PCI: qcom: Disable mirroring of DBI and iATU register space in BAR region

PARF hardware block which is a wrapper on top of DWC PCIe controller
mirrors the DBI and ATU register space. It uses PARF_SLV_ADDR_SPACE_SIZE
register to get the size of the memory block to be mirrored and uses
PARF_DBI_BASE_ADDR, PARF_ATU_BASE_ADDR registers to determine the base
address of DBI and ATU space inside the memory block that is being
mirrored.

When a memory region which is located above the SLV_ADDR_SPACE_SIZE
boundary is used for BAR region then there could be an overlap of DBI and
ATU address space that is getting mirrored and the BAR region. This
results in DBI and ATU address space contents getting updated when a PCIe
function driver tries updating the BAR/MMIO memory region. Reference
memory map of the PCIe memory region with DBI and ATU address space
overlapping BAR region is as below.

                        |---------------|
                        |               |
                        |               |
        ------- --------|---------------|
           |       |    |---------------|
           |       |    |       DBI     |
           |       |    |---------------|---->DBI_BASE_ADDR
           |       |    |               |
           |       |    |               |
           |    PCIe    |               |---->2*SLV_ADDR_SPACE_SIZE
           |    BAR/MMIO|---------------|
           |    Region  |       ATU     |
           |       |    |---------------|---->ATU_BASE_ADDR
           |       |    |               |
        PCIe       |    |---------------|
        Memory     |    |       DBI     |
        Region     |    |---------------|---->DBI_BASE_ADDR
           |       |    |               |
           |    --------|               |
           |            |               |---->SLV_ADDR_SPACE_SIZE
           |            |---------------|
           |            |       ATU     |
           |            |---------------|---->ATU_BASE_ADDR
           |            |               |
           |            |---------------|
           |            |       DBI     |
           |            |---------------|---->DBI_BASE_ADDR
           |            |               |
           |            |               |
        ----------------|---------------|
                        |               |
                        |               |
                        |               |
                        |---------------|

Currently memory region beyond the SLV_ADDR_SPACE_SIZE boundary is not
used for BAR region which is why the above mentioned issue is not
encountered. This issue is discovered as part of internal testing when we
tried moving the BAR region beyond the SLV_ADDR_SPACE_SIZE boundary. Hence
we are trying to fix this.

As PARF hardware block mirrors DBI and ATU register space after every
PARF_SLV_ADDR_SPACE_SIZE (default 0x1000000) boundary multiple, program
maximum possible size to this register by writing 0x80000000 to it(it
considers only powers of 2 as values) to avoid mirroring DBI and ATU to
BAR/MMIO region. Write the physical base address of DBI and ATU register
blocks to PARF_DBI_BASE_ADDR (default 0x0) and PARF_ATU_BASE_ADDR (default
0x1000) respectively to make sure DBI and ATU blocks are at expected
memory locations.

The register offsets PARF_DBI_BASE_ADDR_V2, PARF_SLV_ADDR_SPACE_SIZE_V2
and PARF_ATU_BASE_ADDR are applicable for platforms that use Qcom IP
rev 1.9.0, 2.7.0 and 2.9.0. PARF_DBI_BASE_ADDR_V2 and
PARF_SLV_ADDR_SPACE_SIZE_V2 are applicable for Qcom IP rev 2.3.3.
PARF_DBI_BASE_ADDR and PARF_SLV_ADDR_SPACE_SIZE are applicable for Qcom
IP rev 1.0.0, 2.3.2 and 2.4.0. Update init()/post_init() functions of the
respective Qcom IP versions to program applicable PARF_DBI_BASE_ADDR,
PARF_SLV_ADDR_SPACE_SIZE and PARF_ATU_BASE_ADDR register offsets. Update
the SLV_ADDR_SPACE_SZ macro to 0x80000000 to set highest bit in
PARF_SLV_ADDR_SPACE_SIZE register.

Cache DBI and iATU physical addresses in 'struct dw_pcie' so that
pcie_qcom.c driver can program these addresses in the PARF_DBI_BASE_ADDR
and PARF_ATU_BASE_ADDR registers.

Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/linux-pci/20240814220338.1969668-1-quic_pyarlaga@quicinc.com
Signed-off-by: Prudhvi Yarlagadda <quic_pyarlaga@quicinc.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Mayank Rana <quic_mrana@quicinc.com>

0 files changed, 0 insertions, 0 deletions