From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [PATCH v3 6/7] dmaengine: omap-dma: Remove mapping between virtual channels and requests Date: Tue, 31 Mar 2015 18:44:30 +0300 Message-ID: <551AC0DE.40807@ti.com> References: <1427459213-14611-1-git-send-email-peter.ujfalusi@ti.com> <1427459213-14611-7-git-send-email-peter.ujfalusi@ti.com> <20150327202230.GA4027@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150327202230.GA4027@n2100.arm.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: Russell King - ARM Linux Cc: vinod.koul@intel.com, tony@atomide.com, grant.likely@linaro.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org, nm@ti.com List-Id: devicetree@vger.kernel.org On 03/27/2015 10:22 PM, Russell King - ARM Linux wrote: > On Fri, Mar 27, 2015 at 02:26:52PM +0200, Peter Ujfalusi wrote: >> Do not direct map the virtual channels to sDMA request number. When = the >> sDMA is behind of a crossbar this direct mapping can cause situation= s when >> certain channel can not be requested since the crossbar request numb= er >> will no longer match with the sDMA request line. >> The direct mapping for virtual channels with HW request lines will m= ake it >> harder to implement MEM_TO_MEM mode for the driver. >=20 > There's no point having 127 virtual DMA channels then... is there? > We might as well reduce the number down to a more reasonable set > rather than wasting memory. I was also come to the same conclusion. My plan was to change the virtu= al DMA channels to the same as the sDMA's logical channels. >> @@ -1049,7 +1050,6 @@ static int omap_dma_chan_init(struct omap_dmad= ev *od, int dma_sig) >> return -ENOMEM; >> =20 >> c->reg_map =3D od->reg_map; >> - c->dma_sig =3D dma_sig; >=20 > That's the only user of dma_sig in this function. Why not remove it = from > the function prototype and its caller? >=20 --=20 P=E9ter