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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 9AEF6C32792 for ; Mon, 30 Sep 2019 10:02:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 695A5216F4 for ; Mon, 30 Sep 2019 10:02:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730594AbfI3KC1 (ORCPT ); Mon, 30 Sep 2019 06:02:27 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:48459 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727025AbfI3KC0 (ORCPT ); Mon, 30 Sep 2019 06:02:26 -0400 Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1iEsVc-0005h8-Op; Mon, 30 Sep 2019 12:02:24 +0200 Received: from mfe by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1iEsVa-0005tG-H2; Mon, 30 Sep 2019 12:02:22 +0200 Date: Mon, 30 Sep 2019 12:02:22 +0200 From: Marco Felsch To: Anson Huang Cc: Aisheng Dong , "festevam@gmail.com" , "s.hauer@pengutronix.de" , "linux-kernel@vger.kernel.org" , dl-linux-imx , "kernel@pengutronix.de" , Leonard Crestez , "shawnguo@kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] firmware: imx: Skip return value check for some special SCU firmware APIs Message-ID: <20190930100222.p2cx6xspjeunsm54@pengutronix.de> References: <1569406066-16626-1-git-send-email-Anson.Huang@nxp.com> <20190926075914.i7tsd3cbpitrqe4q@pengutronix.de> <20190926100558.egils3ds37m3s5wo@pengutronix.de> <20190930081434.qrrv3yqczzxihntm@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 11:50:14 up 135 days, 16:08, 87 users, load average: 0.11, 0.12, 0.08 User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Anson, On 19-09-30 08:32, Anson Huang wrote: > Hi, Marco > > > On 19-09-30 07:42, Anson Huang wrote: > > > Hi, Leonard > > > > > > > On 2019-09-27 4:20 AM, Anson Huang wrote: > > > > >> On 2019-09-26 1:06 PM, Marco Felsch wrote: > > > > >>> On 19-09-26 08:03, Anson Huang wrote: > > > > >>>>> On 19-09-25 18:07, Anson Huang wrote: > > > > >>>>>> The SCU firmware does NOT always have return value stored in > > > > >>>>>> message header's function element even the API has response > > > > >>>>>> data, those special APIs are defined as void function in SCU > > > > >>>>>> firmware, so they should be treated as return success always. > > > > >>>>>> > > > > >>>>>> +static const struct imx_sc_rpc_msg whitelist[] = { > > > > >>>>>> + { .svc = IMX_SC_RPC_SVC_MISC, .func = > > > > >>>>> IMX_SC_MISC_FUNC_UNIQUE_ID }, > > > > >>>>>> + { .svc = IMX_SC_RPC_SVC_MISC, .func = > > > > >>>>>> +IMX_SC_MISC_FUNC_GET_BUTTON_STATUS }, }; > > > > >>>>> > > > > >>>>> Is this going to be extended in the near future? I see some > > > > >>>>> upcoming problems here if someone uses a different > > > > >>>>> scu-fw<->kernel combination as nxp would suggest. > > > > >>>> > > > > >>>> Could be, but I checked the current APIs, ONLY these 2 will be > > > > >>>> used in Linux kernel, so I ONLY add these 2 APIs for now. > > > > >>> > > > > >>> Okay. > > > > >>> > > > > >>>> However, after rethink, maybe we should add another imx_sc_rpc > > > > >>>> API for those special APIs? To avoid checking it for all the > > > > >>>> APIs called which > > > > >> may impact some performance. > > > > >>>> Still under discussion, if you have better idea, please advise, thanks! > > > > >> > > > > >> My suggestion is to refactor the code and add a new API for the > > > > >> this "no error value" convention. Internally they can call a > > > > >> common function with flags. > > > > > > > > > > If I understand your point correctly, that means the loop check of > > > > > whether the API is with "no error value" for every API still NOT > > > > > be skipped, it is just refactoring the code, right? > > > > > > > > There would be no "loop" anywhere: the responsibility would fall on > > > > the call to call the right RPC function. In the current layering > > > > scheme (drivers -> RPC -> > > > > mailbox) the RPC layer treats all calls the same and it's up the the > > > > caller to provide information about calling convention. > > > > > > > > An example implementation: > > > > * Rename imx_sc_rpc_call to __imx_sc_rpc_call_flags > > > > * Make a tiny imx_sc_rpc_call wrapper which just converts > > > > resp/noresp to a flag > > > > * Make get button status call __imx_sc_rpc_call_flags with the > > > > _IMX_SC_RPC_NOERROR flag > > > > > > > > Hope this makes my suggestion clearer? Pushing this to the caller is > > > > a bit ugly but I think it's worth preserving the fact that the imx > > > > rpc core treats services in an uniform way. > > > > > > It is clear now, so essentially it is same as 2 separate APIs, still > > > need to change the button driver and uid driver to use the special > > > flag, meanwhile, need to change the third parament of imx_sc_rpc_call() > > from bool to u32. > > > > > > If no one opposes this approach, I will redo the patch together with > > > the button driver and uid driver after holiday. > > > > As Ansons said that are two approaches and in both ways the caller needs to > > know if the error code is valid. Extending the flags seems better to me but it > > looks still not that good. One question, does the scu-fw set the error-msg to > > something? If not than why should we specify a flag or a other api? > > Nowadays the caller needs to know that the error-msg-field isn't set so if the > > caller sets the msg-packet to zero and fills the rpc-id the error-msg-field > > shouldn't be touched by the firmware. So it should be zero. > > The flow are as below for those special APIs with response data but no return value from SCU FW: > > 1. caller sends msg with a header field and data field, the header field has svc ID and function ID; > 2. SCU FW will service the caller and then clear the SVC ID before return, the response data will be > Put in msg data field, and if the APIs has return value, SCU FW will put the return value in function ID of msg; Thanks for the declaration :) > The caller has no chance to set the msg-packet to zero and rpc-id, it needs to pass correct rpc-id to SCU FW and > Get response data from SCU FW, and for those special APIs has function ID NOT over-written by SCU FW's return > Value, but the function ID is a unsigned int, and the SCU FW return value is also a unsigned int, so we have no > idea to separate them for no-return value API or error-return API. I see. > With new approach, I can use below 2 flags, the ugly point is user need to know which API to call. I don't see any improve using flags because the caller still needs to know if the scu-fw works (sorry for that) correctly. So we should go to adapt your approach to handle that within the core and improve the caller usage. What about this: 8<------------------------------------------------------------------------------- diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c index 04a24a863d6e..8f406a0784a4 100644 --- a/drivers/firmware/imx/imx-scu.c +++ b/drivers/firmware/imx/imx-scu.c @@ -184,6 +184,16 @@ int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp) /* response status is stored in hdr->func field */ hdr = msg; ret = hdr->func; + + /* + * Some special SCU firmware APIs do NOT have return value + * in hdr->func, but they do have response data, those special + * APIs are defined as void function in SCU firmware, so they + * should be treated as return success always. + */ + if (hdr->func == IMX_SC_MISC_FUNC_UNIQUE_ID || + hdr->func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS) + ret = 0; } out: 8<------------------------------------------------------------------------------- As you and Leonard said, this scu-fw behaviour is intended. So this will be not changed over the time else we need a scu-fw version check too. Also as you said those special functions shouldn't be extended I think a simple if-statement should work and no performance regressions are expected. Regards, Marco > +++ b/include/linux/firmware/imx/ipc.h > @@ -35,6 +35,11 @@ struct imx_sc_rpc_msg { > uint8_t func; > }; > > +#define IMX_SC_RPC_HAVE_RESP BIT(0) /* caller has response data */ > +#define IMX_SC_RPC_NOERROR BIT(1) /* caller has response data but no return value from SCU FW */ > + > +int imx_scu_call_rpc_flags(struct imx_sc_ipc *ipc, void *msg, u32 flags); > > Anson > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | 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=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 17F3CC32792 for ; 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Mon, 30 Sep 2019 12:02:24 +0200 Received: from mfe by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1iEsVa-0005tG-H2; Mon, 30 Sep 2019 12:02:22 +0200 Date: Mon, 30 Sep 2019 12:02:22 +0200 From: Marco Felsch To: Anson Huang Subject: Re: [PATCH] firmware: imx: Skip return value check for some special SCU firmware APIs Message-ID: <20190930100222.p2cx6xspjeunsm54@pengutronix.de> References: <1569406066-16626-1-git-send-email-Anson.Huang@nxp.com> <20190926075914.i7tsd3cbpitrqe4q@pengutronix.de> <20190926100558.egils3ds37m3s5wo@pengutronix.de> <20190930081434.qrrv3yqczzxihntm@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 11:50:14 up 135 days, 16:08, 87 users, load average: 0.11, 0.12, 0.08 User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190930_030232_918450_34B82651 X-CRM114-Status: GOOD ( 43.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Aisheng Dong , "shawnguo@kernel.org" , "s.hauer@pengutronix.de" , "linux-kernel@vger.kernel.org" , dl-linux-imx , "kernel@pengutronix.de" , Leonard Crestez , "festevam@gmail.com" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Anson, On 19-09-30 08:32, Anson Huang wrote: > Hi, Marco > > > On 19-09-30 07:42, Anson Huang wrote: > > > Hi, Leonard > > > > > > > On 2019-09-27 4:20 AM, Anson Huang wrote: > > > > >> On 2019-09-26 1:06 PM, Marco Felsch wrote: > > > > >>> On 19-09-26 08:03, Anson Huang wrote: > > > > >>>>> On 19-09-25 18:07, Anson Huang wrote: > > > > >>>>>> The SCU firmware does NOT always have return value stored in > > > > >>>>>> message header's function element even the API has response > > > > >>>>>> data, those special APIs are defined as void function in SCU > > > > >>>>>> firmware, so they should be treated as return success always. > > > > >>>>>> > > > > >>>>>> +static const struct imx_sc_rpc_msg whitelist[] = { > > > > >>>>>> + { .svc = IMX_SC_RPC_SVC_MISC, .func = > > > > >>>>> IMX_SC_MISC_FUNC_UNIQUE_ID }, > > > > >>>>>> + { .svc = IMX_SC_RPC_SVC_MISC, .func = > > > > >>>>>> +IMX_SC_MISC_FUNC_GET_BUTTON_STATUS }, }; > > > > >>>>> > > > > >>>>> Is this going to be extended in the near future? I see some > > > > >>>>> upcoming problems here if someone uses a different > > > > >>>>> scu-fw<->kernel combination as nxp would suggest. > > > > >>>> > > > > >>>> Could be, but I checked the current APIs, ONLY these 2 will be > > > > >>>> used in Linux kernel, so I ONLY add these 2 APIs for now. > > > > >>> > > > > >>> Okay. > > > > >>> > > > > >>>> However, after rethink, maybe we should add another imx_sc_rpc > > > > >>>> API for those special APIs? To avoid checking it for all the > > > > >>>> APIs called which > > > > >> may impact some performance. > > > > >>>> Still under discussion, if you have better idea, please advise, thanks! > > > > >> > > > > >> My suggestion is to refactor the code and add a new API for the > > > > >> this "no error value" convention. Internally they can call a > > > > >> common function with flags. > > > > > > > > > > If I understand your point correctly, that means the loop check of > > > > > whether the API is with "no error value" for every API still NOT > > > > > be skipped, it is just refactoring the code, right? > > > > > > > > There would be no "loop" anywhere: the responsibility would fall on > > > > the call to call the right RPC function. In the current layering > > > > scheme (drivers -> RPC -> > > > > mailbox) the RPC layer treats all calls the same and it's up the the > > > > caller to provide information about calling convention. > > > > > > > > An example implementation: > > > > * Rename imx_sc_rpc_call to __imx_sc_rpc_call_flags > > > > * Make a tiny imx_sc_rpc_call wrapper which just converts > > > > resp/noresp to a flag > > > > * Make get button status call __imx_sc_rpc_call_flags with the > > > > _IMX_SC_RPC_NOERROR flag > > > > > > > > Hope this makes my suggestion clearer? Pushing this to the caller is > > > > a bit ugly but I think it's worth preserving the fact that the imx > > > > rpc core treats services in an uniform way. > > > > > > It is clear now, so essentially it is same as 2 separate APIs, still > > > need to change the button driver and uid driver to use the special > > > flag, meanwhile, need to change the third parament of imx_sc_rpc_call() > > from bool to u32. > > > > > > If no one opposes this approach, I will redo the patch together with > > > the button driver and uid driver after holiday. > > > > As Ansons said that are two approaches and in both ways the caller needs to > > know if the error code is valid. Extending the flags seems better to me but it > > looks still not that good. One question, does the scu-fw set the error-msg to > > something? If not than why should we specify a flag or a other api? > > Nowadays the caller needs to know that the error-msg-field isn't set so if the > > caller sets the msg-packet to zero and fills the rpc-id the error-msg-field > > shouldn't be touched by the firmware. So it should be zero. > > The flow are as below for those special APIs with response data but no return value from SCU FW: > > 1. caller sends msg with a header field and data field, the header field has svc ID and function ID; > 2. SCU FW will service the caller and then clear the SVC ID before return, the response data will be > Put in msg data field, and if the APIs has return value, SCU FW will put the return value in function ID of msg; Thanks for the declaration :) > The caller has no chance to set the msg-packet to zero and rpc-id, it needs to pass correct rpc-id to SCU FW and > Get response data from SCU FW, and for those special APIs has function ID NOT over-written by SCU FW's return > Value, but the function ID is a unsigned int, and the SCU FW return value is also a unsigned int, so we have no > idea to separate them for no-return value API or error-return API. I see. > With new approach, I can use below 2 flags, the ugly point is user need to know which API to call. I don't see any improve using flags because the caller still needs to know if the scu-fw works (sorry for that) correctly. So we should go to adapt your approach to handle that within the core and improve the caller usage. What about this: 8<------------------------------------------------------------------------------- diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c index 04a24a863d6e..8f406a0784a4 100644 --- a/drivers/firmware/imx/imx-scu.c +++ b/drivers/firmware/imx/imx-scu.c @@ -184,6 +184,16 @@ int imx_scu_call_rpc(struct imx_sc_ipc *sc_ipc, void *msg, bool have_resp) /* response status is stored in hdr->func field */ hdr = msg; ret = hdr->func; + + /* + * Some special SCU firmware APIs do NOT have return value + * in hdr->func, but they do have response data, those special + * APIs are defined as void function in SCU firmware, so they + * should be treated as return success always. + */ + if (hdr->func == IMX_SC_MISC_FUNC_UNIQUE_ID || + hdr->func == IMX_SC_MISC_FUNC_GET_BUTTON_STATUS) + ret = 0; } out: 8<------------------------------------------------------------------------------- As you and Leonard said, this scu-fw behaviour is intended. So this will be not changed over the time else we need a scu-fw version check too. Also as you said those special functions shouldn't be extended I think a simple if-statement should work and no performance regressions are expected. Regards, Marco > +++ b/include/linux/firmware/imx/ipc.h > @@ -35,6 +35,11 @@ struct imx_sc_rpc_msg { > uint8_t func; > }; > > +#define IMX_SC_RPC_HAVE_RESP BIT(0) /* caller has response data */ > +#define IMX_SC_RPC_NOERROR BIT(1) /* caller has response data but no return value from SCU FW */ > + > +int imx_scu_call_rpc_flags(struct imx_sc_ipc *ipc, void *msg, u32 flags); > > Anson > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel