[RFC 1/2] PCI: imx6: Make sure the DBI register can be changed

[Bjorn Helgaas]

On Tue, Jul 12, 2022 at 01:30:02AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Bjorn Helgaas <helgaas at kernel.org>
> > Sent: 2022年7月12日 6:17
> > To: Hongxing Zhu <hongxing.zhu at nxp.com>
> > Cc: l.stach at pengutronix.de; bhelgaas at google.com;
> > lorenzo.pieralisi at arm.com; festevam at gmail.com; linux-pci at vger.kernel.org;
> > linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org;
> > kernel at pengutronix.de; dl-linux-imx <linux-imx at nxp.com>
> > Subject: Re: [RFC 1/2] PCI: imx6: Make sure the DBI register can be changed
> > 
> > Hi Richard,
> > 
> > On Wed, May 18, 2022 at 05:35:27PM +0800, Richard Zhu wrote:
> > > The PCIE_DBI_RO_WR_EN bit should be set when write some DBI registers.
> > > To make sure that the DBI registers are writable, set the
> > > PCIE_DBI_RO_WR_EN properly when touch the DBI registers.
> > >
> > > Signed-off-by: Richard Zhu <hongxing.zhu at nxp.com>
> > > ---
> > >  drivers/pci/controller/dwc/pci-imx6.c | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > index 6619e3caffe2..30641d2dda14 100644
> > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > @@ -797,10 +797,12 @@ static int imx6_pcie_start_link(struct dw_pcie
> > *pci)
> > >  	 * started in Gen2 mode, there is a possibility the devices on the
> > >  	 * bus will not be detected at all.  This happens with PCIe switches.
> > >  	 */
> > > +	dw_pcie_dbi_ro_wr_en(pci);
> > 
> > What's the status of this patch?  I don't see this change included in your v14
> > series [1].  That series has a lot of imx6 updates, so I would have thought
> > you'd include this change in it.  Or maybe this change turned out not to be
> > needed?
> Hi Bjorn:
> Thanks for your kindly help.
> The v14 series[1] had been reviewing for a quite time. I'm afraid that
>  this series might miss the L5.20 merge window if I add new patch
>  into it from time to time.
> If you don't think so, I can merge the first one, and re-issue the v15 a
> moment later.
> > 
> > What about the 2/2 patch?
> i.MX8MP PCIe supports the PCIe GEN3 speed, the second patch is used to extend
>  the link speed support capability, and prepared for i.MX8MP PCIe support.
> I assumed that these two patches can be contained in i.MX8MP PCIe support
> patch-set before.

I applied both these patches on pci/ctrl/imx6 for v5.20, thanks!

Bjorn