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authorAaron Brice2016-10-06 15:13:04 -0700
committerGreg Kroah-Hartman2016-10-27 16:41:56 +0200
commitd704b2d32c39c256dea659e142a31b875a13c63b (patch)
treee104411d0b6a56d00ed2f6a8b274ce95292e5d66 /drivers/tty
parentf00a7c57569db04633818bc5e0c0e35d62733b02 (diff)
tty: serial: fsl_lpuart: Fix Tx DMA edge case
In the case where head == 0 on the circular buffer, there should be one DMA buffer, not two. The second zero-length buffer would break the lpuart driver, transfer would never complete. Signed-off-by: Aaron Brice <aaron.brice@datasoft.com> Acked-by: Stefan Agner <stefan@agner.ch> Tested-by: Stefan Agner <stefan@agner.ch> Tested-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/fsl_lpuart.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index de9d5107c00a..76103f2c4a80 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -328,7 +328,7 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
sport->dma_tx_bytes = uart_circ_chars_pending(xmit);
- if (xmit->tail < xmit->head) {
+ if (xmit->tail < xmit->head || xmit->head == 0) {
sport->dma_tx_nents = 1;
sg_init_one(sgl, xmit->buf + xmit->tail, sport->dma_tx_bytes);
} else {
@@ -359,7 +359,6 @@ static void lpuart_dma_tx(struct lpuart_port *sport)
sport->dma_tx_in_progress = true;
sport->dma_tx_cookie = dmaengine_submit(sport->dma_tx_desc);
dma_async_issue_pending(sport->dma_tx_chan);
-
}
static void lpuart_dma_tx_complete(void *arg)