[RFC PATCH 14/14] iio: buffer: convert single buffer to list of buffers

Alexandru Ardelean
2020-05-08T13:54:46Z

WIP

Time to add support for multiple buffers.
At this point it should be just managing a list.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/industrialio-buffer.c | 74 ++++++++++++++++++++++---------
drivers/iio/industrialio-core.c | 1 +
include/linux/iio/buffer_impl.h | 3 ++
include/linux/iio/iio.h | 2 +
4 files changed, 58 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index aa2f46c0949f..c335484a6651 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -244,12 +244,13 @@ static int iio_buffer_chrdev_release(struct inode *inode, struct file *filp)
*/
void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
{
- struct iio_buffer *buffer = indio_dev->buffer;
+ struct iio_buffer *b;

- if (!buffer)
+ if (list_empty(&indio_dev->attached_buffers))
return;

- wake_up(&buffer->pollq);
+ list_for_each_entry(b, &indio_dev->attached_buffers, attached_entry)
+ wake_up(&b->pollq);
}

void iio_buffer_init(struct iio_buffer *buffer)
@@ -1547,10 +1548,27 @@ static int iio_device_link_legacy_folders(struct iio_dev *indio_dev,
return ret;
}

+static void __iio_device_buffers_cleanup(struct iio_dev *indio_dev, int idx)
+{
+ struct iio_buffer *b;
+
+ if (list_empty(&indio_dev->attached_buffers))
+ return;
+
+ list_for_each_entry(b, &indio_dev->attached_buffers, attached_entry) {
+ if (idx == 0)
+ break;
+
+ iio_device_buffer_cleanup(b);
+ if (idx > 0)
+ idx--;
+ }
+}
+
int iio_device_buffers_init(struct iio_dev *indio_dev)
{
- struct iio_buffer *buffer = indio_dev->buffer;
const struct iio_chan_spec *channels;
+ struct iio_buffer *b;
int i, ret;

channels = indio_dev->channels;
@@ -1562,32 +1580,38 @@ int iio_device_buffers_init(struct iio_dev *indio_dev)
indio_dev->masklength = ml;
}

- if (!buffer)
+ if (list_empty(&indio_dev->attached_buffers))
return 0;

- ret = iio_device_buffer_init(indio_dev, buffer, 0);
- if (ret)
- return ret;
+ i = 0;
+ list_for_each_entry(b, &indio_dev->attached_buffers, attached_entry) {
+ ret = iio_device_buffer_init(indio_dev, b, i);
+ if (ret)
+ goto error_buffers_cleanup;

- ret = iio_device_link_legacy_folders(indio_dev, buffer);
- if (ret)
- goto error_buffers_cleanup;
+ if (i == 0) {
+ ret = iio_device_link_legacy_folders(indio_dev, b);
+ if (ret) {
+ iio_device_buffer_cleanup(b);
+ goto error_buffers_cleanup;
+ }
+ }
+ i++;
+ }

return 0;

error_buffers_cleanup:
- iio_device_buffer_cleanup(buffer);
- return 0;
+ __iio_device_buffers_cleanup(indio_dev, i);
+ return ret;
}

void iio_device_buffers_cleanup(struct iio_dev *indio_dev)
{
- struct iio_buffer *buffer = indio_dev->buffer;
-
sysfs_remove_link(&indio_dev->dev.kobj, "buffer");
sysfs_remove_link(&indio_dev->dev.kobj, "scan_elements");

- iio_device_buffer_cleanup(buffer);
+ __iio_device_buffers_cleanup(indio_dev, -1);
}

static const struct file_operations iio_buffer_fileops = {
@@ -1615,12 +1639,13 @@ void iio_device_buffer_attach_chrdev(struct iio_dev *indio_dev)

void iio_device_buffers_put(struct iio_dev *indio_dev)
{
- struct iio_buffer *buffer = indio_dev->buffer;
+ struct iio_buffer *b;

- if (!buffer)
+ if (list_empty(&indio_dev->attached_buffers))
return;

- iio_buffer_put(buffer);
+ list_for_each_entry(b, &indio_dev->attached_buffers, attached_entry)
+ iio_buffer_put(b);
}

/**
@@ -1733,7 +1758,7 @@ void iio_buffer_put(struct iio_buffer *buffer)
EXPORT_SYMBOL_GPL(iio_buffer_put);

/**
- * iio_device_attach_buffer - Attach a buffer to a IIO device
+ * iio_device_attach_buffer_dir - Attach a buffer to a IIO device direction
* @indio_dev: The device the buffer should be attached to
* @buffer: The buffer to attach to the device
*
@@ -1744,8 +1769,13 @@ EXPORT_SYMBOL_GPL(iio_buffer_put);
void iio_device_attach_buffer(struct iio_dev *indio_dev,
struct iio_buffer *buffer)
{
- indio_dev->buffer = iio_buffer_get(buffer);
+ buffer = iio_buffer_get(buffer);
+ buffer->indio_dev = indio_dev;
+
+ /* keep this for legacy */
+ if (!indio_dev->buffer)
+ indio_dev->buffer = buffer;

- indio_dev->buffer->indio_dev = indio_dev;
+ list_add_tail(&buffer->attached_entry, &indio_dev->attached_buffers);
}
EXPORT_SYMBOL_GPL(iio_device_attach_buffer);
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index b27fabf13e9c..067e5de76b6c 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1534,6 +1534,7 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
}
dev_set_name(&dev->dev, "iio:device%d", dev->id);
INIT_LIST_HEAD(&dev->buffer_list);
+ INIT_LIST_HEAD(&dev->attached_buffers);
INIT_LIST_HEAD(&dev->ioctl_handlers);

return dev;
diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h
index e8203b6d51a1..9ee3a7c0a657 100644
--- a/include/linux/iio/buffer_impl.h
+++ b/include/linux/iio/buffer_impl.h
@@ -130,6 +130,9 @@ struct iio_buffer {
/* @demux_bounce: Buffer for doing gather from incoming scan. */
void *demux_bounce;

+ /* @attached_buffers: Entry in the devices list of attached buffers. */
+ struct list_head attached_entry;
+
/* @buffer_list: Entry in the devices list of current buffers. */
struct list_head buffer_list;

diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 671f5818fa67..32ba1a303454 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -492,6 +492,7 @@ struct iio_buffer_setup_ops {
* @event_interface: [INTERN] event chrdevs associated with interrupt lines
* @buffer: [DRIVER] any buffer present
* @buffer_list: [INTERN] list of all buffers currently attached
+ * @attached_buffers: [INTERN] list of all attached buffers
* @scan_bytes: [INTERN] num bytes captured to be fed to buffer demux
* @mlock: [INTERN] lock used to prevent simultaneous device state
* changes
@@ -536,6 +537,7 @@ struct iio_dev {

struct iio_buffer *buffer;
struct list_head buffer_list;
+ struct list_head attached_buffers;
int scan_bytes;
struct mutex mlock;

--
2.17.1