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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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