From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] PCI: keystone: update to support multiple pci ports Date: Fri, 05 Sep 2014 23:11:47 +0200 Message-ID: <5769746.NkKjYOOUiv@wuerfel> References: <1409938782-31460-1-git-send-email-m-karicheri2@ti.com> <3654923.JrIGV2dJ70@wuerfel> <540A1F05.80706@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <540A1F05.80706@ti.com> Sender: linux-pci-owner@vger.kernel.org To: linux-arm-kernel@lists.infradead.org Cc: Murali Karicheri , Mark Rutland , devicetree@vger.kernel.org, Pawel Moll , Ian Campbell , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Rob Herring , Santosh Shilimkar , Kumar Gala , Bjorn Helgaas List-Id: devicetree@vger.kernel.org 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