Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754676AbcKNL6x (ORCPT ); Mon, 14 Nov 2016 06:58:53 -0500 Received: from lelnx193.ext.ti.com ([198.47.27.77]:14566 "EHLO lelnx193.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752225AbcKNL6v (ORCPT ); Mon, 14 Nov 2016 06:58:51 -0500 X-Greylist: delayed 408 seconds by postgrey-1.27 at vger.kernel.org; Mon, 14 Nov 2016 06:58:51 EST Subject: Re: [PATCH 2/2] dmaengine: omap-dma: Support for slave devices with data port window To: Russell King - ARM Linux References: <20161025105019.24475-1-peter.ujfalusi@ti.com> <20161025105019.24475-3-peter.ujfalusi@ti.com> <20161114105313.GB23750@n2100.armlinux.org.uk> CC: , , Tony Lindgren , , , , From: Peter Ujfalusi Message-ID: <091f6dce-b1d7-6527-b8c6-147becfd8856@ti.com> Date: Mon, 14 Nov 2016 13:56:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161114105313.GB23750@n2100.armlinux.org.uk> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3001 Lines: 104 On 11/14/2016 12:53 PM, Russell King - ARM Linux wrote: > 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? I will get rid of them. > >> + 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). Yes, I know. "-(port_window - 1)" might be a bit better. > >> + >> + 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? I'll revisit these. > >> + } 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. > -- P?ter