[POWERPC] Xilinx: of_serial support for Xilinx uart 16550.

The Xilinx 16550 uart core is not a standard 16550 because it uses
word-based addressing rather than byte-based addressing. With
additional properties it is compatible with the open firmware
'ns16550' compatible binding.

This code updates the of_serial driver to handle the reg-offset
and reg-shift properties to enable this core to be used.

Signed-off-by: John Linn <john.linn@xilinx.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c
index 8aacfb78deab..25029c7570b6 100644
--- a/drivers/serial/of_serial.c
+++ b/drivers/serial/of_serial.c
@@ -31,7 +31,8 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev,
         struct resource resource;
         struct device_node *np = ofdev->node;
         const unsigned int *clk, *spd;
-        int ret;
+        const u32 *prop;
+        int ret, prop_size;
 
         memset(port, 0, sizeof *port);
         spd = of_get_property(np, "current-speed", NULL);
@@ -49,6 +50,17 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev,
 
         spin_lock_init(&port->lock);
         port->mapbase = resource.start;
+
+        /* Check for shifted address mapping */
+        prop = of_get_property(np, "reg-offset", &prop_size);
+        if (prop && (prop_size == sizeof(u32)))
+                port->mapbase += *prop;
+
+        /* Check for registers offset within the devices address range */
+        prop = of_get_property(np, "reg-shift", &prop_size);
+        if (prop && (prop_size == sizeof(u32)))
+                port->regshift = *prop;
+
         port->irq = irq_of_parse_and_map(np, 0);
         port->iotype = UPIO_MEM;
         port->type = type;