From patchwork Tue Feb 1 17:15:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cristian Marussi X-Patchwork-Id: 12732065 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5F2CEC433EF for ; Tue, 1 Feb 2022 17:19:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Zxb48EbNrt9iVAEzCU0XPPpK/bhBVGf12pV4WpiEv0c=; b=Wk/sp1RWe6cn9m umIhMmZSwmVinwONt8KIrIUw7h9eldQHRCsm3rLDVC68ObBNZnFNJeT3146hiyU+ONOvS2TdK2b5p +NcJw1I+JKYHHw3jx/Sl42d8bECN73DpmoLNeZ3gQ1ZkttDBg5SLF7UzrugNklEu3Bdc3c5zG1e2f /Kpok3+GZYp5DP+khUMIfYi0AKljhx7ZFk53t6cR2vqGFT9lsI98ntCHU1EIlBZGwoNAk+IcP47VC pYMk+uvnU0rEIh9G2i2fbq1bG6UaWLbDS9Z2SgwOP7xjUkLkK0qhldi8lnKOAaJkhnTZp4UugX3e3 wnoxyhih145v7qdBA0Dw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nEwmf-00D739-F1; Tue, 01 Feb 2022 17:17:37 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nEwlX-00D6U2-QU for linux-arm-kernel@lists.infradead.org; Tue, 01 Feb 2022 17:16:29 +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 B6C7F11B3; Tue, 1 Feb 2022 09:16:26 -0800 (PST) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 24F393F40C; Tue, 1 Feb 2022 09:16:25 -0800 (PST) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: sudeep.holla@arm.com, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, f.fainelli@gmail.com, etienne.carriere@linaro.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, peter.hilber@opensynergy.com, igor.skalkin@opensynergy.com, cristian.marussi@arm.com Subject: [PATCH v2 6/9] firmware: arm_scmi: Support optional system wide atomic_threshold Date: Tue, 1 Feb 2022 17:15:58 +0000 Message-Id: <20220201171601.53316-7-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220201171601.53316-1-cristian.marussi@arm.com> References: <20220201171601.53316-1-cristian.marussi@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220201_091627_981752_2968538A X-CRM114-Status: GOOD ( 17.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org An SCMI agent can be configured system-wide with a well-defined atomic threshold: only SCMI synchronous command whose latency has been advertised by the SCMI platform to be lower or equal to this configured threshold will be considered for atomic operations, when requested and if supported by the underlying transport at all. Signed-off-by: Cristian Marussi --- drivers/firmware/arm_scmi/driver.c | 27 ++++++++++++++++++++++++--- include/linux/scmi_protocol.h | 5 ++++- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index dc972a54e93e..d2ac6291b84b 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -131,6 +131,12 @@ struct scmi_protocol_instance { * MAX_PROTOCOLS_IMP elements allocated by the base protocol * @active_protocols: IDR storing device_nodes for protocols actually defined * in the DT and confirmed as implemented by fw. + * @atomic_threshold: Optional system wide DT-configured threshold, expressed + * in microseconds, for atomic operations. + * Only SCMI synchronous commands reported by the platform + * to have an execution latency lesser-equal to the threshold + * should be considered for atomic mode operation: such + * decision is finally left up to the SCMI drivers. * @notify_priv: Pointer to private data structure specific to notifications. * @node: List head * @users: Number of users of this instance @@ -149,6 +155,7 @@ struct scmi_info { struct mutex protocols_mtx; u8 *protocols_imp; struct idr active_protocols; + unsigned int atomic_threshold; void *notify_priv; struct list_head node; int users; @@ -1409,15 +1416,22 @@ static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id) * SCMI instance is configured as atomic. * * @handle: A reference to the SCMI platform instance. + * @atomic_threshold: An optional return value for the system wide currently + * configured threshold for atomic operations. * * Return: True if transport is configured as atomic */ -static bool scmi_is_transport_atomic(const struct scmi_handle *handle) +static bool scmi_is_transport_atomic(const struct scmi_handle *handle, + unsigned int *atomic_threshold) { + bool ret; struct scmi_info *info = handle_to_scmi_info(handle); - return info->desc->atomic_enabled && - is_transport_polling_capable(info); + ret = info->desc->atomic_enabled && is_transport_polling_capable(info); + if (ret && atomic_threshold) + *atomic_threshold = info->atomic_threshold; + + return ret; } static inline @@ -1957,6 +1971,13 @@ static int scmi_probe(struct platform_device *pdev) handle->version = &info->version; handle->devm_protocol_get = scmi_devm_protocol_get; handle->devm_protocol_put = scmi_devm_protocol_put; + + /* System wide atomic threshold for atomic ops .. if any */ + if (!of_property_read_u32(np, "atomic_threshold", + &info->atomic_threshold)) + dev_info(dev, + "SCMI System wide atomic threshold set to %d us\n", + info->atomic_threshold); handle->is_transport_atomic = scmi_is_transport_atomic; if (desc->ops->link_supplier) { diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 9f895cb81818..fdf6bd83cc59 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -619,6 +619,8 @@ struct scmi_notify_ops { * be interested to know if they can assume SCMI * command transactions associated to this handle will * never sleep and act accordingly. + * An optional atomic threshold value could be returned + * where configured. * @notify_ops: pointer to set of notifications related operations */ struct scmi_handle { @@ -629,7 +631,8 @@ struct scmi_handle { (*devm_protocol_get)(struct scmi_device *sdev, u8 proto, struct scmi_protocol_handle **ph); void (*devm_protocol_put)(struct scmi_device *sdev, u8 proto); - bool (*is_transport_atomic)(const struct scmi_handle *handle); + bool (*is_transport_atomic)(const struct scmi_handle *handle, + unsigned int *atomic_threshold); const struct scmi_notify_ops *notify_ops; };