On 11/15/2013 09:54 PM, Stephen Warren wrote: > From: Stephen Warren <swarren@xxxxxxxxxx> > > Add fields to struct snd_dmaengine_pcm_config to allow custom: > > - DMA channel names. > > This is useful when the default "tx" and "rx" channel names don't > apply, for example if a HW module supports multiple channels, each > having different DMA channel names. This is the case with the FIFOs > in Tegra's AHUB. This new facility can replace > SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME. > > - DMA device > > This allows requesting DMA channels for a device other than the device > which is registering the "PCM" driver. This is quite unusual, but is > currently useful on Tegra. In much HW, and in Tegra20, each DAI HW > module contains its own FIFOs which DMA writes to. However, in Tegra30, > the DMA FIFOs were split out AHUB HW module, which then routes the data > through a cross-bar, and into the DAI HW modules. However, the current > ASoC driver structure does not expose this detail, and acts as if the > FIFOs are still part of the DAI HW modules. Consequently, the "PCM" > driver is registered with the DAI HW module, yet the DMA channels must > be looked up in the AHUB HW module's device tree node. This new config > field allows that to happen. Eventually, the Tegra drivers will be > reworked to fully expose the AHUB, and this config field can be > removed. > > Cc: treding@xxxxxxxxxx > Cc: linux-tegra@xxxxxxxxxxxxxxx > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: Liam Girdwood <lgirdwood@xxxxxxxxx> > Cc: Mark Brown <broonie@xxxxxxxxxx> > Cc: alsa-devel@xxxxxxxxxxxxxxxx > Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> Acked-by: Lars-Peter Clausen <lars@xxxxxxxxxx> -- 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
