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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6C52EC25B50 for ; Sat, 21 Jan 2023 19:13:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sBddR3AhJJztIF/ro51w7Wq6MrszAA6WbHe+RieJHIU=; b=Y3Vs7UMngh4IfbLAAIaZRbsy18 jKVf4z3Q4tSdSRTfH4MActaH3ZOU+s8TFK39LBclnCdldHIJP6YkRbocRZJyOiCmvPfLcmh7eqaJP oKpnWMLY1y1KXWCs765QxrtLgI+U0TiTwTC10RH7BMRbHkLw+a870G8PjM/oEkcdNUaR/tG9pzVhF s0PSLgGFU3ljN8N7LJ1oqi7AL8LBHV50l8raLco2fcKuEmWF0PYQ7/bjasWnd8rMVms+FcqLiT3K4 UD7N5IdOqpB+0iKcMsM+yrly6gUIss7l7/sXomYCBIRkmIvR+V7tB9YMEgyVnTqxfhK98dZmTpj1n ShoF44zw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pJJIV-00EKNs-8D; Sat, 21 Jan 2023 19:13:03 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pJJIR-00EKNK-F8 for linux-riscv@lists.infradead.org; Sat, 21 Jan 2023 19:13:01 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D7D3AB80690; Sat, 21 Jan 2023 19:12:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 662FDC433D2; Sat, 21 Jan 2023 19:12:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674328376; bh=PdhfA3rRgIE2e0kyzwK3wCYUpNWtN8PfB8MESxPqJ+g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OI8JbQvzQZ0lJ8r2fM7Uo5WeX8XK4zEzTnirrkRLhCcn4Kl47QPVZ6G2A83YcE9gh bSs0A5RSotc317g3JcOmNG4pgTkoX1RjQm911M4WrT6GyupS+at5Kr3TYSuLRvp8i+ psSBwKQ6250qaZy7MEs6fMW9YLA2aSyxRifEim0rdWdk4mNBf4B72iYM+toHLxlvp2 yAnx6Bv7BXSBDc7KHMmgo1eg4FSjdU5TUr9AJepjlHFYzkXI2wMp/7KHgDMm3kjU/d UvgRgE6jHvGfPjp4HdiNuUJ5pHU/5LtYNJKmd5t+KjDGVyjX8yED6ySf9JEIIOHupE ndfO4jLHvaQuQ== Date: Sat, 21 Jan 2023 19:12:52 +0000 From: Conor Dooley To: Jassi Brar Cc: Conor Dooley , Daire McNamara , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 0/7] MPFS system controller/mailbox fixes Message-ID: References: <20230111134513.2495510-1-conor.dooley@microchip.com> MIME-Version: 1.0 In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230121_111259_846611_AF63A0C5 X-CRM114-Status: GOOD ( 46.37 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============4020236326338598209==" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org --===============4020236326338598209== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="zjBIZyBoxjBkWVzW" Content-Disposition: inline --zjBIZyBoxjBkWVzW Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sat, Jan 21, 2023 at 10:01:41AM -0600, Jassi Brar wrote: > On Wed, Jan 11, 2023 at 7:45 AM Conor Dooley wrote: > > > > In order to differentiate between the service succeeding & the system > > controller being inoperative or otherwise unable to function, I had to > > switch the controller to poll a busy bit in the system controller's > > registers to see if it has completed a service. > > This makes sense anyway, as the interrupt corresponds to "data ready" > > rather than "tx done", so I have changed the mailbox controller driver > > to do that & left the interrupt solely for signalling data ready. > > It just so happened that all of the services that I had worked with and > > tested up to this point were "infallible" & did not set a status, so the > > particular code paths were never tested. > > > > Jassi, the mailbox and soc patches depend on each other, as the change > > in what the interrupt is used for requires changing the client driver's > > behaviour too, as mbox_send_message() will now return when the system > > controller is no longer busy rather than when the data is ready. > > I'm happy to send the lot via the soc tree with your Ack and/or reivew, > > if that also works you? > > > Ok, let me review them and get back to you. FYI, I did sent a v2 on Friday: https://lore.kernel.org/all/20230120143734.3438755-1-conor.dooley@microchip.com/ The change is just a timeout duration though. > > Secondly, I have a question about what to do if a service does fail, but > > not due to a timeout - eg the above example where the "new" image for > > the FPGA is actually older than the one that currently exists. > > Ideally, if a service fails due to something other than the transaction > > timing out, I would go and read the status registers to see what the > > cause of failure was. > > I could not find a function in the mailbox framework that allows the > > client to request that sort of information from the client. Trying to > > do something with the auxiliary bus, or exporting some function to a > > device specific header seemed like a circumvention of the mailbox > > framework. > > Do you think it would be a good idea to implement something like > > mbox_client_peek_status(struct mbox_chan *chan, void *data) to allow > > clients to request this type of information? > > > .last_tx_done() is supposed to make sure everything is ok. Hm, might've explained badly as I think you've misunderstood. Or (see below) I might have mistakenly thought that last_tx_done() was only meant to signify that tx was done. Anyways, I'll try to clarify. Some services don't set a status, but whether a status is, or isn't, set has nothing to do with whether the service has completed. One service that sets a status is "Authenticate Bitstream". This service sets a status of 0x0 if the bitstream in question is okay _and_ something that the FPGA can be upgraded to. It returns a failure of 0x18 if the bitstream is valid _but_ is the same as that currently programmed. (and of course a whole host of other possible errors in-between) These statuses, and whether they are a bad outcome or not, is dependant on the service and I don't think should be handled in the mailbox controller driver. > If the expected status bit is "sometimes not set", that means that bit > is not the complete status. If the "busy" bit goes low, then the transmission must be complete, there should be no need to check other bits for *completion*, but... > You have to check multiple registers to > detect if and what caused the failure. ...maybe I have just misunderstood the role of .last_tx_done(). The comment in mailbox-controller.h lead me to believe that it was used just to check if it had been completed. Am I allowed to use .last_tx_done() to pass information back to the mailbox client? If I could, that'd certainly be a nice way to get the information on whether the service failed etc. Hopefully that, plus when you have a chance to look at the code, will make what I am asking about a little clearer! Thanks, Conor. --zjBIZyBoxjBkWVzW Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCY8w5NAAKCRB4tDGHoIJi 0ldrAQCX/0J7YAojS3DUErApT7uUqiraS8RIYGqZRbdynr1LEwEAvPO8zM9NSaDV pwmyzML3LI7NGdK+VGFlODcPQTtXig4= =dVbB -----END PGP SIGNATURE----- --zjBIZyBoxjBkWVzW-- --===============4020236326338598209== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv --===============4020236326338598209==--