From ddedfd82bc61c8d8d4d0eb754a9bcebb2e84de75 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 9 Apr 2016 22:14:33 -0700 Subject: [PATCH] serial: 8250: Validate dmaengine tx chan meets requirements 8250 dma support requires the dmaegine driver support terminate. Query slave caps to determine if necessary commands/properties are supported; disable dma if not. Note this means dmaengine driver must support slave caps reporting as well. Signed-off-by: Peter Hurley Reviewed-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_dma.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index cf7a2e3288a6..7a26c4d13b18 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -201,6 +201,15 @@ int serial8250_request_dma(struct uart_8250_port *p) goto release_rx; } + /* 8250 tx dma requires dmaengine driver to support terminate */ + ret = dma_get_slave_caps(dma->txchan, &caps); + if (ret) + goto err; + if (!caps.cmd_terminate) { + ret = -EINVAL; + goto err; + } + dmaengine_slave_config(dma->txchan, &dma->txconf); /* RX buffer */ -- 2.20.1