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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 4C4B2C433DB for ; Tue, 5 Jan 2021 07:29:15 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E27FC2256F for ; Tue, 5 Jan 2021 07:29:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E27FC2256F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:To:From: Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5CzrW/uOF6lmAzYPbQaqQ3oKsa/p5Ej9eNWX1/FIfR4=; b=dl9lplqjTn94aS4yX1AbruRIZ mumokCaZNVNZq/SXpY0FNP5257cOOZAIrUhW+fBgnI6Ztta24bvgV1Ihxghp82Y0IeV6uJzYrEP7D bmQXCl9er2UP1rVRPtvaEvWIJB3h7LX97Hhn28kDV0EmQZ7MBOLRv9A/S5Ay+TUdXahl08Fz01JDw oG0mIDcqblkpo8FP1SvDfZOHDGkJmoW7barR4t3KBoT4Y+goOqcuE0l4tH0/MKe/yTcwcGMZ/VRWI IFH41BGhyhe2mNHneKhrzFcFI4kKUCqQXqiYRiy/xnz+jDuT2PDe4laafMj0hqbhzPgwJrC6aauwO Dk/E1xdoA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kwgm3-0000TL-57; Tue, 05 Jan 2021 07:28:59 +0000 Received: from so254-31.mailgun.net ([198.61.254.31]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kwgm0-0000SP-JQ for linux-mediatek@lists.infradead.org; Tue, 05 Jan 2021 07:28:57 +0000 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1609831736; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=rlMezvFGRyW9K07G6YKtgfUDZelNds7a4+4Moz15juI=; b=ZAbo7I2L+Ncg377XL1H3ksz4WYAPYMeN/uMhO7bwx/Q95TeSr/+R94NDskwjkrpsllu9PZPa u+A2uHtkVm+k+qkrhtAJzRhuouRAXFcq/lTNnFUmAPtdflfEkr8aPQggVbwd+BZ9SDEhUaeE NxfynO4NdZBVZ9fn5bbefgHp8PY= X-Mailgun-Sending-Ip: 198.61.254.31 X-Mailgun-Sid: WyI0ZDIyMyIsICJsaW51eC1tZWRpYXRla0BsaXN0cy5pbmZyYWRlYWQub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n06.prod.us-west-2.postgun.com with SMTP id 5ff41530d3eb3c36b4819798 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Tue, 05 Jan 2021 07:28:48 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 7AB34C43461; Tue, 5 Jan 2021 07:28:48 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: cang) by smtp.codeaurora.org (Postfix) with ESMTPSA id 2E8DEC433C6; Tue, 5 Jan 2021 07:28:47 +0000 (UTC) MIME-Version: 1.0 Date: Tue, 05 Jan 2021 15:28:47 +0800 From: Can Guo To: Adrian Hunter Subject: Re: [PATCH RFC v4 1/1] scsi: ufs: Fix ufs power down/on specs violation In-Reply-To: References: <1608644981-46267-1-git-send-email-ziqichen@codeaurora.org> Message-ID: X-Sender: cang@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210105_022856_936684_A47520E2 X-CRM114-Status: GOOD ( 26.18 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bjorn Andersson , Alim Akhtar , vinholikatti@gmail.com, Bean Huo , Satya Tangirala , jejb@linux.vnet.ibm.com, Bart Van Assche , linux-scsi@vger.kernel.org, Ziqi Chen , Andy Gross , kernel-team@android.com, salyzyn@google.com, "open list:ARM/QUALCOMM SUPPORT" , "James E.J. Bottomley" , Avri Altman , "moderated list:UNIVERSAL FLASH STORAGE HOST CONTROLLER DRIVER..." , Matthias Brugger , kwmad.kim@samsung.com, stanley.chu@mediatek.com, "moderated list:ARM/Mediatek SoC support" , rnayak@codeaurora.org, saravanak@google.com, martin.petersen@oracle.com, nguyenb@codeaurora.org, open list , hongwus@codeaurora.org, asutoshd@codeaurora.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On 2021-01-05 15:16, Adrian Hunter wrote: > On 4/01/21 8:55 pm, Bjorn Andersson wrote: >> On Mon 04 Jan 03:15 CST 2021, Adrian Hunter wrote: >> >>> On 22/12/20 3:49 pm, Ziqi Chen wrote: >>>> As per specs, e.g, JESD220E chapter 7.2, while powering >>>> off/on the ufs device, RST_N signal and REF_CLK signal >>>> should be between VSS(Ground) and VCCQ/VCCQ2. >>>> >>>> To flexibly control device reset line, refactor the function >>>> ufschd_vops_device_reset(sturct ufs_hba *hba) to ufshcd_ >>>> vops_device_reset(sturct ufs_hba *hba, bool asserted). The >>>> new parameter "bool asserted" is used to separate device reset >>>> line pulling down from pulling up. >>> >>> This patch assumes the power is controlled by voltage regulators, but >>> for us >>> it is controlled by firmware (ACPI), so it is not correct to change >>> RST_n >>> for all host controllers as you are doing. >>> >>> Also we might need to use a firmware interface for device reset, in >>> which >>> case the 'asserted' value doe not make sense. >>> >> >> Are you saying that the entire flip-flop-the-reset is a single >> firmware >> operation in your case? > > Yes > >> If you look at the Mediatek driver, the >> implementation of ufs_mtk_device_reset_ctrl() is a jump to firmware. >> >> >> But perhaps "asserted" isn't the appropriate English word for saying >> "the reset is in the resetting state"? >> >> I just wanted to avoid the use of "high"/"lo" as if you look at the >> Mediatek code they pass the expected line-level to the firmware, while >> in the Qualcomm code we pass the logical state to the GPIO code which >> is >> setup up as "active low" and thereby flip the meaning before hitting >> the >> pad. >> >>> Can we leave the device reset callback alone, and instead introduce a >>> new >>> variant operation for setting RST_n to match voltage regulator power >>> changes? >> >> Wouldn't this new function just have to look like the proposed >> patches? >> In which case for existing platforms we'd have both? >> >> How would you implement this, or would you simply skip implementing >> this? > > Functionally, doing a device reset is not the same as adjusting signal > levels to meet power up/off ramp requirements. However, the issue is > that > we do not use regulators, so the power is not necessarily being changed > at > those points, and we definitely do not want to reset instead of > entering > DeepSleep for example. > > Off the top of my head, I imagine something like a callback called > ufshcd_vops_prepare_power_ramp(hba, bool on) which is called only if > hba->vreg_info->vcc is not NULL. Hi Adrian, I don't see you have the vops device_reset() implemented anywhere in current code base, how is this change impacting you? Do I miss anything or are you planning to push a change which implements device_reset() soon? Thanks, Can Guo. _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek