Re: [PATCH v6 3/3] PCI: iproc: Add sorted dma ranges resource entries to host bridge

[Bjorn Helgaas <helgaas@kernel.org>]

On Fri, May 03, 2019 at 07:35:34PM +0530, Srinath Mannam wrote:
> The IPROC host controller allows only a subset of physical address space
> as target of inbound PCI memory transactions addresses.
> 
> PCIe devices memory transactions targeting memory regions that
> are not allowed for inbound transactions in the host controller
> are rejected by the host controller and cannot reach the upstream
> buses.
> 
> Firmware device tree description defines the DMA ranges that are
> addressable by devices DMA transactions; parse the device tree
> dma-ranges property and add its ranges to the PCI host bridge dma_ranges
> list; the iova_reserve_pci_windows() call in the driver will reserve the
> IOVA address ranges that are not addressable (ie memory holes in the
> dma-ranges set) so that they are not allocated to PCI devices for DMA
> transfers.
> 
> All allowed address ranges are listed in dma-ranges DT parameter.
> 
> Example:
> 
> dma-ranges = < \
>   0x43000000 0x00 0x80000000 0x00 0x80000000 0x00 0x80000000 \
>   0x43000000 0x08 0x00000000 0x08 0x00000000 0x08 0x00000000 \
>   0x43000000 0x80 0x00000000 0x80 0x00000000 0x40 0x00000000>
> 
> In the above example of dma-ranges, memory address from
> 
> 0x0 - 0x80000000,
> 0x100000000 - 0x800000000,
> 0x1000000000 - 0x8000000000 and
> 0x10000000000 - 0xffffffffffffffff.
> 
> are not allowed to be used as inbound addresses.
> 
> Based-on-patch-by: Oza Pawandeep <oza.oza@broadcom.com>
> Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
> [lorenzo.pieralisi@arm.com: updated commit log]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Reviewed-by: Oza Pawandeep <poza@codeaurora.org>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> ---
>  drivers/pci/controller/pcie-iproc.c | 44 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 43 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
> index c20fd6b..94ba5c0 100644
> --- a/drivers/pci/controller/pcie-iproc.c
> +++ b/drivers/pci/controller/pcie-iproc.c
> @@ -1146,11 +1146,43 @@ static int iproc_pcie_setup_ib(struct iproc_pcie *pcie,
>  	return ret;
>  }
>  
> +static int
> +iproc_pcie_add_dma_range(struct device *dev, struct list_head *resources,
> +			 struct of_pci_range *range)

Just FYI, I cherry-picked these commits from Lorenzo's branch to fix
the formatting of this prototype to match the rest of the file, e.g.:

>  static int iproc_pcie_map_dma_ranges(struct iproc_pcie *pcie)
> ...
>  static int iproce_pcie_get_msi(struct iproc_pcie *pcie,