On Thu, Mar 1, 2018 at 12:17 AM, Wu Hao [off-list ref] wrote:

On Wed, Feb 28, 2018 at 04:55:15PM -0600, Alan Tull wrote:

quoted

On Tue, Feb 13, 2018 at 3:24 AM, Wu Hao [off-list ref] wrote:

Hi Hao,

Hi Alan,

Thanks for the review.

quoted

quoted

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 <redacted>
---
 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@intel.com>
+Description:   FPGA region id for compatibility check.

It would be helpful to add some explanation here that although the
intended function of compat_id is set, the way the actual value is
defined or calculated is set by the layer that is creating the FPGA
region.

quoted

quoted

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.

It sounds good to me.

if (!region->compat_id)
        return -ENOENT;

Yes, thanks!

Alan

quoted

quoted

+
+       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.

Yes.

quoted

quoted

+};
+
+/**
  * 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.

Yes. Will update this patch.

Thanks
Hao

quoted

Alan

quoted

        void *priv;
        int (*get_bridges)(struct fpga_region *region);
        const struct attribute_group **groups;
--
2.7.4

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