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 <peter@xxxxxxxxxxxxxxxxxx>
---
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 cf7a2e3..7a26c4d 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 */
--
2.8.1
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