From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 378B9E7D271 for ; Tue, 26 Sep 2023 10:05:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234206AbjIZKFb (ORCPT ); Tue, 26 Sep 2023 06:05:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229674AbjIZKF2 (ORCPT ); Tue, 26 Sep 2023 06:05:28 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D372597 for ; Tue, 26 Sep 2023 03:05:21 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75B6FC433C7; Tue, 26 Sep 2023 10:05:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695722721; bh=FRY+2/YiUx0GUA9zrZNTOcop5bKxxb0FkPII665yLe8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=c6wXDAvx09MwQSbEG/KS/MCClUoRd8vdwsocvrUHjhzaw52fGEreFjMzciKxioW38 PUlSPMxQ0s2lOi9K0Ah4az6D23Duhh7eKyaR6oi3l91Z/gR5YGk+E62RZwm/2j1pKF 3MGAoo/AAkjx9zD3J867j6X8wOOg25nJF33jWCJg= Date: Tue, 26 Sep 2023 12:05:16 +0200 From: Greg KH To: Abhijit Gangurde Cc: masahiroy@kernel.org, linux-kernel@vger.kernel.org, Nipun.Gupta@amd.com, nikhil.agarwal@amd.com, puneet.gupta@amd.com, git@amd.com, michal.simek@amd.com, Pieter Jansen van Vuuren Subject: Re: [PATCH v5 3/5] cdx: add support for bus enable and disable Message-ID: <2023092613-clean-antitoxic-077c@gregkh> References: <20230922101828.33456-1-abhijit.gangurde@amd.com> <20230922101828.33456-4-abhijit.gangurde@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230922101828.33456-4-abhijit.gangurde@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 22, 2023 at 03:48:26PM +0530, Abhijit Gangurde wrote: > CDX bus needs to be disabled before updating/writing devices > in the FPGA. Once the devices are written, the bus shall be > rescanned. This change provides sysfs entry to enable/disable the > CDX bus. > > Co-developed-by: Nipun Gupta > Signed-off-by: Nipun Gupta > Signed-off-by: Abhijit Gangurde > Reviewed-by: Pieter Jansen van Vuuren > Tested-by: Nikhil Agarwal > --- > Changes in v5: > - Rebased on Linux 6.6 > > Changes in v4: > - Add sparse marking for lock around cdx_find_controller() function > > Changes in v3: > - Use platform bus to locate controller > > Changes in v2: > - Improve documentation > - Split sysfs entry enable to enable and disable > - sysfs entry enable and disable take bus number as an argument > > Documentation/ABI/testing/sysfs-bus-cdx | 27 +++++++ > drivers/cdx/cdx.c | 97 +++++++++++++++++++++++++ > drivers/cdx/controller/cdx_controller.c | 50 +++++++++++++ > drivers/cdx/controller/mc_cdx_pcol.h | 54 ++++++++++++++ > drivers/cdx/controller/mcdi_functions.c | 24 ++++++ > drivers/cdx/controller/mcdi_functions.h | 18 +++++ > include/linux/cdx/cdx_bus.h | 12 +++ > 7 files changed, 282 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-bus-cdx b/Documentation/ABI/testing/sysfs-bus-cdx > index 7af477f49998..04c8dfe7e201 100644 > --- a/Documentation/ABI/testing/sysfs-bus-cdx > +++ b/Documentation/ABI/testing/sysfs-bus-cdx > @@ -11,6 +11,33 @@ Description: > > # echo 1 > /sys/bus/cdx/rescan > > +What: /sys/bus/cdx/enable > +Date: July 2023 > +Contact: nipun.gupta@amd.com > +Description: > + Writing bus number in hex to this file will attempt to enable > + the CDX bus. The bus number for the cdx devices can be found > + at /sys/bus/cdx/devices/cdx-BB:DD, where BB denotes the bus > + number for the respective device. > + > + For example :: > + > + # echo 00 > /sys/bus/cdx/enable > + > +What: /sys/bus/cdx/disable > +Date: July 2023 > +Contact: nipun.gupta@amd.com > +Description: > + Writing bus number in hex to this file will attempt to disable > + the CDX bus. CDX bus should be disabled before updating the > + devices in FPGA. The bus number for the cdx devices can be > + found at /sys/bus/cdx/devices/cdx-BB:DD, where BB denotes the > + bus number for the respective device. > + > + For example :: > + > + # echo 00 > /sys/bus/cdx/disable > + I can't remember, but why aren't these just attributes on the bus controller for that specific bus, and not a bus-wide attribute? Wouldn't that make more sense and remove the need for parsing values of a bus number and make it more obvious what bus was and was not enabled at any point in time (i.e. you can't read to see what bus is enabled/disabled right now with this change.) thanks, greg k-h