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@xxxxxxxxxxxxxx>
---
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 6788e75..1db79ee 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)
--
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