[PATCH] PCI: fu740: Set the number of msix vectors

[PATCH] PCI: fu740: Set the number of msix vectors

[Yong-Xuan Wang]

The fu740 PCIe has 256 msix vectors. We need to specify it in driver code
to enable more msix vectors.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
---
 drivers/pci/controller/dwc/pcie-fu740.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c
index 0c90583c078b..1e9b44b8bba4 100644
--- a/drivers/pci/controller/dwc/pcie-fu740.c
+++ b/drivers/pci/controller/dwc/pcie-fu740.c
@@ -299,6 +299,7 @@ static int fu740_pcie_probe(struct platform_device *pdev)
 	pci->dev = dev;
 	pci->ops = &dw_pcie_ops;
 	pci->pp.ops = &fu740_pcie_host_ops;
+	pci->pp.num_vectors = MAX_MSI_IRQS;
 
 	/* SiFive specific region: mgmt */
 	afp->mgmt_base = devm_platform_ioremap_resource_byname(pdev, "mgmt");
-- 
2.17.1

Re: [PATCH] PCI: fu740: Set the number of msix vectors

[Serge Semin]

On Wed, Jul 12, 2023 at 07:23:11AM +0000, Yong-Xuan Wang wrote:
> The fu740 PCIe has 256 msix vectors. We need to specify it in driver code
> to enable more msix vectors.

AFAIR DW PCIe RP doesn't support MSI-X. It's just MSI implemented in
the framework of iMSI-RX engine. There can be up to eight
MSI_CTRL_INT_i_* registers enabled each of which is equipped with 32
doorbells. The control register and the doorbell flag IDs are encoded
by the MSI data: [7:5] - MSI_CTRL_INT_* register, [4:0] - doorbell. So
when an MSI MWr TLP arrives DW PCIe RP controller detects it by the
target address, then parses its data and raises the IRQ with the
respective doorbell set. Such TLPs is never transferred further to the
system then.

So I'd fix the commit message respectively. Other than that the change
looks good.

Reviewed-by: Serge Semin <fancer.lancer@gmail.com>

-Serge(y)

> 
> Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
> ---
>  drivers/pci/controller/dwc/pcie-fu740.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c
> index 0c90583c078b..1e9b44b8bba4 100644
> --- a/drivers/pci/controller/dwc/pcie-fu740.c
> +++ b/drivers/pci/controller/dwc/pcie-fu740.c
> @@ -299,6 +299,7 @@ static int fu740_pcie_probe(struct platform_device *pdev)
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
>  	pci->pp.ops = &fu740_pcie_host_ops;
> +	pci->pp.num_vectors = MAX_MSI_IRQS;
>  
>  	/* SiFive specific region: mgmt */
>  	afp->mgmt_base = devm_platform_ioremap_resource_byname(pdev, "mgmt");
> -- 
> 2.17.1
> 

Re: [PATCH] PCI: fu740: Set the number of msix vectors

[Bjorn Helgaas]

On Wed, Jul 12, 2023 at 07:23:11AM +0000, Yong-Xuan Wang wrote:
> The fu740 PCIe has 256 msix vectors. We need to specify it in driver code
> to enable more msix vectors.

s/msix/MSI-X/ in subject and commit log to match spec usage.

Also, recast the commit log so it says *what the patch does*, not
"what we need to do."

> Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
> ---
>  drivers/pci/controller/dwc/pcie-fu740.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-fu740.c b/drivers/pci/controller/dwc/pcie-fu740.c
> index 0c90583c078b..1e9b44b8bba4 100644
> --- a/drivers/pci/controller/dwc/pcie-fu740.c
> +++ b/drivers/pci/controller/dwc/pcie-fu740.c
> @@ -299,6 +299,7 @@ static int fu740_pcie_probe(struct platform_device *pdev)
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
>  	pci->pp.ops = &fu740_pcie_host_ops;
> +	pci->pp.num_vectors = MAX_MSI_IRQS;
>  
>  	/* SiFive specific region: mgmt */
>  	afp->mgmt_base = devm_platform_ioremap_resource_byname(pdev, "mgmt");
> -- 
> 2.17.1
>