From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4506F1D54F for ; Mon, 2 Oct 2023 18:36:41 +0000 (UTC) Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6416BAB; Mon, 2 Oct 2023 11:36:39 -0700 (PDT) Received: from pps.filterd (m0279867.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 392ILkAg015794; Mon, 2 Oct 2023 18:36:12 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=luVZOuFEDAuHKP2TvHHHlNuyDeSqZdneQoSyF7czdUk=; b=ngkqdt6imNw7nA+GUyiQ/9A8i9LKiYiiGwAHnqBiyvYzTuwDD3aHMtTGRfXoov1tFM0Y 1i9jk58mniMar7Ou+BYCqgIXb+sS5gZUPtsqFVWN5Zjfyj5+oV3DnGBEdjkcX+CjPaLl TCmr5/NzRWvNbzgy/hxWNG5Blvdv/r1PmjLOWgV0CJs1/LDGp7iuHVKo8Z2w0uyc0Ce3 GelY3P9RoJUd75k2MURQdLd9CzibR+Qj2ykn0gKsx3y3oFRkYtA3LNfBoH4YsLggdIdH 1hECfZseIJqPYvQED5HQBkRv/Hl2q8WTzdmVe6XVHvo4cKog5jbH7V0KFRMB8uSi+urh 2w== Received: from nalasppmta02.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3te9cmmnpm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 02 Oct 2023 18:36:11 +0000 Received: from nalasex01c.na.qualcomm.com (nalasex01c.na.qualcomm.com [10.47.97.35]) by NALASPPMTA02.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 392IaA2F028964 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 2 Oct 2023 18:36:10 GMT Received: from [10.110.71.113] (10.80.80.8) by nalasex01c.na.qualcomm.com (10.47.97.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Mon, 2 Oct 2023 11:36:10 -0700 Message-ID: <8d5af4d7-23fc-a03e-bad8-760209b537a0@quicinc.com> Date: Mon, 2 Oct 2023 11:36:01 -0700 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH v4 1/4] firmware: arm_scmi: Add polling support for completion in smc To: Brian Masney CC: , , , , , , , , , , References: <20230718160833.36397-1-quic_nkela@quicinc.com> <20230911194359.27547-1-quic_nkela@quicinc.com> <20230911194359.27547-2-quic_nkela@quicinc.com> Content-Language: en-US From: Nikunj Kela In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01c.na.qualcomm.com (10.47.97.35) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: AyPeROoQvaxvd8njlrW4LG-36WoauSg9 X-Proofpoint-ORIG-GUID: AyPeROoQvaxvd8njlrW4LG-36WoauSg9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-02_12,2023-10-02_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 lowpriorityscore=0 adultscore=0 suspectscore=0 bulkscore=0 impostorscore=0 mlxlogscore=999 priorityscore=1501 mlxscore=0 malwarescore=0 clxscore=1015 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2310020144 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 10/2/2023 11:18 AM, Brian Masney wrote: > On Mon, Sep 11, 2023 at 12:43:56PM -0700, Nikunj Kela wrote: >> Currently, the return from the smc call assumes the completion of >> the scmi request. However this may not be true in virtual platforms >> that are using hvc doorbell. >> >> This change adds a Kconfig to enable the polling for the request >> completion. >> >> Signed-off-by: Nikunj Kela >> --- >> drivers/firmware/arm_scmi/Kconfig | 14 ++++++++++++++ >> drivers/firmware/arm_scmi/smc.c | 15 ++++++++++++++- >> 2 files changed, 28 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig >> index ea0f5083ac47..771d60f8319f 100644 >> --- a/drivers/firmware/arm_scmi/Kconfig >> +++ b/drivers/firmware/arm_scmi/Kconfig >> @@ -125,6 +125,20 @@ config ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE >> in atomic context too, at the price of using a number of busy-waiting >> primitives all over instead. If unsure say N. >> >> +config ARM_SCMI_TRANSPORT_SMC_POLL_COMPLETION >> + bool "Enable polling support for SCMI SMC transport" >> + depends on ARM_SCMI_TRANSPORT_SMC >> + help >> + Enable completion polling support for SCMI SMC based transport. >> + >> + If you want the SCMI SMC based transport to poll for the completion, >> + answer Y. >> + Enabling completion polling might be desired in the absence of the a2p >> + irq when the return from smc/hvc call doesn't indicate the completion >> + of the SCMI requests. This might be useful for instances used in >> + virtual platforms. >> + If unsure say N. >> + >> config ARM_SCMI_TRANSPORT_VIRTIO >> bool "SCMI transport based on VirtIO" >> depends on VIRTIO=y || VIRTIO=ARM_SCMI_PROTOCOL >> diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c >> index c193516a254d..0a0b7e401159 100644 >> --- a/drivers/firmware/arm_scmi/smc.c >> +++ b/drivers/firmware/arm_scmi/smc.c >> @@ -250,6 +250,16 @@ static void smc_mark_txdone(struct scmi_chan_info *cinfo, int ret, >> smc_channel_lock_release(scmi_info); >> } >> >> +#ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC_POLL_COMPLETION >> +static bool >> +smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer) >> +{ >> + struct scmi_smc *scmi_info = cinfo->transport_info; >> + >> + return shmem_poll_done(scmi_info->shmem, xfer); >> +} >> +#endif >> + >> static const struct scmi_transport_ops scmi_smc_ops = { >> .chan_available = smc_chan_available, >> .chan_setup = smc_chan_setup, >> @@ -257,6 +267,9 @@ static const struct scmi_transport_ops scmi_smc_ops = { >> .send_message = smc_send_message, >> .mark_txdone = smc_mark_txdone, >> .fetch_response = smc_fetch_response, >> +#ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC_POLL_COMPLETION >> + .poll_done = smc_poll_done, >> +#endif >> }; >> >> const struct scmi_desc scmi_smc_desc = { >> @@ -272,6 +285,6 @@ const struct scmi_desc scmi_smc_desc = { >> * for the issued command will be immmediately ready to be fetched >> * from the shared memory area. >> */ >> - .sync_cmds_completed_on_ret = true, >> + .sync_cmds_completed_on_ret = !IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_POLL_COMPLETION), >> .atomic_enabled = IS_ENABLED(CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE), > From a Linux distributor viewpoint, it would be nice if this was > determined at runtime, rather than at compile time. We generate a single > kernel binary that's used on systems from multiple hardware > manufacturers. We'd run into an issue if one company required this, but > another one didn't. We may potentially run into this same type of issue > with the upstream arm64 defconfig. > > Brian This is a transport dependent property. Either the transport supports "completion on return of the smc call" or not. For a given platform, this will be fixed for all channels. This is similar to CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE which is also a Kconfig.