From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758381Ab2EJJuh (ORCPT ); Thu, 10 May 2012 05:50:37 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:37428 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758244Ab2EJJue (ORCPT ); Thu, 10 May 2012 05:50:34 -0400 Message-ID: <4FAB8F51.3010004@mvista.com> Date: Thu, 10 May 2012 13:50:09 +0400 From: Sergei Shtylyov User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: "Thang Q. Nguyen" CC: Jeff Garzik , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Subject: Re: [PATCH 3/5] sata_dwc: Add support ATAPI transfer References: <1336623449-7697-1-git-send-email-tqnguyen@apm.com> In-Reply-To: <1336623449-7697-1-git-send-email-tqnguyen@apm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On 10-05-2012 8:17, Thang Q. Nguyen wrote: > Signed-off-by: Thang Q. Nguyen > --- > drivers/ata/sata_dwc_460ex.c | 64 ++++++++++++++++++++++++++++++++++++++++-- > 1 files changed, 61 insertions(+), 3 deletions(-) > diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c > index 937aeb3..6175e01 100755 > --- a/drivers/ata/sata_dwc_460ex.c > +++ b/drivers/ata/sata_dwc_460ex.c [...] > @@ -1385,6 +1389,58 @@ static void sata_dwc_port_stop(struct ata_port *ap) > ap->private_data = NULL; > } > > +/** > + * sata_dwc_check_atapi_dma - Filter ATAPI cmds which are unsuitable for DMA. > + * @qc: queued command to check for chipset/DMA compatibility. > + * > + * The bmdma engines cannot handle speculative data sizes (bytecount > + * under/over flow). So only allow DMA for data transfer commands with > + * known data sizes. > + */ > +static int sata_dwc_check_atapi_dma(struct ata_queued_cmd *qc) > +{ [...] > + > + /* -45150 (FFFF4FA2) to -1 (FFFFFFFF) shall use PIO mode */ Sector numbers are unsigned entities. > + if (scmd->cmnd[0] == WRITE_10) { > + lba = (scmd->cmnd[2] << 24) | > + (scmd->cmnd[3] << 16) | > + (scmd->cmnd[4] << 8) | > + scmd->cmnd[5]; > + if (lba>= 0xFFFF4FA2) > + pio = 1; > + } > + /* > + * WORK AROUND: Fix DMA issue when blank CD/DVD disc in the drive > + * and user use the 'fdisk -l' command. No DMA data returned so > + * we can not complete the QC. The user shouldn't use 'fdisk' command on CD/DVD disks. On the other hand, he could use something like 'hdparm -t' od 'dd' with offset in which case I'm not sure this heuristics will work. > + */ > + else if (scmd->cmnd[0] == READ_10) { > + lba = (scmd->cmnd[2] << 24) | > + (scmd->cmnd[3] << 16) | > + (scmd->cmnd[4] << 8) | > + scmd->cmnd[5]; > + if (lba < 0x20) > + pio = 1; > + } > + } > + return pio; > +} > + > /* > * Function : sata_dwc_exec_command_by_tag > * arguments : ata_port *ap, ata_taskfile *tf, u8 tag, u32 cmd_issued WBR, Sergei