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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 C2AD7C433DF for ; Thu, 20 Aug 2020 19:18:47 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 93A19206DA for ; Thu, 20 Aug 2020 19:18:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="dSYqy3bO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 93A19206DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fTnK+rXxDLW1CWqAznOrQHGEAmJgltx61mV5+rtbWYo=; b=dSYqy3bOVGidT+j90Z4q3kVlZ f2f0lhR7QqbakrMYU9oKTvADLDRN1nzF/MTbU+uZuNhlxBq0CtqXUNRcdHibmpRHFxJ+IyHD9nhnV q4P5aCmMHVzo4OpQUwz7wKUQ7InZ7yNz9M97S7UR/3Px1D9Pcfn9OLiBGLLyTyFh/DnoO55RMx9Qp 7AKWpy6SAN0jbhfTH5BIyX5DAPfE8boADAfWyPhFVxWGNt9oz5OF2XfxbfW5LVHvxoRVcdt0QJRF2 FWcz56bQRlihhyA8u7mcm3j8TKOtJTdE8qdKvUJZSf5YVr60xNWHGUNuVRBLSLKlx6bOc0UfVCgDV wav6dpdww==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8q5G-0001pp-KU for linux-i3c@archiver.kernel.org; Thu, 20 Aug 2020 19:18:46 +0000 Received: from bhuna.collabora.co.uk ([2a00:1098:0:82:1000:25:2eeb:e3e3]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1k8q5E-0001pU-1J for linux-i3c@lists.infradead.org; Thu, 20 Aug 2020 19:18:44 +0000 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 A797C29AC9B; Thu, 20 Aug 2020 20:18:42 +0100 (BST) Date: Thu, 20 Aug 2020 21:18:39 +0200 From: Boris Brezillon To: Parshuram Raju Thombare Subject: Re: [PATCH v3] i3c: master: fix for SETDASA and DAA process Message-ID: <20200820211839.54a42cf6@collabora.com> In-Reply-To: <20200820210311.5934fc2a@collabora.com> References: <1597930706-15744-1-git-send-email-pthombar@cadence.com> <20200820164820.4fec97b3@collabora.com> <20200820210311.5934fc2a@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.6 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200820_151844_220073_DB7355A8 X-CRM114-Status: GOOD ( 34.24 ) X-BeenThere: linux-i3c@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Milind Parab , "bbrezillon@kernel.org" , "praneeth@ti.com" , "linux-kernel@vger.kernel.org" , "vitor.soares@synopsys.com" , Przemyslaw Gaj , "linux-i3c@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-i3c" Errors-To: linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org On Thu, 20 Aug 2020 21:03:11 +0200 Boris Brezillon wrote: > On Thu, 20 Aug 2020 18:16:14 +0000 > Parshuram Raju Thombare wrote: > > > >Hm, not sure that qualifies as a fix. The current implementation was > > >correct, it was just reserving a slot in the device table for devices > > >that didn't have an init address or on which SETDASA failed. > > If I3C controllers like ours use hardware slots to store slave devices info, > > due to limited available slots this can cause issue. > > If some slots are lost due to > > 1. only init_dyn_addr and no static_addr in DT > > OR > > 2. SETDASA failed > > Well, having a slot with a static address is valid, though I agree > it's not really useful. > > > at the end of DAA some devices may be left without dyn_addr allocated from master > > and hence can't work properly. > > My point is, there's no address or device slot leak, it's just that > reserving a slot for I3C devices that only have a static address is > kind of useless. But let's be honest, given the number of I3C devices > available out there, I don't think it will hurt us before quite some > time :P. That's not to say we shouldn't address that, I just don't > think it deserves a Fixes tag. > > > I think during our discussion we recognized this change as a bug. > > IIRC, I was talking about the first patch in the series. > > > That is the reason I added fixes tag, but if you think otherwise I can remove this tag. > > > > >> -static void i3c_master_pre_assign_dyn_addr(struct i3c_dev_desc *dev) > > >> +static int i3c_master_pre_assign_dyn_addr(struct i3c_master_controller > > >That function now does more than just assigning a dynamic address: it > > >also creates the i3c_dev_desc. It should be renamed accordingly > > >(i3c_master_early_i3c_dev_add() maybe). > > Ok > > > > >You should reserve the address before calling > > >i3c_master_pre_assign_dyn_addr(): > > > > > > /* > > > * We don't attach devices which are not addressable > > > * (no static_addr and dyn_addr) and devices with > > > * static_addr but no init_dyn_addr will participate in DAA. > > > */ > > > if (!i3cboardinfo->init_dyn_addr || > > > !i3cboardinfo->static_addr) > > > continue; > > Don't we want to cover the case when only init_dyn_addr is present ? > > Uh, yes, my bad. > > > I am not sure if we can't have init_dyn_addr without static_addr. > > You can, when you want to assign a specific dynamic address to a device > that doesn't have a static address (see the 'try to assign init_addr > dance' in i3c_dev_add()). > > > May be what we need is > > if (!i3cboardinfo->init_dyn_addr) > > continue; > > > > ret = i3c_bus_get_addr_slot_status(&master->bus, > > i3cboardinfo->init_dyn_addr); > > if (ret != I3C_ADDR_SLOT_FREE) { > > ret = -EBUSY; > > goto err_rstdaa; > > } > > > > i3c_bus_set_addr_slot_status(&master->bus, > > i3cboardinfo->init_dyn_addr, > > I3C_ADDR_SLOT_I3C_DEV); > > > > if (i3cboardinfo->static_addr) > > i3c_master_pre_assign_dyn_addr(master, i3cboardinfo); > > Yep, that's correct. > > > IMHO this is functionally same to what I sent. Just that init_dyn_addr is reserved before, > > and we leverage the change in reattach to bypass failure due to second attempt > > to get init_dyn_addr in reattach called from i3c_master_pre_assign_dyn_addr(). > > Unless I'm missing something, your solution didn't reserve the > init address when there's no static address, and we definitely want > that to happen, otherwise another device might steal it during DAA. My bad, it did. This being said, I find it much easier to follow when the reservation happens in one place, so I'm still in favor of the new version. -- linux-i3c mailing list linux-i3c@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-i3c