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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 36FA4C10DCE for ; Thu, 12 Mar 2020 13:51:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 157382071C for ; Thu, 12 Mar 2020 13:51:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727563AbgCLNv4 (ORCPT ); Thu, 12 Mar 2020 09:51:56 -0400 Received: from foss.arm.com ([217.140.110.172]:35130 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727270AbgCLNv4 (ORCPT ); Thu, 12 Mar 2020 09:51:56 -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 A810D30E; Thu, 12 Mar 2020 06:51:55 -0700 (PDT) Received: from [10.37.12.166] (unknown [10.37.12.166]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4A2B83F534; Thu, 12 Mar 2020 06:51:54 -0700 (PDT) Subject: Re: [PATCH v4 07/13] firmware: arm_scmi: Add notification dispatch and delivery To: Cristian Marussi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: sudeep.holla@arm.com, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com References: <20200304162558.48836-1-cristian.marussi@arm.com> <20200304162558.48836-8-cristian.marussi@arm.com> From: Lukasz Luba Message-ID: <45d4aee9-57df-6be9-c176-cf0d03940c21@arm.com> Date: Thu, 12 Mar 2020 13:51:52 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200304162558.48836-8-cristian.marussi@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Cristian, just one comment below... On 3/4/20 4:25 PM, Cristian Marussi wrote: > Add core SCMI Notifications dispatch and delivery support logic which is > able, at first, to dispatch well-known received events from the RX ISR to > the dedicated deferred worker, and then, from there, to final deliver the > events to the registered users' callbacks. > > Dispatch and delivery is just added here, still not enabled. > > Signed-off-by: Cristian Marussi > --- > V3 --> V4 > - dispatcher now handles dequeuing of events in chunks (header+payload): > handling of these in_flight events let us remove one unneeded memcpy > on RX interrupt path (scmi_notify) > - deferred dispatcher now access their own per-protocol handlers' table > reducing locking contention on the RX path > V2 --> V3 > - exposing wq in sysfs via WQ_SYSFS > V1 --> V2 > - splitted out of V1 patch 04 > - moved from IDR maps to real HashTables to store event_handlers > - simplified delivery logic > --- > drivers/firmware/arm_scmi/notify.c | 334 ++++++++++++++++++++++++++++- > drivers/firmware/arm_scmi/notify.h | 9 + > 2 files changed, 342 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c [snip] > + > +/** > + * scmi_notify - Queues a notification for further deferred processing > + * > + * This is called in interrupt context to queue a received event for > + * deferred processing. > + * > + * @handle: The handle identifying the platform instance from which the > + * dispatched event is generated > + * @proto_id: Protocol ID > + * @evt_id: Event ID (msgID) > + * @buf: Event Message Payload (without the header) > + * @len: Event Message Payload size > + * @ts: RX Timestamp in nanoseconds (boottime) > + * > + * Return: 0 on Success > + */ > +int scmi_notify(const struct scmi_handle *handle, u8 proto_id, u8 evt_id, > + const void *buf, size_t len, u64 ts) > +{ > + struct scmi_registered_event *r_evt; > + struct scmi_event_header eh; > + struct scmi_notify_instance *ni = handle->notify_priv; > + > + /* Ensure atomic value is updated */ > + smp_mb__before_atomic(); > + if (unlikely(!atomic_read(&ni->enabled))) > + return 0; > + > + r_evt = SCMI_GET_REVT(ni, proto_id, evt_id); > + if (unlikely(!r_evt)) > + return -EINVAL; > + > + if (unlikely(len > r_evt->evt->max_payld_sz)) { > + pr_err("SCMI Notifications: discard badly sized message\n"); > + return -EINVAL; > + } > + if (unlikely(kfifo_avail(&r_evt->proto->equeue.kfifo) < > + sizeof(eh) + len)) { > + pr_warn("SCMI Notifications: queue full dropping proto_id:%d evt_id:%d ts:%lld\n", > + proto_id, evt_id, ts); > + return -ENOMEM; > + } > + > + eh.timestamp = ts; > + eh.evt_id = evt_id; > + eh.payld_sz = len; > + kfifo_in(&r_evt->proto->equeue.kfifo, &eh, sizeof(eh)); > + kfifo_in(&r_evt->proto->equeue.kfifo, buf, len); > + queue_work(r_evt->proto->equeue.wq, > + &r_evt->proto->equeue.notify_work); Is it safe to ignore the return value from the queue_work here? Regards, Lukasz