Thread (24 messages) 24 messages, 2 authors, 2020-06-08

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

From: Rob Herring <robh@kernel.org>
Date: 2020-05-22 15:54:42
Also in: linux-devicetree, linux-omap, linux-pci, lkml

On Thu, May 21, 2020 at 9:37 PM Kishon Vijay Abraham I [off-list ref] 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

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