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From: Bjorn Helgaas <helgaas@kernel.org>
To: Vidya Sagar <vidyas@nvidia.com>
Cc: lorenzo.pieralisi@arm.com, bhelgaas@google.com,
	robh+dt@kernel.org, amurray@thegoodpenguin.co.uk,
	gustavo.pimentel@synopsys.com, jingoohan1@gmail.com,
	Joao.Pinto@synopsys.com, Jonathan Hunter <jonathanh@nvidia.com>,
	Thierry Reding <treding@nvidia.com>,
	Krishna Thota <kthota@nvidia.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Query regarding the use of pcie-designware-plat.c file
Date: Wed, 9 Jun 2021 11:30:10 -0500	[thread overview]
Message-ID: <20210609163010.GA2643779@bjorn-Precision-5520> (raw)
In-Reply-To: <34650ed1-6567-3c8f-fe29-8816f0fd74f2@nvidia.com>

On Wed, Jun 09, 2021 at 12:52:37AM +0530, Vidya Sagar wrote:
> Hi,
> I would like to know what is the use of pcie-designware-plat.c file. This
> looks like a skeleton file and can't really work with any specific hardware
> as such.
> Some context for this mail thread is, if the config CONFIG_PCIE_DW_PLAT is
> enabled in a system where a Synopsys DesignWare IP based PCIe controller is
> present and its configuration is enabled (Ex:- Tegra194 system with
> CONFIG_PCIE_TEGRA194_HOST enabled), then, it can so happen that the probe of
> pcie-designware-plat.c called first (because all DWC based PCIe controller
> nodes have "snps,dw-pcie" compatibility string) and can crash the system.

What's the crash?  If a device claims to be compatible with
"snps,dw-pcie" and pcie-designware-plat.c claims to know how to
operate "snps,dw-pcie" devices, it seems like something is wrong.

"snps,dw-pcie" is a generic device type, so pcie-designware-plat.c
might not know how to operate device-specific details of some of those
devices, but basic functionality should work and it certainly
shouldn't crash.

Bjorn

  parent reply	other threads:[~2021-06-09 16:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 19:22 Query regarding the use of pcie-designware-plat.c file Vidya Sagar
2021-06-08 21:17 ` Gustavo Pimentel
2021-06-09  5:26   ` Vidya Sagar
2021-06-09  9:49     ` Thierry Reding
2021-06-15  3:28       ` Vidya Sagar
2021-06-09 16:30 ` Bjorn Helgaas [this message]
2021-06-09 16:54   ` Jon Hunter
2021-06-15 19:42     ` Bjorn Helgaas
2021-06-15 21:05       ` Rob Herring
2021-06-16  7:54       ` Jon Hunter
2021-06-20 13:35         ` Vidya Sagar

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