soc: aspeed: xdma: Add reset ioctl

Users of the XDMA engine need a way to reset it if something goes wrong.
Problems on the host side, or user error, such as incorrect host
address, may result in the DMA operation never completing and no way to
determine what went wrong. Therefore, add an ioctl to reset the engine
so that users can recover in this situation.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/1588697905-23444-5-git-send-email-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>
2 files changed