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path: root/drivers/tty/hvc/hvc_dcc.c
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Diffstat (limited to 'drivers/tty/hvc/hvc_dcc.c')
-rw-r--r--drivers/tty/hvc/hvc_dcc.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvc_dcc.c b/drivers/tty/hvc/hvc_dcc.c
index 02629a1f193d..8e0edb7d93fd 100644
--- a/drivers/tty/hvc/hvc_dcc.c
+++ b/drivers/tty/hvc/hvc_dcc.c
@@ -1,7 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2010, 2014 The Linux Foundation. All rights reserved. */
+#include <linux/console.h>
#include <linux/init.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
#include <asm/dcc.h>
#include <asm/processor.h>
@@ -12,6 +15,31 @@
#define DCC_STATUS_RX (1 << 30)
#define DCC_STATUS_TX (1 << 29)
+static void dcc_uart_console_putchar(struct uart_port *port, int ch)
+{
+ while (__dcc_getstatus() & DCC_STATUS_TX)
+ cpu_relax();
+
+ __dcc_putchar(ch);
+}
+
+static void dcc_early_write(struct console *con, const char *s, unsigned n)
+{
+ struct earlycon_device *dev = con->data;
+
+ uart_console_write(&dev->port, s, n, dcc_uart_console_putchar);
+}
+
+static int __init dcc_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ device->con->write = dcc_early_write;
+
+ return 0;
+}
+
+EARLYCON_DECLARE(dcc, dcc_early_console_setup);
+
static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)
{
int i;