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 <[EMAIL PROTECTED]>
---
V3 has fixes suggested by Grant. They were incorporated and tested.
Documentation/powerpc/booting-without-of.txt | 10 ++++++++++
drivers/serial/of_serial.c | 14 +++++++++++++-
2 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/Documentation/powerpc/booting-without-of.txt
b/Documentation/powerpc/booting-without-of.txt
index 87f4d84..4066ec8 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -2539,6 +2539,16 @@ platforms are moved over to use the
flattened-device-tree model.
differ between different families. May be
'virtex2p', 'virtex4', or 'virtex5'.
+ iv) Xilinx Uart 16550
+
+ Xilinx UART 16550 devices are very similar to the NS16550 but with
+ different register spacing and an offset from the base address.
+
+ Requred properties:
+ - clock-frequency : Frequency of the clock input
+ - reg-offset : A value of 3 is required
+ - reg-shift : A value of 2 is required
+
More devices will be defined as this spec matures.
VII - Specifying interrupt information for devices
diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c
index 2efb892..73c47a5 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;
--
1.5.2.1
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