Re: [PATCH] PCI: endpoint: Add prefetch bar support

[Bjorn Helgaas]

On Wed, Jan 19, 2022 at 10:39:49AM +0000, Li Chen wrote:
> Before this commit, epf cannot set bar to be prefetchable.
> Prefetchable bar can also help epf device to use bridge's
> prefetch memory window.

Please capitalize "BAR" in subject and commit log (as you did in
comment below) so we know it's an acronym.

> Signed-off-by: Li Chen <lchen@xxxxxxxxxxxxx>
> Change-Id: I1691a946d715cc161711d6eef56e7a74678a3578

Drop the Change-Id since it is not useful upstream.

> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 4 ++++
>  include/linux/pci-epc.h                       | 2 ++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 90d84d3bc868..96489cfdf58d 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -817,15 +817,19 @@ static void pci_epf_configure_bar(struct pci_epf *epf,
>  {
>  	struct pci_epf_bar *epf_bar;
>  	bool bar_fixed_64bit;
> +	bool bar_prefetch;
>  	int i;
>  
>  	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		epf_bar = &epf->bar[i];
>  		bar_fixed_64bit = !!(epc_features->bar_fixed_64bit & (1 << i));
> +		bar_prefetch = !!(epc_features->bar_prefetch & (1 << i));
>  		if (bar_fixed_64bit)
>  			epf_bar->flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;
>  		if (epc_features->bar_fixed_size[i])
>  			bar_size[i] = epc_features->bar_fixed_size[i];
> +		if (bar_prefetch)
> +			epf_bar->flags |= PCI_BASE_ADDRESS_MEM_PREFETCH;
>  	}
>  }
>  
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index a48778e1a4ee..825632d581d0 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -161,6 +161,7 @@ struct pci_epc {
>   * @msix_capable: indicate if the endpoint function has MSI-X capability
>   * @reserved_bar: bitmap to indicate reserved BAR unavailable to function driver
>   * @bar_fixed_64bit: bitmap to indicate fixed 64bit BARs
> + * @bar_prefetch: bitmap to indicate prefetchable BARs
>   * @bar_fixed_size: Array specifying the size supported by each BAR
>   * @align: alignment size required for BAR buffer allocation
>   */
> @@ -171,6 +172,7 @@ struct pci_epc_features {
>  	unsigned int	msix_capable : 1;
>  	u8	reserved_bar;
>  	u8	bar_fixed_64bit;
> +	u8	bar_prefetch;
>  	u64	bar_fixed_size[PCI_STD_NUM_BARS];
>  	size_t	align;
>  };
> -- 
> 2.34.1
> 
> Regards,
> Li
> 
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