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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 D6F26C07E9D for ; Mon, 19 Jul 2021 16:29:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8B5F61947 for ; Mon, 19 Jul 2021 16:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347773AbhGSPsg (ORCPT ); Mon, 19 Jul 2021 11:48:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:59138 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243447AbhGSPAk (ORCPT ); Mon, 19 Jul 2021 11:00:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 18AE360FE9; Mon, 19 Jul 2021 15:41:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626709278; bh=bPwJDCKfWoR0IDXqGkDAnaIMMdlnEtfGPPsuGDmehUc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MRedARlCeb481WmlCpNdUHvd2X9VDmGNHa9Aw2JkZlFFDR6WOCYXqZ3kD11Seo5Ug 7GjrnPT+cZ08JjKFuKN1+EFoTBX5/Xye39HhAqW59Cp3VZts5mBuXIdR61Xt/Lg72C lA6ba/UKaXy37JdHLifOfEf/dyvXGV9EA+1G+vVM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christian Loehle , Ulf Hansson Subject: [PATCH 4.19 292/421] mmc: core: Allow UHS-I voltage switch for SDSC cards if supported Date: Mon, 19 Jul 2021 16:51:43 +0200 Message-Id: <20210719144956.446741203@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144946.310399455@linuxfoundation.org> References: <20210719144946.310399455@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christian Löhle commit 09247e110b2efce3a104e57e887c373e0a57a412 upstream. While initializing an UHS-I SD card, the mmc core first tries to switch to 1.8V I/O voltage, before it continues to change the settings for the bus speed mode. However, the current behaviour in the mmc core is inconsistent and doesn't conform to the SD spec. More precisely, an SD card that supports UHS-I must set both the SD_OCR_CCS bit and the SD_OCR_S18R bit in the OCR register response. When switching to 1.8V I/O the mmc core correctly checks both of the bits, but only the SD_OCR_S18R bit when changing the settings for bus speed mode. Rather than actually fixing the code to confirm to the SD spec, let's deliberately deviate from it by requiring only the SD_OCR_S18R bit for both parts. This enables us to support UHS-I for SDSC cards (outside spec), which is actually being supported by some existing SDSC cards. Moreover, this fixes the inconsistent behaviour. Signed-off-by: Christian Loehle Link: https://lore.kernel.org/r/CWXP265MB26803AE79E0AD5ED083BF2A6C4529@CWXP265MB2680.GBRP265.PROD.OUTLOOK.COM Cc: stable@vger.kernel.org [Ulf: Rewrote commit message and comments to clarify the changes] Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/core/sd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -781,11 +781,13 @@ try_again: return err; /* - * In case CCS and S18A in the response is set, start Signal Voltage - * Switch procedure. SPI mode doesn't support CMD11. + * In case the S18A bit is set in the response, let's start the signal + * voltage switch procedure. SPI mode doesn't support CMD11. + * Note that, according to the spec, the S18A bit is not valid unless + * the CCS bit is set as well. We deliberately deviate from the spec in + * regards to this, which allows UHS-I to be supported for SDSC cards. */ - if (!mmc_host_is_spi(host) && rocr && - ((*rocr & 0x41000000) == 0x41000000)) { + if (!mmc_host_is_spi(host) && rocr && (*rocr & 0x01000000)) { err = mmc_set_uhs_voltage(host, pocr); if (err == -EAGAIN) { retries--;