Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755466Ab3EPHIS (ORCPT ); Thu, 16 May 2013 03:08:18 -0400 Received: from mga03.intel.com ([143.182.124.21]:42188 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755130Ab3EPHIN (ORCPT ); Thu, 16 May 2013 03:08:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,681,1363158000"; d="scan'208";a="334928909" Date: Thu, 16 May 2013 12:02:44 +0530 From: Vinod Koul To: Lee Jones Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, balbi@ti.com, linux-usb@vger.kernel.org, linux-crypto@vger.kernel.org, davem@davemloft.net, herbert@gondor.hengli.com.au, arnd@arndb.de, linus.walleij@stericsson.com, srinidhi.kasagar@stericsson.com, Dan Williams , Per Forlin , Rabin Vincent Subject: Re: [PATCH 34/39] dmaengine: ste_dma40: Convert data_width from register bit format to value Message-ID: <20130516063244.GA14863@intel.com> References: <1368611522-9984-1-git-send-email-lee.jones@linaro.org> <1368611522-9984-35-git-send-email-lee.jones@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1368611522-9984-35-git-send-email-lee.jones@linaro.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3178 Lines: 93 On Wed, May 15, 2013 at 10:51:57AM +0100, Lee Jones wrote: > When a DMA client requests and configures a DMA channel, it requests > data_width in Bytes. The DMA40 driver then swiftly converts it over to > the necessary register bit value. Unfortunately, for any subsequent > calculations we have to shift '1' by the bit pattern (1 << data_width) > times to make any sense of it. > > This patch flips the semantics on its head and only converts the value > to its respective register bit pattern when writing to registers. This > way we can use the true data_width (in Bytes) value. > > Cc: Vinod Koul > Cc: Dan Williams > Cc: Per Forlin > Cc: Rabin Vincent > Signed-off-by: Lee Jones > --- > @@ -2804,14 +2781,24 @@ static int d40_set_runtime_config(struct dma_chan *chan, > src_maxburst = dst_maxburst * dst_addr_width / src_addr_width; > } > > + /* Only valid widths are; 1, 2, 4 and 8. */ > + if (src_addr_width <= DMA_SLAVE_BUSWIDTH_UNDEFINED || > + src_addr_width > DMA_SLAVE_BUSWIDTH_8_BYTES || > + dst_addr_width <= DMA_SLAVE_BUSWIDTH_UNDEFINED || > + dst_addr_width > DMA_SLAVE_BUSWIDTH_8_BYTES || > + ((src_addr_width > 1) && (src_addr_width & 1)) || > + ((dst_addr_width > 1) && (dst_addr_width & 1))) > + return -EINVAL; how about a simple macro to check above.. > + > + cfg->src_info.data_width = src_addr_width; > + cfg->dst_info.data_width = dst_addr_width; > + > ret = dma40_config_to_halfchannel(d40c, &cfg->src_info, > - src_addr_width, > src_maxburst); > if (ret) > return ret; > > ret = dma40_config_to_halfchannel(d40c, &cfg->dst_info, > - dst_addr_width, > dst_maxburst); > if (ret) > return ret; > diff --git a/drivers/dma/ste_dma40_ll.c b/drivers/dma/ste_dma40_ll.c > index 5ddd724..a035dfe 100644 > --- a/drivers/dma/ste_dma40_ll.c > +++ b/drivers/dma/ste_dma40_ll.c > @@ -10,6 +10,18 @@ > > #include "ste_dma40_ll.h" > > +u8 d40_width_to_bits(enum dma_slave_buswidth width) > +{ > + if (width == DMA_SLAVE_BUSWIDTH_1_BYTE) > + return STEDMA40_ESIZE_8_BIT; > + else if (width == DMA_SLAVE_BUSWIDTH_2_BYTES) > + return STEDMA40_ESIZE_16_BIT; > + else if (width == DMA_SLAVE_BUSWIDTH_8_BYTES) > + return STEDMA40_ESIZE_64_BIT; > + else > + return STEDMA40_ESIZE_32_BIT; > +} > + Switch looks better for this and how about return fls(width); as your defines are 0...3 and dmaengine define 1,2,..8 for same thing then you can also get rid of STEDMA40_XXX_WIDTH macros! > @@ -70,13 +70,6 @@ enum stedma40_flow_ctrl { > STEDMA40_FLOW_CTRL, > }; > > -enum stedma40_periph_data_width { > - STEDMA40_BYTE_WIDTH = STEDMA40_ESIZE_8_BIT, > - STEDMA40_HALFWORD_WIDTH = STEDMA40_ESIZE_16_BIT, > - STEDMA40_WORD_WIDTH = STEDMA40_ESIZE_32_BIT, > - STEDMA40_DOUBLEWORD_WIDTH = STEDMA40_ESIZE_64_BIT > -}; nice -- ~Vinod -- 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/