From 4d691f75924171787bce2853eb236f89b62ec736 Mon Sep 17 00:00:00 2001 From: Neeraj Upadhyay Date: Mon, 7 Aug 2017 11:51:25 +0530 Subject: [PATCH] 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"); msm_uart_irq() msm_handle_rx_dm() msm_start_rx_dma() dma->desc = dma_map_single() Signed-off-by: Neeraj Upadhyay Reviewd-by: Andy Gross Reviewed-by: Stephen Boyd Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/msm_serial.c | 19 ++++++++++++++----- 1 file 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)