From: Sjur Brændeland <sjur.brandel...@stericsson.com>
Add feature VIRTIO_CONSOLE_F_DMA_MEM. If the architecture has
DMA support and this feature bit is set, the virtio data buffers
will be allocated from DMA memory. If the device requests
the feature VIRTIO_CONSOLE_F_DMA_MEM, but the architecture
don't support DMA the driver's probe function will fail.
This is needed for using virtio_console from the remoteproc
framework.
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: virtualizat...@lists.linux-foundation.org
cc: linux-kernel@vger.kernel.org
---
drivers/char/virtio_console.c | 91 +++++++++++++++++++++++++++++++++-------
include/linux/virtio_console.h | 1 +
2 files changed, 77 insertions(+), 15 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index cdf2f54..469c05f 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -35,8 +35,15 @@
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/module.h>
+#include <linux/dma-mapping.h>
#include "../tty/hvc/hvc_console.h"
+#ifdef CONFIG_HAS_DMA
+#define VIRTIO_CONSOLE_HAS_DMA (1)
+#else
+#define VIRTIO_CONSOLE_HAS_DMA (0)
+#endif
+
/*
* This is a global struct for storing common data for all the devices
* this driver handles.
@@ -334,20 +341,56 @@ 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)
+/* Allocate data buffer from DMA memory if requested */
+static inline void *
+alloc_databuf(struct virtio_device *vdev, size_t size, gfp_t flag)
+{
+ if (VIRTIO_CONSOLE_HAS_DMA &&
+ virtio_has_feature(vdev, VIRTIO_CONSOLE_F_DMA_MEM)) {
+ struct device *dev = &vdev->dev;
+ dma_addr_t dma;
+ /*
+ * 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 (VIRTIO_CONSOLE_HAS_DMA &&
+ virtio_has_feature(vdev, VIRTIO_CONSOLE_F_DMA_MEM)) {
+ struct device *dev = &vdev->dev;
+ dma_addr_t dma = 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);
+ return;
+ }
+ kfree(cpu_addr);
+}
+
+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);
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 +457,7 @@ 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 +528,7 @@ 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 +715,7 @@ 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 +738,10 @@ 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 +765,8 @@ 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;
}
@@ -1102,7 +1148,7 @@ 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 +1156,7 @@ 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++;
@@ -1234,7 +1280,7 @@ 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 +1322,7 @@ 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 +1524,7 @@ 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 +1720,10 @@ 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);
}
/*
@@ -1698,6 +1744,17 @@ static int __devinit virtcons_probe(struct virtio_device
*vdev)
/* Ensure to read early_put_chars now */
barrier();
+ /* Refuse to bind if F_DMA_MEM request cannot be met */
+ if (!VIRTIO_CONSOLE_HAS_DMA &&
+ (vdev->config->get_features(vdev) &
+ (1 << VIRTIO_CONSOLE_F_DMA_MEM))) {
+
+ dev_err(&vdev->dev,
+ "DMA_MEM requested but arch does not support DMA\n");
+ err = -ENODEV;
+ goto fail;
+ }
+
portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
if (!portdev) {
err = -ENOMEM;
@@ -1836,6 +1893,10 @@ static struct virtio_device_id id_table[] = {
static unsigned int features[] = {
VIRTIO_CONSOLE_F_SIZE,
VIRTIO_CONSOLE_F_MULTIPORT,
+#if VIRTIO_CONSOLE_HAS_DMA
+ VIRTIO_CONSOLE_F_DMA_MEM,
+#endif
+
};
#ifdef CONFIG_PM
diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h
index bdf4b00..b27f7fa 100644
--- a/include/linux/virtio_console.h
+++ b/include/linux/virtio_console.h
@@ -38,6 +38,7 @@
/* Feature bits */
#define VIRTIO_CONSOLE_F_SIZE 0 /* Does host provide console size? */
#define VIRTIO_CONSOLE_F_MULTIPORT 1 /* Does host provide multiple ports? */
+#define VIRTIO_CONSOLE_F_DMA_MEM 2 /* Use DMA memory in vrings */
#define VIRTIO_CONSOLE_BAD_ID (~(u32)0)
--
1.7.9.5
--
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