From patchwork Thu Feb 4 16:59:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cristian Marussi X-Patchwork-Id: 12067871 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=-17.1 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=ham 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 A4D16C433E0 for ; Thu, 4 Feb 2021 17:01:54 +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 6D2A964F65 for ; Thu, 4 Feb 2021 17:01:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D2A964F65 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=NAZsvSLkBTOQVTb/pwRYroVVvmN6hAhWV0WQqRUBJow=; b=XqWEvIyZkfXbPw5V1kgXUennYp +6LLvW8E933TnIAF07K1IKkkABfgleffG0XVNLTZdXkJakiLdxKuxNFYw/un8WxNJw4m8gq/jGtVo dzBMra2EufkXqKXpZRIDqPG7gXVuivjuEMEIZHE/LVEtHUJEKGMzQEe9R0CA8zlNBqpy74A7hdH/f EBHKLFbSHu11UKzO8dddWk7nr1m+FIkop5xiRR4DpkJDkIOlIxq4iry6ohBD3cuW+z9XPmxvmM2kt qPQ2r+t6q0cJoIkOMiBOwNFf3thSrWCs3uFEAF0Dd879kmRyhN0s59ZL9vewfwU6Fkeb3cameUetl Fjp2f0NQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7hzj-00086X-CY; Thu, 04 Feb 2021 17:00:39 +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 1l7hzc-000844-49 for linux-arm-kernel@lists.infradead.org; Thu, 04 Feb 2021 17:00:33 +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 084F711FB; Thu, 4 Feb 2021 09:00:24 -0800 (PST) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 477BC3F73B; Thu, 4 Feb 2021 09:00:22 -0800 (PST) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 1/3] firmware: arm_scmi: support only one single SystemPower device Date: Thu, 4 Feb 2021 16:59:11 +0000 Message-Id: <20210204165913.42582-2-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210204165913.42582-1-cristian.marussi@arm.com> References: <20210204165913.42582-1-cristian.marussi@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210204_120032_515829_CB024D06 X-CRM114-Status: GOOD ( 13.81 ) 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: robh@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org, sudeep.holla@arm.com, lukasz.luba@arm.com, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, cristian.marussi@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 In order to minimize SCMI platform fw-side complexity, only one platform should be in charge of SCMI SystemPower protocol communications with the OSPM: enforce the existence of one single unique device associated with SystemPower protocol across any possible number of SCMI platforms, and warn if a system tries to register different SystemPower devices from multiple platforms. Signed-off-by: Cristian Marussi --- drivers/firmware/arm_scmi/bus.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index 88149a46e6d9..e8542a7e8862 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -19,6 +19,9 @@ static DEFINE_IDA(scmi_bus_id); static DEFINE_IDR(scmi_available_protocols); static DEFINE_SPINLOCK(protocol_lock); +/* Track globally the creation of SCMI SystemPower related devices */ +static bool scmi_syspower_registered; + static const struct scmi_device_id * scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv) { @@ -175,6 +178,23 @@ scmi_device_create(struct device_node *np, struct device *parent, int protocol, int id, retval; struct scmi_device *scmi_dev; + /* + * Check if any SCMI SystemPower device was already created. + * + * Note that, shared global @scmi_syspower_registered is not protected + * by a mutex since: + * - scmi_device_create() is not concurrently invoked by the SCMI core + * - scmi_device_destroy() is effectively called only upon SCMI core + * unloading/unbinding, so no race is either possible between create + * and destroy. + */ + if (protocol == SCMI_PROTOCOL_SYSTEM && scmi_syspower_registered) { + dev_warn(parent, + "SCMI SystemPower protocol device must be unique !\n"); + dump_stack(); + return NULL; + } + scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL); if (!scmi_dev) return NULL; @@ -204,6 +224,9 @@ scmi_device_create(struct device_node *np, struct device *parent, int protocol, if (retval) goto put_dev; + if (protocol == SCMI_PROTOCOL_SYSTEM) + scmi_syspower_registered = true; + return scmi_dev; put_dev: kfree_const(scmi_dev->name); @@ -218,6 +241,8 @@ void scmi_device_destroy(struct scmi_device *scmi_dev) scmi_handle_put(scmi_dev->handle); ida_simple_remove(&scmi_bus_id, scmi_dev->id); device_unregister(&scmi_dev->dev); + if (scmi_dev->protocol_id == SCMI_PROTOCOL_SYSTEM) + scmi_syspower_registered = false; } void scmi_set_handle(struct scmi_device *scmi_dev)