From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 1FFF2C48BE0 for ; Fri, 11 Jun 2021 17:01:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0945F61246 for ; Fri, 11 Jun 2021 17:01:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231584AbhFKRDk (ORCPT ); Fri, 11 Jun 2021 13:03:40 -0400 Received: from foss.arm.com ([217.140.110.172]:35850 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231534AbhFKRDX (ORCPT ); Fri, 11 Jun 2021 13:03:23 -0400 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 D0CE4143D; Fri, 11 Jun 2021 10:01:24 -0700 (PDT) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9DE6D3F719; Fri, 11 Jun 2021 10:01:19 -0700 (PDT) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, virtualization@lists.linux-foundation.org, virtio-dev@lists.oasis-open.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, cristian.marussi@arm.com, igor.skalkin@opensynergy.com, peter.hilber@opensynergy.com, alex.bennee@linaro.org, jean-philippe@linaro.org, mikhail.golubev@opensynergy.com, anton.yakovlev@opensynergy.com, Vasyl.Vavrychuk@opensynergy.com, Andriy.Tryshnivskyy@opensynergy.com Subject: [PATCH v4 16/16] firmware: arm_scmi: Add polling mode to virtio transport Date: Fri, 11 Jun 2021 17:59:37 +0100 Message-Id: <20210611165937.701-17-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210611165937.701-1-cristian.marussi@arm.com> References: <20210611165937.701-1-cristian.marussi@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Enable polling mode support to virtio transport. Upon reception of a synchronous command response for a transfer that has the hdr.poll_completion flag set, virtio transport now simply completes the same completion which .poll_done() is spinning on. Signed-off-by: Cristian Marussi --- Note that as of now in order to test this you have to forcibly enable hdr.poll_completion in the core and increase SCMI_MAX_POLL_TO_NS. These workarounds won't be needed anymore once addressed by a distinct series currently under review. --- drivers/firmware/arm_scmi/virtio.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/arm_scmi/virtio.c b/drivers/firmware/arm_scmi/virtio.c index 4412bc590ca7..f77c7f288d4c 100644 --- a/drivers/firmware/arm_scmi/virtio.c +++ b/drivers/firmware/arm_scmi/virtio.c @@ -158,12 +158,12 @@ static void scmi_process_vqueue_input(struct scmi_vio_channel *vioch, /* Drop processed virtio message anyway */ scmi_finalize_message(vioch, msg); + /* Deliver DRESP, NOTIF and non-polled RESP */ if (vioch->is_rx || !xfer->hdr.poll_completion) scmi_rx_callback(vioch->cinfo, msg_hdr); else - dev_warn(vioch->cinfo->dev, - "Polling mode NOT supported. Dropped hdr:0X%X\n", - msg_hdr); + /* poll_done() is busy-waiting on this */ + complete(&xfer->done); scmi_transfer_release(vioch->cinfo, xfer); } @@ -414,10 +414,16 @@ static void dummy_clear_channel(struct scmi_chan_info *cinfo) { } -static bool dummy_poll_done(struct scmi_chan_info *cinfo, - struct scmi_xfer *xfer) +static bool virtio_poll_done(struct scmi_chan_info *cinfo, + struct scmi_xfer *xfer) { - return false; + /* + * In polling mode SCMI core does not use xfer->done completion, + * so we can busy-wait on this same completion without adding + * a new flag: this is completed properly upon msg reception in + * scmi_process_vqueue_input(). + */ + return try_wait_for_completion(&xfer->done); } static const struct scmi_transport_ops scmi_virtio_ops = { @@ -430,7 +436,7 @@ static const struct scmi_transport_ops scmi_virtio_ops = { .fetch_response = virtio_fetch_response, .fetch_notification = virtio_fetch_notification, .clear_channel = dummy_clear_channel, - .poll_done = dummy_poll_done, + .poll_done = virtio_poll_done, }; static int scmi_vio_probe(struct virtio_device *vdev) -- 2.17.1