tty: serial: fsl_lpuart: Use cyclic DMA for Rx
authorBhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Tue, 19 Jul 2016 07:43:07 +0000 (13:13 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 31 Aug 2016 13:48:29 +0000 (15:48 +0200)
commit5887ad43ee02a00f17a6132b7fb256dc6865474c
treeaa36ae183f9ca030beb1f1150bca40994388b4c6
parentaa9e7d78039e34ac0f56b370e21ac719482823ee
tty: serial: fsl_lpuart: Use cyclic DMA for Rx

The initial approach of DMA implementatin for RX is inefficient due to switching
from PIO to DMA, this leads to overruns especially on instances with the smaller
FIFO. To address these issues this patch uses a cyclic DMA for receiver path.

Some part of the code is borrowed from atmel serial driver.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/fsl_lpuart.c