# Re: \[PATCH V4 5/7\] vDPA/ifcvf: fetch device feature bits when probe

- From: Jason Wang \<hidden\>
- Date: 2021-03-17 03:59:17 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/03/6304395
- Thread: https://ratatoskr.run/netdev/2021/03/6300136/t.md

```text

在 2021/3/15 下午3:44, Zhu Lingshan 写道:
> This commit would read and store device feature
> bits when probe.
>
> rename ifcvf_get_features() to ifcvf_get_hw_features(),
> it reads and stores features of the probed device.
>
> new ifcvf_get_features() simply returns stored
> feature bits.
>
> Signed-off-by: Zhu Lingshan <redacted>


Acked-by: Jason Wang <redacted>


> ---
>   drivers/vdpa/ifcvf/ifcvf_base.c | 12 ++++++++++--
>   drivers/vdpa/ifcvf/ifcvf_base.h |  2 ++
>   drivers/vdpa/ifcvf/ifcvf_main.c |  2 ++
>   3 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vdpa/ifcvf/ifcvf_base.c b/drivers/vdpa/ifcvf/ifcvf_base.c
> index f2a128e56de5..ea6a78791c9b 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_base.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_base.c
> @@ -202,10 +202,11 @@ static void ifcvf_add_status(struct ifcvf_hw *hw, u8 status)
>   	ifcvf_get_status(hw);
>   }
>   
> -u64 ifcvf_get_features(struct ifcvf_hw *hw)
> +u64 ifcvf_get_hw_features(struct ifcvf_hw *hw)
>   {
>   	struct virtio_pci_common_cfg __iomem *cfg = hw->common_cfg;
>   	u32 features_lo, features_hi;
> +	u64 features;
>   
>   	ifc_iowrite32(0, &cfg->device_feature_select);
>   	features_lo = ifc_ioread32(&cfg->device_feature);
> @@ -213,7 +214,14 @@ u64 ifcvf_get_features(struct ifcvf_hw *hw)
>   	ifc_iowrite32(1, &cfg->device_feature_select);
>   	features_hi = ifc_ioread32(&cfg->device_feature);
>   
> -	return ((u64)features_hi << 32) | features_lo;
> +	features = ((u64)features_hi << 32) | features_lo;
> +
> +	return features;
> +}
> +
> +u64 ifcvf_get_features(struct ifcvf_hw *hw)
> +{
> +	return hw->hw_features;
>   }
>   
>   void ifcvf_read_net_config(struct ifcvf_hw *hw, u64 offset,
> diff --git a/drivers/vdpa/ifcvf/ifcvf_base.h b/drivers/vdpa/ifcvf/ifcvf_base.h
> index 794d1505d857..dbb8c10aa3b1 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_base.h
> +++ b/drivers/vdpa/ifcvf/ifcvf_base.h
> @@ -83,6 +83,7 @@ struct ifcvf_hw {
>   	void __iomem *notify_base;
>   	u32 notify_off_multiplier;
>   	u64 req_features;
> +	u64 hw_features;
>   	struct virtio_pci_common_cfg __iomem *common_cfg;
>   	void __iomem *net_cfg;
>   	struct vring_info vring[IFCVF_MAX_QUEUE_PAIRS * 2];
> @@ -121,6 +122,7 @@ void ifcvf_set_status(struct ifcvf_hw *hw, u8 status);
>   void io_write64_twopart(u64 val, u32 *lo, u32 *hi);
>   void ifcvf_reset(struct ifcvf_hw *hw);
>   u64 ifcvf_get_features(struct ifcvf_hw *hw);
> +u64 ifcvf_get_hw_features(struct ifcvf_hw *hw);
>   u16 ifcvf_get_vq_state(struct ifcvf_hw *hw, u16 qid);
>   int ifcvf_set_vq_state(struct ifcvf_hw *hw, u16 qid, u16 num);
>   struct ifcvf_adapter *vf_to_adapter(struct ifcvf_hw *hw);
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index c34e1eec6b6c..25fb9dfe23f0 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -458,6 +458,8 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>   	for (i = 0; i < IFCVF_MAX_QUEUE_PAIRS * 2; i++)
>   		vf->vring[i].irq = -EINVAL;
>   
> +	vf->hw_features = ifcvf_get_hw_features(vf);
> +
>   	ret = vdpa_register_device(&adapter->vdpa);
>   	if (ret) {
>   		IFCVF_ERR(pdev, "Failed to register ifcvf to vdpa bus");

```