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From: "Z.q. Hou" <zhiqiang.hou@nxp.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"l.subrahmanya@mobiveil.co.in" <l.subrahmanya@mobiveil.co.in>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	Leo Li <leoyang.li@nxp.com>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"will.deacon@arm.com" <will.deacon@arm.com>,
	Mingkai Hu <mingkai.hu@nxp.com>,
	"M.h. Lian" <minghuan.lian@nxp.com>,
	Xiaowei Bao <xiaowei.bao@nxp.com>
Subject: RE: [PATCHv5 04/20] PCI: mobiveil: Remove the flag MSI_FLAG_MULTI_PCI_MSI
Date: Mon, 1 Jul 2019 10:07:51 +0000	[thread overview]
Message-ID: <DB8PR04MB67471CA3A4E8D76F2E0DC49484F90@DB8PR04MB6747.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20190628113555.GA21829@e121166-lin.cambridge.arm.com>

Hi Lorenzo,

Thanks a lot for your comments!

> -----Original Message-----
> From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Sent: 2019年6月28日 19:36
> To: Z.q. Hou <zhiqiang.hou@nxp.com>
> Cc: linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org;
> bhelgaas@google.com; robh+dt@kernel.org; mark.rutland@arm.com;
> l.subrahmanya@mobiveil.co.in; shawnguo@kernel.org; Leo Li
> <leoyang.li@nxp.com>; catalin.marinas@arm.com; will.deacon@arm.com;
> Mingkai Hu <mingkai.hu@nxp.com>; M.h. Lian <minghuan.lian@nxp.com>;
> Xiaowei Bao <xiaowei.bao@nxp.com>
> Subject: Re: [PATCHv5 04/20] PCI: mobiveil: Remove the flag
> MSI_FLAG_MULTI_PCI_MSI
> 
> On Mon, Jun 17, 2019 at 10:34:35AM +0000, Z.q. Hou wrote:
> 
> [...]
> 
> > > 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.
> 
> And that's wrong. Marc explained why this controller does not support Multi
> MSI and that's what should go in the commit log, triggering a WARN_ON is
> the least of the problems (and the WARN_ON can even be removed after
> this patch is applied), if it was used as a bandaid to prevent allocating Multi
> MSI it is even more broken.
>

Yes, I agree, the root cause is hardware limitation, is the following changelog
acceptable?

Changelog:
The Mobiveil internal MSI controller uses separate target address per MSI,
so, it is unable to support Multiple MSI feature, which requires the same
target address and incremental MSI_DATA values. This patch is to remove
the flag MSI_FLAG_MULTI_PCI_MSI.

Thanks,
Zhiqiang
 
> Lorenzo
> 
> > 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@nxp.com>
> > > > > > > > Reviewed-by: Minghuan Lian <Minghuan.Lian@nxp.com>
> > > > > > > > ---
> > > > > > > > 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
> > > > > > > >

  reply	other threads:[~2019-07-01 10:08 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-12  8:35 [PATCHv5 00/20] PCI: mobiveil: fixes for Mobiveil PCIe Host Bridge IP driver Z.q. Hou
2019-04-12  8:35 ` [PATCHv5 01/20] PCI: mobiveil: Unify register accessors Z.q. Hou
2019-04-12  8:35 ` [PATCHv5 02/20] PCI: mobiveil: Format the code without functionality change Z.q. Hou
2019-07-03 15:10   ` Lorenzo Pieralisi
2019-07-04  2:41     ` Z.q. Hou
2019-07-03 15:19   ` Lorenzo Pieralisi
2019-07-03 15:24     ` Lorenzo Pieralisi
2019-07-04  3:00     ` Z.q. Hou
2019-07-04 10:56       ` Lorenzo Pieralisi
2019-07-05  2:24         ` Z.q. Hou
2019-04-12  8:35 ` [PATCHv5 03/20] PCI: mobiveil: Correct the returned error number Z.q. Hou
2019-07-03 14:17   ` Lorenzo Pieralisi
2019-07-04  2:38     ` Z.q. Hou
2019-04-12  8:35 ` [PATCHv5 04/20] PCI: mobiveil: Remove the flag MSI_FLAG_MULTI_PCI_MSI Z.q. Hou
2019-06-11 16:59   ` Lorenzo Pieralisi
2019-06-11 17:29     ` Marc Zyngier
2019-06-12 10:54       ` Lorenzo Pieralisi
2019-06-12 11:22       ` Marc Zyngier
2019-06-12 11:34     ` Z.q. Hou
2019-06-12 13:08       ` Lorenzo Pieralisi
2019-06-15  1:30         ` Z.q. Hou
2019-06-17  9:33           ` Lorenzo Pieralisi
2019-06-17 10:34             ` Z.q. Hou
2019-06-28 11:35               ` Lorenzo Pieralisi
2019-07-01 10:07                 ` Z.q. Hou [this message]
2019-04-12  8:35 ` [PATCHv5 05/20] PCI: mobiveil: Correct PCI base address in MEM/IO outbound windows Z.q. Hou
2019-04-12  8:35 ` [PATCHv5 06/20] PCI: mobiveil: Replace the resource list iteration function Z.q. Hou
2019-04-12  8:35 ` [PATCHv5 07/20] PCI: mobiveil: Use WIN_NUM_0 explicitly for CFG outbound window Z.q. Hou
2019-06-12 15:13   ` Lorenzo Pieralisi
2019-04-12  8:36 ` [PATCHv5 08/20] PCI: mobiveil: Use the 1st inbound window for MEM inbound transactions Z.q. Hou
2019-06-28 16:02   ` Lorenzo Pieralisi
2019-07-01 10:18     ` Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 09/20] PCI: mobiveil: Correct inbound/outbound window setup routines Z.q. Hou
2019-06-28 16:41   ` Lorenzo Pieralisi
2019-07-01 10:24     ` Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 10/20] PCI: mobiveil: Fix the INTx process errors Z.q. Hou
2019-06-12 15:08   ` Lorenzo Pieralisi
2019-06-14  7:08     ` Karthikeyan Mitran
2019-06-14 10:43       ` Lorenzo Pieralisi
2019-06-19  5:28         ` Karthikeyan Mitran
2019-06-19  7:24           ` Z.q. Hou
2019-06-28 17:05   ` Lorenzo Pieralisi
2019-07-01 10:27     ` Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 11/20] PCI: mobiveil: Correct the fixup of Class Code field Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 12/20] PCI: mobiveil: Move the link up waiting out of mobiveil_host_init() Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 13/20] PCI: mobiveil: Move IRQ chained handler setup out of DT parse Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 14/20] PCI: mobiveil: Initialize Primary/Secondary/Subordinate bus numbers Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 15/20] PCI: mobiveil: Fix the checking of valid device Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 16/20] PCI: mobiveil: Add link up condition check Z.q. Hou
2019-06-11 17:17   ` Lorenzo Pieralisi
2019-06-12 11:36     ` Z.q. Hou
2019-04-12  8:36 ` [PATCHv5 17/20] PCI: mobiveil: Complete initialization of host even if no PCIe link Z.q. Hou
2019-06-12 14:34   ` Lorenzo Pieralisi
2019-06-15  2:34     ` Z.q. Hou
2019-04-12  8:37 ` [PATCHv5 18/20] PCI: mobiveil: Disable IB and OB windows set by bootloader Z.q. Hou
2019-06-12 16:23   ` Lorenzo Pieralisi
2019-06-15  5:03     ` Z.q. Hou
2019-06-17  9:30       ` Lorenzo Pieralisi
2019-06-17 10:42         ` Z.q. Hou
2019-04-12  8:37 ` [PATCHv5 19/20] PCI: mobiveil: Add 8-bit and 16-bit register accessors Z.q. Hou
2019-06-12 13:54   ` Lorenzo Pieralisi
2019-06-15  1:13     ` Z.q. Hou
2019-06-17  9:29       ` Lorenzo Pieralisi
2019-06-17 10:16         ` Z.q. Hou
2019-04-12  8:37 ` [PATCHv5 20/20] dt-bindings: PCI: mobiveil: Change gpio_slave and apb_csr to optional Z.q. Hou
2019-07-03 10:33 ` [PATCHv5 00/20] PCI: mobiveil: fixes for Mobiveil PCIe Host Bridge IP driver Lorenzo Pieralisi
2019-07-04  2:36   ` Z.q. Hou

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