chrdev:
+ unregister_chrdev(portdev->chr_major, "virtio-portsdev");
+ free:
+ kfree(portdev);
+ fail:
+ return err;
+ }
+
+ static void virtcons_remove(struct virtio_device *vdev)
+ {
+ struct ports_device *portdev;
+ struct port *port, *port2;
+
+ portdev = vdev->priv;
+
+ spin_lock_irq(&pdrvdata_lock);
+ list_del(&portdev->list);
+ spin_unlock_irq(&pdrvdata_lock);
+
+ /* Disable interrupts for vqs */
+ vdev->config->reset(vdev);
+ /* Finish up work that's lined up */
+ cancel_work_sync(&portdev->control_work);
+
+ list_for_each_entry_safe(port, port2, &portdev->ports, list)
+ unplug_port(port);
+
+ unregister_chrdev(portdev->chr_major, "virtio-portsdev");
+
+ /*
+ * When yanking out a device, we immediately lose the
+ * (device-side) queues. So there's no point in keeping the
+ * guest side around till we drop our final reference. This
+ * also means that any ports which are in an open state will
+ * have to just stop using the port, as the vqs are going
+ * away.
+ */
+ if (use_multiport(portdev)) {
+ struct port_buffer *buf;
+ unsigned int len;
+
+ while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
+ free_buf(buf);
+
+ while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
+ free_buf(buf);
+ }
+
+ vdev->config->del_vqs(vdev);
+ kfree(portdev->in_vqs);
+ kfree(portdev->out_vqs);
+
+ kfree(portdev);
+ }
+
+ 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,
+ .remove = virtcons_remove,
+ .config_changed = config_intr,
+ };
+
+ static int __init init(void)
+ {
+ int err;
+
+ pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
+ if (IS_ERR(pdrvdata.class)) {
+ err = PTR_ERR(pdrvdata.class);
+ pr_err("Error %d creating virtio-ports class\n", err);
+ return err;
+ }
+
+ pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
+ if (!pdrvdata.debugfs_dir) {
+ pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
+ PTR_ERR(pdrvdata.debugfs_dir));
+ }
+ INIT_LIST_HEAD(&pdrvdata.consoles);
+ INIT_LIST_HEAD(&pdrvdata.portdevs);
+
+ return register_virtio_driver(&virtio_console);
+ }
+
+ static void __exit fini(void)
+ {
+ unregister_virtio_driver(&virtio_console);
+
+ class_destroy(pdrvdata.class);
+ if (pdrvdata.debugfs_dir)
+ debugfs_remove_recursive(pdrvdata.debugfs_dir);
+ }
+ module_init(init);
+ module_exit(fini);
+
+ MODULE_DEVICE_TABLE(virtio, id_table);
+ MODULE_DESCRIPTION("Virtio console driver");
+ MODULE_LICENSE("GPL");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff