Re: [PATCH v1 6/7] fpga: dfl: Handle dfl's starting with AFU

Tom Rix
2022-02-15T16:10:00Z

On 2/14/22 3:26 AM, Tianfei zhang wrote:
> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
>
> Allow for a Device Feature List (DFL) to start with
> a Device Feature Header (DFH) of type Accelerator Function Unit (AFU)
> by doing nothing. This allows for PCIe VFs to be created.
>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> Signed-off-by: Tianfei Zhang <tianfei.zhang@intel.com>
> ---
> drivers/fpga/dfl-pci.c | 7 ++++++-
> drivers/fpga/dfl.c | 23 ++++++++++++++---------
> 2 files changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index 8abd9b408403..83b604d6dbe6 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -277,7 +277,12 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
>
> dfl_fpga_enum_info_add_dfl(info, start, len);
> } else {
> - ret = -ENODEV;
> + v = readq(base + DFH);

This isn't likely to work on older cards.

Is there there a version to key off of ?

Tom

> + if (FIELD_GET(DFH_TYPE, v) != DFH_TYPE_AFU) {
> + dev_info(&pcidev->dev, "Unknown feature type 0x%llx id 0x%llx\n",
> + FIELD_GET(DFH_TYPE, v), FIELD_GET(DFH_ID, v));
> + ret = -ENODEV;
> + }
> }
>
> /* release I/O mappings for next step enumeration */
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index a5263ac258c5..25bd24a4cca0 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -900,9 +900,11 @@ static void build_info_free(struct build_feature_devs_info *binfo)
> dfl_id_free(feature_dev_id_type(binfo->feature_dev),
> binfo->feature_dev->id);
>
> - list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
> - list_del(&finfo->node);
> - kfree(finfo);
> + if (!list_empty(&binfo->sub_features)) {
> + list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
> + list_del(&finfo->node);
> + kfree(finfo);
> + }
> }
> }
>
> @@ -1437,6 +1439,7 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
>
> binfo->dev = info->dev;
> binfo->cdev = cdev;
> + INIT_LIST_HEAD(&binfo->sub_features);
>
> binfo->nr_irqs = info->nr_irqs;
> if (info->nr_irqs)
> @@ -1446,12 +1449,14 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
> * start enumeration for all feature devices based on Device Feature
> * Lists.
> */
> - list_for_each_entry(dfl, &info->dfls, node) {
> - ret = parse_feature_list(binfo, dfl->start, dfl->len);
> - if (ret) {
> - remove_feature_devs(cdev);
> - build_info_free(binfo);
> - goto unregister_region_exit;
> + if (!list_empty(&info->dfls)) {
> + list_for_each_entry(dfl, &info->dfls, node) {
> + ret = parse_feature_list(binfo, dfl->start, dfl->len);
> + if (ret) {
> + remove_feature_devs(cdev);
> + build_info_free(binfo);
> + goto unregister_region_exit;
> + }
> }
> }
>