[Xen-devel] xen/arm: uart interrupts handling

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

Hi Tim,

I see that on uart interrupt, ICR is written to clear the all
interrupts except TX, RX and RX timeout. With this, cpu always finds
TX/RX is active and never
comes out of the loop.

With the below changes, TX, RX & RTI are cleared before handling this
interrupts.

Is my observation is correct?. If so I wonder how it is working on
platforms that
are using pl011. Without this for my cpu just keeps looping here.

  index fba0a55..d21bce3 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -63,7 +63,7 @@ static void pl011_interrupt(int irq, void *data,
struct cpu_user_regs *regs)
     {
         do
         {
-            pl011_write(uart, ICR, status & ~(TXI|RTI|RXI));
+            pl011_write(uart, ICR, status & (TXI|RTI|RXI));

             if ( status & (RTI|RXI) )
                 serial_rx_interrupt(port, regs);
@@ -157,7 +157,7 @@ static void pl011_resume(struct serial_port *port)
 {
     BUG(); // XXX
 }


Regards
Vijay

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