-/*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
*/
#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 "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;
+/*
+ * 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;
+};
-/* This is our input buffer, and how much data is left in it. */
-static unsigned int in_len;
-static char *in, *inbuf;
+/*
+ * This is a per-device struct that stores data common to all the
+ * ports for that device (vdev->priv).
+ */
+struct ports_device {
+ /* Array of per-port IO virtqueues */
+ struct virtqueue **in_vqs, **out_vqs;
-/* The operations for our console. */
-static struct hv_ops virtio_cons;
+ struct virtio_device *vdev;
+};
-/* The hvc device */
-static struct hvc_struct *hvc;
+struct port_buffer {
+ char *buf;
-/*D:310 The put_chars() callback is pretty straightforward.
+ /* 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 struct holds the per-port data */
+struct port {
+ /* 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;
+};
+
+/* 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_vq(struct ports_device *portdev,
+ struct virtqueue *vq)
+{
+ struct port *port;
+ struct console *cons;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pdrvdata_lock, flags);
+ list_for_each_entry(cons, &pdrvdata.consoles, list) {
+ port = container_of(cons, struct port, cons);
+ if (port->in_vq == vq || port->out_vq == vq)
+ goto out;
+ }
+ port = NULL;
+out:
+ spin_unlock_irqrestore(&pdrvdata_lock, flags);
+ return port;
+}
+
+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.
*
- * 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). */
+ * 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;
+}
+
+/*
+ * 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 scatterlist sg[1];
+ struct port *port;
+ struct virtqueue *out_vq;
unsigned int len;
+ port = find_port_by_vtermno(vtermno);
+ if (!port)
+ return 0;
+
+ if (unlikely(early_put_chars))
+ return early_put_chars(vtermno, buf, count);
+
+ out_vq = port->out_vq;
/* 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 (out_vq->vq_ops->add_buf(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))
cpu_relax();
}
return count;
}
-/* Create a scatter-gather list representing our input buffer and put it in the
- * queue. */
-static void add_inbuf(void)
-{
- struct scatterlist sg[1];
- sg_init_one(sg, 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)
- BUG();
- 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. */
+ * 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)
{
- /* If we don't have an input queue yet, we can't get input. */
- BUG_ON(!in_vq);
-
- /* No buffer? Try to get one. */
- if (!in_len) {
- in = in_vq->vq_ops->get_buf(in_vq, &in_len);
- if (!in)
- return 0;
- }
-
- /* You want more than we have to give? Well, try wanting less! */
- if (in_len < count)
- count = in_len;
-
- /* Copy across to their buffer and increment offset. */
- memcpy(buf, in, count);
- in += count;
- in_len -= count;
+ struct port *port;
- /* Finished? Re-register buffer so Host will use it again. */
- if (in_len == 0)
- add_inbuf();
+ port = find_port_by_vtermno(vtermno);
+ if (!port)
+ return 0;
- return count;
-}
-/*:*/
+ /* If we don't have an input queue yet, we can't get input. */
+ BUG_ON(!port->in_vq);
-/*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.
- *
- * 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;
- return hvc_instantiate(0, 0, &virtio_cons);
+ return fill_readbuf(port, buf, count);
}
-/*
- * virtio console configuration. This supports:
- * - console resize
- */
-static void virtcons_apply_config(struct virtio_device *dev)
+static void resize_console(struct port *port)
{
+ struct virtio_device *vdev;
struct winsize ws;
- if (virtio_has_feature(dev, VIRTIO_CONSOLE_F_SIZE)) {
- dev->config->get(dev,
- offsetof(struct virtio_console_config, cols),
- &ws.ws_col, sizeof(u16));
- dev->config->get(dev,
- offsetof(struct virtio_console_config, rows),
- &ws.ws_row, sizeof(u16));
- hvc_resize(hvc, 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);
}
}
-/*
- * 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 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;
- virtcons_apply_config(vdev);
+ resize_console(port);
return 0;
}
static void hvc_handle_input(struct virtqueue *vq)
{
- if (hvc_poll(hvc))
+ 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 (hvc_poll(port->cons.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.
- *
- * 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.
+/* The operations for the console. */
+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.
*
- * Finally we put our input buffer in the input queue, ready to receive. */
-static int __devinit virtcons_probe(struct virtio_device *dev)
+ * 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 __devinit 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;
+}
+
+static int __devinit add_port(struct ports_device *portdev)
+{
+ struct port *port;
+ struct port_buffer *inbuf;
int err;
- vdev = dev;
+ port = kmalloc(sizeof(*port), GFP_KERNEL);
+ if (!port) {
+ err = -ENOMEM;
+ goto fail;
+ }
+
+ port->portdev = portdev;
+
+ port->inbuf = NULL;
- /* This is the scratch page we use to receive console input */
- inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ port->in_vq = portdev->in_vqs[0];
+ port->out_vq = portdev->out_vqs[0];
+
+ spin_lock_init(&port->inbuf_lock);
+
+ inbuf = alloc_buf(PAGE_SIZE);
if (!inbuf) {
err = -ENOMEM;
- goto fail;
+ goto free_port;
}
- /* 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, hvc_handle_input, "input");
- if (IS_ERR(in_vq)) {
- err = PTR_ERR(in_vq);
- goto free;
+ /* Register the input buffer the first time. */
+ add_inbuf(port->in_vq, inbuf);
+
+ err = init_port_console(port);
+ if (err)
+ goto free_inbuf;
+
+ 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 nr_ports, nr_queues;
+ int err;
+
+ /* We currently only have one port and two queues for that port */
+ nr_ports = 1;
+ nr_queues = 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;
+ }
+
+ io_callbacks[0] = hvc_handle_input;
+ io_callbacks[1] = NULL;
+ io_names[0] = "input";
+ io_names[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;
+
+ portdev->in_vqs[0] = vqs[0];
+ portdev->out_vqs[0] = vqs[1];
- out_vq = vdev->config->find_vq(vdev, 1, NULL, "output");
- if (IS_ERR(out_vq)) {
- err = PTR_ERR(out_vq);
- goto free_in_vq;
+ 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.
+ */
+static int __devinit virtcons_probe(struct virtio_device *vdev)
+{
+ struct ports_device *portdev;
+ int err;
+
+ portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
+ if (!portdev) {
+ err = -ENOMEM;
+ goto fail;
}
- /* 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;
- 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 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);
- goto free_out_vq;
+ /* Attach this portdev to this virtio_device, and vice-versa. */
+ portdev->vdev = vdev;
+ vdev->priv = portdev;
+
+ err = init_vqs(portdev);
+ if (err < 0) {
+ dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
+ goto free;
}
- /* Register the input buffer the first time. */
- add_inbuf();
+ /* We only have one port. */
+ err = add_port(portdev);
+ if (err)
+ goto free_vqs;
+
+ /* Start using the new console output. */
+ early_put_chars = NULL;
return 0;
-free_out_vq:
- vdev->config->del_vq(out_vq);
-free_in_vq:
- vdev->config->del_vq(in_vq);
+free_vqs:
+ vdev->config->del_vqs(vdev);
+ kfree(portdev->in_vqs);
+ kfree(portdev->out_vqs);
free:
- kfree(inbuf);
+ kfree(portdev);
fail:
return err;
}
static int __init init(void)
{
+ INIT_LIST_HEAD(&pdrvdata.consoles);
+
return register_virtio_driver(&virtio_console);
}
module_init(init);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff