RE: [PATCHv5 04/20] PCI: mobiveil: Remove the flag MSI_FLAG_MULTI_PCI_MSI

[Z.q. Hou]

Hi Lorenzo,

> -----Original Message-----
> From: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Sent: 2019å6æ17æ 17:34
> To: Z.q. Hou <zhiqiang.hou@xxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> l.subrahmanya@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx; Leo Li
> <leoyang.li@xxxxxxx>; catalin.marinas@xxxxxxx; will.deacon@xxxxxxx;
> Mingkai Hu <mingkai.hu@xxxxxxx>; M.h. Lian <minghuan.lian@xxxxxxx>;
> Xiaowei Bao <xiaowei.bao@xxxxxxx>
> Subject: Re: [PATCHv5 04/20] PCI: mobiveil: Remove the flag
> MSI_FLAG_MULTI_PCI_MSI
> 
> On Sat, Jun 15, 2019 at 01:30:39AM +0000, Z.q. Hou wrote:
> > Hi Lorenzo,
> >
> > > -----Original Message-----
> > > From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@xxxxxxx]
> > > Sent: 2019å6æ12æ 21:08
> > > To: Z.q. Hou <zhiqiang.hou@xxxxxxx>
> > > Cc: linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> > > l.subrahmanya@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx; Leo Li
> > > <leoyang.li@xxxxxxx>; catalin.marinas@xxxxxxx;
> will.deacon@xxxxxxx;
> > > Mingkai Hu <mingkai.hu@xxxxxxx>; M.h. Lian
> <minghuan.lian@xxxxxxx>;
> > > Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > > Subject: Re: [PATCHv5 04/20] PCI: mobiveil: Remove the flag
> > > MSI_FLAG_MULTI_PCI_MSI
> > >
> > > On Wed, Jun 12, 2019 at 11:34:51AM +0000, Z.q. Hou wrote:
> > > > Hi Lorenzo,
> > > >
> > > > Thanks a lot for your comments!
> > > >
> > > > > -----Original Message-----
> > > > > From: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> > > > > Sent: 2019å6æ12æ 1:00
> > > > > To: Z.q. Hou <zhiqiang.hou@xxxxxxx>
> > > > > Cc: linux-pci@xxxxxxxxxxxxxxx;
> > > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > > > > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > > > bhelgaas@xxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> > > > > l.subrahmanya@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx; Leo Li
> > > > > <leoyang.li@xxxxxxx>; catalin.marinas@xxxxxxx;
> > > will.deacon@xxxxxxx;
> > > > > Mingkai Hu <mingkai.hu@xxxxxxx>; M.h. Lian
> > > <minghuan.lian@xxxxxxx>;
> > > > > Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > > > > Subject: Re: [PATCHv5 04/20] PCI: mobiveil: Remove the flag
> > > > > MSI_FLAG_MULTI_PCI_MSI
> > > > >
> > > > > On Fri, Apr 12, 2019 at 08:35:36AM +0000, Z.q. Hou wrote:
> > > > > > From: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
> > > > > >
> > > > > > The current code does not support multiple MSIs, so remove the
> > > > > > corresponding flag from the msi_domain_info structure.
> > > > >
> > > > > Please explain me what's the problem before removing multi MSI
> support.
> > > >
> > > > NXP LX2 PCIe use the GIC-ITS instead of Mobiveil IP internal MSI
> > > > controller, so, I didn't encounter problem.
> > >
> > > Well, you sent a patch to fix an issue, explain me the issue you are
> > > fixing then, aka what have you sent this patch for ?
> >
> > I did not face issue, as I have explained NXP does not use the
> > Mobiveil IP's MSI controller.  But obviously the MSI allocate function
> > does not support multiple MSI, so I submitted this patch.
> 
> There is nothing obvious. Write what you are fixing in the commit log and I will
> apply the patch, I won't write the commit log for you. Anyone should be able
> to understand why a patch was needed by reading the commit log, it is as
> important as writing the code itself.

With the flag MSI_FLAG_MULTI_PCI_MSI, when the Endpoint allocates multiple
MSI, it will trigger the "WARN_ON(nr_irqs != 1);" in mobiveil_irq_msi_domain_alloc(),
this is the issue this patch want to fix. 

Thanks,
Zhiqiang

> 
> Thanks,
> Lorenzo
> 
> > Thanks,
> > Zhiqiang
> >
> > >
> > > Lorenzo
> > >
> > > > Subbu, did you test with Endpoint supporting multi MSI?
> > > >
> > > > Thanks,
> > > > Zhiqiang
> > > >
> > > > >
> > > > > Thanks,
> > > > > Lorenzo
> > > > >
> > > > > > Fixes: 1e913e58335f ("PCI: mobiveil: Add MSI support")
> > > > > > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
> > > > > > Reviewed-by: Minghuan Lian <Minghuan.Lian@xxxxxxx>
> > > > > > ---
> > > > > > V5:
> > > > > >  - Corrected the subject.
> > > > > >
> > > > > >  drivers/pci/controller/pcie-mobiveil.c | 2 +-
> > > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/drivers/pci/controller/pcie-mobiveil.c
> > > > > > b/drivers/pci/controller/pcie-mobiveil.c
> > > > > > index 563210e731d3..a0dd337c6214 100644
> > > > > > --- a/drivers/pci/controller/pcie-mobiveil.c
> > > > > > +++ b/drivers/pci/controller/pcie-mobiveil.c
> > > > > > @@ -703,7 +703,7 @@ static struct irq_chip
> > > > > > mobiveil_msi_irq_chip = {
> > > > > >
> > > > > >  static struct msi_domain_info mobiveil_msi_domain_info = {
> > > > > >  	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS |
> > > > > MSI_FLAG_USE_DEF_CHIP_OPS |
> > > > > > -		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
> > > > > > +		   MSI_FLAG_PCI_MSIX),
> > > > > >  	.chip	= &mobiveil_msi_irq_chip,
> > > > > >  };
> > > > > >
> > > > > > --
> > > > > > 2.17.1
> > > > > >