From: Stefan Agner <stefan@agner.ch>
Date: Mon, 26 Jan 2015 00:10:16 +0000 (+0100)
Subject: tty: serial: fsl_lpuart: terminate DMA on buffer flush
X-Git-Tag: omap-for-v4.1/prcm-dts-mfd-syscon-fix~82^2~55
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bfc2e07f910891516c8eeef61859fa17369fea9f;p=pandora-kernel.git

tty: serial: fsl_lpuart: terminate DMA on buffer flush

On uart buffer flush, serial core resets the circular buffer.
If a DMA transfer is in progress at that time, the callback
lpuart_dma_tx_complete will move buffer's tail unconditionally,
hence tail moves beyond head. Use the flush_buffer hook to
terminate the DMA imeaditely and avoid lpuart_dma_tx_complete
being called in this situation.

This bug often showed up while shutdown and lead to duplicate
serial console output.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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