[PATCH v2 07/10] PCI: layerscape: Modify the MSIX to the doorbell way

[Xiaowei Bao]

> -----Original Message-----
> From: Gustavo Pimentel <Gustavo.Pimentel at synopsys.com>
> Sent: 2019年11月6日 17:40
> To: Kishon Vijay Abraham I <kishon at ti.com>; Andrew Murray
> <andrew.murray at arm.com>; Xiaowei Bao <xiaowei.bao at nxp.com>;
> gustavo.pimentel at synopsys.com
> Cc: bhelgaas at google.com; robh+dt at kernel.org; mark.rutland at arm.com;
> shawnguo at kernel.org; Leo Li <leoyang.li at nxp.com>;
> lorenzo.pieralisi at arm.co; arnd at arndb.de; gregkh at linuxfoundation.org; M.h.
> Lian <minghuan.lian at nxp.com>; Mingkai Hu <mingkai.hu at nxp.com>; Roy
> Zang <roy.zang at nxp.com>; jingoohan1 at gmail.com;
> linux-pci at vger.kernel.org; devicetree at vger.kernel.org;
> linux-kernel at vger.kernel.org; linux-arm-kernel at lists.infradead.org;
> linuxppc-dev at lists.ozlabs.org
> Subject: RE: [PATCH v2 07/10] PCI: layerscape: Modify the MSIX to the
> doorbell way
> 
> On Thu, Aug 29, 2019 at 6:13:18, Kishon Vijay Abraham I <kishon at ti.com>
> wrote:
> 
> Hi, this email slip away from my attention...
> 
> > Gustavo,
> >
> > On 27/08/19 6:55 PM, Andrew Murray wrote:
> > > On Sat, Aug 24, 2019 at 12:08:40AM +0000, Xiaowei Bao wrote:
> > >>
> > >>
> > >>> -----Original Message-----
> > >>> From: Andrew Murray <andrew.murray at arm.com>
> > >>> Sent: 2019年8月23日 21:58
> > >>> To: Xiaowei Bao <xiaowei.bao at nxp.com>
> > >>> Cc: bhelgaas at google.com; robh+dt at kernel.org;
> mark.rutland at arm.com;
> > >>> shawnguo at kernel.org; Leo Li <leoyang.li at nxp.com>; kishon at ti.com;
> > >>> lorenzo.pieralisi at arm.co; arnd at arndb.de; gregkh at linuxfoundation.org;
> M.h.
> > >>> Lian <minghuan.lian at nxp.com>; Mingkai Hu <mingkai.hu at nxp.com>;
> Roy
> > >>> Zang <roy.zang at nxp.com>; jingoohan1 at gmail.com;
> > >>> gustavo.pimentel at synopsys.com; linux-pci at vger.kernel.org;
> > >>> devicetree at vger.kernel.org; linux-kernel at vger.kernel.org;
> > >>> linux-arm-kernel at lists.infradead.org;
> > >>> linuxppc-dev at lists.ozlabs.org
> > >>> Subject: Re: [PATCH v2 07/10] PCI: layerscape: Modify the MSIX to
> > >>> the doorbell way
> > >>>
> > >>> On Thu, Aug 22, 2019 at 07:22:39PM +0800, Xiaowei Bao wrote:
> > >>>> The layerscape platform use the doorbell way to trigger MSIX
> > >>>> interrupt in EP mode.
> > >>>>
> > >>>
> > >>> I have no problems with this patch, however...
> > >>>
> > >>> Are you able to add to this message a reason for why you are
> > >>> making this change? Did dw_pcie_ep_raise_msix_irq not work when
> > >>> func_no != 0? Or did it work yet dw_pcie_ep_raise_msix_irq_doorbell is
> more efficient?
> > >>
> > >> The fact is that, this driver is verified in ls1046a platform of
> > >> NXP before, and ls1046a don't support MSIX feature, so I set the
> > >> msix_capable of pci_epc_features struct is false, but in other
> > >> platform, e.g. ls1088a, it support the MSIX feature, I verified the MSIX
> feature in ls1088a, it is not OK, so I changed to another way. Thanks.
> > >
> > > Right, so the existing pci-layerscape-ep.c driver never supported
> > > MSIX yet it erroneously had a switch case statement to call
> > > dw_pcie_ep_raise_msix_irq which would never get used.
> > >
> > > Now that we're adding a platform with MSIX support the existing
> > > dw_pcie_ep_raise_msix_irq doesn't work (for this platform) so we are
> > > adding a different method.
> >
> > Gustavo, can you confirm dw_pcie_ep_raise_msix_irq() works for
> > designware as it didn't work for both me and Xiaowei?
> 
> When I implemented the dw_pcie_ep_raise_msix_irq(), the implementation
> was working quite fine on DesignWare solution. Otherwise, I wouldn't submit
> it to the kernel.
> From what I have seen and if I recall well, Xiaowei implementation was done
> having PF's configurated on his solution, which is a configuration that I don't
> have in my solution, I believe this could be the missing piece that differs
> between our 2 implementations.
> 
> Since patch submission into the kernel related to msix feature on pcitest tool, I
> didn't touch or re-tested the msix feature by lack of time (other projects
> requires my full attention for now). However is on my roadmap to came back
> to add some other features on DesignWare eDMA driver and I can do at that
> time some tests to see if the
> dw_pcie_ep_raise_msix_irq_doorbell() is compatible or not with my solution.
> If so, I can do some patch to simplify and use the
> dw_pcie_ep_raise_msix_irq_doorbell() if it still works as expected like on
> dw_pcie_ep_raise_msix_irq(). Agree?
> 

Thanks Gustavo, it looks well for me.

Thanks
Xiaowei

> Gustavo
> 
> >
> > Thanks
> > Kishon
>