From patchwork Tue Feb 7 01:41:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saravana Kannan X-Patchwork-Id: 652580 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 6CB81C61DA4 for ; Tue, 7 Feb 2023 01:43:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230456AbjBGBnB (ORCPT ); Mon, 6 Feb 2023 20:43:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40852 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230376AbjBGBma (ORCPT ); Mon, 6 Feb 2023 20:42:30 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2FC635267 for ; Mon, 6 Feb 2023 17:42:24 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id k14-20020aa7972e000000b00593a8232ac3so7377202pfg.22 for ; Mon, 06 Feb 2023 17:42:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=GzemyWsbe1874/35X2pGE6I7zLC/qObwAXplkSqm2aE=; b=b7u37IEj5Fvd6YXLTEOU720DHRSwTWNj09MbzD4MFmQBovqJgQg/oKrS1P046uOL3W wTyWtdFCoTfoIgRQeaARkhnceMX2583Jt9ShPGALCTgQifsrFvgU/DdEOZxYTEIquAsw HrxCZ06UNjYJMftUEHe1ow4Tv6q2XYScigicpVP27au4gdTVa6EeeO+wgmUNMe9cCEog LaNPQCCahp25YO89ePuDfYwQXExsNtfJ7zTvd1EnsoPpeBtfm+oghEapmUp893sivQJM 0+clHCPHG1Hnj1tLQRTLevMmypFLA7Tn8AWn71fXIYRoOpq4aLcl0otIKMQmn6405jAT RNAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=GzemyWsbe1874/35X2pGE6I7zLC/qObwAXplkSqm2aE=; b=VKmAiFsH+PzrjDewB81vyL2cs40b+JOM0qUTmAKRgo/st4SEX3DngZ/fGC4nSKhZqJ gLy8zX9M7mIQvqZGRE4i19ZWxQMQvJLBMP5YoTACvS9PZPyiNimv4eJY+dFr9lMEOG6i AvmKYAPiDEEjXGdNirujtGx+4ysK+07xRJZqAtJFiZ/JhO3VG4omUThCbbwx46lWPH10 MIjfLp46kJd8ivZeBH6FYqyriLrKlGIKzWf3yRziWmrfLgZ5ZMZztZncLOi3HMeV878I fkfbF02+ONd352+WuhtwhM90l5fGLWoLmIGOsF10caM2cWz6L7Fl2q5+KXU357oDyZA2 TA3g== X-Gm-Message-State: AO0yUKVTLokTzVLCgVd/am1q/B/iPdJpgGe6fB5O4m1iytytAFVSgnUS Q4gtVU6VZpxt7Be4H5iRP24XHNsx1lkRefY= X-Google-Smtp-Source: AK7set+0IxdeFoc+Kn+E3OD6+a3ZeegbPKAGCsgRpOcmEvW2y10wLjL8U1hVM8p0ddZt3HY7VH3NvMmLcJc1hoM= X-Received: from saravanak.san.corp.google.com ([2620:15c:2d:3:ae1:aba6:f21c:4a94]) (user=saravanak job=sendgmr) by 2002:a17:90a:148:b0:230:e030:844f with SMTP id z8-20020a17090a014800b00230e030844fmr409952pje.77.1675734143942; Mon, 06 Feb 2023 17:42:23 -0800 (PST) Date: Mon, 6 Feb 2023 17:41:57 -0800 In-Reply-To: <20230207014207.1678715-1-saravanak@google.com> Message-Id: <20230207014207.1678715-6-saravanak@google.com> Mime-Version: 1.0 References: <20230207014207.1678715-1-saravanak@google.com> X-Mailer: git-send-email 2.39.1.519.gcb327c4b5f-goog Subject: [PATCH v3 05/12] driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Sudeep Holla , Cristian Marussi , Linus Walleij , Bartosz Golaszewski , Thomas Gleixner , Marc Zyngier , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Rob Herring , Frank Rowand , Geert Uytterhoeven , Magnus Damm , Andy Shevchenko , Daniel Scally , Heikki Krogerus , Sakari Ailus , Len Brown , Saravana Kannan , " =?utf-8?b?UmFmYcWCIE1pxYJlY2tp?= " Cc: Abel Vesa , Alexander Stein , Tony Lindgren , Geert Uytterhoeven , John Stultz , Doug Anderson , Guenter Roeck , Dmitry Baryshkov , Maxim Kiselev , Maxim Kochetkov , Luca Weiss , Colin Foster , Martin Kepplinger , Jean-Philippe Brucker , Vladimir Oltean , kernel-team@android.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org, linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-acpi@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org fw_devlink uses DL_FLAG_SYNC_STATE_ONLY device link flag for two purposes: 1. To allow a parent device to proxy its child device's dependency on a supplier so that the supplier doesn't get its sync_state() callback before the child device/consumer can be added and probed. In this usage scenario, we need to ignore cycles for ensure correctness of sync_state() callbacks. 2. When there are dependency cycles in firmware, we don't know which of those dependencies are valid. So, we have to ignore them all wrt probe ordering while still making sure the sync_state() callbacks come correctly. However, when detecting dependency cycles, there can be multiple dependency cycles between two devices that we need to detect. For example: A -> B -> A and A -> C -> B -> A. To detect multiple cycles correct, we need to be able to differentiate DL_FLAG_SYNC_STATE_ONLY device links used for (1) vs (2) above. To allow this differentiation, add a DL_FLAG_CYCLE that can be use to mark use case (2). We can then use the DL_FLAG_CYCLE to decide which DL_FLAG_SYNC_STATE_ONLY device links to follow when looking for dependency cycles. Fixes: 2de9d8e0d2fe ("driver core: fw_devlink: Improve handling of cyclic dependencies") Signed-off-by: Saravana Kannan Tested-by: Colin Foster Tested-by: Sudeep Holla --- drivers/base/core.c | 28 ++++++++++++++++++---------- include/linux/device.h | 1 + 2 files changed, 19 insertions(+), 10 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 368bfd96b511..071c454844d6 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -322,6 +322,12 @@ static bool device_is_ancestor(struct device *dev, struct device *target) return false; } +static inline bool device_link_flag_is_sync_state_only(u32 flags) +{ + return (flags & ~(DL_FLAG_INFERRED | DL_FLAG_CYCLE)) == + (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED); +} + /** * device_is_dependent - Check if one device depends on another one * @dev: Device to check dependencies for. @@ -348,8 +354,7 @@ int device_is_dependent(struct device *dev, void *target) return ret; list_for_each_entry(link, &dev->links.consumers, s_node) { - if ((link->flags & ~DL_FLAG_INFERRED) == - (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) + if (device_link_flag_is_sync_state_only(link->flags)) continue; if (link->consumer == target) @@ -422,8 +427,7 @@ static int device_reorder_to_tail(struct device *dev, void *not_used) device_for_each_child(dev, NULL, device_reorder_to_tail); list_for_each_entry(link, &dev->links.consumers, s_node) { - if ((link->flags & ~DL_FLAG_INFERRED) == - (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) + if (device_link_flag_is_sync_state_only(link->flags)) continue; device_reorder_to_tail(link->consumer, NULL); } @@ -684,7 +688,8 @@ postcore_initcall(devlink_class_init); DL_FLAG_AUTOREMOVE_SUPPLIER | \ DL_FLAG_AUTOPROBE_CONSUMER | \ DL_FLAG_SYNC_STATE_ONLY | \ - DL_FLAG_INFERRED) + DL_FLAG_INFERRED | \ + DL_FLAG_CYCLE) #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) @@ -753,8 +758,6 @@ struct device_link *device_link_add(struct device *consumer, if (!consumer || !supplier || consumer == supplier || flags & ~DL_ADD_VALID_FLAGS || (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || - (flags & DL_FLAG_SYNC_STATE_ONLY && - (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) || (flags & DL_FLAG_AUTOPROBE_CONSUMER && flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) @@ -770,6 +773,10 @@ struct device_link *device_link_add(struct device *consumer, if (!(flags & DL_FLAG_STATELESS)) flags |= DL_FLAG_MANAGED; + if (flags & DL_FLAG_SYNC_STATE_ONLY && + !device_link_flag_is_sync_state_only(flags)) + return NULL; + device_links_write_lock(); device_pm_lock(); @@ -1729,7 +1736,7 @@ static void fw_devlink_relax_link(struct device_link *link) if (!(link->flags & DL_FLAG_INFERRED)) return; - if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE)) + if (device_link_flag_is_sync_state_only(link->flags)) return; pm_runtime_drop_link(link); @@ -1853,8 +1860,8 @@ static int fw_devlink_relax_cycle(struct device *con, void *sup) return ret; list_for_each_entry(link, &con->links.consumers, s_node) { - if ((link->flags & ~DL_FLAG_INFERRED) == - (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) + if (!(link->flags & DL_FLAG_CYCLE) && + device_link_flag_is_sync_state_only(link->flags)) continue; if (!fw_devlink_relax_cycle(link->consumer, sup)) @@ -1863,6 +1870,7 @@ static int fw_devlink_relax_cycle(struct device *con, void *sup) ret = 1; fw_devlink_relax_link(link); + link->flags |= DL_FLAG_CYCLE; } return ret; } diff --git a/include/linux/device.h b/include/linux/device.h index 44e3acae7b36..f4d20655d2d7 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -328,6 +328,7 @@ enum device_link_state { #define DL_FLAG_MANAGED BIT(6) #define DL_FLAG_SYNC_STATE_ONLY BIT(7) #define DL_FLAG_INFERRED BIT(8) +#define DL_FLAG_CYCLE BIT(9) /** * enum dl_dev_state - Device driver presence tracking information.