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Message-Id: <1346680277-5887-1-git-send-email-sjur.brandeland@stericsson.com>
Date: Mon, 3 Sep 2012 15:51:16 +0200
From: sjur.brandeland@...ricsson.com
To: Amit Shah <amit.shah@...hat.com>
Cc: Sjur Brændeland <sjurbren@...il.com>,
linux-kernel@...r.kernel.org,
Sjur Brændeland <sjur.brandeland@...ricsson.com>,
Rusty Russell <rusty@...tcorp.com.au>,
"Michael S. Tsirkin" <mst@...hat.com>,
Ohad Ben-Cohen <ohad@...ery.com>,
Linus Walleij <linus.walleij@...aro.org>,
virtualization@...ts.linux-foundation.org
Subject: [RFC 1/2] virtio_console: Add support for DMA memory allocation
From: Sjur Brændeland <sjur.brandeland@...ricsson.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.
This is needed for using virtio_console from the remoteproc
framework.
Signed-off-by: Sjur Brændeland <sjur.brandeland@...ricsson.com>
cc: Rusty Russell <rusty@...tcorp.com.au>
cc: Michael S. Tsirkin <mst@...hat.com>
cc: Ohad Ben-Cohen <ohad@...ery.com>
cc: Linus Walleij <linus.walleij@...aro.org>
cc: virtualization@...ts.linux-foundation.org
---
drivers/char/virtio_console.c | 76 ++++++++++++++++++++++++++++++++--------
include/linux/virtio_console.h | 1 +
2 files changed, 62 insertions(+), 15 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index cdf2f54..6bfbd09 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"
/*
@@ -334,20 +335,60 @@ 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)
+/* Allcoate data buffer from DMA memory if requested */
+static inline void *
+alloc_databuf(struct virtio_device *vdev, size_t size, dma_addr_t *dma_handle,
+ gfp_t flag)
{
- kfree(buf->buf);
+#ifdef CONFIG_HAS_DMA
+ if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_DMA_MEM)) {
+ 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_handle, flag);
+ }
+#endif
+ return kzalloc(size, flag);
+}
+
+static inline void
+free_databuf(struct virtio_device *vdev, size_t size, void *cpu_addr)
+{
+#ifdef CONFIG_HAS_DMA
+ dma_addr_t dma_handle = virt_to_bus(cpu_addr);
+ if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_DMA_MEM)) {
+ struct device *dev = &vdev->dev;
+
+ dev = dev->parent ? dev->parent : dev;
+ dev = dev->parent ? dev->parent : dev;
+ dma_free_coherent(dev, size, cpu_addr, dma_handle);
+ return;
+ }
+#endif
+ kfree(cpu_addr);
+}
+
+static void
+free_buf(struct virtqueue *vq, struct port_buffer *buf, size_t buf_size)
+{
+ 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;
+ dma_addr_t dma;
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, &dma, GFP_KERNEL);
if (!buf->buf)
goto free_buf;
buf->len = 0;
@@ -414,7 +455,7 @@ 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 +526,7 @@ 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 +713,8 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
char *buf;
ssize_t ret;
bool nonblock;
+ struct virtio_device *vdev;
+ dma_addr_t dma;
/* Userspace could be out to fool us */
if (!count)
@@ -694,9 +737,10 @@ 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, &dma, GFP_KERNEL);
if (!buf)
return -ENOMEM;
@@ -720,7 +764,8 @@ 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 +1147,7 @@ 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 +1155,7 @@ 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 +1279,7 @@ 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 +1321,7 @@ 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 +1523,7 @@ 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 +1719,10 @@ 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);
}
/*
@@ -1836,6 +1881,7 @@ static struct virtio_device_id id_table[] = {
static unsigned int features[] = {
VIRTIO_CONSOLE_F_SIZE,
VIRTIO_CONSOLE_F_MULTIPORT,
+ VIRTIO_CONSOLE_F_DMA_MEM,
};
#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)
--
1.7.5.4
--
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