Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759809Ab0FJUOw (ORCPT ); Thu, 10 Jun 2010 16:14:52 -0400 Received: from mail-gw0-f46.google.com ([74.125.83.46]:46458 "EHLO mail-gw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759785Ab0FJUOu (ORCPT ); Thu, 10 Jun 2010 16:14:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=e9G0B6EFsZlqY1Zxv0SDdai/F6ex8KL0scWypSs91XtBX8U4uw4n+Qk8SP4A0AQuVF o2tj28GX4Z6SaBVBwYKY3mqmwbIJwPXiPJ47X0eDu/LmEeKtr93GPJEWGrA/cZ0nxboh 91DIQUE2Xx0nUw8UmXKiHXr6R4fK6tDrVmKLc= Message-ID: <4C1147B2.7090207@garzik.org> Date: Thu, 10 Jun 2010 16:14:42 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Catalin Marinas CC: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Colin Tuckley Subject: Re: [PATCH v2] sata_sil24: Use memory barriers before issuing commands References: <20100610160212.18091.29856.stgit@e102109-lin.cambridge.arm.com> In-Reply-To: <20100610160212.18091.29856.stgit@e102109-lin.cambridge.arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1860 Lines: 50 On 06/10/2010 12:02 PM, Catalin Marinas wrote: > The data in the cmd_block buffers may reach the main memory after the > writel() to the device ports. This patch introduces two calls to wmb() > to ensure the relative ordering. > > Signed-off-by: Catalin Marinas > Tested-by: Colin Tuckley > Cc: Tejun Heo > Cc: Jeff Garzik > --- > drivers/ata/sata_sil24.c | 10 ++++++++++ > 1 files changed, 10 insertions(+), 0 deletions(-) > > diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c > index e925051..a5d5aff 100644 > --- a/drivers/ata/sata_sil24.c > +++ b/drivers/ata/sata_sil24.c > @@ -622,6 +622,11 @@ static int sil24_exec_polled_cmd(struct ata_port *ap, int pmp, > irq_enabled = readl(port + PORT_IRQ_ENABLE_SET); > writel(PORT_IRQ_COMPLETE | PORT_IRQ_ERROR, port + PORT_IRQ_ENABLE_CLR); > > + /* > + * The barrier is required to ensure that writes to cmd_block reach > + * the memory before the write to PORT_CMD_ACTIVATE. > + */ > + wmb(); > writel((u32)paddr, port + PORT_CMD_ACTIVATE); > writel((u64)paddr>> 32, port + PORT_CMD_ACTIVATE + 4); > > @@ -895,6 +900,11 @@ static unsigned int sil24_qc_issue(struct ata_queued_cmd *qc) > paddr = pp->cmd_block_dma + tag * sizeof(*pp->cmd_block); > activate = port + PORT_CMD_ACTIVATE + tag * 8; > > + /* > + * The barrier is required to ensure that writes to cmd_block reach > + * the memory before the write to PORT_CMD_ACTIVATE. > + */ > + wmb(); > writel((u32)paddr, activate); > writel((u64)paddr>> 32, activate + 4); > applied -- 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/