[PATCH 1/2] PCI: Disable MSI for Freescale PCIe RC mode

[M.h. Lian]

Hi Bjorn,

Thanks for your review.
Yes. All the freescale's PCIe controllers do not support to generate MSI interrupt.
The PCIe controllers developed for the next generation SoC do not support it either.

Acked-by: Minghuan Lian <minghuan.Lian at nxp.com>

> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas at kernel.org]
> Sent: Thursday, October 12, 2017 3:38 AM
> To: Z.q. Hou <zhiqiang.hou at nxp.com>
> Cc: linux-kernel at vger.kernel.org; linux-arm-kernel at lists.infradead.org; linux-
> pci at vger.kernel.org; bhelgaas at google.com; Roy Zang <roy.zang at nxp.com>;
> Mingkai Hu <mingkai.hu at nxp.com>; M.h. Lian <minghuan.lian at nxp.com>
> Subject: Re: [PATCH 1/2] PCI: Disable MSI for Freescale PCIe RC mode
> 
> On Fri, Sep 22, 2017 at 03:25:21PM +0800, Zhiqiang Hou wrote:
> > From: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
> >
> > The Freescale PCIe controller advertises the MSI/MSI-X capability in
> > both RC and Endpoint mode, but in RC mode it doesn't support MSI/MSI-X
> > by it self, it can only transfer MSI/MSI-X from downstream
> 
> s/it self,/itself;/
> 
> > devices. So add this quirk to prevent use of MSI/MSI-X in RC mode.
> >
> > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
> > ---
> >  drivers/pci/quirks.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index
> > a4d33619a7bb..c1063a420f0c 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -4799,3 +4799,11 @@ static void quirk_no_ats(struct pci_dev *pdev)
> >  /* AMD Stoney platform GPU */
> >  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x98e4, quirk_no_ats);
> > #endif /* CONFIG_PCI_ATS */
> > +
> > +/* Freescale PCIe doesn't support MSI in RC mode */ static void
> > +quirk_fsl_no_msi(struct pci_dev *pdev) {
> > +	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT)
> > +		pdev->no_msi = 1;
> > +}
> > +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_FREESCALE, PCI_ANY_ID,
> > +quirk_fsl_no_msi);
> 
> This disables MSI for all Freescale root ports, past, present, and future.  Is that
> really what you want?  This is a bug (the root port shouldn't advertise MSI if it
> doesn't support it), and presumably it might be fixed in some future device?
> 
> This needs an ack from Minghuan or Mingkai (based on MAINTAINERS).
> 
> Bjorn