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=-8.2 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 CD9D2C43603 for ; Tue, 10 Dec 2019 18:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC7E120836 for ; Tue, 10 Dec 2019 18:14:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727747AbfLJSOu (ORCPT ); Tue, 10 Dec 2019 13:14:50 -0500 Received: from foss.arm.com ([217.140.110.172]:52834 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727349AbfLJSOu (ORCPT ); Tue, 10 Dec 2019 13:14:50 -0500 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 E79181FB; Tue, 10 Dec 2019 10:14:48 -0800 (PST) Received: from [10.1.197.50] (e120937-lin.cambridge.arm.com [10.1.197.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 795A93F6CF; Tue, 10 Dec 2019 10:14:48 -0800 (PST) Subject: Re: [PATCH 03/15] firmware: arm_scmi: Skip protocol initialisation for additional devices To: Sudeep Holla , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20191210145345.11616-1-sudeep.holla@arm.com> <20191210145345.11616-4-sudeep.holla@arm.com> From: Cristian Marussi Message-ID: <944a2d76-a3d3-9238-1960-63c3f29bea05@arm.com> Date: Tue, 10 Dec 2019 18:14:47 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <20191210145345.11616-4-sudeep.holla@arm.com> Content-Type: text/plain; charset=utf-8 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 On 10/12/2019 14:53, Sudeep Holla wrote: > The scmi bus now supports adding multiple devices per protocol, > and since scmi_protocol_init is called for each scmi device created, > we must avoid allocating protocol private data and initialising the > protocol itself if it is already initialised. > > Signed-off-by: Sudeep Holla > --- Wouldn't be better to add some kind of per-protocol 'initialized' flag somewhere in the bus abstraction so that the protocol_id itself could be marked as initialized once bus::scmi_protocol_init() completes successfully so that we could just skip the invocation itself of bus::scmi_protocol_init() for all the protocols already detected as initialized ? Or, if not a flag, maybe deactivating the registered protocol init function itself once it has been successfully called once .....something along the lines of: diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index 7a30952b463d..a551a00586c6 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -73,6 +73,8 @@ static int scmi_dev_probe(struct device *dev) ret = scmi_protocol_init(scmi_dev->protocol_id, scmi_dev->handle); if (ret) return ret; + idr_replace(&scmi_protocols, dummy_return_0_callback, + scmi_dev->protocol_id); return scmi_drv->probe(scmi_dev); [not really tested eh ... :D] This way we can drop this patch as a whole and avoid any future needs to remember to add this same sort of logic in the next XYZ protocol implementation. Cheers Cristian > drivers/firmware/arm_scmi/clock.c | 3 +++ > drivers/firmware/arm_scmi/perf.c | 3 +++ > drivers/firmware/arm_scmi/power.c | 3 +++ > drivers/firmware/arm_scmi/reset.c | 3 +++ > drivers/firmware/arm_scmi/sensors.c | 3 +++ > 5 files changed, 15 insertions(+) > > diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c > index 32526a793f3a..922b22aaaf84 100644 > --- a/drivers/firmware/arm_scmi/clock.c > +++ b/drivers/firmware/arm_scmi/clock.c > @@ -316,6 +316,9 @@ static int scmi_clock_protocol_init(struct scmi_handle *handle) > int clkid, ret; > struct clock_info *cinfo; > > + if (handle->clk_ops && handle->clk_priv) > + return 0; /* initialised already for the first device */ > + > scmi_version_get(handle, SCMI_PROTOCOL_CLOCK, &version); > > dev_dbg(handle->dev, "Clock Version %d.%d\n", > diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c > index 601af4edad5e..55c2a4c21ccb 100644 > --- a/drivers/firmware/arm_scmi/perf.c > +++ b/drivers/firmware/arm_scmi/perf.c > @@ -710,6 +710,9 @@ static int scmi_perf_protocol_init(struct scmi_handle *handle) > u32 version; > struct scmi_perf_info *pinfo; > > + if (handle->perf_ops && handle->perf_priv) > + return 0; /* initialised already for the first device */ > + > scmi_version_get(handle, SCMI_PROTOCOL_PERF, &version); > > dev_dbg(handle->dev, "Performance Version %d.%d\n", > diff --git a/drivers/firmware/arm_scmi/power.c b/drivers/firmware/arm_scmi/power.c > index 5abef7079c0a..9a7593238b8f 100644 > --- a/drivers/firmware/arm_scmi/power.c > +++ b/drivers/firmware/arm_scmi/power.c > @@ -185,6 +185,9 @@ static int scmi_power_protocol_init(struct scmi_handle *handle) > u32 version; > struct scmi_power_info *pinfo; > > + if (handle->power_ops && handle->power_priv) > + return 0; /* initialised already for the first device */ > + > scmi_version_get(handle, SCMI_PROTOCOL_POWER, &version); > > dev_dbg(handle->dev, "Power Version %d.%d\n", > diff --git a/drivers/firmware/arm_scmi/reset.c b/drivers/firmware/arm_scmi/reset.c > index ab42c21c5517..809dc8faee1e 100644 > --- a/drivers/firmware/arm_scmi/reset.c > +++ b/drivers/firmware/arm_scmi/reset.c > @@ -195,6 +195,9 @@ static int scmi_reset_protocol_init(struct scmi_handle *handle) > u32 version; > struct scmi_reset_info *pinfo; > > + if (handle->reset_ops && handle->reset_priv) > + return 0; /* initialised already for the first device */ > + > scmi_version_get(handle, SCMI_PROTOCOL_RESET, &version); > > dev_dbg(handle->dev, "Reset Version %d.%d\n", > diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c > index a400ea805fc2..b7f92c37c8a4 100644 > --- a/drivers/firmware/arm_scmi/sensors.c > +++ b/drivers/firmware/arm_scmi/sensors.c > @@ -276,6 +276,9 @@ static int scmi_sensors_protocol_init(struct scmi_handle *handle) > u32 version; > struct sensors_info *sinfo; > > + if (handle->sensor_ops && handle->sensor_priv) > + return 0; /* initialised already for the first device */ > + > scmi_version_get(handle, SCMI_PROTOCOL_SENSOR, &version); > > dev_dbg(handle->dev, "Sensor Version %d.%d\n", > -- > 2.17.1 >