Re: [alsa-devel] [PATCH v4 01/12] iio: Add hardware consumer buffer support

On Thu, 9 Nov 2017 11:12:23 +0100 Arnaud Pouliquen arnaud.pouliquen@st.com wrote:

From: Lars-Peter Clausen lars@metafoo.de

Hardware consumer interface can be used when one IIO device has a direct connection to another device in hardware.

Signed-off-by: Lars-Peter Clausen lars@metafoo.de Signed-off-by: Arnaud Pouliquen arnaud.pouliquen@st.com

I think this is fine though it is something we will have to keep an eye on to make sure it is appropriately used...

Jonathan

---

drivers/iio/buffer/Kconfig | 10 ++ drivers/iio/buffer/Makefile | 1 + drivers/iio/buffer/industrialio-hw-consumer.c | 182 ++++++++++++++++++++++++++ include/linux/iio/hw-consumer.h | 20 +++ 4 files changed, 213 insertions(+) create mode 100644 drivers/iio/buffer/industrialio-hw-consumer.c create mode 100644 include/linux/iio/hw-consumer.h

diff --git a/drivers/iio/buffer/Kconfig b/drivers/iio/buffer/Kconfig index 4ffd3db..338774c 100644 --- a/drivers/iio/buffer/Kconfig +++ b/drivers/iio/buffer/Kconfig @@ -29,6 +29,16 @@ config IIO_BUFFER_DMAENGINE

 Should be selected by drivers that want to use this functionality.

+config IIO_BUFFER_HW_CONSUMER

• tristate "Industrial I/O HW buffering"
• help

•  Provides a way to bonding when an IIO device has a direct connection
  

•  to another device in hardware. In this case buffers for data transfers
  

•  are handled by hardware.
  

•  Should be selected by drivers that want to use the generic Hw consumer
  

•  interface.
  

config IIO_KFIFO_BUF tristate "Industrial I/O buffering based on kfifo" help diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile index 85beaae..324a36b 100644 --- a/drivers/iio/buffer/Makefile +++ b/drivers/iio/buffer/Makefile @@ -6,5 +6,6 @@ obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o obj-$(CONFIG_IIO_BUFFER_DMA) += industrialio-buffer-dma.o obj-$(CONFIG_IIO_BUFFER_DMAENGINE) += industrialio-buffer-dmaengine.o +obj-$(CONFIG_IIO_BUFFER_HW_CONSUMER) += industrialio-hw-consumer.o obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o diff --git a/drivers/iio/buffer/industrialio-hw-consumer.c b/drivers/iio/buffer/industrialio-hw-consumer.c new file mode 100644 index 0000000..7d4d800 --- /dev/null +++ b/drivers/iio/buffer/industrialio-hw-consumer.c @@ -0,0 +1,182 @@ +/*

• • Copyright 2017 Analog Devices Inc.
• • Author: Lars-Peter Clausen lars@metafoo.de
• • Licensed under the GPL-2 or later.
• */

+#include <linux/err.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/module.h>

+#include <linux/iio/iio.h> +#include <linux/iio/consumer.h> +#include <linux/iio/hw-consumer.h> +#include <linux/iio/buffer_impl.h>

+/**

• • struct iio_hw_consumer - IIO hw consumer block
• • @buffers: hardware buffers list head.
• • @channels: IIO provider channels.
• */

+struct iio_hw_consumer {

• struct list_head buffers;
• struct iio_channel *channels;

+};

+struct hw_consumer_buffer {

• struct list_head head;
• struct iio_dev *indio_dev;
• struct iio_buffer buffer;
• long scan_mask[];

+};

+static struct hw_consumer_buffer *iio_buffer_to_hw_consumer_buffer(

• struct iio_buffer *buffer)

+{

• return container_of(buffer, struct hw_consumer_buffer, buffer);

+}

+static void iio_hw_buf_release(struct iio_buffer *buffer) +{

• struct hw_consumer_buffer *hw_buf =

• iio_buffer_to_hw_consumer_buffer(buffer);
  

• kfree(hw_buf);

+}

+static const struct iio_buffer_access_funcs iio_hw_buf_access = {

• .release = &iio_hw_buf_release,
• .modes = INDIO_BUFFER_HARDWARE,

+};

+static struct hw_consumer_buffer *iio_hw_consumer_get_buffer(

• struct iio_hw_consumer *hwc, struct iio_dev *indio_dev)

+{

• size_t mask_size = BITS_TO_LONGS(indio_dev->masklength) * sizeof(long);
• struct hw_consumer_buffer *buf;
• list_for_each_entry(buf, &hwc->buffers, head) {

• if (buf->indio_dev == indio_dev)
  

• 	return buf;
  

• }
• buf = kzalloc(sizeof(*buf) + mask_size, GFP_KERNEL);
• if (!buf)

• return NULL;
  

• buf->buffer.access = &iio_hw_buf_access;
• buf->indio_dev = indio_dev;
• buf->buffer.scan_mask = buf->scan_mask;
• iio_buffer_init(&buf->buffer);
• list_add_tail(&buf->head, &hwc->buffers);
• return buf;

+}

+/**

• • iio_hw_consumer_alloc() - Allocate IIO hardware consumer
• • @dev: Pointer to consumer device.
• • Returns a valid iio_hw_consumer on success or a ERR_PTR() on failure.
• */

+struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev) +{

• struct hw_consumer_buffer *buf;
• struct iio_hw_consumer *hwc;
• struct iio_channel *chan;
• int ret;
• hwc = kzalloc(sizeof(*hwc), GFP_KERNEL);
• if (!hwc)

• return ERR_PTR(-ENOMEM);
  

• INIT_LIST_HEAD(&hwc->buffers);
• hwc->channels = iio_channel_get_all(dev);
• if (IS_ERR(hwc->channels)) {

• ret = PTR_ERR(hwc->channels);
  

• goto err_free_hwc;
  

• }
• chan = &hwc->channels[0];
• while (chan->indio_dev) {

• buf = iio_hw_consumer_get_buffer(hwc, chan->indio_dev);
  

• if (!buf) {
  

• 	ret = -ENOMEM;
  

• 	goto err_put_buffers;
  

• }
  

• set_bit(chan->channel->scan_index, buf->buffer.scan_mask);
  

• chan++;
  

• }
• return hwc;

+err_put_buffers:

• list_for_each_entry(buf, &hwc->buffers, head)

• iio_buffer_put(&buf->buffer);
  

• iio_channel_release_all(hwc->channels);

+err_free_hwc:

• kfree(hwc);
• return ERR_PTR(ret);

+} +EXPORT_SYMBOL_GPL(iio_hw_consumer_alloc);

+/**

• • iio_hw_consumer_free() - Free IIO hardware consumer
• • @hwc: hw consumer to free.
• */

+void iio_hw_consumer_free(struct iio_hw_consumer *hwc) +{

• struct hw_consumer_buffer *buf;
• iio_channel_release_all(hwc->channels);
• list_for_each_entry(buf, &hwc->buffers, head)

• iio_buffer_put(&buf->buffer);
  

• kfree(hwc);

+} +EXPORT_SYMBOL_GPL(iio_hw_consumer_free);

+/**

• • iio_hw_consumer_enable() - Enable IIO hardware consumer
• • @hwc: iio_hw_consumer to enable.
• • Returns 0 on success.
• */

+int iio_hw_consumer_enable(struct iio_hw_consumer *hwc) +{

• struct hw_consumer_buffer *buf;
• int ret;
• list_for_each_entry(buf, &hwc->buffers, head) {

• ret = iio_update_buffers(buf->indio_dev, &buf->buffer, NULL);
  

• if (ret)
  

• 	goto err_disable_buffers;
  

• }
• return 0;

+err_disable_buffers:

• list_for_each_entry_continue_reverse(buf, &hwc->buffers, head)

• iio_update_buffers(buf->indio_dev, NULL, &buf->buffer);
  

• return ret;

+} +EXPORT_SYMBOL_GPL(iio_hw_consumer_enable);

+/**

• • iio_hw_consumer_disable() - Disable IIO hardware consumer
• • @hwc: iio_hw_consumer to disable.
• */

+void iio_hw_consumer_disable(struct iio_hw_consumer *hwc) +{

• struct hw_consumer_buffer *buf;
• list_for_each_entry(buf, &hwc->buffers, head)

• iio_update_buffers(buf->indio_dev, NULL, &buf->buffer);
  

+} +EXPORT_SYMBOL_GPL(iio_hw_consumer_disable);

+MODULE_AUTHOR("Lars-Peter Clausen lars@metafoo.de"); +MODULE_DESCRIPTION("Hardware consumer buffer the IIO framework"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/iio/hw-consumer.h b/include/linux/iio/hw-consumer.h new file mode 100644 index 0000000..f16791b --- /dev/null +++ b/include/linux/iio/hw-consumer.h @@ -0,0 +1,20 @@ +/*

• • Industrial I/O in kernel hardware consumer interface
• • Copyright 2017 Analog Devices Inc.
• • Author: Lars-Peter Clausen lars@metafoo.de
• • Licensed under the GPL-2 or later.
• */

+#ifndef LINUX_IIO_HW_CONSUMER_H +#define LINUX_IIO_HW_CONSUMER_H

+struct iio_hw_consumer;

+struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev); +void iio_hw_consumer_free(struct iio_hw_consumer *hwc); +int iio_hw_consumer_enable(struct iio_hw_consumer *hwc); +void iio_hw_consumer_disable(struct iio_hw_consumer *hwc);

+#endif