1 files changed, 135 insertions, 0 deletions
diff --git a/arch/v850/kernel/memcons.c b/arch/v850/kernel/memcons.c
new file mode 100644
index 0000000..491614c
--- /dev/null
+++ b/arch/v850/kernel/memcons.c
@@ -0,0 +1,135 @@
+/*
+ * arch/v850/kernel/memcons.c -- Console I/O to a memory buffer
+ *
+ *  Copyright (C) 2001,02  NEC Corporation
+ *  Copyright (C) 2001,02  Miles Bader <miles@gnu.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file COPYING in the main directory of this
+ * archive for more details.
+ *
+ * Written by Miles Bader <miles@gnu.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/init.h>
+
+/* If this device is enabled, the linker map should define start and
+   end points for its buffer. */
+extern char memcons_output[], memcons_output_end;
+
+/* Current offset into the buffer.  */
+static unsigned long memcons_offs = 0;
+
+/* Spinlock protecting memcons_offs.  */
+static DEFINE_SPINLOCK(memcons_lock);
+
+
+static size_t write (const char *buf, size_t len)
+{
+	int flags;
+	char *point;
+
+	spin_lock_irqsave (memcons_lock, flags);
+
+	point = memcons_output + memcons_offs;
+	if (point + len >= &memcons_output_end) {
+		len = &memcons_output_end - point;
+		memcons_offs = 0;
+	} else
+		memcons_offs += len;
+
+	spin_unlock_irqrestore (memcons_lock, flags);
+
+	memcpy (point, buf, len);
+
+	return len;
+}
+
+
+/*  Low-level console. */
+
+static void memcons_write (struct console *co, const char *buf, unsigned len)
+{
+	while (len > 0)
+		len -= write (buf, len);
+}
+
+static struct tty_driver *tty_driver;
+
+static struct tty_driver *memcons_device (struct console *co, int *index)
+{
+	*index = co->index;
+	return tty_driver;
+}
+
+static struct console memcons =
+{
+    .name	= "memcons",
+    .write	= memcons_write,
+    .device	= memcons_device,
+    .flags	= CON_PRINTBUFFER,
+    .index	= -1,
+};
+
+void memcons_setup (void)
+{
+	register_console (&memcons);
+	printk (KERN_INFO "Console: static memory buffer (memcons)\n");
+}
+
+/* Higher level TTY interface.  */
+
+int memcons_tty_open (struct tty_struct *tty, struct file *filp)
+{
+	return 0;
+}
+
+int memcons_tty_write (struct tty_struct *tty, const unsigned char *buf, int len)
+{
+	return write (buf, len);
+}
+
+int memcons_tty_write_room (struct tty_struct *tty)
+{
+	return &memcons_output_end - (memcons_output + memcons_offs);
+}
+
+int memcons_tty_chars_in_buffer (struct tty_struct *tty)
+{
+	/* We have no buffer.  */
+	return 0;
+}
+
+static struct tty_operations ops = {
+	.open = memcons_tty_open,
+	.write = memcons_tty_write,
+	.write_room = memcons_tty_write_room,
+	.chars_in_buffer = memcons_tty_chars_in_buffer,
+};
+
+int __init memcons_tty_init (void)
+{
+	int err;
+	struct tty_driver *driver = alloc_tty_driver(1);
+	if (!driver)
+		return -ENOMEM;
+
+	driver->name = "memcons";
+	driver->major = TTY_MAJOR;
+	driver->minor_start = 64;
+	driver->type = TTY_DRIVER_TYPE_SYSCONS;
+	driver->init_termios = tty_std_termios;
+	tty_set_operations(driver, &ops);
+	err = tty_register_driver(driver);
+	if (err) {
+		put_tty_driver(driver);
+		return err;
+	}
+	tty_driver = driver;
+	return 0;
+}
+__initcall (memcons_tty_init);