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From: Bjorn Helgaas <helgaas@kernel.org>
To: Vidya Sagar <vidyas@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	lorenzo.pieralisi@arm.com, robh+dt@kernel.org,
	mark.rutland@arm.com, thierry.reding@gmail.com,
	jonathanh@nvidia.com, kishon@ti.com, catalin.marinas@arm.com,
	will.deacon@arm.com, jingoohan1@gmail.com,
	gustavo.pimentel@synopsys.com, mperttunen@nvidia.com,
	linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kthota@nvidia.com,
	mmaddireddy@nvidia.com, sagar.tv@gmail.com
Subject: Re: [PATCH V6 02/15] PCI/PME: Export pcie_pme_disable_msi() & pcie_pme_no_msi() APIs
Date: Thu, 16 May 2019 08:34:26 -0500	[thread overview]
Message-ID: <20190516133426.GC101793@google.com> (raw)
In-Reply-To: <3a8cea93-2aeb-e5e2-4d56-f0c6449073c3@nvidia.com>

On Tue, May 14, 2019 at 09:00:19AM +0530, Vidya Sagar wrote:
> On 5/13/2019 12:55 PM, Christoph Hellwig wrote:
> > On Mon, May 13, 2019 at 10:36:13AM +0530, Vidya Sagar wrote:
> > > Export pcie_pme_disable_msi() & pcie_pme_no_msi() APIs to enable drivers
> > > using these APIs be able to build as loadable modules.
> > 
> > But this is a global setting.  If you root port is broken you need
> > a per-rootport quirk instead.
> > 
> There is nothing broken in Tegra194 root port as such, rather, this
> is more of software configuration choice and we are going with
> legacy interrupts than MSI interrupts (as Tegra194 doesn't support
> raising PME interrupts through MSI and please note that this doesn't
> mean root port is broken).

I think the port *is* broken.  PCIe r4.0, sec 6.1.6, says

  If the Root Port is enabled for edge-triggered interrupt signaling
  using MSI or MSI-X, an interrupt message must be sent every time the
  logical AND of the following conditions transitions from FALSE to
  TRUE:

    * The associated vector is unmasked (not applicable if MSI does
      not support PVM).

    * The PME Interrupt Enable bit in the Root Control register is set
      to 1b.

    * The PME Status bit in the Root Status register is set.

The Tegra194 root port advertises MSI support, so the above should
apply.

> Since Tegra194 has only Synopsys DesignWare core based host
> controllers and not any other hosts, I think it is fine to call this
> API in driver.

It's fine to add a per-device quirk to set pdev->no_msi or something
similar.

Bjorn

WARNING: multiple messages have this Message-ID (diff)
From: Bjorn Helgaas <helgaas@kernel.org>
To: Vidya Sagar <vidyas@nvidia.com>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
	lorenzo.pieralisi@arm.com, mperttunen@nvidia.com,
	mmaddireddy@nvidia.com, linux-pci@vger.kernel.org,
	catalin.marinas@arm.com, will.deacon@arm.com,
	linux-kernel@vger.kernel.org, robh+dt@kernel.org,
	jonathanh@nvidia.com, Christoph Hellwig <hch@infradead.org>,
	kthota@nvidia.com, thierry.reding@gmail.com,
	gustavo.pimentel@synopsys.com, jingoohan1@gmail.com,
	linux-tegra@vger.kernel.org, kishon@ti.com,
	linux-arm-kernel@lists.infradead.org, sagar.tv@gmail.com
Subject: Re: [PATCH V6 02/15] PCI/PME: Export pcie_pme_disable_msi() & pcie_pme_no_msi() APIs
Date: Thu, 16 May 2019 08:34:26 -0500	[thread overview]
Message-ID: <20190516133426.GC101793@google.com> (raw)
In-Reply-To: <3a8cea93-2aeb-e5e2-4d56-f0c6449073c3@nvidia.com>

On Tue, May 14, 2019 at 09:00:19AM +0530, Vidya Sagar wrote:
> On 5/13/2019 12:55 PM, Christoph Hellwig wrote:
> > On Mon, May 13, 2019 at 10:36:13AM +0530, Vidya Sagar wrote:
> > > Export pcie_pme_disable_msi() & pcie_pme_no_msi() APIs to enable drivers
> > > using these APIs be able to build as loadable modules.
> > 
> > But this is a global setting.  If you root port is broken you need
> > a per-rootport quirk instead.
> > 
> There is nothing broken in Tegra194 root port as such, rather, this
> is more of software configuration choice and we are going with
> legacy interrupts than MSI interrupts (as Tegra194 doesn't support
> raising PME interrupts through MSI and please note that this doesn't
> mean root port is broken).

I think the port *is* broken.  PCIe r4.0, sec 6.1.6, says

  If the Root Port is enabled for edge-triggered interrupt signaling
  using MSI or MSI-X, an interrupt message must be sent every time the
  logical AND of the following conditions transitions from FALSE to
  TRUE:

    * The associated vector is unmasked (not applicable if MSI does
      not support PVM).

    * The PME Interrupt Enable bit in the Root Control register is set
      to 1b.

    * The PME Status bit in the Root Status register is set.

The Tegra194 root port advertises MSI support, so the above should
apply.

> Since Tegra194 has only Synopsys DesignWare core based host
> controllers and not any other hosts, I think it is fine to call this
> API in driver.

It's fine to add a per-device quirk to set pdev->no_msi or something
similar.

Bjorn

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  parent reply	other threads:[~2019-05-16 13:34 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13  5:06 [PATCH V6 00/15] Add Tegra194 PCIe support Vidya Sagar
2019-05-13  5:06 ` Vidya Sagar
2019-05-13  5:06 ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 01/15] PCI: Add #defines for some of PCIe spec r4.0 features Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 02/15] PCI/PME: Export pcie_pme_disable_msi() & pcie_pme_no_msi() APIs Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  7:25   ` Christoph Hellwig
2019-05-13  7:25     ` Christoph Hellwig
2019-05-14  3:30     ` Vidya Sagar
2019-05-14  3:30       ` Vidya Sagar
2019-05-14  3:30       ` Vidya Sagar
2019-05-14  6:02       ` Christoph Hellwig
2019-05-14  6:02         ` Christoph Hellwig
2019-05-14  6:02         ` Christoph Hellwig
2019-05-16 13:34       ` Bjorn Helgaas [this message]
2019-05-16 13:34         ` Bjorn Helgaas
2019-05-17  8:19         ` Vidya Sagar
2019-05-17  8:19           ` Vidya Sagar
2019-05-17  8:19           ` Vidya Sagar
2019-05-17 13:24           ` Bjorn Helgaas
2019-05-17 13:24             ` Bjorn Helgaas
2019-05-17 17:53             ` Vidya Sagar
2019-05-17 17:53               ` Vidya Sagar
2019-05-17 17:53               ` Vidya Sagar
2019-05-17 18:55               ` Bjorn Helgaas
2019-05-17 18:55                 ` Bjorn Helgaas
2019-05-18  1:58                 ` Vidya Sagar
2019-05-18  1:58                   ` Vidya Sagar
2019-05-18  1:58                   ` Vidya Sagar
2019-05-20 17:57                   ` Bjorn Helgaas
2019-05-20 17:57                     ` Bjorn Helgaas
2019-05-21  5:06                     ` Vidya Sagar
2019-05-21  5:06                       ` Vidya Sagar
2019-05-21  5:06                       ` Vidya Sagar
2019-05-16 13:28   ` Bjorn Helgaas
2019-05-16 13:28     ` Bjorn Helgaas
2019-05-13  5:06 ` [PATCH V6 03/15] PCI: dwc: Perform dbi regs write lock towards the end Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 04/15] PCI: dwc: Move config space capability search API Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 05/15] PCI: dwc: Add ext " Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 06/15] dt-bindings: PCI: designware: Add binding for CDM register check Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13 15:10   ` Rob Herring
2019-05-13 15:10     ` Rob Herring
2019-05-14  5:27     ` Vidya Sagar
2019-05-14  5:27       ` Vidya Sagar
2019-05-14  5:27       ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 07/15] PCI: dwc: Add support to enable " Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 08/15] dt-bindings: Add PCIe supports-clkreq property Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 09/15] dt-bindings: PCI: tegra: Add device tree support for Tegra194 Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 10/15] dt-bindings: PHY: P2U: Add Tegra194 P2U block Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13 15:22   ` Rob Herring
2019-05-13 15:22     ` Rob Herring
2019-05-13 15:22     ` Rob Herring
2019-05-13  5:06 ` [PATCH V6 11/15] arm64: tegra: Add P2U and PCIe controller nodes to Tegra194 DT Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 12/15] arm64: tegra: Enable PCIe slots in P2972-0000 board Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 13/15] phy: tegra: Add PCIe PIPE2UPHY support Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 14/15] PCI: tegra: Add Tegra194 PCIe support Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06 ` [PATCH V6 15/15] arm64: Add Tegra194 PCIe driver to defconfig Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar
2019-05-13  5:06   ` Vidya Sagar

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