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| author | Neeraj Upadhyay <neeraju@codeaurora.org> | 2017-08-07 11:51:25 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-28 20:51:19 +0200 |
| commit | 4d691f75924171787bce2853eb236f89b62ec736 (patch) | |
| tree | 5d6b5c8b2b4a1abd87bbde236a215bbab912d36f | |
| parent | 62f466ee0398d9c67e7a867090324794afff1525 (diff) | |
| download | linux-4d691f75924171787bce2853eb236f89b62ec736.tar.bz2 | |
tty: serial: msm: Move request_irq to the end of startup
Move the request_irq() call to the end of the msm_startup(),
so that we don't handle interrupts while msm_startup() is
running. This avoids potential races while initialization
is in progress. For example, consider below scenario
where rx handler reads the intermediate value of dma->chan,
set in msm_request_rx_dma(), and tries to do dma mapping,
which results in data abort.
uart_port_startup()
msm_startup()
request_irq()
...
msm_request_rx_dma()
...
dma->chan = dma_request_slave_channel_reason(dev, "rx");
<UART RX IRQ>
msm_uart_irq()
msm_handle_rx_dm()
msm_start_rx_dma()
dma->desc = dma_map_single()
<data abort>
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Reviewd-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/msm_serial.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index 6788e7532dff..1db79ee8a886 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -1175,11 +1175,6 @@ static int msm_startup(struct uart_port *port) snprintf(msm_port->name, sizeof(msm_port->name), "msm_serial%d", port->line); - ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH, - msm_port->name, port); - if (unlikely(ret)) - return ret; - msm_init_clock(port); if (likely(port->fifosize > 12)) @@ -1206,7 +1201,21 @@ static int msm_startup(struct uart_port *port) msm_request_rx_dma(msm_port, msm_port->uart.mapbase); } + ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH, + msm_port->name, port); + if (unlikely(ret)) + goto err_irq; + return 0; + +err_irq: + if (msm_port->is_uartdm) + msm_release_dma(msm_port); + + clk_disable_unprepare(msm_port->pclk); + clk_disable_unprepare(msm_port->clk); + + return ret; } static void msm_shutdown(struct uart_port *port) |