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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 CA548C47088 for ; Wed, 26 May 2021 07:23:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A691C61408 for ; Wed, 26 May 2021 07:23:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233006AbhEZHZB (ORCPT ); Wed, 26 May 2021 03:25:01 -0400 Received: from so254-9.mailgun.net ([198.61.254.9]:18960 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232971AbhEZHY6 (ORCPT ); Wed, 26 May 2021 03:24:58 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1622013807; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=HzIPuifBsSrOAMCIHmn9qh/aKUR9SCIU/XmPKKlgABg=; b=KPu8q4+XJTqS92WcrZUEhEJVIClldJCf1RQMxOt0qU6V/soO+cIgEGqq6PmdZHoaiDTHcqAh LcuWABHbeNMYNCUZC93wzltVDw8mJSkQelEqJbaWLUZcKQK98aWDlicpTXbvTMnQRyPldUWl 6o2h/F5655HkxcjStxniwbVqCgQ= X-Mailgun-Sending-Ip: 198.61.254.9 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 60adf75c8dd30e785f0cdfb6 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 26 May 2021 07:23:07 GMT Sender: nitirawa=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 156E1C4360C; Wed, 26 May 2021 07:23:07 +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: nitirawa) by smtp.codeaurora.org (Postfix) with ESMTPSA id 34254C433F1; Wed, 26 May 2021 07:23:05 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 26 May 2021 12:53:05 +0530 From: nitirawa@codeaurora.org To: Bjorn Andersson Cc: asutoshd@codeaurora.org, cang@codeaurora.org, stummala@codeaurora.org, vbadigan@codeaurora.org, alim.akhtar@samsung.com, avri.altman@wdc.com, jejb@linux.ibm.com, martin.petersen@oracle.com, stanley.chu@mediatek.com, beanhuo@micron.com, adrian.hunter@intel.com, bvanassche@acm.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2 3/3] scsi: ufs-qcom: configure VCC voltage level in vendor file In-Reply-To: <20210401151234.GO904837@yoga> References: <1616363857-26760-1-git-send-email-nitirawa@codeaurora.org> <1616363857-26760-4-git-send-email-nitirawa@codeaurora.org> <20210323152834.GH5254@yoga> <20210331181959.GL904837@yoga> <20210401151234.GO904837@yoga> Message-ID: <7fb8b7a30c1e24e5102772e7c5acf55a@codeaurora.org> X-Sender: nitirawa@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-04-01 20:42, Bjorn Andersson wrote: > On Thu 01 Apr 09:58 CDT 2021, nitirawa@codeaurora.org wrote: > >> On 2021-03-31 23:49, Bjorn Andersson wrote: >> > On Wed 24 Mar 16:55 CDT 2021, nitirawa@codeaurora.org wrote: >> > >> > > On 2021-03-23 20:58, Bjorn Andersson wrote: >> > > > On Sun 21 Mar 16:57 CDT 2021, Nitin Rawat wrote: >> > > > >> > > > > As a part of vops handler, VCC voltage is updated >> > > > > as per the ufs device probed after reading the device >> > > > > descriptor. We follow below steps to configure voltage >> > > > > level. >> > > > > >> > > > > 1. Set the device to SLEEP state. >> > > > > 2. Disable the Vcc Regulator. >> > > > > 3. Set the vcc voltage according to the device type and reenable >> > > > > the regulator. >> > > > > 4. Set the device mode back to ACTIVE. >> > > > > >> > > > >> > > > When we discussed this a while back this was described as a requirement >> > > > from the device specification, you only operate on objects "owned" by >> > > > ufshcd and you invoke ufshcd operations to perform the actions. >> > > > >> > > > So why is this a ufs-qcom patch and not something in ufshcd? >> > > > >> > > > Regards, >> > > > Bjorn >> > > > >> > > > > Signed-off-by: Nitin Rawat >> > > > > Signed-off-by: Veerabhadrarao Badiganti >> > > > > --- >> > > > > drivers/scsi/ufs/ufs-qcom.c | 51 >> > > > > +++++++++++++++++++++++++++++++++++++++++++++ >> > > > > 1 file changed, 51 insertions(+) >> > > > > >> > > > > diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c >> > > > > index f97d7b0..ca35f5c 100644 >> > > > > --- a/drivers/scsi/ufs/ufs-qcom.c >> > > > > +++ b/drivers/scsi/ufs/ufs-qcom.c >> > > > > @@ -21,6 +21,17 @@ >> > > > > #define UFS_QCOM_DEFAULT_DBG_PRINT_EN \ >> > > > > (UFS_QCOM_DBG_PRINT_REGS_EN | UFS_QCOM_DBG_PRINT_TEST_BUS_EN) >> > > > > >> > > > > +#define ANDROID_BOOT_DEV_MAX 30 >> > > > > +static char android_boot_dev[ANDROID_BOOT_DEV_MAX]; >> > > > > + >> > > > > +/* Min and Max VCC voltage values for ufs 2.x and >> > > > > + * ufs 3.x devices >> > > > > + */ >> > > > > +#define UFS_3X_VREG_VCC_MIN_UV 2540000 /* uV */ >> > > > > +#define UFS_3X_VREG_VCC_MAX_UV 2700000 /* uV */ >> > > > > +#define UFS_2X_VREG_VCC_MIN_UV 2950000 /* uV */ >> > > > > +#define UFS_2X_VREG_VCC_MAX_UV 2960000 /* uV */ >> > > > > + >> > > > > enum { >> > > > > TSTBUS_UAWM, >> > > > > TSTBUS_UARM, >> > > > > @@ -1293,6 +1304,45 @@ static void >> > > > > ufs_qcom_print_hw_debug_reg_all(struct ufs_hba *hba, >> > > > > print_fn(hba, reg, 9, "UFS_DBG_RD_REG_TMRLUT ", priv); >> > > > > } >> > > > > >> > > > > + /** >> > > > > + * ufs_qcom_setup_vcc_regulators - Update VCC voltage >> > > > > + * @hba: host controller instance >> > > > > + * Update VCC voltage based on UFS device(ufs 2.x or >> > > > > + * ufs 3.x probed) >> > > > > + */ >> > > > > +static int ufs_qcom_setup_vcc_regulators(struct ufs_hba *hba) >> > > > > +{ >> > > > > + struct ufs_dev_info *dev_info = &hba->dev_info; >> > > > > + struct ufs_vreg *vreg = hba->vreg_info.vcc; >> > > > > + int ret; >> > > > > + >> > > > > + /* Put the device in sleep before lowering VCC level */ >> > > > > + ret = ufshcd_set_dev_pwr_mode(hba, UFS_SLEEP_PWR_MODE); >> > > > > + >> > > > > + /* Switch off VCC before switching it ON at 2.5v or 2.96v */ >> > > > > + ret = ufshcd_disable_vreg(hba->dev, vreg); >> > > > > + >> > > > > + /* add ~2ms delay before renabling VCC at lower voltage */ >> > > > > + usleep_range(2000, 2100); >> > > > > + >> > > > > + /* set VCC min and max voltage according to ufs device type */ >> > > > > + if (dev_info->wspecversion >= 0x300) { >> > > > > + vreg->min_uV = UFS_3X_VREG_VCC_MIN_UV; >> > > > > + vreg->max_uV = UFS_3X_VREG_VCC_MAX_UV; >> > > > > + } >> > > > > + >> > > > > + else { >> > > > > + vreg->min_uV = UFS_2X_VREG_VCC_MIN_UV; >> > > > > + vreg->max_uV = UFS_2X_VREG_VCC_MAX_UV; >> > > > > + } >> > > > > + >> > > > > + ret = ufshcd_enable_vreg(hba->dev, vreg); >> > > > > + >> > > > > + /* Bring the device in active now */ >> > > > > + ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE); >> > > > > + return ret; >> > > > > +} >> > > > > + >> > > > > static void ufs_qcom_enable_test_bus(struct ufs_qcom_host *host) >> > > > > { >> > > > > if (host->dbg_print_en & UFS_QCOM_DBG_PRINT_TEST_BUS_EN) { >> > > > > @@ -1490,6 +1540,7 @@ static const struct ufs_hba_variant_ops >> > > > > ufs_hba_qcom_vops = { >> > > > > .device_reset = ufs_qcom_device_reset, >> > > > > .config_scaling_param = ufs_qcom_config_scaling_param, >> > > > > .program_key = ufs_qcom_ice_program_key, >> > > > > + .setup_vcc_regulators = ufs_qcom_setup_vcc_regulators, >> > > > > }; >> > > > > >> > > > > /** >> > > > > -- >> > > > > 2.7.4 >> > > > > >> > > >> > > Hi Bjorn, >> > > Thanks for your review. >> > > But As per the earlier discussion regarding handling of vcc voltage >> > > for platform supporting both ufs 2.x and ufs 3.x , it was finally >> > > concluded >> > > to >> > > use "vops and let vendors handle it, until specs or someone >> > > has a better suggestion". Please correct me in case i am wrong. >> > > >> > >> > I was under the impression that this would result in something custom >> > per platform, but what I'm objecting to now that I see the code is that >> > this is completely generic. >> > >> > And the concerns we discussed regarding these regulators being shared >> > with other devices is not considered in this implementation. But in >> > practice I don't see how you could support 2.x, 3.x and rail sharing at >> > the same time. >> > >> > Regards, >> > Bjorn >> > >> > > https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2399116.html >> > > >> > > Regards, >> > > Nitin >> >> Hi Bjorn, >> Thanks for your feedback. >> Regarding your query for regulator being shared with other device, >> Imho, the soc/pmic designer should share only those device >> with ufs regulator which has the same voltage range (2.4-3.6v). >> If that is not considered by the pmic designer, >> wouldn't that would be a board design issue ??? >> > > It's not only that the rail needs to stay within 2.4-3.6V, depending on > operating mode of this device it either need to be at 2.54-2.7V or > 2.95-2.96V depending on wspecversion for this instance. > > So either that other device need to be completely flexible in that > range > and support the voltage jumping between them without notice, or such > design isn't possible. > > And as you say, that would be something that the hardware designers > would need to handle for us. > >> And I agree with you that - the code looks generic but >> since the below steps is not part of the specs, >> I had to keep it in vendor specific file for which I >> had to export few api from ufshcd.c to use in vendor >> specific files. >> >> 1. Set the device to SLEEP state. >> 2. Disable the Vcc Regulator. >> 3. Set the vcc voltage according to the device type and reenable >> the regulator. >> 4. Set the device mode back to ACTIVE. >> >> Please correct me if my understanding is not correct. >> > > Are you saying that steps 1 to 4 here are not defined in the > specification and therefor Qualcomm specific? Do we expect other > vendors > to not follow this sequence, or do they simply not have these voltage > constraints? > > And again, isn't this the voltage for the attached UFS device? (Rather > than a Qualcomm thing) > > Regards, > Bjorn Hi Bjorn, Sorry for quite late reply. Yes Bjorn above steps(1-4) are not mentioned in the specs. But definitely other vendor can follow the same steps . If no vendor have any concerns, I can put these steps as generic in ufshcd.c file. Let me know what's you opinion on this ?? Thanks, Nitin