From patchwork Fri Aug 4 14:31:36 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep Holla X-Patchwork-Id: 109416 Delivered-To: patch@linaro.org Received: by 10.140.101.6 with SMTP id t6csp2237566qge; Fri, 4 Aug 2017 07:34:51 -0700 (PDT) X-Received: by 10.84.225.147 with SMTP id u19mr3009868plj.313.1501857291408; Fri, 04 Aug 2017 07:34:51 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1501857291; cv=none; d=google.com; s=arc-20160816; b=cgCmZtKxgWp3APJupxjV7c+dn8v/GW65UZ9S9183B439+Ge16jYpWfN2tPiJqSwOf2 3diRyZaex+ThWuFid/tS/7BQiTVrYdE9QL0pGDQwyH0ZksIe4Xj7Lqx2a57zlq90x0CW iGAqAf9ORpD/UgB2FJRYZIOvonAy9YwnG2sQBkE7Yh4a/c/NmG9wwkteS5lZlUS7z2VL QPW56uWKY6KRCXzR1V5zMCgjZYSxOjPuobM5njf0ePa0yqYNElL/DSAkatkI3H4Abgva RSHVKtXZ5QjsUxs5bsIWSOFBI+KOuCPi6VOYwQ3gVpvTMV/P+nCUdjssnykqxsSI0hRY NEKw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=QIYA6sojTxP6Tq5nnUvxIGj7kNx6mWTm8Ul5HaGNQxo=; b=daR7H17VK617KFejZUaaSdH5C+c/91vFRFdUB/No/VHLqVJ47mU3lrKgSFotzV+Mb9 B2OyLqWYKvvqWItV40JZenhXijPK4mzzO69Wmo8es57Plb2x9HvCCMKCo++vjpSOf66P F1mIPIvvnuLVZpkQwito7AH1A9ZCPYcRJCSSHZBIkAYTAJaBFF5+MpjFBUhCkFSpGMCm 5hUgUJ7TBorj2VoeFVg5NT/lqTsnbbTqm/MYQhwhVC9xKD28Xcs78vu9FlU4eBRQxHq/ lj/492535RNSz2VRhkYJo2olmNxoBwcI8zgw9XwhT3BwcqAieADMzmqsaJiru8N39UJg llrQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id v184si1083795pfb.668.2017.08.04.07.34.51; Fri, 04 Aug 2017 07:34:51 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753107AbdHDOes (ORCPT + 25 others); Fri, 4 Aug 2017 10:34:48 -0400 Received: from foss.arm.com ([217.140.101.70]:54350 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752464AbdHDOc2 (ORCPT ); Fri, 4 Aug 2017 10:32:28 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 87F2D80D; Fri, 4 Aug 2017 07:32:28 -0700 (PDT) Received: from e107155-lin.cambridge.arm.com (unknown [10.1.210.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6ACFE3F3E1; Fri, 4 Aug 2017 07:32:26 -0700 (PDT) From: Sudeep Holla To: ALKML , LKML , DTML Cc: Sudeep Holla , Roy Franz , Harb Abdulhamid , Nishanth Menon , Arnd Bergmann , Loc Ho , Alexey Klimov , Ryan Harkin , Jassi Brar Subject: [PATCH v2 10/18] firmware: arm_scmi: add support for polling based SCMI transfers Date: Fri, 4 Aug 2017 15:31:36 +0100 Message-Id: <1501857104-11279-11-git-send-email-sudeep.holla@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1501857104-11279-1-git-send-email-sudeep.holla@arm.com> References: <1501857104-11279-1-git-send-email-sudeep.holla@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It would be useful to have options to perform some SCMI transfers atomically by polling for the completion flag instead of interrupt driven. The SCMI specification has option to disable the interrupt and poll for the completion flag in the shared memory. This patch adds support for polling based SCMI transfers using that option. This might be used for uninterrupted/atomic DVFS operations from the scheduler context. Cc: Arnd Bergmann Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/driver.c | 40 ++++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-) -- 2.7.4 diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 6f31761043e2..8257315cf3eb 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -26,6 +26,7 @@ */ #include +#include #include #include #include @@ -370,6 +371,19 @@ void scmi_one_xfer_put(const struct scmi_handle *handle, struct scmi_xfer *xfer) up(&minfo->sem_xfer_count); } +static bool +scmi_xfer_poll_done(const struct scmi_info *info, struct scmi_xfer *xfer) +{ + struct scmi_shared_mem *mem = info->tx_payload; + u16 xfer_id = MSG_XTRACT_TOKEN(mem->msg_header); + + if (xfer->hdr.seq != xfer_id) + return false; + + return mem->channel_status & (SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR | + SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE); +} + /** * scmi_do_xfer() - Do one transfer * @@ -396,14 +410,24 @@ int scmi_do_xfer(const struct scmi_handle *handle, struct scmi_xfer *xfer) /* mbox_send_message returns non-negative value on success, so reset */ ret = 0; - /* And we wait for the response. */ - timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms); - if (!wait_for_completion_timeout(&xfer->done, timeout)) { - dev_err(dev, "mbox timed out in resp(caller: %pF)\n", - (void *)_RET_IP_); - ret = -ETIMEDOUT; - } else if (xfer->hdr.status) { - ret = scmi_to_linux_errno(xfer->hdr.status); + if (xfer->hdr.poll_completion) { + timeout = info->desc->max_rx_timeout_ms * 100; + while (!scmi_xfer_poll_done(info, xfer) && timeout--) + udelay(10); + if (timeout) + scmi_fetch_response(xfer, info->tx_payload); + else + ret = -ETIMEDOUT; + } else { + /* And we wait for the response. */ + timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms); + if (!wait_for_completion_timeout(&xfer->done, timeout)) { + dev_err(dev, "mbox timed out in resp(caller: %pF)\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } else if (xfer->hdr.status) { + ret = scmi_to_linux_errno(xfer->hdr.status); + } } /* * NOTE: we might prefer not to need the mailbox ticker to manage the