From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932827AbcKNKxe (ORCPT ); Mon, 14 Nov 2016 05:53:34 -0500 Received: from pandora.armlinux.org.uk ([78.32.30.218]:51954 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454AbcKNKxa (ORCPT ); Mon, 14 Nov 2016 05:53:30 -0500 Date: Mon, 14 Nov 2016 10:53:13 +0000 From: Russell King - ARM Linux To: Peter Ujfalusi Cc: vinod.koul@intel.com, dan.j.williams@intel.com, Tony Lindgren , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, arnd@arndb.de Subject: Re: [PATCH 2/2] dmaengine: omap-dma: Support for slave devices with data port window Message-ID: <20161114105313.GB23750@n2100.armlinux.org.uk> References: <20161025105019.24475-1-peter.ujfalusi@ti.com> <20161025105019.24475-3-peter.ujfalusi@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161025105019.24475-3-peter.ujfalusi@ti.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 25, 2016 at 01:50:19PM +0300, Peter Ujfalusi wrote: > Based on the src/dst_port_window_size - if it is set - configure the DMA > channel to use double indexing in order to be able to loop within the > address window. > > Signed-off-by: Peter Ujfalusi > --- > drivers/dma/omap-dma.c | 45 +++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 43 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c > index 025f499cb20d..29350f936154 100644 > --- a/drivers/dma/omap-dma.c > +++ b/drivers/dma/omap-dma.c > @@ -166,6 +166,9 @@ enum { > CSDP_DST_BURST_16 = 1 << 14, > CSDP_DST_BURST_32 = 2 << 14, > CSDP_DST_BURST_64 = 3 << 14, > + CSDP_WRITE_NON_POSTED = (0 << 16), > + CSDP_WRITE_POSTED = (1 << 16), > + CSDP_WRITE_LAST_NON_POSTED = (2 << 16), Why the useless parens? > + if (port_window) { > + d->ccr |= CCR_SRC_AMODE_DBLIDX; > + d->ei = 1; > + d->fi = (-1) * (port_window - 1); You know that's 1 - port_window, or -(port_window - 1). > + > + if (port_window / 64) > + d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED; > + else if (port_window / 32) > + d->csdp = CSDP_SRC_BURST_32 | CSDP_SRC_PACKED; > + else if (port_window / 16) > + d->csdp = CSDP_SRC_BURST_16 | CSDP_SRC_PACKED; Why these divisions? Wouldn't >= be more suitable here? Do they even make sense here? > + } else { > + d->ccr |= CCR_SRC_AMODE_CONSTANT; > + } > } else { > - d->ccr |= CCR_DST_AMODE_CONSTANT | CCR_SRC_AMODE_POSTINC; > d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED; > + > + d->ccr |= CCR_SRC_AMODE_POSTINC; > + if (port_window) { > + d->ccr |= CCR_DST_AMODE_DBLIDX; > + > + if (port_window / 64) > + d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED; > + else if (port_window / 32) > + d->csdp = CSDP_DST_BURST_32 | CSDP_DST_PACKED; > + else if (port_window / 16) > + d->csdp = CSDP_DST_BURST_16 | CSDP_DST_PACKED; Ditto. > + } else { > + d->ccr |= CCR_DST_AMODE_CONSTANT; > + } > } > > d->cicr = CICR_DROP_IE | CICR_BLOCK_IE; > @@ -945,6 +979,9 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( > d->ccr |= CCR_TRIGGER_SRC; > > d->cicr |= CICR_MISALIGNED_ERR_IE | CICR_TRANS_ERR_IE; > + > + if (port_window) > + d->csdp |= CSDP_WRITE_LAST_NON_POSTED; > } > if (od->plat->errata & DMA_ERRATA_PARALLEL_CHANNELS) > d->clnk_ctrl = c->dma_ch; > @@ -970,6 +1007,10 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( > osg->addr = sg_dma_address(sgent); > osg->en = en; > osg->fn = sg_dma_len(sgent) / frame_bytes; > + if (port_window && dir == DMA_MEM_TO_DEV) { > + osg->ei = 1; > + osg->fi = (-1) * (port_window - 1); Same as above. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.