Re: [PATCH v5 03/14] PCI: cadence: Convert all r/w accessors to perform only 32-bit accesses

Rob Herring
2020-05-22T15:54:43Z

On Thu, May 21, 2020 at 9:37 PM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Certain platforms like TI's J721E using Cadence PCIe IP can perform only
> 32-bit accesses for reading or writing to Cadence registers. Convert all
> read and write accesses to 32-bit in Cadence PCIe driver in preparation
> for adding PCIe support in TI's J721E SoC.

Looking more closely I don't think cdns_pcie_ep_assert_intx is okay
with this and never can be given the PCI_COMMAND and PCI_STATUS
registers are in the same word (IIRC, that's the main reason 32-bit
config space accesses are broken). So this isn't going to work at
least for EP accesses. And maybe you need a custom .raise_irq() hook
to minimize any problems (such as making the RMW atomic at least from
the endpoint's perspective).

Rob