> -----Original Message----- > From: Vinod Koul [mailto:vinod.koul@xxxxxxxxx] > Sent: Tuesday, September 03, 2013 7:32 PM > To: Lu Jingchang-B35083 > Cc: shawn.guo@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v4 3/3] dma: Add Freescale eDMA engine driver support > > On Tue, Sep 03, 2013 at 05:43:21AM +0000, Lu Jingchang-B35083 wrote: > > Do you mean the DMA_SLAVE_CONFIG device_control? Yeah, the slave > driver could pass > > the slave_id. But the DMA_SLAVE_CONFIG may be called more than once, > and the eDMA > > driver just needs to set the slave id once for any given channel, after > that the > > transfer is transparent to the device. > It depends, for a channel requested, if you are only tranferring to a > particular > slave device then it can be confugured once. > so > 1. allocate channel > 2. dmaengine_slave_config() > > then you cnan do preare etc multiple times based on need. Yeah, I think we should just configure the slave id once and this would make the configuration simply. But by debugging, I find the dmaengine_slave_config() may be called more one times after requested by on user. So I put the slave id configuration in the channel request phase. And the effect is the same for exclusive channel. Thanks! Best Regards, Jingchang ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
