Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756134AbZCKN0X (ORCPT ); Wed, 11 Mar 2009 09:26:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753721AbZCKN0N (ORCPT ); Wed, 11 Mar 2009 09:26:13 -0400 Received: from mx1.auerswald.de ([212.185.163.234]:2157 "EHLO mail.auerswald.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753857AbZCKN0M convert rfc822-to-8bit (ORCPT ); Wed, 11 Mar 2009 09:26:12 -0400 From: Wolfgang =?iso-8859-15?q?M=FCes?= Organization: Auerswald GmbH & Co. KG To: Pierre Ossman Subject: [PATCH 4/7] mmc_spi: do not check CID and CSD blocks with CRC16 Date: Wed, 11 Mar 2009 14:25:48 +0100 User-Agent: KMail/1.9.10 Cc: "Andrew Morton" , "Matt Fleming" , "David Brownell" , "Mike Frysinger" , linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200903111425.48656.wolfgang.mues@auerswald.de> Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2114 Lines: 55 From: Wolfgang Muees o Some cards are not able to calculate a valid CRC16 value for CID and CSD reads (CRC for 512 byte data blocks is OK). So ommit the check for CRC16, as CID and CSD have a checksum inside the block. Signed-off-by: Wolfgang Muees --- This is one of a line of patches to enhance the usability of the mmc spi host port driver from "don't work with most SD cards" to "work with nearly all SD cards" (including those ugly cards with non-byte-aligned responses). diff -uprN 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/host/mmc_spi.c --- 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2009-03-11 13:42:48.000000000 +0100 +++ 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/host/mmc_spi.c 2009-03-11 13:43:13.000000000 +0100 @@ -762,7 +762,11 @@ mmc_spi_readblock(struct mmc_spi_host *h return -EIO; } - if (host->mmc->use_spi_crc) { + /* Omitt the CRC check for CID and CSD reads. There are some SDHC + * cards which don't supply a valid CRC after CID reads. + * Note that the CID has it's own CRC7 value inside the data block. + */ + if (host->mmc->use_spi_crc && (t->len == MMC_SPI_BLOCKSIZE)) { u16 crc = crc_itu_t(0, t->rx_buf, t->len); be16_to_cpus(&scratch->crc_val); --- regards i. A. Wolfgang M?es -- Auerswald GmbH & Co. KG Hardware Development Telefon: +49 (0)5306 9219 0 Telefax: +49 (0)5306 9219 94 E-Mail: Wolfgang.Mues@Auerswald.de Web: http://www.auerswald.de ? -------------------------------------------------------------- Auerswald GmbH & Co. KG, Vor den Grash?fen 1, 38162 Cremlingen Registriert beim AG Braunschweig HRA 13289 p.h.G Auerswald Gesch?ftsf?hrungsges. mbH Registriert beim AG Braunschweig HRB 7463 Gesch?ftsf?hrer: Dipl-Ing. Gerhard Auerswald -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/