On Fri, 5 Feb 2021 14:57:29 +0200 Alexandru Ardelean <ardeleanalex@xxxxxxxxx> wrote: > On Fri, Feb 5, 2021 at 2:40 PM Jonathan Cameron > <Jonathan.Cameron@xxxxxxxxxx> wrote: > > > > On Fri, 5 Feb 2021 11:17:04 +0200 > > Alexandru Ardelean <ardeleanalex@xxxxxxxxx> wrote: > > > > > On Thu, Feb 4, 2021 at 8:26 PM Jonathan Cameron > > > <Jonathan.Cameron@xxxxxxxxxx> wrote: > > > > > > > > On Mon, 1 Feb 2021 16:51:02 +0200 > > > > Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote: > > > > > > > > > This change wraps all buffer attributes into iio_dev_attr objects, and > > > > > assigns a reference to the IIO buffer they belong to. > > > > > > > > > > With the addition of multiple IIO buffers per one IIO device, we need a way > > > > > to know which IIO buffer is being enabled/disabled/controlled. > > > > > > > > > > We know that all buffer attributes are device_attributes. So we can wrap > > > > > them with a iio_dev_attr types. In the iio_dev_attr type, we can also hold > > > > > a reference to an IIO buffer. > > > > > So, we end up being able to allocate wrapped attributes for all buffer > > > > > attributes (even the one from other drivers). > > > > > > > > > > The neat part with this mechanism, is that we don't need to add any extra > > > > > cleanup, because these attributes are being added to a dynamic list that > > > > > will get cleaned up via iio_free_chan_devattr_list(). > > > > > > > > > > > > > > > > > > With this change, the 'buffer->scan_el_dev_attr_list' list is being renamed > > > > > to 'buffer->buffer_attr_list', effectively merging (or finalizing the > > > > > merge) of the buffer/ & scan_elements/ attributes internally. > > > > > > > > > > Accessing these new buffer attributes can now be done via > > > > > 'to_iio_dev_attr(attr)->buffer' inside the show/store handlers. > > > > > > > > That is going to look a bit odd in any drivers that use it given they > > > > will appear to not be embedded. > > > > > > > > There seem to be very few such attributes from a quick grep, so maybe > > > > we may want to unwind this and change all the types. Might still need > > > > to set .buffer for some of them though (only applying to new drivers as > > > > clearly current ones don't care!) > > > > > > > > Looking at what they actually are, some perhaps shouldn't have been in the buffer > > > > directory in the first place (with hindsight!). > > > > > > > > Anyhow, aside from that oddity this looks good to me. > > > > > > I'm a little vague here. > > > If there is a suggestion for a change, I may have missed it. > > > > It was vague because I wasn't sure if it it made sense :) > > > > > > I'm a bit vague on the part of "we may want to unwind this and change > > > all the types" > > > Is it referring to something like this patch? > > > https://lore.kernel.org/linux-iio/20210122162529.84978-10-alexandru.ardelean@xxxxxxxxxx/ > > > > Exactly, that was what I was wondering about. > > So, from a perspective of API for drivers, it would probably make > sense to have those sort of store/show hook types. > But I am leaning towards maybe moving the HW fifo stuff into IIO core somehow. > Which would make these [new] store/show hooks unneeded [for now at least]. Agreed. It probably makes sense to look at pulling these into the core. When we first did this I was a little unsure how common these would be but now it's been a while we know they do occur on multiple devices (even if not that many of them!) > > > > > > We could do a show/store version that takes an iio_buf_attr or > > > iio_dev_attr parameter. > > > But maybe at a later point? > > > I don't feel it adds much benefit over the current usage of > > > buffer->attrs, because we need to kmalloc these iio_dev_attr anyways > > > to store the reference to the iio_buffer. > > > > > > I would have liked to get rid of these user/external buffer->attrs. > > > That would have made things easier. > > > > > > But, it looks like there are several drivers using them. > > > I usually find them by grepping for iio_triggered_buffer_setup_ext > > > It's only 5 drivers that provide these attributes. > > > It used to be a bit easier to find them by grepping > > > iio_buffer_set_attrs(), but I removed that. > > > > We could look at whether some can be brought into the core. They tend > > to be around hwfifo parameters. Those could be specific to individual > > buffers rather than device wide so at least some of them are correctly > > placed in the buffer directory (I think - I've argued with myself about > > this a few times in the past). > > I think they could be brought into core. > But they would take some time (because of testing) > These HW Fifo attributes were copied around between drivers and ended > being the same. > So, some IIO core logic would make sense. It's 5 drivers now. Agree entirely. This is ready for some tidying up, but not a quick job as you say because of testing so let us leave it for now. (better things to be doing :) > > > > > The only oddity we'll get from current approach is callbacks appearing > > to access a container structure that they aren't associated with in the > > driver. Its the sort of interface that no one would ever realize was > > possible. > > > > Jonathan > > > > > > > > > > > > > > > > Jonathan > > > > > > > > > > > > > > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > > > > > --- > > > > > drivers/iio/industrialio-buffer.c | 66 +++++++++++++++++++++---------- > > > > > include/linux/iio/buffer_impl.h | 4 +- > > > > > 2 files changed, 48 insertions(+), 22 deletions(-) > > > > > > > > > > diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c > > > > > index a525e88b302f..49996bed5f4c 100644 > > > > > --- a/drivers/iio/industrialio-buffer.c > > > > > +++ b/drivers/iio/industrialio-buffer.c > > > > > @@ -448,7 +448,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev, > > > > > IIO_SEPARATE, > > > > > &indio_dev->dev, > > > > > buffer, > > > > > - &buffer->scan_el_dev_attr_list); > > > > > + &buffer->buffer_attr_list); > > > > > if (ret) > > > > > return ret; > > > > > attrcount++; > > > > > @@ -460,7 +460,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev, > > > > > 0, > > > > > &indio_dev->dev, > > > > > buffer, > > > > > - &buffer->scan_el_dev_attr_list); > > > > > + &buffer->buffer_attr_list); > > > > > if (ret) > > > > > return ret; > > > > > attrcount++; > > > > > @@ -473,7 +473,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev, > > > > > 0, > > > > > &indio_dev->dev, > > > > > buffer, > > > > > - &buffer->scan_el_dev_attr_list); > > > > > + &buffer->buffer_attr_list); > > > > > else > > > > > ret = __iio_add_chan_devattr("en", > > > > > chan, > > > > > @@ -483,7 +483,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev, > > > > > 0, > > > > > &indio_dev->dev, > > > > > buffer, > > > > > - &buffer->scan_el_dev_attr_list); > > > > > + &buffer->buffer_attr_list); > > > > > if (ret) > > > > > return ret; > > > > > attrcount++; > > > > > @@ -495,8 +495,7 @@ static ssize_t iio_buffer_read_length(struct device *dev, > > > > > struct device_attribute *attr, > > > > > char *buf) > > > > > { > > > > > - struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > > > > > > return sprintf(buf, "%d\n", buffer->length); > > > > > } > > > > > @@ -506,7 +505,7 @@ static ssize_t iio_buffer_write_length(struct device *dev, > > > > > const char *buf, size_t len) > > > > > { > > > > > struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > unsigned int val; > > > > > int ret; > > > > > > > > > > @@ -538,8 +537,7 @@ static ssize_t iio_buffer_show_enable(struct device *dev, > > > > > struct device_attribute *attr, > > > > > char *buf) > > > > > { > > > > > - struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > > > > > > return sprintf(buf, "%d\n", iio_buffer_is_active(buffer)); > > > > > } > > > > > @@ -1154,7 +1152,7 @@ static ssize_t iio_buffer_store_enable(struct device *dev, > > > > > int ret; > > > > > bool requested_state; > > > > > struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > bool inlist; > > > > > > > > > > ret = strtobool(buf, &requested_state); > > > > > @@ -1185,8 +1183,7 @@ static ssize_t iio_buffer_show_watermark(struct device *dev, > > > > > struct device_attribute *attr, > > > > > char *buf) > > > > > { > > > > > - struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > > > > > > return sprintf(buf, "%u\n", buffer->watermark); > > > > > } > > > > > @@ -1197,7 +1194,7 @@ static ssize_t iio_buffer_store_watermark(struct device *dev, > > > > > size_t len) > > > > > { > > > > > struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > unsigned int val; > > > > > int ret; > > > > > > > > > > @@ -1230,8 +1227,7 @@ static ssize_t iio_dma_show_data_available(struct device *dev, > > > > > struct device_attribute *attr, > > > > > char *buf) > > > > > { > > > > > - struct iio_dev *indio_dev = dev_to_iio_dev(dev); > > > > > - struct iio_buffer *buffer = indio_dev->buffer; > > > > > + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; > > > > > > > > > > return sprintf(buf, "%zu\n", iio_buffer_data_available(buffer)); > > > > > } > > > > > @@ -1256,6 +1252,26 @@ static struct attribute *iio_buffer_attrs[] = { > > > > > &dev_attr_data_available.attr, > > > > > }; > > > > > > > > > > +#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) > > > > > + > > > > > +static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer, > > > > > + struct attribute *attr) > > > > > +{ > > > > > + struct device_attribute *dattr = to_dev_attr(attr); > > > > > + struct iio_dev_attr *iio_attr; > > > > > + > > > > > + iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL); > > > > > + if (!iio_attr) > > > > > + return NULL; > > > > > + > > > > > + iio_attr->buffer = buffer; > > > > > + memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr)); > > > > > + > > > > > + list_add(&iio_attr->l, &buffer->buffer_attr_list); > > > > > + > > > > > + return &iio_attr->dev_attr.attr; > > > > > +} > > > > > + > > > > > static int iio_buffer_register_legacy_sysfs_groups(struct iio_dev *indio_dev, > > > > > struct attribute **buffer_attrs, > > > > > int buffer_attrcount, > > > > > @@ -1331,7 +1347,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer, > > > > > } > > > > > > > > > > scan_el_attrcount = 0; > > > > > - INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list); > > > > > + INIT_LIST_HEAD(&buffer->buffer_attr_list); > > > > > channels = indio_dev->channels; > > > > > if (channels) { > > > > > /* new magic */ > > > > > @@ -1378,9 +1394,19 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer, > > > > > > > > > > buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs); > > > > > > > > > > - attrn = buffer_attrcount; > > > > > + for (i = 0; i < buffer_attrcount; i++) { > > > > > + struct attribute *wrapped; > > > > > + > > > > > + wrapped = iio_buffer_wrap_attr(buffer, attr[i]); > > > > > + if (!wrapped) { > > > > > + ret = -ENOMEM; > > > > > + goto error_free_scan_mask; > > > > > + } > > > > > + attr[i] = wrapped; > > > > > + } > > > > > > > > > > - list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l) > > > > > + attrn = 0; > > > > > + list_for_each_entry(p, &buffer->buffer_attr_list, l) > > > > > attr[attrn++] = &p->dev_attr.attr; > > > > > > > > > > buffer->buffer_group.name = kasprintf(GFP_KERNEL, "buffer%d", index); > > > > > @@ -1412,7 +1438,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer, > > > > > error_free_scan_mask: > > > > > bitmap_free(buffer->scan_mask); > > > > > error_cleanup_dynamic: > > > > > - iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list); > > > > > + iio_free_chan_devattr_list(&buffer->buffer_attr_list); > > > > > > > > > > return ret; > > > > > } > > > > > @@ -1443,7 +1469,7 @@ static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer) > > > > > bitmap_free(buffer->scan_mask); > > > > > kfree(buffer->buffer_group.name); > > > > > kfree(buffer->buffer_group.attrs); > > > > > - iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list); > > > > > + iio_free_chan_devattr_list(&buffer->buffer_attr_list); > > > > > } > > > > > > > > > > void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev) > > > > > diff --git a/include/linux/iio/buffer_impl.h b/include/linux/iio/buffer_impl.h > > > > > index 3e555e58475b..41044320e581 100644 > > > > > --- a/include/linux/iio/buffer_impl.h > > > > > +++ b/include/linux/iio/buffer_impl.h > > > > > @@ -97,8 +97,8 @@ struct iio_buffer { > > > > > /* @scan_timestamp: Does the scan mode include a timestamp. */ > > > > > bool scan_timestamp; > > > > > > > > > > - /* @scan_el_dev_attr_list: List of scan element related attributes. */ > > > > > - struct list_head scan_el_dev_attr_list; > > > > > + /* @buffer_attr_list: List of buffer attributes. */ > > > > > + struct list_head buffer_attr_list; > > > > > > > > > > /* > > > > > * @buffer_group: Attributes of the new buffer group. > > > > > >
