[PATCH] PCI: iproc: Fix incorrect MSI address alignment

[PATCH] PCI: iproc: Fix incorrect MSI address alignment

[Ray Jui]

In the code to handle PAXB v2 based MSI steering, the logic aligns the
MSI register address to the size of supported inbound mapping range.
This is incorrect since it rounds "up" the starting address to the next
aligned address, but what we want is the starting address to be rounded
"down" to the aligned address.

This patch fixes the issue and allows MSI writes to be properly steered
to the GIC

Fixes: 4b073155fbd3 ("PCI: iproc: Add support for the next-gen PAXB
controller")

Signed-off-by: Ray Jui <ray.jui@broadcom.com>
---
 drivers/pci/host/pcie-iproc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
index 8ffb9d4..fb09668 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -1018,7 +1018,7 @@ static int iproc_pcie_paxb_v2_msi_steer(struct iproc_pcie *pcie, u64 msi_addr)
 
 	memset(&range, 0, sizeof(range));
 	range.size = SZ_32K;
-	range.pci_addr = range.cpu_addr = ALIGN(msi_addr, range.size);
+	range.pci_addr = range.cpu_addr = msi_addr & ~(range.size - 1);
 
 	ret = iproc_pcie_setup_ib(pcie, &range, IPROC_PCIE_IB_MAP_IO);
 	return ret;
-- 
2.1.4

Re: [PATCH] PCI: iproc: Fix incorrect MSI address alignment

[Bjorn Helgaas]

On Mon, Nov 21, 2016 at 05:48:30PM -0800, Ray Jui wrote:
> In the code to handle PAXB v2 based MSI steering, the logic aligns the
> MSI register address to the size of supported inbound mapping range.
> This is incorrect since it rounds "up" the starting address to the next
> aligned address, but what we want is the starting address to be rounded
> "down" to the aligned address.
> 
> This patch fixes the issue and allows MSI writes to be properly steered
> to the GIC
> 
> Fixes: 4b073155fbd3 ("PCI: iproc: Add support for the next-gen PAXB
> controller")
> 
> Signed-off-by: Ray Jui <ray.jui@broadcom.com>

Applied to pci/host-iproc for v4.10, thanks, Ray!

> ---
>  drivers/pci/host/pcie-iproc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
> index 8ffb9d4..fb09668 100644
> --- a/drivers/pci/host/pcie-iproc.c
> +++ b/drivers/pci/host/pcie-iproc.c
> @@ -1018,7 +1018,7 @@ static int iproc_pcie_paxb_v2_msi_steer(struct iproc_pcie *pcie, u64 msi_addr)
>  
>  	memset(&range, 0, sizeof(range));
>  	range.size = SZ_32K;
> -	range.pci_addr = range.cpu_addr = ALIGN(msi_addr, range.size);
> +	range.pci_addr = range.cpu_addr = msi_addr & ~(range.size - 1);
>  
>  	ret = iproc_pcie_setup_ib(pcie, &range, IPROC_PCIE_IB_MAP_IO);
>  	return ret;
> -- 
> 2.1.4
>