From patchwork Wed Dec 2 20:39:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cristian Marussi X-Patchwork-Id: 11947061 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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 BC061C64E7B for ; Wed, 2 Dec 2020 20:45:08 +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 41202205F4 for ; Wed, 2 Dec 2020 20:45:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41202205F4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=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:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=m86hqo9ALFzuBJCvXmSbaso/DglzGxDo5dUgxuYtg8A=; b=h09yYynBAn6+jiNUV1WYwUgSiT rw1sOhcS99feZiJ210N6uK9RN89aIkdTZE4wDxpvdolUw4WlwWdqQ9Fh6MQBuAS+VteYu5eSCQHTm GPZO1DvzysiH6pKPj2BCIy9FK3nGrSch7j/AQfoU+eVNPYWogTKBAOqtCVAxgWvGJ6vzt+oo0l8IL Diwevl063I+rmVBgCHE4Jr67FApiKZvEDuP780ult0uM3PziX/FswgVZVXtFEcU9W+oXhD63zaIx8 9GDhpBf0LWthhtD6Aj6+Ta8pA8BBMDnuZkkPXuKYN0EoABfE7QUM6uG0N5ZN6CX3JOWjmylcXwtw1 0VfW6IhA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkYxW-00038d-FJ; Wed, 02 Dec 2020 20:42:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkYvd-0002Nk-7q for linux-arm-kernel@lists.infradead.org; Wed, 02 Dec 2020 20:40:50 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 65B9D143D; Wed, 2 Dec 2020 12:40:39 -0800 (PST) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A85183F575; Wed, 2 Dec 2020 12:40:32 -0800 (PST) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 05/37] firmware: arm_scmi: make notifications aware of protocols users Date: Wed, 2 Dec 2020 20:39:37 +0000 Message-Id: <20201202204009.32073-6-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201202204009.32073-1-cristian.marussi@arm.com> References: <20201202204009.32073-1-cristian.marussi@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201202_154045_608633_CFAC8899 X-CRM114-Status: GOOD ( 17.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: f.fainelli@gmail.com, vincent.guittot@linaro.org, sudeep.holla@arm.com, thara.gopinath@linaro.org, Cristian Marussi , james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, souvik.chakravarty@arm.com, etienne.carriere@linaro.org, lukasz.luba@arm.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Account for any active registered notifier against the proper related protocol; do not consider pending event handlers, only active handlers will concur to protocol usage accounting. Signed-off-by: Cristian Marussi --- drivers/firmware/arm_scmi/notify.c | 51 ++++++++++++++++++++++++++---- 1 file changed, 44 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c index 66196b293b6c..cdaf0f962d84 100644 --- a/drivers/firmware/arm_scmi/notify.c +++ b/drivers/firmware/arm_scmi/notify.c @@ -91,6 +91,7 @@ #include #include +#include "common.h" #include "notify.h" #define SCMI_MAX_PROTO 256 @@ -368,7 +369,7 @@ static struct scmi_event_handler * scmi_get_active_handler(struct scmi_notify_instance *ni, u32 evt_key); static void scmi_put_active_handler(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl); -static void scmi_put_handler_unlocked(struct scmi_notify_instance *ni, +static bool scmi_put_handler_unlocked(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl); /** @@ -900,9 +901,21 @@ static inline int scmi_bind_event_handler(struct scmi_notify_instance *ni, if (!r_evt) return -EINVAL; - /* Remove from pending and insert into registered */ + /* + * Remove from pending and insert into registered while getting hold + * of protocol instance. + */ hash_del(&hndl->hash); + /* + * Acquire protocols only for NON pending handlers, so as NOT to trigger + * protocol initialization when a notifier is registered against a still + * not registered protocol, since it would make little sense to force init + * protocols for which still no SCMI driver user exists: they wouldn't + * emit any event anyway till some SCMI driver starts using it. + */ + scmi_acquire_protocol(ni->handle, KEY_XTRACT_PROTO_ID(hndl->key)); hndl->r_evt = r_evt; + mutex_lock(&r_evt->proto->registered_mtx); hash_add(r_evt->proto->registered_events_handlers, &hndl->hash, hndl->key); @@ -1193,41 +1206,65 @@ static int scmi_disable_events(struct scmi_event_handler *hndl) * * unregister and free the handler itself * * Context: Assumes all the proper locking has been managed by the caller. + * + * Return: True if handler was freed (users dropped to zero) */ -static void scmi_put_handler_unlocked(struct scmi_notify_instance *ni, +static bool scmi_put_handler_unlocked(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl) { + bool freed = false; + if (refcount_dec_and_test(&hndl->users)) { if (!IS_HNDL_PENDING(hndl)) scmi_disable_events(hndl); scmi_free_event_handler(hndl); + freed = true; } + + return freed; } static void scmi_put_handler(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl) { + bool freed; + u8 protocol_id; struct scmi_registered_event *r_evt = hndl->r_evt; mutex_lock(&ni->pending_mtx); - if (r_evt) + if (r_evt) { + protocol_id = r_evt->proto->id; mutex_lock(&r_evt->proto->registered_mtx); + } - scmi_put_handler_unlocked(ni, hndl); + freed = scmi_put_handler_unlocked(ni, hndl); - if (r_evt) + if (r_evt) { mutex_unlock(&r_evt->proto->registered_mtx); + /* + * Only registered handler acquired protocol; must be here + * released only AFTER unlocking registered_mtx, since + * releasing a protocol can trigger its de-initialization + * (ie. including r_evt and registered_mtx) + */ + if (freed) + scmi_release_protocol(ni->handle, protocol_id); + } mutex_unlock(&ni->pending_mtx); } static void scmi_put_active_handler(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl) { + bool freed; struct scmi_registered_event *r_evt = hndl->r_evt; + u8 protocol_id = r_evt->proto->id; mutex_lock(&r_evt->proto->registered_mtx); - scmi_put_handler_unlocked(ni, hndl); + freed = scmi_put_handler_unlocked(ni, hndl); mutex_unlock(&r_evt->proto->registered_mtx); + if (freed) + scmi_release_protocol(ni->handle, protocol_id); } /**