From patchwork Wed Jun 28 04:04:37 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Finn Thain X-Patchwork-Id: 9813425 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 97AF1603F3 for ; Wed, 28 Jun 2017 04:05:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 838F727FB1 for ; Wed, 28 Jun 2017 04:05:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 70C922846B; Wed, 28 Jun 2017 04:05:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2514428414 for ; Wed, 28 Jun 2017 04:05:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753941AbdF1EFa (ORCPT ); Wed, 28 Jun 2017 00:05:30 -0400 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:54094 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751225AbdF1EEj (ORCPT ); Wed, 28 Jun 2017 00:04:39 -0400 Received: by kvm5.telegraphics.com.au (Postfix, from userid 502) id 8A7DF29698; Wed, 28 Jun 2017 00:04:37 -0400 (EDT) To: "James E.J. Bottomley" , "Martin K. Petersen" , Ondrej Zary Cc: , , Michael Schmitz Message-Id: <10c24e9d9aee2b4cf004dcdf5eed92ef2c0bb994.1498622056.git.fthain@telegraphics.com.au> In-Reply-To: References: From: Finn Thain Subject: [PATCH v4 4/5] g_NCR5380: Limit PDMA send to 512 B to avoid random corruption on DTC3181E Date: Wed, 28 Jun 2017 00:04:37 -0400 (EDT) Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Ondrej Zary The corruption is always the same: one byte missing at the beginning of a 128 B block. It happens only with slow Quantum LPS 240 drive, not with faster IBM DORS-32160. It's not clear what causes this. Documentation for the DTC436 chip has not been made available. Hence this workaround. Signed-off-by: Finn Thain --- drivers/scsi/g_NCR5380.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c index 9f18082415c4..b1e0a08e49c1 100644 --- a/drivers/scsi/g_NCR5380.c +++ b/drivers/scsi/g_NCR5380.c @@ -45,7 +45,8 @@ int c400_blk_cnt; \ int c400_host_buf; \ int io_width; \ - int pdma_residual + int pdma_residual; \ + int board #define NCR5380_dma_xfer_len generic_NCR5380_dma_xfer_len #define NCR5380_dma_recv_setup generic_NCR5380_pread @@ -316,6 +317,7 @@ static int generic_NCR5380_init_one(struct scsi_host_template *tpnt, } hostdata = shost_priv(instance); + hostdata->board = board; hostdata->io = iomem; hostdata->region_size = region_size; @@ -644,7 +646,12 @@ static int generic_NCR5380_dma_xfer_len(struct NCR5380_hostdata *hostdata, /* 53C400 datasheet: non-modulo-128-byte transfers should use PIO */ if (transfersize % 128) - transfersize = 0; + return 0; + + /* Limit PDMA send to 512 B to avoid random corruption on DTC3181E */ + if (hostdata->board == BOARD_DTC3181E && + cmd->sc_data_direction == DMA_TO_DEVICE) + transfersize = min(cmd->SCp.this_residual, 512); return min(transfersize, DMA_MAX_SIZE); }