From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ray Jui Subject: Re: [PATCH 2/4] PCI: iproc: Add Broadcom iProc PCIe driver Date: Wed, 10 Dec 2014 12:40:38 -0800 Message-ID: <5488AFC6.3000209@broadcom.com> References: <1418169871-19232-3-git-send-email-rjui@broadcom.com> <9707535.Y78sV0TgX4@wuerfel> <54887901.8070501@broadcom.com> <5488AC64.9010306@hauke-m.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5488AC64.9010306-5/S+JYg5SzeELgA04lAiVw@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Hauke Mehrtens , Florian Fainelli , Scott Branden Cc: Arnd Bergmann , Bjorn Helgaas , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Grant Likely , Christian Daudt , Matt Porter , Russell King , linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , bcm-kernel-feedback-list , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org On 12/10/2014 12:26 PM, Hauke Mehrtens wrote: > On 12/10/2014 07:46 PM, Florian Fainelli wrote: >> 2014-12-10 8:46 GMT-08:00 Scott Branden : >>> On 14-12-10 03:31 AM, Arnd Bergmann wrote: >>>> >>>> On Tuesday 09 December 2014 16:04:29 Ray Jui wrote: >>>>> >>>>> Add initial version of the Broadcom iProc PCIe driver. This driver >>>>> has been tested on NSP and Cygnus and is expected to work on all iProc >>>>> family of SoCs that deploys the same PCIe host controller >>>>> >>>>> The driver also supports MSI >>>>> >>>>> Signed-off-by: Ray Jui >>>>> Reviewed-by: Scott Branden >>>> >>>> >>>> The driver looks suspiciously like the one that Hauke already submitted a >>>> while ago for bcm53xx. Please come up with a merged driver that works for >>>> both. >>> >>> Could you please be a little more specific. What driver did "Hauke already >>> submitted"? I do not see any driver in the kernel you are talking about. >> >> https://www.marc.info/?l=linux-pci&m=141547043110684&w=2 > > Yes it also looks similar to me. Your code also contains the same > comments as the driver used on Northstar (BCM5301X).Your driver has > some more features, but I just have access to the consumer SoC Northstar > where the PCIe controller is only used to connect some Broadcom Wifi > chips to the SoC. I do not know If this controller does not have these > features or the driver I used as a reference does not implement them. > Right, I wrote this driver based on some old Broadcom internal PCIe driver from a 3.6 kernel and might have copied some of the comments (especially in the check link function). The 3.6 driver is probably what you received? > When I find some time I will try this driver on a Northstar device. I > think your driver is more advanced then the one I send to the mailing list. > Please do that. I tested this driver on Cygnus and one of my colleagues helped to test it on North Star Plus. We do expect the same driver to work on NorthStar as well. > When you want to stay with pure device tree I will send a patch adding > additional support for registering to bcma. > What exactly is bcma? I guess I'll need to look into it in more details myself. > Does your SoC also have a third PCIe controller which shares the PHY > with the USB 3 controller? No. Cygnus has only two PCIe controllers, each has its own dedicated PHY. > > Why is this stuff in the iproc_pcie_check_link() function needed? I > think it is strange that the controller driver has to check if the > device is there and set the correct speed. When we do not check if the > card is there on BCM5301X the device stops working. > I need to check with our ASIC engineer on this. In theory we should be able to support hot plug eventually, but maybe not in the initial version of this driver. >>>> Are you sure that iProc isn't based on the BCMA bus infrastructure after >>>> all? Even the physical address of your PCI host falls into the address >>>> range that is used for the internal BCMA bus on the other chips! >>> >>> BCMA seems to be for MIPS architectures. It seems to be quite specific to >>> those architectures using BCMA. I see no use of it in bcm53xx code? >> >> BCMA lives in its own directory in drivers/bcma/ and is not specific >> to MIPS actually. Older BCM47xx/BCM53xx MIPS-based SoCs traditionally >> started with a discoverable Silicon Sonics Backplane (drivers/ssb) and >> progressively migrated to BCMA (drivers/bcma), both subsystems offer a >> very similar bus/device/driver abstraction and discovery mechanism. > > With mainline kernel 3.18 you can boot Linux on a BCM5301X SoC and bcma > will find all the cores. > > Hauke > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html