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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71F23C3A59F for ; Thu, 29 Aug 2019 15:37:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DB492339E for ; Thu, 29 Aug 2019 15:37:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727834AbfH2PhR (ORCPT ); Thu, 29 Aug 2019 11:37:17 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:34482 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726283AbfH2PhR (ORCPT ); Thu, 29 Aug 2019 11:37:17 -0400 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id CC30F283C49; Thu, 29 Aug 2019 16:37:13 +0100 (BST) Date: Thu, 29 Aug 2019 17:37:09 +0200 From: Boris Brezillon To: Vitor Soares Cc: "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-i3c@lists.infradead.org" , "bbrezillon@kernel.org" , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "Joao.Pinto@synopsys.com" , Przemyslaw Gaj Subject: Re: [PATCH 1/4] i3c: master: detach and free device if pre_assign_dyn_addr() fails Message-ID: <20190829173709.79c093dd@collabora.com> In-Reply-To: References: <20190829124115.482cd8ec@collabora.com> <20190829163520.126d42d6@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 29 Aug 2019 15:23:30 +0000 Vitor Soares wrote: > From: Boris Brezillon > Date: Thu, Aug 29, 2019 at 15:35:20 > > > On Thu, 29 Aug 2019 13:53:24 +0000 > > Vitor Soares wrote: > > > > > Hi Boris, > > > > > > From: Boris Brezillon > > > Date: Thu, Aug 29, 2019 at 11:41:15 > > > > > > > +Przemek > > > > > > > > Please try to Cc active I3C contributors so they get a chance to > > > > comment on your patches. > > > > > > I can do that next time. > > > > > > > > > > > On Thu, 29 Aug 2019 12:19:32 +0200 > > > > Vitor Soares wrote: > > > > > > > > > On pre_assing_dyn_addr() the devices that fail: > > > > > i3c_master_setdasa_locked() > > > > > i3c_master_reattach_i3c_dev() > > > > > i3c_master_retrieve_dev_info() > > > > > > > > > > are kept in memory and master->bus.devs list. This makes the i3c devices > > > > > without a dynamic address are sent on DEFSLVS CCC command. Fix this by > > > > > detaching and freeing the devices that fail on pre_assign_dyn_addr(). > > > > > > > > I don't think removing those entries is a good strategy, as one might > > > > want to try to use a different dynamic address if the requested one > > > > is not available. > > > > > > Do you mean same 'assigned-address' attribute in DT? > > > > Yes, or say it's another device that got the address we want and this > > device doesn't want to release the address (I'm assuming the !SA case). > > > > > > > > If so, it is checked here: > > > > > > static int i3c_master_bus_init(struct i3c_master_controller *master) > > > ... > > > list_for_each_entry(i3cboardinfo, &master->boardinfo.i3c, node) { > > > struct i3c_device_info info = { > > > .static_addr = i3cboardinfo->static_addr, > > > }; > > > > > > if (i3cboardinfo->init_dyn_addr) { > > > status = i3c_bus_get_addr_slot_status(&master->bus, > > > ^ > > > i3cboardinfo->init_dyn_addr); > > > if (status != I3C_ADDR_SLOT_FREE) { > > > ret = -EBUSY; > > > goto err_detach_devs; > > > } > > > } > > > > > > i3cdev = i3c_master_alloc_i3c_dev(master, &info); > > > if (IS_ERR(i3cdev)) { > > > ret = PTR_ERR(i3cdev); > > > goto err_detach_devs; > > > } > > > > > > i3cdev->boardinfo = i3cboardinfo; > > > > > > ret = i3c_master_attach_i3c_dev(master, i3cdev); > > > if (ret) { > > > i3c_master_free_i3c_dev(i3cdev); > > > goto err_detach_devs; > > > } > > > } > > > ... > > > > > > and later if it fails i3c_master_pre_assign_dyn_addr(), the device can > > > participate in Enter Dynamic Address Assignment process. > > > I may need to check the boardinfo->init_dyn_addr status on > > > i3c_master_add_i3c_dev_locked before i3c_master_setnewda_locked(). > > > > I need to double check but I thought we were already handling that case > > properly. > > Yes, it is handled in the code above. No, I meant the 'assign init_dyn_addr even if !SA', and the code I pointed in my other reply tends to confirm that this is something we already take into account (maybe not correctly, but the code is here). > > > > > > > > > > Why not simply skipping entries that have ->dyn_addr > > > > set to 0 when preparing a DEFSLVS frame > > > > > > I considered that solution too but if the device isn't enumerated why > > > should it be attached and kept in memory? > > > > Might be a device that supports HJ, and in that case we might want the > > controller to reserve a slot in its device table for that device. > > Anyway, it doesn't hurt to have it around as long as we don't pass the > > device through DEFSLVS if it doesn't have a dynamic address. I really > > prefer to keep the logic unchanged and fix it if it needs to be fixed. > > Well, we aren't reserving a slot because we need another one to attach > the device when it is enumerated and hence a device may be using 2 slots > in the controller. Right, you shouldn't reserve a slot when ->static_address == 0 && ->dynamic_address == 0, but I still don't see where the problem is with the solution we have right now, sorry. Note that even if you reserve a slot in that case, the device only occupies 2 slots for a short amount of time, because the add_i3c_dev() logic will detect that the descriptor already exists and reattach the device with its new address. > It may cause problems in HC with reduced slots and it is another reason > why I think we should detach device without dynamic address after the > enumeration phase. Can you please try the approach I suggest? => fix the existing logic to make it work without this "free undiscovered dev desc, reallocate later" dance.