From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Hogan Subject: [PATCH v2 4/4] mmc: dw_mmc: reset FIFO after an error Date: Wed, 06 Jul 2011 10:40:25 +0100 Message-ID: <4E142D89.2070704@imgtec.com> References: <4E142C10.3050508@imgtec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from multi.imgtec.com ([194.200.65.239]:65213 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752204Ab1GFJk2 (ORCPT ); Wed, 6 Jul 2011 05:40:28 -0400 In-Reply-To: <4E142C10.3050508@imgtec.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: James Hogan Cc: Chris Ball , Will , Jaehoon Chung , Kyungmin Park , linux-mmc , linux-kernel If an error occurs mid way through a transaction (such as a missing CRC status response after the 2nd block written out of 3), then the FIFO may still contain data which will interfere with the next transaction. Therefore after an error has been detected, reset the fifo using the CTRL register. Signed-off-by: James Hogan Acked-by: Will Newton Tested-by: Jaehoon Chung --- drivers/mmc/host/dw_mmc.c | 12 +++++++++++- 1 files changed, 11 insertions(+), 1 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 0dac397..0c839d3 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -849,7 +849,7 @@ static void dw_mci_tasklet_func(unsigned long priv) struct mmc_command *cmd; enum dw_mci_state state; enum dw_mci_state prev_state; - u32 status; + u32 status, ctrl; spin_lock(&host->lock); @@ -929,6 +929,16 @@ static void dw_mci_tasklet_func(unsigned long priv) status); data->error = -EIO; } + /* + * After an error, there may be data lingering + * in the FIFO, so reset it - doing so + * generates a block interrupt, hence setting + * the scatter-gather pointer to NULL. + */ + host->sg = NULL; + ctrl = mci_readl(host, CTRL); + ctrl |= SDMMC_CTRL_FIFO_RESET; + mci_writel(host, CTRL, ctrl); } else { data->bytes_xfered = data->blocks * data->blksz; data->error = 0; -- 1.7.2.3