From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752237AbdHQGiU (ORCPT ); Thu, 17 Aug 2017 02:38:20 -0400 Received: from mga07.intel.com ([134.134.136.100]:5609 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751549AbdHQGiT (ORCPT ); Thu, 17 Aug 2017 02:38:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,386,1498546800"; d="scan'208";a="301254118" Subject: Re: [RFC PATCH 1/7] mmc: sdhci: Add quirk to indicate no CRC stripping in MMC_RSP_136 To: Kishon Vijay Abraham I , Ulf Hansson , Tony Lindgren , Rob Herring Cc: nsekhar@ti.com, linux-omap@vger.kernel.org, linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20170807160142.12134-1-kishon@ti.com> <20170807160142.12134-2-kishon@ti.com> <872c7194-3d48-47e5-6396-7189bf841a42@intel.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: Date: Thu, 17 Aug 2017 09:31:50 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/08/17 08:20, Kishon Vijay Abraham I wrote: > Hi Adrian, > > On Tuesday 15 August 2017 12:57 PM, Adrian Hunter wrote: >> On 07/08/17 19:01, Kishon Vijay Abraham I wrote: >>> TI's implementation of sdhci controller used in DRA7 SoC's doesn't >>> strip CRC in responses with length 136 bits. Add quirk to indicate >>> the controller does not strip CRC in MMC_RSP_136. If this quirk is >>> set sdhci library shouldn't shift the response present in >>> SDHCI_RESPONSE register. >>> >>> Signed-off-by: Kishon Vijay Abraham I >>> --- >>> drivers/mmc/host/sdhci.c | 27 +++++++++++++++++++-------- >>> drivers/mmc/host/sdhci.h | 2 ++ >>> 2 files changed, 21 insertions(+), 8 deletions(-) >>> >>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>> index ecd0d4350e8a..ece3751d2a25 100644 >>> --- a/drivers/mmc/host/sdhci.c >>> +++ b/drivers/mmc/host/sdhci.c >>> @@ -1182,14 +1182,25 @@ static void sdhci_finish_command(struct sdhci_host *host) >>> >>> if (cmd->flags & MMC_RSP_PRESENT) { >>> if (cmd->flags & MMC_RSP_136) { >>> - /* CRC is stripped so we need to do some shifting. */ >>> - for (i = 0;i < 4;i++) { >>> - cmd->resp[i] = sdhci_readl(host, >>> - SDHCI_RESPONSE + (3-i)*4) << 8; >>> - if (i != 3) >>> - cmd->resp[i] |= >>> - sdhci_readb(host, >>> - SDHCI_RESPONSE + (3-i)*4-1); >>> + if (!(host->quirks2 & SDHCI_QUIRK2_NO_CRC_STRIPPING)) { >> >> This is about the 136-bit response so let's put that in the quirk name. How about SDHCI_QUIRK2_RSP_136_HAS_CRC > > Since omap seems to be the only platform that doesn't have CRC, I prefer adding > SDHCI_QUIRK2_RSP_136_NO_CRC. That way we can add the quirk only in sdhci-omap > instead of all the existing sdhci drivers. Except that it is the way I described. All the others strip the CRC and we have to shift to pretend it is still there. > >> >>> + /* >>> + * CRC is stripped so we need to do some >>> + * shifting. >>> + */ >>> + for (i = 0; i < 4; i++) { >>> + cmd->resp[i] = >>> + sdhci_readl(host, SDHCI_RESPONSE >>> + + (3 - i) * 4) << 8; >>> + if (i != 3) >>> + cmd->resp[i] |= >>> + sdhci_readb(host, SDHCI_RESPONSE >>> + + (3 - i) * 4 - 1); >>> + } >>> + } else { >>> + for (i = 0; i < 4; i++) >>> + cmd->resp[i] = >>> + sdhci_readl(host, SDHCI_RESPONSE + >>> + (3 - i) * 4); >>> } >> >> This is all very jammed up against the 80 column margin. Please make a new patch to separate it into a new function sdhci_read_rsp_136() and then another patch to add the quirk. >> i.e. completely untested! > > Sure. Thanks for the patch. > > Thanks > Kishon >