Re: [PATCH v4 01/17] PCI: dwc: Use the DMA-API to get the MSI address

From: Joao Pinto
Date: Wed Nov 08 2017 - 07:46:25 EST


Hello to all,

Ãs 12:56 AM de 11/8/2017, Bjorn Helgaas escreveu:
> On Fri, Nov 03, 2017 at 02:47:05PM +0100, Niklas Cassel wrote:
>> Use the DMA-API to get the MSI address. This address will be written to
>> our PCI config space and to the register which determines which AXI
>> address the DWC IP will spoof for incoming MSI irqs.
>>
>> Since it is a PCIe endpoint device, rather than the CPU, that is supposed
>> to write to the MSI address, the proper way to get the MSI address is by
>> using the DMA API, not by using virt_to_phys().
>>
>> Using virt_to_phys() might work on some systems, but using the DMA API
>> should work on all systems.
>>
>> This is essentially the same thing as allocating a buffer in a driver
>> to which the endpoint will write to. To do this, we use the DMA API.
>>
>> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxx>
>
> I'm expecting Jingoo and/or Joao to chime in and ack the
> DesignWare-related patches. I think all the others are in
> pretty good shape.
>
>> ---
>> drivers/pci/dwc/pcie-designware-host.c | 15 ++++++++++++---
>> drivers/pci/dwc/pcie-designware.h | 3 ++-
>> 2 files changed, 14 insertions(+), 4 deletions(-)
>> ...

Let me test this patch-set in my setup first!
I will give feedback until Friday.

Thanks,
Joao