serial: cadence: Add generic earlycon support

Add earlycon support for the cadence serial port.
This is based on recent patches:
"tty/serial: pl011: add generic earlycon support"
(sha1: 0d3c673e7881e691991b2a4745bd4f149603baa2)
"tty/serial: add arm/arm64 semihosting earlycon"
(sha1: d50d7269ebcb438afa346cdffce0f4e2a1b9e831)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 10d51c2f10d7..adc1cd7c3bc7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -921,6 +921,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
         earlycon=       [KNL] Output early console device and options.
 
+                cdns,<addr>
+                        Start an early, polled-mode console on a cadence serial
+                        port at the specified address. The cadence serial port
+                        must already be setup and configured. Options are not
+                        yet supported.
+
                 uart[8250],io,<addr>[,options]
                 uart[8250],mmio,<addr>[,options]
                 uart[8250],mmio32,<addr>[,options]