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. ~Vinod > On the other hand, the DMAMUX's setting procedure requires first disable > the dmamux > before setting, then if it is set in DMA_SLAVE_CONFIG, the repeated setting > may be > complex and unnecessary. The channel is occupied exclusively by the > peripheral. > So, according the HW feature, I think the eDMA needs only set the slave id > once, > and since the of_dma helper has pass the slave id in on xlate, we can get and > set > the slave id here. How do you think about this? -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
