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 81602C3DA64 for ; Tue, 6 Aug 2024 13:42:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: 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=RcdboZ1xQ6MExeKC1j6Tjh2qzS3vGHUL94xdFAEu590=; b=YCl1v2+tx7gI5SLdN6PA2wIUeq 2XN09ac7ht4XTOv+8s4/TN7Wvus/eFduZd1hn6LUcYUoX5SyiVGF+niBxfEML4hgXFW9y8U1HBfxx jmnwqMr+7SZHzIOYxSd3QW+9RCpvGOaTrlajNOpyI2ttilz7BgtSdCA7Nvs0IQdsrVJB8yX6EA1QN 0Me/iiMEAoMdXVpIsrHW7r9pmOQ7g2clyN3hRm+BI4HBmGd4/26WnDIF5lt9rOWMryoXVuBRbrsJH 6EmjQSKCKOpwq7fuws6EH8T8+A+PqQQwbroMRrDz3nydUIZAd9lWQ9XGqV9budO+b91e/2rd462jc qj6j21yw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sbKSW-00000001pNO-45nd; Tue, 06 Aug 2024 13:42:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sbKRz-00000001pCg-2UmK for linux-arm-kernel@lists.infradead.org; Tue, 06 Aug 2024 13:42:09 +0000 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 ACBEEFEC; Tue, 6 Aug 2024 06:42:31 -0700 (PDT) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1AFD13F766; Tue, 6 Aug 2024 06:42:05 -0700 (PDT) Date: Tue, 6 Aug 2024 14:42:02 +0100 From: Sudeep Holla To: Cristian Marussi Cc: Etienne Carriere , linux-kernel@vger.kernel.org, arm-scmi@vger.kernel.org, Sudeep Holla , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] firmware: arm_scmi: fix voltage description in failure cases Message-ID: References: <20240725065317.3758165-1-etienne.carriere@foss.st.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240806_064207_739799_C35CB157 X-CRM114-Status: GOOD ( 33.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Aug 01, 2024 at 11:58:19AM +0100, Cristian Marussi wrote: > On Fri, Jul 26, 2024 at 04:16:03PM +0100, Sudeep Holla wrote: > > On Thu, Jul 25, 2024 at 08:53:17AM +0200, Etienne Carriere wrote: > > > Reset the reception buffer max size when a voltage domain description > > > request fails, for example when the voltage domain returns an access > > > permission error (SCMI_ERR_ACCESS) unless what only a single 32bit > > > word is read back for the remaining voltage description requests > > > responses leading to invalid information. The side effect of this > > > issue is that the voltage regulators registered from those remaining > > > SCMI voltage domain were assigned a wrong regulator name. > > > > > > Signed-off-by: Etienne Carriere > > > --- > > > drivers/firmware/arm_scmi/voltage.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/firmware/arm_scmi/voltage.c b/drivers/firmware/arm_scmi/voltage.c > > > index 2175ffd6cef5..f1a7c04ae820 100644 > > > --- a/drivers/firmware/arm_scmi/voltage.c > > > +++ b/drivers/firmware/arm_scmi/voltage.c > > > @@ -229,8 +229,10 @@ static int scmi_voltage_descriptors_get(const struct scmi_protocol_handle *ph, > > > /* Retrieve domain attributes at first ... */ > > > put_unaligned_le32(dom, td->tx.buf); > > > /* Skip domain on comms error */ > > > - if (ph->xops->do_xfer(ph, td)) > > > + if (ph->xops->do_xfer(ph, td)) { > > > + ph->xops->reset_rx_to_maxsz(ph, td); > > > > I am fine with this to keep it simple, but thought I will check my thoughts. > > We usually use reset_rx_to_maxsz in iterators as we don't know the expected > > size of the response, whereas here it must be max sizeof(*resp_dom). > > > > That said, we don't have any helpers and changing xfer->rx.len directly > > doesn't looks good ? Or may be it is OK ? Thoughts ? > > We do not access those xfer internal field explicitly from the protocol layer > (beside once in Base)...and surely not on write....in the past I was even > tempted to try to make these internal stuff untouchable by the protocol layer... > ...that's the reason of course for the existence of reset_rx_to_maxsz() helpers > ....not sure if it is worth adding another helper for this, given that the > using the maxsz should have any adverse effect (unless I am missing > something of course :P). > > This kind of 'issues' are really common whenever in the SCMI stack we > reuse the same allocated xfer across multiple do_xfers in a loop > (reusing seq_nums is another thing...) since we wanted to avoid the > penalty of resetting some of these automatically on each do_xfer()... > > ....we could think of some mechanism to transparently reset/fill such xfer > fields automatically if the core detects a 'reuse'....got to check first, > though, if this does not break some of the current usage patterns...and > I would not say it is a high prio thing to explore as of now... > Fair enough, I will merge this as is. I think it should be fine. My suggestion might simply complicates things unnecessarily. Lets not do it unless this becomes repeating pattern. -- Regards, Sudeep