Commit ee708e6b authored by Alexandru Ardelean's avatar Alexandru Ardelean Committed by Jonathan Cameron
Browse files

iio: buffer: introduce support for attaching more IIO buffers 



With this change, calling iio_device_attach_buffer() will actually attach
more buffers.
Right now this doesn't do any validation of whether a buffer is attached
twice; maybe that can be added later (if needed). Attaching a buffer more
than once should yield noticeably bad results.

The first buffer is the legacy buffer, so a reference is kept to it.

At this point, accessing the data for the extra buffers (that are added
after the first one) isn't possible yet.

The iio_device_attach_buffer() is also changed to return an error code,
which for now is -ENOMEM if the array could not be realloc-ed for more
buffers.
To adapt to this new change iio_device_attach_buffer() is called last in
all place where it's called. The realloc failure is a bit difficult to
handle during un-managed calls when unwinding, so it's better to have this
as the last error in the setup_buffer calls.

At this point, no driver should call iio_device_attach_buffer() directly,
it should call one of the {devm_}iio_triggered_buffer_setup() or
devm_iio_kfifo_buffer_setup() or devm_iio_dmaengine_buffer_setup()
functions. This makes iio_device_attach_buffer() a bit easier to handle.

Signed-off-by: default avatarAlexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210215104043.91251-20-alexandru.ardelean@analog.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 738f6ba1

drivers/iio/buffer/industrialio-buffer-dmaengine.c

+1 −3
Original line number Diff line number Diff line
@@ -290,9 +290,7 @@ int devm_iio_dmaengine_buffer_setup(struct device *dev, 


	indio_dev->modes |= INDIO_BUFFER_HARDWARE;



	iio_device_attach_buffer(indio_dev, buffer);



	return 0;

	return iio_device_attach_buffer(indio_dev, buffer);

}

EXPORT_SYMBOL_GPL(devm_iio_dmaengine_buffer_setup);

drivers/iio/buffer/industrialio-triggered-buffer.c

+7 −3
Original line number Diff line number Diff line
@@ -50,8 +50,6 @@ int iio_triggered_buffer_setup_ext(struct iio_dev *indio_dev, 
		goto error_ret;

	}



	iio_device_attach_buffer(indio_dev, buffer);



	indio_dev->pollfunc = iio_alloc_pollfunc(h,

						 thread,

						 IRQF_ONESHOT,
@@ -72,10 +70,16 @@ int iio_triggered_buffer_setup_ext(struct iio_dev *indio_dev, 


	buffer->attrs = buffer_attrs;



	ret = iio_device_attach_buffer(indio_dev, buffer);

	if (ret < 0)

		goto error_dealloc_pollfunc;



	return 0;



error_dealloc_pollfunc:

	iio_dealloc_pollfunc(indio_dev->pollfunc);

error_kfifo_free:

	iio_kfifo_free(indio_dev->buffer);

	iio_kfifo_free(buffer);

error_ret:

	return ret;

}

drivers/iio/buffer/kfifo_buf.c

+1 −3
Original line number Diff line number Diff line
@@ -235,12 +235,10 @@ int devm_iio_kfifo_buffer_setup(struct device *dev, 
	if (!buffer)

		return -ENOMEM;



	iio_device_attach_buffer(indio_dev, buffer);



	indio_dev->modes |= mode_flags;

	indio_dev->setup_ops = setup_ops;



	return 0;

	return iio_device_attach_buffer(indio_dev, buffer);

}

EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup);

drivers/iio/iio_core.h

+6 −4
Original line number Diff line number Diff line
@@ -69,29 +69,31 @@ __poll_t iio_buffer_poll(struct file *filp, 
ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,

			      size_t n, loff_t *f_ps);



int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev);

void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev);

int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev);

void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev);



#define iio_buffer_poll_addr (&iio_buffer_poll)

#define iio_buffer_read_outer_addr (&iio_buffer_read_outer)



void iio_disable_all_buffers(struct iio_dev *indio_dev);

void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);

void iio_buffers_put(struct iio_dev *indio_dev);



#else



#define iio_buffer_poll_addr NULL

#define iio_buffer_read_outer_addr NULL



static inline int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)

static inline int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)

{

	return 0;

}



static inline void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) {}

static inline void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev) {}



static inline void iio_disable_all_buffers(struct iio_dev *indio_dev) {}

static inline void iio_buffer_wakeup_poll(struct iio_dev *indio_dev) {}

static inline void iio_buffers_put(struct iio_dev *indio_dev) {}



#endif

drivers/iio/industrialio-buffer.c

+81 −19
Original line number Diff line number Diff line
@@ -193,13 +193,15 @@ __poll_t iio_buffer_poll(struct file *filp, 
 */

void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)

{

	struct iio_buffer *buffer = indio_dev->buffer;



	if (!buffer)

		return;

	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

	struct iio_buffer *buffer;

	unsigned int i;



	for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {

		buffer = iio_dev_opaque->attached_buffers[i];

		wake_up(&buffer->pollq);

	}

}



void iio_buffer_init(struct iio_buffer *buffer)

{
@@ -212,6 +214,18 @@ void iio_buffer_init(struct iio_buffer *buffer) 
}

EXPORT_SYMBOL(iio_buffer_init);



void iio_buffers_put(struct iio_dev *indio_dev)

{

	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

	struct iio_buffer *buffer;

	unsigned int i;



	for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {

		buffer = iio_dev_opaque->attached_buffers[i];

		iio_buffer_put(buffer);

	}

}



static ssize_t iio_show_scan_index(struct device *dev,

				   struct device_attribute *attr,

				   char *buf)
@@ -1452,11 +1466,13 @@ static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer) 
	iio_free_chan_devattr_list(&buffer->buffer_attr_list);

}



int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)

int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)

{

	struct iio_buffer *buffer = indio_dev->buffer;

	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

	const struct iio_chan_spec *channels;

	int i;

	struct iio_buffer *buffer;

	int unwind_idx;

	int ret, i;



	channels = indio_dev->channels;

	if (channels) {
@@ -1467,24 +1483,48 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) 
		indio_dev->masklength = ml;

	}



	if (!buffer)

	if (!iio_dev_opaque->attached_buffers_cnt)

		return 0;



	for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {

		buffer = iio_dev_opaque->attached_buffers[i];

		ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, i);

		if (ret) {

			unwind_idx = i;

			goto error_unwind_sysfs_and_mask;

		}

	}



	return 0;



	return __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, 0);

error_unwind_sysfs_and_mask:

	for (; unwind_idx >= 0; unwind_idx--) {

		buffer = iio_dev_opaque->attached_buffers[unwind_idx];

		__iio_buffer_free_sysfs_and_mask(buffer);

	}

	kfree(iio_dev_opaque->attached_buffers);

	return ret;

}



void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)

void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev)

{

	struct iio_buffer *buffer = indio_dev->buffer;

	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

	struct iio_buffer *buffer;

	int i;



	if (!buffer)

	if (!iio_dev_opaque->attached_buffers_cnt)

		return;



	iio_buffer_unregister_legacy_sysfs_groups(indio_dev);



	for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {

		buffer = iio_dev_opaque->attached_buffers[i];

		__iio_buffer_free_sysfs_and_mask(buffer);

	}



	kfree(iio_dev_opaque->attached_buffers);

}



/**

 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected

 * @indio_dev: the iio device
@@ -1600,13 +1640,35 @@ EXPORT_SYMBOL_GPL(iio_buffer_put); 
 * @indio_dev: The device the buffer should be attached to

 * @buffer: The buffer to attach to the device

 *

 * Return 0 if successful, negative if error.

 *

 * This function attaches a buffer to a IIO device. The buffer stays attached to

 * the device until the device is freed. The function should only be called at

 * most once per device.

 * the device until the device is freed. For legacy reasons, the first attached

 * buffer will also be assigned to 'indio_dev->buffer'.

 */

void iio_device_attach_buffer(struct iio_dev *indio_dev,

int iio_device_attach_buffer(struct iio_dev *indio_dev,

			     struct iio_buffer *buffer)

{

	indio_dev->buffer = iio_buffer_get(buffer);

	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

	struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers;

	unsigned int cnt = iio_dev_opaque->attached_buffers_cnt;



	cnt++;



	new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL);

	if (!new)

		return -ENOMEM;

	iio_dev_opaque->attached_buffers = new;



	buffer = iio_buffer_get(buffer);



	/* first buffer is legacy; attach it to the IIO device directly */

	if (!indio_dev->buffer)

		indio_dev->buffer = buffer;



	iio_dev_opaque->attached_buffers[cnt - 1] = buffer;

	iio_dev_opaque->attached_buffers_cnt = cnt;



	return 0;

}

EXPORT_SYMBOL_GPL(iio_device_attach_buffer);