[POWERPC] Open Firmware serial port driver

This can be used for serial ports that are connected to an
OF platform bus but are not autodetected by the lecacy
serial support.
It will automatically take over devices that come from the
legacy serial detection, which usually is only one device.

In some cases, rtas may be set up to use the serial port
in the firmware, which allows easier debugging before probing
the serial ports. In this case, the "used-by-rtas" property
must be set by the firmware. This patch also adds code to the
legacy serial driver to check for this.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
index 89f46f3..325f490 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -124,6 +124,10 @@ static int __init add_legacy_soc_port(struct device_node *np,
 	if (get_property(np, "clock-frequency", NULL) == NULL)
 		return -1;
 
+	/* if rtas uses this device, don't try to use it as well */
+	if (get_property(np, "used-by-rtas", NULL) != NULL)
+		return -1;
+
 	/* Get the address */
 	addrp = of_get_address(soc_dev, 0, NULL, NULL);
 	if (addrp == NULL)
@@ -334,6 +338,17 @@ void __init find_legacy_serial_ports(void)
 		of_node_put(tsi);
 	}
 
+	/* First fill our array with opb bus ports */
+	for (np = NULL; (np = of_find_compatible_node(np, "serial", "ns16750")) != NULL;) {
+		struct device_node *opb = of_get_parent(np);
+		if (opb && !strcmp(opb->type, "opb")) {
+			index = add_legacy_soc_port(np, np);
+			if (index >= 0 && np == stdout)
+				legacy_serial_console = index;
+		}
+		of_node_put(opb);
+	}
+
 #ifdef CONFIG_PCI
 	/* Next, try to locate PCI ports */
 	for (np = NULL; (np = of_find_all_nodes(np));) {