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 D6A27C3DA64 for ; Thu, 1 Aug 2024 10:59:26 +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=f40hWkmpIBnYXS91307/QXLGa7IVTSWyudKLgyV4LBU=; b=e2x1/kbYwQdU8dtmihLcqLUfRa 9tUf58F4/kEASGxtQ650nWKvigqtlLwT7EyYlC5rMGsr2xlIL+NB7ib+s1eh2AwkotaAWQk55EgY4 CXALoCMbhx3xc916UkYfkgRwld0RHWVbUHs/xT6AAWwyAqDwXvWl8BsuwhnHCGrIFC8mH1P0jSyRD 3vQGvJnHj60AdzB0Qdk2ppTlb8433LRPMk+Wp41Th+ZoQjymzYa7bIgiFUtU5ZcO4e2VOYHcuQ/Tl 4yC68aT2/nBckzBIFYAL3w5MXampwshgm7tg9brKlSwsRRK/GSWwKFAjDlxGncFPePVBoeH/AZAdi k84I7AQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZTWc-00000004pg9-2WQg; Thu, 01 Aug 2024 10:59:14 +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 1sZTVv-00000004pVl-0gIN for linux-arm-kernel@lists.infradead.org; Thu, 01 Aug 2024 10:58:32 +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 AF97F15A1; Thu, 1 Aug 2024 03:58:55 -0700 (PDT) Received: from pluto (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 31AD63F5A1; Thu, 1 Aug 2024 03:58:29 -0700 (PDT) Date: Thu, 1 Aug 2024 11:58:19 +0100 From: Cristian Marussi To: Sudeep Holla Cc: Etienne Carriere , linux-kernel@vger.kernel.org, Cristian Marussi , arm-scmi@vger.kernel.org, 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-20240801_035831_269566_BC432D3E X-CRM114-Status: GOOD ( 27.98 ) 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 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... Thanks, Cristian