From patchwork Fri Aug 24 06:00:18 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paul Walmsley X-Patchwork-Id: 1369921 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id B7A64DF264 for ; Fri, 24 Aug 2012 06:07:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753742Ab2HXGHD (ORCPT ); Fri, 24 Aug 2012 02:07:03 -0400 Received: from utopia.booyaka.com ([74.50.51.50]:60199 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754317Ab2HXGHA (ORCPT ); Fri, 24 Aug 2012 02:07:00 -0400 Received: (qmail 20993 invoked by uid 1019); 24 Aug 2012 06:00:18 -0000 Date: Fri, 24 Aug 2012 06:00:18 +0000 (UTC) From: Paul Walmsley To: Jarkko Lavinen , linux-mmc@vger.kernel.org cc: Chris Ball , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tony@atomide.com, =?ISO-8859-15?Q?Juha_Yrj=F6l=E4?= , Carlos Aguiar , Russell King Subject: [PATCH] MMC: OMAP MSDI: fix broken PIO mode Message-ID: User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org After commit 26b88520b80695a6fa5fd95b5d97c03f4daf87e0 ("mmc: omap_hsmmc: remove private DMA API implementation"), the Nokia N800 here stopped booting: [ 2.086181] Waiting for root device /dev/mmcblk0p1... [ 2.324066] Unhandled fault: imprecise external abort (0x406) at 0x00000000 [ 2.331451] Internal error: : 406 [#1] ARM [ 2.335784] Modules linked in: [ 2.339050] CPU: 0 Not tainted (3.6.0-rc3 #60) [ 2.344146] PC is at default_idle+0x28/0x30 [ 2.348602] LR is at trace_hardirqs_on_caller+0x15c/0x1b0 ... This turned out to be due to memory corruption caused by long-broken PIO code in drivers/mmc/host/omap.c. (Previously, this driver had been using DMA; but the above commit caused the MMC driver to fall back to PIO mode with an unmodified Kconfig.) The PIO code, added with the rest of the driver in commit 730c9b7e6630f786fcec026fb11d2e6f2c90fdcb ("[MMC] Add OMAP MMC host driver"), confused bytes with 16-bit words. This bug caused memory located after the PIO transfer buffer to be corrupted with transfers larger than 32 bytes. The driver also did not increment the buffer pointer after the transfer occurred. This bug resulted in data corruption during any transfer larger than 64 bytes. Signed-off-by: Paul Walmsley Cc: Juha Yrjölä Cc: Tony Lindgren Cc: Carlos Aguiar Cc: Russell King Reviewed-by: Felipe Balbi Tested-by: Tony Lindgren --- drivers/mmc/host/omap.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c index 50e08f0..a5999a7 100644 --- a/drivers/mmc/host/omap.c +++ b/drivers/mmc/host/omap.c @@ -668,7 +668,7 @@ mmc_omap_clk_timer(unsigned long data) static void mmc_omap_xfer_data(struct mmc_omap_host *host, int write) { - int n; + int n, nwords; if (host->buffer_bytes_left == 0) { host->sg_idx++; @@ -678,15 +678,23 @@ mmc_omap_xfer_data(struct mmc_omap_host *host, int write) n = 64; if (n > host->buffer_bytes_left) n = host->buffer_bytes_left; + + nwords = n / 2; + nwords += n & 1; /* handle odd number of bytes to transfer */ + host->buffer_bytes_left -= n; host->total_bytes_left -= n; host->data->bytes_xfered += n; if (write) { - __raw_writesw(host->virt_base + OMAP_MMC_REG(host, DATA), host->buffer, n); + __raw_writesw(host->virt_base + OMAP_MMC_REG(host, DATA), + host->buffer, nwords); } else { - __raw_readsw(host->virt_base + OMAP_MMC_REG(host, DATA), host->buffer, n); + __raw_readsw(host->virt_base + OMAP_MMC_REG(host, DATA), + host->buffer, nwords); } + + host->buffer += nwords; } static inline void mmc_omap_report_irq(u16 status)