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 24D45C10DCE for ; Thu, 12 Mar 2020 14:07:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04AC520716 for ; Thu, 12 Mar 2020 14:07:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727496AbgCLOHC (ORCPT ); Thu, 12 Mar 2020 10:07:02 -0400 Received: from foss.arm.com ([217.140.110.172]:35392 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725978AbgCLOHC (ORCPT ); Thu, 12 Mar 2020 10:07:02 -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 99FD830E; Thu, 12 Mar 2020 07:07:01 -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 594A53F534; Thu, 12 Mar 2020 07:07:00 -0700 (PDT) Subject: Re: [PATCH v4 07/13] firmware: arm_scmi: Add notification dispatch and delivery From: Lukasz Luba 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> <45d4aee9-57df-6be9-c176-cf0d03940c21@arm.com> Message-ID: Date: Thu, 12 Mar 2020 14:06:58 +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: <45d4aee9-57df-6be9-c176-cf0d03940c21@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/12/20 1:51 PM, Lukasz Luba wrote: > 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? and also from the kfifo_in > > Regards, > Lukasz > >