On 7/26/21 1:26 PM, trix@xxxxxxxxxx wrote:
> From: Tom Rix <trix@xxxxxxxxxx>
>
> An fpga region's compat_id is exported by the sysfs
> as a 128 bit hex string formed by concatenating two
> 64 bit values together.
>
> The only user of compat_id is dfl. Its user library
> opae converts this value into a uuid.
>
> ex/
> $ cat /sys/class/fpga_region/region1/compat_id
> f3c9941350814aadbced07eb84a6d0bb
>
> Is reported as
> $ fpgainfo bmc
> ...
> Pr Interface Id : f3c99413-5081-4aad-bced-07eb84a6d0bb
>
> Storing a uuid as 2 64 bit values is vendor specific.
> And concatenating them together is vendor specific.
>
> It is better to store and print out as a vendor neutral uuid.
>
> Change fpga_compat_id from a struct to a union.
> Keep the old 64 bit values for dfl.
> Sysfs output is now
> f3c99413-5081-4aad-bced-07eb84a6d0bb
I'm fowarding feedback from Tim Whisonant, one of the OPAE userspace
developers:
I think that this change to the sysfs for the compat_id node will
end up breaking the SDK, which does not expect the '-' characters to
be included when parsing the sysfs value. Currently, it is parsed as
a raw hex string without regard to any '-' characters. This goes for
any "guid" currently exported by sysfs and for what we read in the
device MMIO space.
- Russ
>
> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> ---
> .../ABI/testing/sysfs-class-fpga-region | 4 ++--
> drivers/fpga/dfl-fme-mgr.c | 8 ++++----
> drivers/fpga/fpga-region.c | 4 +---
> include/linux/fpga/fpga-mgr.h | 18 ++++++++++++------
> include/linux/fpga/fpga-region.h | 2 +-
> 5 files changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-fpga-region b/Documentation/ABI/testing/sysfs-class-fpga-region
> index bc7ec644acc9a..241359fb74a55 100644
> --- a/Documentation/ABI/testing/sysfs-class-fpga-region
> +++ b/Documentation/ABI/testing/sysfs-class-fpga-region
> @@ -5,5 +5,5 @@ Contact: Wu Hao <hao.wu@xxxxxxxxx>
> Description: FPGA region id for compatibility check, e.g. compatibility
> of the FPGA reconfiguration hardware and image. This value
> is defined or calculated by the layer that is creating the
> - FPGA region. This interface returns the compat_id value or
> - just error code -ENOENT in case compat_id is not used.
> + FPGA region. This interface returns a uuid value or just
> + error code -ENOENT in case compat_id is not used.
> diff --git a/drivers/fpga/dfl-fme-mgr.c b/drivers/fpga/dfl-fme-mgr.c
> index d5861d13b3069..012b72712684c 100644
> --- a/drivers/fpga/dfl-fme-mgr.c
> +++ b/drivers/fpga/dfl-fme-mgr.c
> @@ -273,16 +273,16 @@ static const struct fpga_manager_ops fme_mgr_ops = {
> };
>
> static void fme_mgr_get_compat_id(void __iomem *fme_pr,
> - struct fpga_compat_id *id)
> + union fpga_compat_id *id)
> {
> - id->id_l = readq(fme_pr + FME_PR_INTFC_ID_L);
> - id->id_h = readq(fme_pr + FME_PR_INTFC_ID_H);
> + id->id_l = cpu_to_be64(readq(fme_pr + FME_PR_INTFC_ID_L));
> + id->id_h = cpu_to_be64(readq(fme_pr + FME_PR_INTFC_ID_H));
> }
>
> static int fme_mgr_probe(struct platform_device *pdev)
> {
> struct dfl_fme_mgr_pdata *pdata = dev_get_platdata(&pdev->dev);
> - struct fpga_compat_id *compat_id;
> + union fpga_compat_id *compat_id;
> struct device *dev = &pdev->dev;
> struct fme_mgr_priv *priv;
> struct fpga_manager *mgr;
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index a4838715221ff..f1083b5894635 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -166,9 +166,7 @@ static ssize_t compat_id_show(struct device *dev,
> if (!region->compat_id)
> return -ENOENT;
>
> - return sprintf(buf, "%016llx%016llx\n",
> - (unsigned long long)region->compat_id->id_h,
> - (unsigned long long)region->compat_id->id_l);
> + return sprintf(buf, "%pU\n", ®ion->compat_id->uuid);
> }
>
> static DEVICE_ATTR_RO(compat_id);
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index ec2cd8bfceb00..b12f9994932e1 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -10,6 +10,7 @@
>
> #include <linux/mutex.h>
> #include <linux/platform_device.h>
> +#include <linux/uuid.h>
>
> struct fpga_manager;
> struct sg_table;
> @@ -144,14 +145,19 @@ struct fpga_manager_ops {
> #define FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR BIT(4)
>
> /**
> - * struct fpga_compat_id - id for compatibility check
> - *
> + * union fpga_compat_id - id for compatibility check
> + * Can be accessed as either:
> + * @uuid: the base uuid_t type
> + * or
> * @id_h: high 64bit of the compat_id
> * @id_l: low 64bit of the compat_id
> */
> -struct fpga_compat_id {
> - u64 id_h;
> - u64 id_l;
> +union fpga_compat_id {
> + uuid_t uuid;
> + struct {
> + u64 id_h;
> + u64 id_l;
> + };
> };
>
> /**
> @@ -169,7 +175,7 @@ struct fpga_manager {
> struct device dev;
> struct mutex ref_mutex;
> enum fpga_mgr_states state;
> - struct fpga_compat_id *compat_id;
> + union fpga_compat_id *compat_id;
> const struct fpga_manager_ops *mops;
> void *priv;
> };
> diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
> index 27cb706275dba..7cc2ee543efb4 100644
> --- a/include/linux/fpga/fpga-region.h
> +++ b/include/linux/fpga/fpga-region.h
> @@ -24,7 +24,7 @@ struct fpga_region {
> struct list_head bridge_list;
> struct fpga_manager *mgr;
> struct fpga_image_info *info;
> - struct fpga_compat_id *compat_id;
> + union fpga_compat_id *compat_id;
> void *priv;
> int (*get_bridges)(struct fpga_region *region);
> };
