From patchwork Mon Jun 3 08:30:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peng Fan X-Patchwork-Id: 10972533 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 01BFD14C0 for ; Mon, 3 Jun 2019 08:28:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E0BEB281F9 for ; Mon, 3 Jun 2019 08:28:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D1AE6285BA; Mon, 3 Jun 2019 08:28:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 23EA8281F9 for ; Mon, 3 Jun 2019 08:28:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.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=iV0uZbOEW54DylmX/n0Vgi28ETO6NTs9bvow3kK6hhw=; b=pj31EuxTVjvH2/+Kr4aDBqBAt7 K3U8sZMb5Sk62tNFcvKa7PDDpzTxFtC7Ki69OJtOHKB8bPJajhpLzX+6jwk/XqA35rhQAzLYSukVR Lc72dyfJZaVurp5pGzqhkn+8XwJhW2BmNmtaJCbAnUdztmAqPepL6CRs0+wde2kYaq1G6Jr0VKIpL hNsDiVwPNqTbf7QoJIWtH4ZZbwe0DM+JPjW2R/+rBI6Ebn5IYTvU74AHNATt1wpXHqinNDO4P71ib fwCYUm3rsr1YJfaKWdJPjstDMFSQldgX98vl6+5J38ME5G6uclMupeJ6gT8exig33VJLNrskUJuEe xndUJYaA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hXiKf-0004fO-Qt; Mon, 03 Jun 2019 08:28:41 +0000 Received: from inva020.nxp.com ([92.121.34.13]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hXiKV-0004XK-KW for linux-arm-kernel@lists.infradead.org; Mon, 03 Jun 2019 08:28:33 +0000 Received: from inva020.nxp.com (localhost [127.0.0.1]) by inva020.eu-rdc02.nxp.com (Postfix) with ESMTP id C1C8B1A03A4; Mon, 3 Jun 2019 10:28:28 +0200 (CEST) Received: from invc005.ap-rdc01.nxp.com (invc005.ap-rdc01.nxp.com [165.114.16.14]) by inva020.eu-rdc02.nxp.com (Postfix) with ESMTP id 200A31A03C4; Mon, 3 Jun 2019 10:28:22 +0200 (CEST) Received: from localhost.localdomain (mega.ap.freescale.net [10.192.208.232]) by invc005.ap-rdc01.nxp.com (Postfix) with ESMTP id DEBEA402DD; Mon, 3 Jun 2019 16:28:13 +0800 (SGT) From: peng.fan@nxp.com To: robh+dt@kernel.org, mark.rutland@arm.com, jassisinghbrar@gmail.com, sudeep.holla@arm.com, f.fainelli@gmail.com Subject: [PATCH V2 1/2] DT: mailbox: add binding doc for the ARM SMC mailbox Date: Mon, 3 Jun 2019 16:30:04 +0800 Message-Id: <20190603083005.4304-2-peng.fan@nxp.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190603083005.4304-1-peng.fan@nxp.com> References: <20190603083005.4304-1-peng.fan@nxp.com> X-Virus-Scanned: ClamAV using ClamSMTP X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190603_012831_952753_1C9F456F X-CRM114-Status: GOOD ( 14.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Peng Fan , shawnguo@kernel.org, linux-kernel@vger.kernel.org, linux-imx@nxp.com, kernel@pengutronix.de, andre.przywara@arm.com, van.freenix@gmail.com, festevam@gmail.com, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Peng Fan The ARM SMC mailbox binding describes a firmware interface to trigger actions in software layers running in the EL2 or EL3 exception levels. The term "ARM" here relates to the SMC instruction as part of the ARM instruction set, not as a standard endorsed by ARM Ltd. Signed-off-by: Peng Fan --- V2: Introduce interrupts as a property. V1: arm,func-ids is still kept as an optional property, because there is no defined SMC funciton id passed from SCMI. So in my test, I still use arm,func-ids for ARM SIP service. .../devicetree/bindings/mailbox/arm-smc.txt | 101 +++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 Documentation/devicetree/bindings/mailbox/arm-smc.txt diff --git a/Documentation/devicetree/bindings/mailbox/arm-smc.txt b/Documentation/devicetree/bindings/mailbox/arm-smc.txt new file mode 100644 index 000000000000..401887118c09 --- /dev/null +++ b/Documentation/devicetree/bindings/mailbox/arm-smc.txt @@ -0,0 +1,101 @@ +ARM SMC Mailbox Interface +========================= + +This mailbox uses the ARM smc (secure monitor call) instruction to trigger +a mailbox-connected activity in firmware, executing on the very same core +as the caller. By nature this operation is synchronous and this mailbox +provides no way for asynchronous messages to be delivered the other way +round, from firmware to the OS, but asynchronous notification could also +be supported. However the value of r0/w0/x0 the firmware returns after +the smc call is delivered as a received message to the mailbox framework, +so a synchronous communication can be established, for a asynchronous +notification, no value will be returned. The exact meaning of both the +action the mailbox triggers as well as the return value is defined by +their users and is not subject to this binding. + +One use case of this mailbox is the SCMI interface, which uses shared memory +to transfer commands and parameters, and a mailbox to trigger a function +call. This allows SoCs without a separate management processor (or when +such a processor is not available or used) to use this standardized +interface anyway. + +This binding describes no hardware, but establishes a firmware interface. +Upon receiving an SMC using one of the described SMC function identifiers, +the firmware is expected to trigger some mailbox connected functionality. +The communication follows the ARM SMC calling convention[1]. +Firmware expects an SMC function identifier in r0 or w0. The supported +identifiers are passed from consumers, or listed in the the arm,func-ids +properties as described below. The firmware can return one value in +the first SMC result register, it is expected to be an error value, +which shall be propagated to the mailbox client. + +Any core which supports the SMC or HVC instruction can be used, as long as +a firmware component running in EL3 or EL2 is handling these calls. + +Mailbox Device Node: +==================== + +This node is expected to be a child of the /firmware node. + +Required properties: +-------------------- +- compatible: Shall be "arm,smc-mbox" +- #mbox-cells Shall be 1 - the index of the channel needed. +- arm,num-chans The number of channels supported. +- method: A string, either: + "hvc": if the driver shall use an HVC call, or + "smc": if the driver shall use an SMC call. + +Optional properties: +- arm,func-ids An array of 32-bit values specifying the function + IDs used by each mailbox channel. Those function IDs + follow the ARM SMC calling convention standard [1]. + There is one identifier per channel and the number + of supported channels is determined by the length + of this array. +- interrupts SPI interrupts may be listed for notification, + each channel should use a dedicated interrupt + line. + +Example: +-------- + + sram@910000 { + compatible = "mmio-sram"; + reg = <0x0 0x93f000 0x0 0x1000>; + #address-cells = <1>; + #size-cells = <1>; + ranges = <0 0x0 0x93f000 0x1000>; + + cpu_scp_lpri: scp-shmem@0 { + compatible = "arm,scmi-shmem"; + reg = <0x0 0x200>; + }; + + cpu_scp_hpri: scp-shmem@200 { + compatible = "arm,scmi-shmem"; + reg = <0x200 0x200>; + }; + }; + + smc_mbox: mailbox { + #mbox-cells = <1>; + compatible = "arm,smc-mbox"; + method = "smc"; + arm,num-chans = <0x2>; + /* Optional */ + arm,func-ids = <0xc20000fe>, <0xc20000ff>; + }; + + firmware { + scmi { + compatible = "arm,scmi"; + mboxes = <&mailbox 0 &mailbox 1>; + mbox-names = "tx", "rx"; + shmem = <&cpu_scp_lpri &cpu_scp_hpri>; + }; + }; + + +[1] +http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.den0028a/index.html