On Tue, Feb 13, 2018 at 3:24 AM, Wu Hao <hao.wu@xxxxxxxxx> wrote:
Hi Hao,
> This patch introduces a compat_id member and sysfs interface for each
> fpga-region, e.g userspace applications could read the compat_id
> from the sysfs interface for compatibility checking before PR.
>
> Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-class-fpga-region | 5 +++++
> drivers/fpga/fpga-region.c | 19 +++++++++++++++++++
> include/linux/fpga/fpga-region.h | 13 +++++++++++++
> 3 files changed, 37 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-class-fpga-region
>
> diff --git a/Documentation/ABI/testing/sysfs-class-fpga-region b/Documentation/ABI/testing/sysfs-class-fpga-region
> new file mode 100644
> index 0000000..419d930
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-fpga-region
> @@ -0,0 +1,5 @@
> +What: /sys/class/fpga_region/<region>/compat_id
> +Date: February 2018
> +KernelVersion: 4.16
> +Contact: Wu Hao <hao.wu@xxxxxxxxx>
> +Description: FPGA region id for compatibility check.
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index 660a91b..babec96 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -162,6 +162,24 @@ int fpga_region_program_fpga(struct fpga_region *region)
> }
> EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
>
> +static ssize_t compat_id_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct fpga_region *region = to_fpga_region(dev);
This looks good, but not all users of FPGA are going to use compat_id.
How would you feel about making it a pointer in struct fpga_region?
With compat_id as a pointer, could check for non-null compat_id
pointer and return an error if it wasn't initialized.
> +
> + return sprintf(buf, "%016llx%016llx\n",
> + (unsigned long long)region->compat_id.id_h,
> + (unsigned long long)region->compat_id.id_l);
> +}
> +
> +static DEVICE_ATTR_RO(compat_id);
> +
> +static struct attribute *fpga_region_attrs[] = {
> + &dev_attr_compat_id.attr,
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(fpga_region);
> +
> int fpga_region_register(struct fpga_region *region)
> {
> struct device *dev = region->parent;
> @@ -226,6 +244,7 @@ static int __init fpga_region_init(void)
> if (IS_ERR(fpga_region_class))
> return PTR_ERR(fpga_region_class);
>
> + fpga_region_class->dev_groups = fpga_region_groups;
> fpga_region_class->dev_release = fpga_region_dev_release;
>
> return 0;
> diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
> index 423c87e..bf97dcc 100644
> --- a/include/linux/fpga/fpga-region.h
> +++ b/include/linux/fpga/fpga-region.h
> @@ -6,6 +6,17 @@
> #include <linux/fpga/fpga-bridge.h>
>
> /**
> + * struct fpga_region_compat_id - FPGA Region id for compatibility check
> + *
> + * @id_h: high 64bit of the compat_id
> + * @id_l: low 64bit of the compat_id
> + */
> +struct fpga_region_compat_id {
> + u64 id_h;
> + u64 id_l;
I guess each user will choose how to define these bits.
> +};
> +
> +/**
> * struct fpga_region - FPGA Region structure
> * @dev: FPGA Region device
> * @parent: parent device
> @@ -13,6 +24,7 @@
> * @bridge_list: list of FPGA bridges specified in region
> * @mgr: FPGA manager
> * @info: FPGA image info
> + * @compat_id: FPGA region id for compatibility check.
> * @priv: private data
> * @get_bridges: optional function to get bridges to a list
> * @groups: optional attribute groups.
> @@ -24,6 +36,7 @@ struct fpga_region {
> struct list_head bridge_list;
> struct fpga_manager *mgr;
> struct fpga_image_info *info;
> + struct fpga_region_compat_id compat_id;
Here it would be a pointer instead.
Alan
> void *priv;
> int (*get_bridges)(struct fpga_region *region);
> const struct attribute_group **groups;
> --
> 2.7.4
>
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