Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759179Ab0FJQC2 (ORCPT ); Thu, 10 Jun 2010 12:02:28 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:41396 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751979Ab0FJQC0 (ORCPT ); Thu, 10 Jun 2010 12:02:26 -0400 Subject: [PATCH v2] sata_sil24: Use memory barriers before issuing commands To: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org From: Catalin Marinas Cc: Tejun Heo , Colin Tuckley , Jeff Garzik Date: Thu, 10 Jun 2010 17:02:12 +0100 Message-ID: <20100610160212.18091.29856.stgit@e102109-lin.cambridge.arm.com> User-Agent: StGit/0.15-83-g972d5 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 10 Jun 2010 16:02:12.0435 (UTC) FILETIME=[49BC7A30:01CB08B6] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1727 Lines: 46 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); -- 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/