From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Murali Karicheri <m-karicheri2@ti.com>,
Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org, Pawel Moll <pawel.moll@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
Rob Herring <robh+dt@kernel.org>,
Santosh Shilimkar <santosh.shilimkar@ti.com>,
Kumar Gala <galak@codeaurora.org>,
Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH] PCI: keystone: update to support multiple pci ports
Date: Fri, 05 Sep 2014 23:11:47 +0200 [thread overview]
Message-ID: <5769746.NkKjYOOUiv@wuerfel> (raw)
In-Reply-To: <540A1F05.80706@ti.com>
On Friday 05 September 2014 16:37:25 Murali Karicheri wrote:
> On 09/05/2014 03:00 PM, Arnd Bergmann wrote:
> > On Friday 05 September 2014 14:33:54 Murali Karicheri wrote:
> >>> This looks like it's a shared register of some sort that doesn't
> >>> really belong into the registers of a particular port. Could it
> >>> be that it's actually for the PHY?
> >>>
> >> This a shared device configuration register between the two ports the
> >> desciption states it is bootstrap configuration of the PCIe module as
> >> Endpoint or Root complex and Not Phy. Hope below text will help.
> >
> > Ok. Why do you want to have this user-selectable though? Can't it
> > just be set by the boot loader before starting Linux?
>
> Arnd,
>
> As the driver is responsible for configuring the device to support the
> device functionality, it make sense to do this in the device driver. The
> driver enables clock to the IP and this is an addition thing to be
> configured so that when the device is powered up, it should function as
> RC. The IP can be configured to work as Root Complex or Endpoint. So not
> sure why you want to me to move this functionality to boot loader.
But the driver can only do root complex mode, and we would probably
want a completely different driver if we were to start supporting
endpoint mode.
This also implies that the firmware has to pass a different DT for
endpoint mode, so it should be responsible for setting up the hardware
to match the DT.
Arnd
next prev parent reply other threads:[~2014-09-05 21:12 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-05 17:39 [PATCH] PCI: keystone: update to support multiple pci ports Murali Karicheri
2014-09-05 17:54 ` Arnd Bergmann
2014-09-05 18:33 ` Murali Karicheri
2014-09-05 19:00 ` Arnd Bergmann
2014-09-05 20:37 ` Murali Karicheri
2014-09-05 21:11 ` Arnd Bergmann [this message]
2014-09-08 15:52 ` Murali Karicheri
2014-09-09 10:24 ` Arnd Bergmann
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