summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorNeeraj Upadhyay <neeraju@codeaurora.org>2017-08-07 11:51:25 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-28 20:51:19 +0200
commit4d691f75924171787bce2853eb236f89b62ec736 (patch)
tree5d6b5c8b2b4a1abd87bbde236a215bbab912d36f
parent62f466ee0398d9c67e7a867090324794afff1525 (diff)
downloadlinux-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.c19
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)