Subject: [PATCH v6 01/13] iio: Add hardware consumer buffer support

From: [email-masked] (Jonathan Cameron)
Date: Sat, 2 Dec 2017 14:50:56 +0000

On Fri, 1 Dec 2017 18:40:08 +0100
Arnaud Pouliquen <[email-masked]> wrote:

> From: Lars-Peter Clausen <[email-masked]>
> 
> Hardware consumer interface can be used when one IIO device has
> a direct connection to another device in hardware.

Given I'm not totally sure who will do the immutable branch I'm going
to starting adding tags to make it clear what I'm happy with.
(might rip them off again if I end up handling the final merge)
> 
> Signed-off-by: Lars-Peter Clausen <[email-masked]>
> Signed-off-by: Arnaud Pouliquen <[email-masked]>

Reviewed-by: Jonathan Cameron <[email-masked]>

> ---
>  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..0253be1
> --- /dev/null
> +++ b/drivers/iio/buffer/industrialio-hw-consumer.c
> @@ -0,0 +1,182 @@
> +/*
> + * Copyright 2017 Analog Devices Inc.
> + *  Author: Lars-Peter Clausen <[email-masked]>
> + *
> + * 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, *n;
> +
> +	iio_channel_release_all(hwc->channels);
> +	list_for_each_entry_safe(buf, n, &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 <[email-masked]>");
> +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 <[email-masked]>
> + *
> + * 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