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serial: 8250: Validate dmaengine tx chan meets requirements

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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@hurleysoftware.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2016-04-09 22:14:33 -07:00 committed by Greg Kroah-Hartman
parent ec5a11a91e
commit ddedfd82bc
1 changed files with 9 additions and 0 deletions
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9
drivers/tty/serial/8250/8250_dma.c
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@ -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 */