From patchwork Tue Oct 5 06:45:39 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Ujfalusi X-Patchwork-Id: 231201 X-Patchwork-Delegate: tony@atomide.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.3) with ESMTP id o956k9b1032466 for ; Tue, 5 Oct 2010 06:46:09 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757580Ab0JEGp4 (ORCPT ); Tue, 5 Oct 2010 02:45:56 -0400 Received: from mgw-sa02.nokia.com ([147.243.1.48]:20642 "EHLO mgw-sa02.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757489Ab0JEGpz (ORCPT ); Tue, 5 Oct 2010 02:45:55 -0400 Received: from cseresznye.nmp.nokia.com (cseresznye.nmp.nokia.com [172.22.211.20]) by mgw-sa02.nokia.com (Switch-3.4.3/Switch-3.4.3) with ESMTP id o956jcEx004850; Tue, 5 Oct 2010 09:45:39 +0300 From: Peter Ujfalusi To: Tony Lindgren Cc: linux-omap@vger.kernel.org, Jarkko Nikula , linux-arm-kernel@lists.infradead.org, Russell King Subject: [PATCH v5 1/3] omap: dma: Fix buffering disable bit setting for omap24xx Date: Tue, 5 Oct 2010 09:45:39 +0300 Message-Id: <1286261141-1039-2-git-send-email-peter.ujfalusi@nokia.com> X-Mailer: git-send-email 1.7.3.1 In-Reply-To: <1286261141-1039-1-git-send-email-peter.ujfalusi@nokia.com> References: <1286261141-1039-1-git-send-email-peter.ujfalusi@nokia.com> X-Nokia-AV: Clean Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter1.kernel.org [140.211.167.41]); Tue, 05 Oct 2010 06:46:09 +0000 (UTC) different but related problem. I don't have access to OMAP2420 errata but I believe this old workaround here is put for a reason but unfortunately a wrong bit was typed and problem showed up only now. Signed-off-by: Jarkko Nikula Signed-off-by: Peter Ujfalusi --- arch/arm/plat-omap/dma.c | 14 ++++++++++---- arch/arm/plat-omap/include/plat/dma.h | 1 + 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index ec7eddf..420cef3 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -996,11 +996,17 @@ void omap_start_dma(int lch) l = dma_read(CCR(lch)); /* - * Errata: On ES2.0 BUFFERING disable must be set. - * This will always fail on ES1.0 + * Errata: Inter Frame DMA buffering issue (All OMAP2420 and + * OMAP2430ES1.0): DMA will wrongly buffer elements if packing and + * bursting is enabled. This might result in data gets stalled in + * FIFO at the end of the block. + * Workaround: DMA channels must have BUFFERING_DISABLED bit set to + * guarantee no data will stay in the DMA FIFO in case inter frame + * buffering occurs. */ - if (cpu_is_omap24xx()) - l |= OMAP_DMA_CCR_EN; + if (cpu_is_omap2420() || + (cpu_is_omap2430() && (omap_type() == OMAP2430_REV_ES1_0))) + l |= OMAP_DMA_CCR_BUFFERING_DISABLE; l |= OMAP_DMA_CCR_EN; dma_write(l, CCR(lch)); diff --git a/arch/arm/plat-omap/include/plat/dma.h b/arch/arm/plat-omap/include/plat/dma.h index 098f154..6f70f7c 100644 --- a/arch/arm/plat-omap/include/plat/dma.h +++ b/arch/arm/plat-omap/include/plat/dma.h @@ -337,6 +337,7 @@ #define OMAP2_DMA_MISALIGNED_ERR_IRQ (1 << 11) #define OMAP_DMA_CCR_EN (1 << 7) +#define OMAP_DMA_CCR_BUFFERING_DISABLE (1 << 25) #define OMAP_DMA_DATA_TYPE_S8 0x00 #define OMAP_DMA_DATA_TYPE_S16 0x01