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Subject[ 36/62] pch_uart: Fix dma channel unallocated issue
3.3-stable review patch.  If anyone has any objections, please let me know.

------------------
From: Tomoya MORINAGA <tomoya.rohm@gmail.com>

commit af6d17cdc8c89aeb3101f0d27cd32fc0592b40b2 upstream.

This driver anticipates pch_uart_verify_port() is not called
during installation.
However, actually pch_uart_verify_port() is called during
installation.
As a result, memory access violation occurs like below.

0. initial value: use_dma=0
1. starup()
- dma channel is not allocated because use_dma=0
2. pch_uart_verify_port()
- Set use_dma=1
3. UART processing acts DMA mode because use_dma=1
- memory access violation occurs!

This patch fixes the issue.

Solution:
Whenever pch_uart_verify_port() is called and then
dma channel is not allocated, the channel should be allocated.

Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/tty/serial/pch_uart.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1366,9 +1366,11 @@ static int pch_uart_verify_port(struct u
__func__);
return -EOPNOTSUPP;
#endif
- priv->use_dma = 1;
priv->use_dma_flag = 1;
dev_info(priv->port.dev, "PCH UART : Use DMA Mode\n");
+ if (!priv->use_dma)
+ pch_request_dma(port);
+ priv->use_dma = 1;
}

return 0;



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