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    Subject[PATCH v9 03/27] dmaengine: dw-edma: Convert ll/dt phys-address to PCIe bus/DMA address
    Date
    In accordance with the dw_edma_region.paddr field semantics it is supposed
    to be initialized with a memory base address visible by the DW eDMA
    controller. If the DMA engine is embedded into the DW PCIe Host/EP
    controller, then the address should belong to the Local CPU/Application
    memory. If eDMA is remotely accessible across the PCIe bus via the PCIe
    memory IOs, then the address needs to be a part of the PCIe bus memory
    space. The later case hasn't been well covered in the corresponding
    glue-driver. Since in general the PCIe memory space doesn't have to match
    the CPU memory space and the pci_dev.resource[] arrays contain the
    resources defined in the CPU memory space, a proper conversion needs to be
    performed, otherwise either the driver won't properly work or much worse
    the memory corruption will happen. The conversion can be done by means of
    the pci_bus_address() method. Let's use it to retrieve the LL, DT and CSRs
    PCIe memory ranges.

    Note in addition to that we need to extend the dw_edma_region.paddr field
    size. The field normally contains a memory range base address to be set in
    the DW eDMA Linked-List pointer register or as a base address of the
    Linked-List data buffer. In accordance with [1] the LL range is supposed
    to be created in the Local CPU/Application memory, but depending on the DW
    eDMA utilization the memory can be created as a part of the PCIe bus
    address space (as in the case of the DW PCIe EP prototype kit). Thus in
    the former case the dw_edma_region.paddr field should have the dma_addr_t
    type, while in the later one - pci_bus_addr_t. Seeing the corresponding
    CSRs are always 64-bits wide let's convert the dw_edma_region.paddr field
    type to be u64 and let the client code logic to make sure it has a valid
    address visible by the DW eDMA controller. For instance the DW eDMA PCIe
    glue-driver initializes the field with the addresses from the PCIe bus
    memory space.

    [1] DesignWare Cores PCI Express Controller Databook - DWC PCIe Root Port,
    v.5.40a, March 2019, p.1103

    Fixes: 41aaff2a2ac0 ("dmaengine: Add Synopsys eDMA IP PCIe glue-logic")
    Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
    Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
    Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
    Acked-by: Vinod Koul <vkoul@kernel.org>
    ---
    drivers/dma/dw-edma/dw-edma-pcie.c | 8 ++++----
    include/linux/dma/edma.h | 2 +-
    2 files changed, 5 insertions(+), 5 deletions(-)

    diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
    index d6b5e2463884..04c95cba1244 100644
    --- a/drivers/dma/dw-edma/dw-edma-pcie.c
    +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
    @@ -231,7 +231,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
    return -ENOMEM;

    ll_region->vaddr += ll_block->off;
    - ll_region->paddr = pdev->resource[ll_block->bar].start;
    + ll_region->paddr = pci_bus_address(pdev, ll_block->bar);
    ll_region->paddr += ll_block->off;
    ll_region->sz = ll_block->sz;

    @@ -240,7 +240,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
    return -ENOMEM;

    dt_region->vaddr += dt_block->off;
    - dt_region->paddr = pdev->resource[dt_block->bar].start;
    + dt_region->paddr = pci_bus_address(pdev, dt_block->bar);
    dt_region->paddr += dt_block->off;
    dt_region->sz = dt_block->sz;
    }
    @@ -256,7 +256,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
    return -ENOMEM;

    ll_region->vaddr += ll_block->off;
    - ll_region->paddr = pdev->resource[ll_block->bar].start;
    + ll_region->paddr = pci_bus_address(pdev, ll_block->bar);
    ll_region->paddr += ll_block->off;
    ll_region->sz = ll_block->sz;

    @@ -265,7 +265,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
    return -ENOMEM;

    dt_region->vaddr += dt_block->off;
    - dt_region->paddr = pdev->resource[dt_block->bar].start;
    + dt_region->paddr = pci_bus_address(pdev, dt_block->bar);
    dt_region->paddr += dt_block->off;
    dt_region->sz = dt_block->sz;
    }
    diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
    index 7d8062e9c544..a864978ddd27 100644
    --- a/include/linux/dma/edma.h
    +++ b/include/linux/dma/edma.h
    @@ -18,7 +18,7 @@
    struct dw_edma;

    struct dw_edma_region {
    - phys_addr_t paddr;
    + u64 paddr;
    void __iomem *vaddr;
    size_t sz;
    };
    --
    2.39.0

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