Re: [PATCH v2] PCI: dwc: endpoint: Fix dw_pcie_ep_raise_msix_irq() alignment support

[Manivannan Sadhasivam <mani@kernel.org>]

On Tue, Nov 28, 2023 at 02:22:30PM +0100, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@wdc.com>
> 
> Commit 6f5e193bfb55 ("PCI: dwc: Fix dw_pcie_ep_raise_msix_irq() to get
> correct MSI-X table address") modified dw_pcie_ep_raise_msix_irq() to
> support iATUs which require a specific alignment.
> 
> However, this support cannot have been properly tested.
> 
> The whole point is for the iATU to map an address that is aligned,
> using dw_pcie_ep_map_addr(), and then let the writel() write to
> ep->msi_mem + aligned_offset.
> 
> Thus, modify the address that is mapped such that it is aligned.
> With this change, dw_pcie_ep_raise_msix_irq() matches the logic in
> dw_pcie_ep_raise_msi_irq().
> 
> Cc: Kishon Vijay Abraham I <kishon@kernel.org>
> Fixes: 6f5e193bfb55 ("PCI: dwc: Fix dw_pcie_ep_raise_msix_irq() to get correct MSI-X table address")
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>

Cc: stable@vger.kernel.org # 5.7

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

- Mani

> ---
> Changes since v1:
> -Clarified commit message.
> -Add a working email for Kishon to CC.
> 
>  drivers/pci/controller/dwc/pcie-designware-ep.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index f6207989fc6a..bc94d7f39535 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -615,6 +615,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>  	}
>  
>  	aligned_offset = msg_addr & (epc->mem->window.page_size - 1);
> +	msg_addr &= ~aligned_offset;
>  	ret = dw_pcie_ep_map_addr(epc, func_no, 0, ep->msi_mem_phys, msg_addr,
>  				  epc->mem->window.page_size);
>  	if (ret)
> -- 
> 2.43.0
> 

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