[RFC 5/8] serial: amba-pl011: Pass on FIQ information to KGDB.

[Daniel Thompson]

It is important this information comes from the serial driver because, by
doing so, the driver offers "permission" for KGDB to route its interrupt
signal from the drivers own handler to KGDBs FIQ handler (which will
handle the interrupt signal by making polled I/O callbacks).

Signed-off-by: Daniel Thompson <daniel.thompson at linaro.org>
---
 drivers/tty/serial/amba-pl011.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index dacf0a0..aac817a 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -58,6 +58,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/sizes.h>
 #include <linux/io.h>
+#include <linux/kgdb.h>
 
 #define UART_NR			14
 
@@ -2091,6 +2092,18 @@ static int pl011_probe_dt_alias(int index, struct device *dev)
 	return ret;
 }
 
+#ifdef CONFIG_KGDB_FIQ
+/* Register with KGDB if there is a FIQ linked to this device */
+static void pl011_register_fiq(struct amba_device *dev)
+{
+	int fiq = dev->irq[1];
+	if (fiq > 0)
+		kgdb_register_fiq(fiq);
+}
+#else
+static void pl011_register_fiq(struct platform_device *pdev) {}
+#endif
+
 static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 {
 	struct uart_amba_port *uap;
@@ -2164,11 +2177,14 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 	}
 
 	ret = uart_add_one_port(&amba_reg, &uap->port);
-	if (ret) {
+	if (0 == ret) {
+		pl011_register_fiq(dev);
+	} else {
 		amba_ports[i] = NULL;
 		uart_unregister_driver(&amba_reg);
 		pl011_dma_remove(uap);
 	}
+
  out:
 	return ret;
 }
-- 
1.9.0