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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>
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parent
62f466ee03
commit
4d691f7592
1 changed files with 14 additions and 5 deletions
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@ -1175,11 +1175,6 @@ static int msm_startup(struct uart_port *port)
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snprintf(msm_port->name, sizeof(msm_port->name),
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"msm_serial%d", port->line);
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ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
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msm_port->name, port);
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if (unlikely(ret))
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return ret;
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msm_init_clock(port);
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if (likely(port->fifosize > 12))
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@ -1206,7 +1201,21 @@ static int msm_startup(struct uart_port *port)
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msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
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}
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ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
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msm_port->name, port);
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if (unlikely(ret))
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goto err_irq;
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return 0;
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err_irq:
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if (msm_port->is_uartdm)
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msm_release_dma(msm_port);
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clk_disable_unprepare(msm_port->pclk);
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clk_disable_unprepare(msm_port->clk);
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return ret;
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}
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static void msm_shutdown(struct uart_port *port)
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