From: Sjur Brændeland <sjur.brandel...@stericsson.com>
Add a virtio remoteproc serial driver: VIRTIO_ID_RPROC_SERIAL (0xB)
for communicating with a remote processor in an asymmetric
multi-processing configuration.
The virtio remoteproc serial driver reuses the existing virtio_console
implementation, and adds support for DMA allocation of data buffers
but disables support for tty console, mutiple ports, and the control queue.
Signed-off-by: Sjur Brændeland <sjur.brandel...@stericsson.com>
cc: Rusty Russell <ru...@rustcorp.com.au>
cc: Michael S. Tsirkin <m...@redhat.com>
cc: Amit Shah <amit.s...@redhat.com>
cc: Ohad Ben-Cohen <o...@wizery.com>
cc: Linus Walleij <linus.wall...@linaro.org>
cc: virtualization@lists.linux-foundation.org
cc: linux-ker...@vger.kernel.org
---
Hi Rusty,
...
>Sorry for the back and forth, I've been pondering MST's points.
>If we make a new dma-multiport device (eg. ID 11), how ugly is the code?
I don't think it's too bad.
It's a few more code lines - as I have added a new virtio_driver
definition and feature table. The rest is just replacing the check
on feature bits with driver type. I no longer need to check on
feature bits in the probe function, as the match on device type is
done automatically by the driver framework.
I actually like this new approach better.
It solves the issues Michael has pointed out, and we don't have to
think through side effects of weired combination of feature bits.
>It would be a virtio console with DMA buffers and no console, just the
>multiport stuff. This would have no impact on the current spec for
>virtio console.
Yes, and this way it will also be easier to explain what this new
feature does.
Regards,
Sjur
drivers/char/virtio_console.c | 133 +++++++++++++++++++++++++++++++++--------
include/linux/virtio_ids.h | 1 +
2 files changed, 109 insertions(+), 25 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index cdf2f54..08593aa 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -35,6 +35,7 @@
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/module.h>
+#include <linux/dma-mapping.h>
#include "../tty/hvc/hvc_console.h"
/*
@@ -323,6 +324,52 @@ static bool is_console_port(struct port *port)
return false;
}
+#ifdef CONFIG_HAS_DMA
+static inline bool is_rproc_serial(struct virtio_device *vdev)
+{
+ return vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
+}
+#else
+static inline bool is_rproc_serial(struct virtio_device *vdev)
+{
+ return false;
+}
+#endif
+
+/* Allocate data buffer from DMA memory if requested */
+static inline void *
+alloc_databuf(struct virtio_device *vdev, size_t size, gfp_t flag)
+{
+ if (is_rproc_serial(vdev)) {
+ dma_addr_t dma;
+ struct device *dev = &vdev->dev;
+ /*
+ * Allocate DMA memory from ancestors. Finding the ancestor
+ * is a bit quirky when DMA_MEMORY_INCLUDES_CHILDREN is not
+ * implemented.
+ */
+ dev = dev->parent ? dev->parent : dev;
+ dev = dev->parent ? dev->parent : dev;
+ return dma_alloc_coherent(dev, size, &dma, flag);
+ }
+ return kzalloc(size, flag);
+}
+
+static inline void
+free_databuf(struct virtio_device *vdev, size_t size, void *cpu_addr)
+{
+
+ if (is_rproc_serial(vdev)) {
+ struct device *dev = &vdev->dev;
+ dma_addr_t dma_handle = virt_to_bus(cpu_addr);
+ dev = dev->parent ? dev->parent : dev;
+ dev = dev->parent ? dev->parent : dev;
+ dma_free_coherent(dev, size, cpu_addr, dma_handle);
+ return;
+ }
+ kfree(cpu_addr);
+}
+
static inline bool use_multiport(struct ports_device *portdev)
{
/*
@@ -334,20 +381,21 @@ static inline bool use_multiport(struct ports_device
*portdev)
return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
}
-static void free_buf(struct port_buffer *buf)
+static void
+free_buf(struct virtqueue *vq, struct port_buffer *buf, size_t buf_size)
{
- kfree(buf->buf);
+ free_databuf(vq->vdev, buf_size, buf->buf);
kfree(buf);
}
-static struct port_buffer *alloc_buf(size_t buf_size)
+static struct port_buffer *alloc_buf(struct virtqueue *vq, 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);
+ buf->buf = alloc_databuf(vq->vdev, buf_size, GFP_KERNEL);
if (!buf->buf)
goto free_buf;
buf->len = 0;
@@ -414,7 +462,7 @@ static void discard_port_data(struct port *port)
port->stats.bytes_discarded += buf->len - buf->offset;
if (add_inbuf(port->in_vq, buf) < 0) {
err++;
- free_buf(buf);
+ free_buf(port->in_vq, buf, PAGE_SIZE);
}
port->inbuf = NULL;
buf = get_inbuf(port);
@@ -485,7 +533,7 @@ static void reclaim_consumed_buffers(struct port *port)
return;
}
while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
- kfree(buf);
+ free_databuf(port->portdev->vdev, len, buf);
port->outvq_full = false;
}
}
@@ -672,6 +720,7 @@ static ssize_t port_fops_write(struct file *filp, const
char __user *ubuf,
char *buf;
ssize_t ret;
bool nonblock;
+ struct virtio_device *vdev;
/* Userspace could be out to fool us */
if (!count)
@@ -694,9 +743,10 @@ static ssize_t port_fops_write(struct file *filp, const
char __user *ubuf,
if (!port->guest_connected)
return -ENODEV;
+ vdev = port->portdev->vdev;
count = min((size_t)(32 * 1024), count);
- buf = kmalloc(count, GFP_KERNEL);
+ buf = alloc_databuf(vdev, count, GFP_KERNEL);
if (!buf)
return -ENOMEM;
@@ -720,7 +770,7 @@ static ssize_t port_fops_write(struct file *filp, const
char __user *ubuf,
goto out;
free_buf:
- kfree(buf);
+ free_databuf(vdev, count, buf);
out:
return ret;
}
@@ -918,7 +968,8 @@ static void resize_console(struct port *port)
return;
vdev = port->portdev->vdev;
- if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
+ if (!is_rproc_serial(vdev) &&
+ virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
hvc_resize(port->cons.hvc, port->cons.ws);
}
@@ -1102,7 +1153,7 @@ static unsigned int fill_queue(struct virtqueue *vq,
spinlock_t *lock)
nr_added_bufs = 0;
do {
- buf = alloc_buf(PAGE_SIZE);
+ buf = alloc_buf(vq, PAGE_SIZE);
if (!buf)
break;
@@ -1110,7 +1161,7 @@ static unsigned int fill_queue(struct virtqueue *vq,
spinlock_t *lock)
ret = add_inbuf(vq, buf);
if (ret < 0) {
spin_unlock_irq(lock);
- free_buf(buf);
+ free_buf(vq, buf, PAGE_SIZE);
break;
}
nr_added_bufs++;
@@ -1198,10 +1249,18 @@ static int add_port(struct ports_device *portdev, u32
id)
goto free_device;
}
- /*
- * If we're not using multiport support, this has to be a console port
- */
- if (!use_multiport(port->portdev)) {
+ if (is_rproc_serial(port->portdev->vdev))
+ /*
+ * For rproc_serial assume remote processor is connected.
+ * rproc_serial does not want the console port, but
+ * the generic port implementation.
+ */
+ port->host_connected = true;
+ else if (!use_multiport(port->portdev)) {
+ /*
+ * If we're not using multiport support,
+ * this has to be a console port.
+ */
err = init_port_console(port);
if (err)
goto free_inbufs;
@@ -1234,7 +1293,7 @@ static int add_port(struct ports_device *portdev, u32 id)
free_inbufs:
while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
- free_buf(buf);
+ free_buf(port->in_vq, buf, PAGE_SIZE);
free_device:
device_destroy(pdrvdata.class, port->dev->devt);
free_cdev:
@@ -1276,7 +1335,7 @@ static void remove_port_data(struct port *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);
+ free_buf(port->in_vq, buf, PAGE_SIZE);
}
/*
@@ -1478,7 +1537,7 @@ static void control_work_handler(struct work_struct *work)
if (add_inbuf(portdev->c_ivq, buf) < 0) {
dev_warn(&portdev->vdev->dev,
"Error adding buffer to queue\n");
- free_buf(buf);
+ free_buf(portdev->c_ivq, buf, PAGE_SIZE);
}
}
spin_unlock(&portdev->cvq_lock);
@@ -1674,10 +1733,10 @@ static void remove_controlq_data(struct ports_device
*portdev)
return;
while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
- free_buf(buf);
+ free_buf(portdev->c_ivq, buf, PAGE_SIZE);
while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
- free_buf(buf);
+ free_buf(portdev->c_ivq, buf, PAGE_SIZE);
}
/*
@@ -1724,10 +1783,12 @@ static int __devinit virtcons_probe(struct
virtio_device *vdev)
multiport = false;
portdev->config.max_nr_ports = 1;
- if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
- offsetof(struct virtio_console_config,
- max_nr_ports),
- &portdev->config.max_nr_ports) == 0)
+ if (is_rproc_serial(vdev))
+ multiport = false;
+ else if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
+ offsetof(struct virtio_console_config,
+ max_nr_ports),
+ &portdev->config.max_nr_ports) == 0)
multiport = true;
err = init_vqs(portdev);
@@ -1838,6 +1899,16 @@ static unsigned int features[] = {
VIRTIO_CONSOLE_F_MULTIPORT,
};
+static struct virtio_device_id rproc_serial_id_table[] = {
+#ifdef CONFIG_HAS_DMA
+ { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
+#endif
+ { 0 },
+};
+
+static unsigned int rproc_serial_features[] = {
+};
+
#ifdef CONFIG_PM
static int virtcons_freeze(struct virtio_device *vdev)
{
@@ -1922,6 +1993,16 @@ static struct virtio_driver virtio_console = {
#endif
};
+static struct virtio_driver virtio_rproc_serial = {
+ .feature_table = rproc_serial_features,
+ .feature_table_size = ARRAY_SIZE(rproc_serial_features),
+ .driver.name = "virtio_rproc_serial",
+ .driver.owner = THIS_MODULE,
+ .id_table = rproc_serial_id_table,
+ .probe = virtcons_probe,
+ .remove = virtcons_remove,
+};
+
static int __init init(void)
{
int err;
@@ -1941,12 +2022,14 @@ static int __init init(void)
INIT_LIST_HEAD(&pdrvdata.consoles);
INIT_LIST_HEAD(&pdrvdata.portdevs);
- return register_virtio_driver(&virtio_console);
+ return register_virtio_driver(&virtio_console) &&
+ register_virtio_driver(&virtio_rproc_serial);
}
static void __exit fini(void)
{
unregister_virtio_driver(&virtio_console);
+ unregister_virtio_driver(&virtio_rproc_serial);
class_destroy(pdrvdata.class);
if (pdrvdata.debugfs_dir)
diff --git a/include/linux/virtio_ids.h b/include/linux/virtio_ids.h
index 270fb22..07cf6f7 100644
--- a/include/linux/virtio_ids.h
+++ b/include/linux/virtio_ids.h
@@ -37,5 +37,6 @@
#define VIRTIO_ID_RPMSG 7 /* virtio remote processor messaging
*/
#define VIRTIO_ID_SCSI 8 /* virtio scsi */
#define VIRTIO_ID_9P 9 /* 9p virtio console */
+#define VIRTIO_ID_RPROC_SERIAL 0xB /* virtio remoteproc serial link */
#endif /* _LINUX_VIRTIO_IDS_H */
--
1.7.5.4
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