From patchwork Mon Nov 22 23:06:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cristian Marussi X-Patchwork-Id: 12693391 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 A624AC433F5 for ; Mon, 22 Nov 2021 23:20:29 +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=rhPbTvm/RpKi+OhLHCsJLCTiEVZF6uy8731/Rhn3MZ0=; b=EC4L4m6wnnRCvK Ac8CmzdZdTE8aa+ChmYD+g3+kY2JdLJCpMEAtlnjlmUXZB8lkQJiUE9u9yZtuXyw370wtWqw6VfvW 64TuV0oAwQT8shC6FFNC794VyTToiGSLz6v/DVhs7X1MGDBZeXr7PtabR0USSq6gJ2jFHiGuBzpIf A61IK/23HhkAdHD2L9JSEyPiobmCa3BIbe1zebsXL6NfJTge4nVckov+e/IXA3PC1C9viXZM0972Z Qv2IEnfpRqL53VUIT2H6FEWCY6b5GIWOzTWnT7X55D3WgyKLPlAIhyS76kv0PJGLkqC8AxdG7pATU QhBN+W3aU1GgHIN/m4rg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mpIaO-000NCY-4s; Mon, 22 Nov 2021 23:18:57 +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 1mpIP5-000JZM-1P for linux-arm-kernel@lists.infradead.org; Mon, 22 Nov 2021 23:07:16 +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 7E1F21063; Mon, 22 Nov 2021 15:07:14 -0800 (PST) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E80343F5A1; Mon, 22 Nov 2021 15:07:12 -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, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, cristian.marussi@arm.com Subject: [PATCH v6 06/16] firmware: arm_scmi: Add configurable polling mode for transports Date: Mon, 22 Nov 2021 23:06:30 +0000 Message-Id: <20211122230640.1345-7-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211122230640.1345-1-cristian.marussi@arm.com> References: <20211122230640.1345-1-cristian.marussi@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211122_150715_268325_46916F12 X-CRM114-Status: GOOD ( 18.95 ) 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 SCMI communications along TX channels can optionally be provided of a completion interrupt; when such interrupt is not available, command transactions should rely on polling, where the SCMI core takes care to repeatedly evaluate the transport-specific .poll_done() function, if available, to determine if and when a request was fully completed or timed out. Such mechanism is already present and working on a single transfer base: SCMI protocols can indeed enable hdr.poll_completion on specific commands ahead of each transfer and cause that transaction to be handled with polling. Introduce a couple of flags to be able to enforce such polling behaviour globally at will: - scmi_desc.force_polling: to statically switch the whole transport to polling mode. - scmi_chan_info.no_completion_irq: to switch a single channel dynamically to polling mode if, at runtime, is determined that no completion interrupt was available for such channel. Signed-off-by: Cristian Marussi --- v5 --> v6 - removed check on replies received by IRQs when xfer was requested as poll_completion (not all transport can suppress IRQs on an xfer basis) v4 --> v5 - make force_polling const - introduce polling_enabled flag to simplify checks on do_xfer v3 --> v4: - renamed .needs_polling flag to .no_completion_irq - refactored error path when polling needed but not supported --- drivers/firmware/arm_scmi/common.h | 11 +++++++++++ drivers/firmware/arm_scmi/driver.c | 17 +++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 6438b5248c24..99b74f4d39b6 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -339,11 +339,19 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id); * @dev: Reference to device in the SCMI hierarchy corresponding to this * channel * @handle: Pointer to SCMI entity handle + * @no_completion_irq: Flag to indicate that this channel has no completion + * interrupt mechanism for synchronous commands. + * This can be dynamically set by transports at run-time + * inside their provided .chan_setup(). + * @polling_enabled: Flag used to annotate if polling mode is currently enabled + * on this channel. * @transport_info: Transport layer related information */ struct scmi_chan_info { struct device *dev; struct scmi_handle *handle; + bool no_completion_irq; + bool polling_enabled; void *transport_info; }; @@ -402,6 +410,8 @@ struct scmi_device *scmi_child_dev_find(struct device *parent, * be pending simultaneously in the system. May be overridden by the * get_max_msg op. * @max_msg_size: Maximum size of data per message that can be handled. + * @force_polling: Flag to force this whole transport to use SCMI core polling + * mechanism instead of completion interrupts even if available. */ struct scmi_desc { int (*transport_init)(void); @@ -410,6 +420,7 @@ struct scmi_desc { int max_rx_timeout_ms; int max_msg; int max_msg_size; + const bool force_polling; }; #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 476b91845e40..8a30b832899c 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -817,6 +817,7 @@ static int do_xfer(const struct scmi_protocol_handle *ph, struct device *dev = info->dev; struct scmi_chan_info *cinfo; + /* Check for polling request on custom command xfers at first */ if (xfer->hdr.poll_completion && !info->desc->ops->poll_done) { dev_warn_once(dev, "Polling mode is not supported by transport.\n"); @@ -827,6 +828,10 @@ static int do_xfer(const struct scmi_protocol_handle *ph, if (unlikely(!cinfo)) return -EINVAL; + /* Initialized to true ONLY if also supported by transport. */ + if (cinfo->polling_enabled) + xfer->hdr.poll_completion = true; + /* * Initialise protocol id now from protocol handle to avoid it being * overridden by mistake (or malice) by the protocol code mangling with @@ -1527,6 +1532,18 @@ static int scmi_chan_setup(struct scmi_info *info, struct device *dev, if (ret) return ret; + if (tx && (cinfo->no_completion_irq || info->desc->force_polling)) { + if (info->desc->ops->poll_done) { + dev_info(dev, + "Enabled polling mode TX channel - prot_id:%d\n", + prot_id); + cinfo->polling_enabled = true; + } else { + dev_warn(dev, + "Polling mode NOT supported by transport.\n"); + } + } + idr_alloc: ret = idr_alloc(idr, cinfo, prot_id, prot_id + 1, GFP_KERNEL); if (ret != prot_id) {