Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755988Ab2JRN1v (ORCPT ); Thu, 18 Oct 2012 09:27:51 -0400 Received: from mail-ie0-f174.google.com ([209.85.223.174]:50961 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755722Ab2JRN0F (ORCPT ); Thu, 18 Oct 2012 09:26:05 -0400 From: Matt Porter To: Tony Lindgren , Sekhar Nori , Grant Likely , Mark Brown , Benoit Cousson , Russell King , Vinod Koul , Rob Landley , Chris Ball Cc: Devicetree Discuss , Linux OMAP List , Linux ARM Kernel List , Linux DaVinci Kernel List , Linux Kernel Mailing List , Linux Documentation List , Linux MMC List , Linux SPI Devel List , Arnd Bergmann , Dan Williams , Rob Herring Subject: [RFC PATCH v3 11/16] mmc: omap_hsmmc: limit max_segs with the EDMA DMAC Date: Thu, 18 Oct 2012 09:26:50 -0400 Message-Id: <1350566815-409-12-git-send-email-mporter@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1350566815-409-1-git-send-email-mporter@ti.com> References: <1350566815-409-1-git-send-email-mporter@ti.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1516 Lines: 42 The EDMA DMAC has a hardware limitation that prevents supporting scatter gather lists with any number of segments. Since the EDMA DMA Engine driver sets the maximum segments to 16, we do the same. TODO: this will be replaced once the DMA Engine API supports an API to query the DMAC's segment size limit. Signed-off-by: Matt Porter --- drivers/mmc/host/omap_hsmmc.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index b327cd0..52bab01 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -1828,6 +1828,16 @@ static int __devinit omap_hsmmc_probe(struct platform_device *pdev) * as we want. */ mmc->max_segs = 1024; + /* Eventually we should get our max_segs limitation for EDMA by + * querying the dmaengine API */ + if (pdev->dev.of_node) { + struct device_node *parent = pdev->dev.of_node->parent; + struct device_node *node; + node = of_find_node_by_name(parent, "edma"); + if (node) + mmc->max_segs = 16; + } + mmc->max_blk_size = 512; /* Block Length at max can be 1024 */ mmc->max_blk_count = 0xFFFF; /* No. of Blocks is 16 bits */ mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count; -- 1.7.9.5 -- 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/