Re: [PATCH v3 11/21] fpga: dfl: fme: add header sub feature support

[Alan Tull <atull@kernel.org>]

On Mon, Nov 27, 2017 at 12:42 AM, Wu Hao <hao.wu@intel.com> wrote:
> From: Kang Luwei <luwei.kang@intel.com>
>
> The header register set is always present for FPGA Management Engine (FME),
> this patch implements init and uinit function for header sub feature and
> introduce several read-only sysfs interfaces for the capability and status.
>
> Sysfs interfaces:
> * /sys/class/fpga_region/<regionX>/<fpga-dfl-fme.x>/ports_num
>   Read-only. Number of ports implemented
>
> * /sys/class/fpga_region/<regionX>/<fpga-dfl-fme.x>/bitstream_id
>   Read-only. Blue Bitstream (static FPGA region) identifier number
>
> * /sys/class/fpga_region/<regionX>/<fpga-dfl-fme.x>/bitstream_metadata
>   Read-only. Blue Bitstream (static FPGA region) meta data

Please document the meta data.  I don't see anywhere that describes it
or how it differs from the bitstream_id.  So it could be useful to
document it in this header a bit, and in the code, in the sysfs
document, and in the Documentation/fpga so that people don't have to
go hunting.

We discussed elsewhere the static region bitstream_id verses the other
interface_ids, so that's been discussed.

Besides that, this patch looks good and straightforward.

Thanks,
Alan

>
> Signed-off-by: Tim Whisonant <tim.whisonant@intel.com>
> Signed-off-by: Enno Luebbers <enno.luebbers@intel.com>
> Signed-off-by: Shiva Rao <shiva.rao@intel.com>
> Signed-off-by: Christopher Rauer <christopher.rauer@intel.com>
> Signed-off-by: Kang Luwei <luwei.kang@intel.com>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> Signed-off-by: Wu Hao <hao.wu@intel.com>
> ----
> v2: add sysfs documentation
> v3: rename driver to fpga-dfl-fme.
>     improve sysfs doc and commit description.
>     replace bitfield.
> ---
>  .../ABI/testing/sysfs-platform-fpga-dfl-fme        | 21 ++++++++
>  drivers/fpga/dfl-fme-main.c                        | 60 ++++++++++++++++++++++
>  2 files changed, 81 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme
>
> diff --git a/Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme b/Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme
> new file mode 100644
> index 0000000..6b32799
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme
> @@ -0,0 +1,21 @@
> +What:          /sys/bus/platform/devices/fpga-dfl-fme.0/ports_num
> +Date:          November 2017
> +KernelVersion:  4.15
> +Contact:       Wu Hao <hao.wu@intel.com>
> +Description:   Read-only. One DFL FPGA device may have more than 1
> +               port/Accelerator Function Unit (AFU). It returns the
> +               number of ports on the FPGA device when read it.
> +
> +What:          /sys/bus/platform/devices/fpga-dfl-fme.0/bitstream_id
> +Date:          November 2017
> +KernelVersion:  4.15
> +Contact:       Wu Hao <hao.wu@intel.com>
> +Description:   Read-only. It returns Blue Bitstream (static FPGA region)
> +               identifier number.
> +
> +What:          /sys/bus/platform/devices/fpga-dfl-fme.0/bitstream_meta
> +Date:          November 2017
> +KernelVersion:  4.15
> +Contact:       Wu Hao <hao.wu@intel.com>
> +Description:   Read-only. It returns Blue Bitstream (static FPGA region)
> +               meta data.
> diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
> index f7b5f7d..d17c66a 100644
> --- a/drivers/fpga/dfl-fme-main.c
> +++ b/drivers/fpga/dfl-fme-main.c
> @@ -21,9 +21,68 @@
>
>  #include "fpga-dfl.h"
>
> +static ssize_t ports_num_show(struct device *dev,
> +                             struct device_attribute *attr, char *buf)
> +{
> +       void __iomem *base;
> +       u64 v;
> +
> +       base = get_feature_ioaddr_by_index(dev, FME_FEATURE_ID_HEADER);
> +
> +       v = readq(base + FME_HDR_CAP);
> +
> +       return scnprintf(buf, PAGE_SIZE, "%u\n",
> +                        (unsigned int)FIELD_GET(FME_CAP_NUM_PORTS, v));
> +}
> +static DEVICE_ATTR_RO(ports_num);
> +
> +static ssize_t bitstream_id_show(struct device *dev,
> +                                struct device_attribute *attr, char *buf)
> +{
> +       void __iomem *base;
> +       u64 v;
> +
> +       base = get_feature_ioaddr_by_index(dev, FME_FEATURE_ID_HEADER);
> +
> +       v = readq(base + FME_HDR_BITSTREAM_ID);
> +
> +       return scnprintf(buf, PAGE_SIZE, "0x%llx\n", (unsigned long long)v);
> +}
> +static DEVICE_ATTR_RO(bitstream_id);
> +
> +static ssize_t bitstream_metadata_show(struct device *dev,
> +                                      struct device_attribute *attr, char *buf)
> +{
> +       void __iomem *base;
> +       u64 v;
> +
> +       base = get_feature_ioaddr_by_index(dev, FME_FEATURE_ID_HEADER);
> +
> +       v = readq(base + FME_HDR_BITSTREAM_MD);
> +
> +       return scnprintf(buf, PAGE_SIZE, "0x%llx\n", (unsigned long long)v);
> +}
> +static DEVICE_ATTR_RO(bitstream_metadata);
> +
> +static const struct attribute *fme_hdr_attrs[] = {
> +       &dev_attr_ports_num.attr,
> +       &dev_attr_bitstream_id.attr,
> +       &dev_attr_bitstream_metadata.attr,
> +       NULL,
> +};
> +
>  static int fme_hdr_init(struct platform_device *pdev, struct feature *feature)
>  {
> +       void __iomem *base = feature->ioaddr;
> +       int ret;
> +
>         dev_dbg(&pdev->dev, "FME HDR Init.\n");
> +       dev_dbg(&pdev->dev, "FME cap %llx.\n",
> +               (unsigned long long)readq(base + FME_HDR_CAP));
> +
> +       ret = sysfs_create_files(&pdev->dev.kobj, fme_hdr_attrs);
> +       if (ret)
> +               return ret;
>
>         return 0;
>  }
> @@ -31,6 +90,7 @@ static int fme_hdr_init(struct platform_device *pdev, struct feature *feature)
>  static void fme_hdr_uinit(struct platform_device *pdev, struct feature *feature)
>  {
>         dev_dbg(&pdev->dev, "FME HDR UInit.\n");
> +       sysfs_remove_files(&pdev->dev.kobj, fme_hdr_attrs);
>  }
>
>  static const struct feature_ops fme_hdr_ops = {
> --
> 1.8.3.1
>