On 12/03/2013 06:34 PM, Arnd Bergmann wrote: > On Tuesday 03 December 2013, Stephen Warren wrote: >> From: Stephen Warren <swarren@xxxxxxxxxx> >> >> Call of_dma_controller_register() so that DMA clients can look up the >> Tegra DMA controller using standard APIs. This requires the of_xlate() >> function to save off the DMA slave ID, and for tegra_dma_slave_config() >> not to over-write this information; once DMA client drivers are converted >> to dma_request_slave_channel() and DT-based lookups, they won't set this >> field of struct dma_slave_config anymore. ... > Also, one (long-running, not just for this driver) comment I have is > about this snippet: > >> @@ -340,6 +342,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc, >> } >> >> memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig)); >> + if (!tdc->slave_id) >> + tdc->slave_id = sconfig->slave_id; >> tdc->config_init = true; >> return 0; >> } > > We really need to be better at having a common set of rules regarding what > it actually means to set the slave_id through dma_slave_config(). IMHO > we should just treat it as a bug for any dmaengine driver that is configured > through DT, or we should get rid of this entirely. By the end of this series (for the Tegra driver) I can remove those "+" lines you quoted above; the slave ID will only come from DT through of_xlate, and any slave ID in the slave_config will simply be ignored. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
