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>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 10d51c2..adc1cd7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -921,6 +921,12 @@
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]
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 81f6ee7..02a896f 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1429,6 +1429,7 @@
bool "Cadence UART console support"
depends on SERIAL_XILINX_PS_UART=y
select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
help
Enable a Cadence UART port to be the system console.
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 7f8027f..200c1af 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1051,6 +1051,25 @@
cdns_uart_writel(ch, CDNS_UART_FIFO_OFFSET);
}
+static void cdns_early_write(struct console *con, const char *s, unsigned n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, cdns_uart_console_putchar);
+}
+
+static int __init cdns_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = cdns_early_write;
+
+ return 0;
+}
+EARLYCON_DECLARE(cdns, cdns_early_console_setup);
+
/**
* cdns_uart_console_write - perform write operation
* @co: Console handle