Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754923AbcDKMvW (ORCPT ); Mon, 11 Apr 2016 08:51:22 -0400 Received: from mga11.intel.com ([192.55.52.93]:35211 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754326AbcDKMvR (ORCPT ); Mon, 11 Apr 2016 08:51:17 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,462,1455004800"; d="scan'208";a="684363057" From: Andy Shevchenko To: "Bryan O'Donoghue" , Peter Hurley , linux-serial@vger.kernel.org, Vinod Koul , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Greg Kroah-Hartman , ismo.puustinen@intel.com, Heikki Krogerus Cc: Andy Shevchenko Subject: [PATCH v2 04/11] dmaengine: dw: override LLP support if asked in platform data Date: Mon, 11 Apr 2016 15:51:04 +0300 Message-Id: <1460379071-132591-5-git-send-email-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1460379071-132591-1-git-send-email-andriy.shevchenko@linux.intel.com> References: <1460379071-132591-1-git-send-email-andriy.shevchenko@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2147 Lines: 54 There is at least one known device, i.e. UART on Intel Galileo, that works unreliably in case of use of multi block transfer support in DMA mode. Override autodetection by user provided data. Signed-off-by: Andy Shevchenko --- drivers/dma/dw/core.c | 10 +++++++--- include/linux/platform_data/dma-dw.h | 2 ++ 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index 57105ca..193ecde 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -1634,9 +1634,13 @@ int dw_dma_probe(struct dw_dma_chip *chip) dwc->block_size = pdata->block_size; /* Check if channel supports multi block transfer */ - channel_writel(dwc, LLP, DWC_LLP_LOC(0xffffffff)); - dwc->nollp = DWC_LLP_LOC(channel_readl(dwc, LLP)) == 0; - channel_writel(dwc, LLP, 0); + if (pdata->is_nollp) { + dwc->nollp = pdata->is_nollp; + } else { + channel_writel(dwc, LLP, DWC_LLP_LOC(0xffffffff)); + dwc->nollp = DWC_LLP_LOC(channel_readl(dwc, LLP)) == 0; + channel_writel(dwc, LLP, 0); + } } } diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h index 6196139..8a9d132 100644 --- a/include/linux/platform_data/dma-dw.h +++ b/include/linux/platform_data/dma-dw.h @@ -40,6 +40,7 @@ struct dw_dma_slave { * @is_private: The device channels should be marked as private and not for * by the general purpose DMA channel allocator. * @is_memcpy: The device channels do support memory-to-memory transfers. + * @is_nollp: The device channels does not support multi block transfers. * @chan_allocation_order: Allocate channels starting from 0 or 7 * @chan_priority: Set channel priority increasing from 0 to 7 or 7 to 0. * @block_size: Maximum block size supported by the controller @@ -50,6 +51,7 @@ struct dw_dma_platform_data { unsigned int nr_channels; bool is_private; bool is_memcpy; + bool is_nollp; #define CHAN_ALLOCATION_ASCENDING 0 /* zero to seven */ #define CHAN_ALLOCATION_DESCENDING 1 /* seven to zero */ unsigned char chan_allocation_order; -- 2.8.0.rc3