IOMUX: Add console multiplexing support.

Modifications to support console multiplexing.  This is controlled using
CONFIG_SYS_CONSOLE_MUX in the board configuration file.

This allows a user to specify multiple console devices in the environment
with a command like this: setenv stdin serial,nc.  As a result, the user can
enter text on both the serial and netconsole interfaces.

All devices - stdin, stdout and stderr - can be set in this manner.

1) common/iomux.c and include/iomux.h contain the environment setting
implementation.
2) doc/README.iomux contains a somewhat more detailed description.
3) The implementation in (1) is called from common/cmd_nvedit.c to
handle setenv and from common/console.c to handle initialization of
input/output devices at boot time.
4) common/console.c also contains the code needed to poll multiple console
devices for input and send output to all devices registered for output.
5) include/common.h includes iomux.h and common/Makefile generates iomux.o
when CONFIG_SYS_CONSOLE_MUX is set.

Signed-off-by: Gary Jennejohn <garyj@denx.de>

1 files changed, 48 insertions, 0 deletions

diff --git a/include/iomux.h b/include/iomux.h
new file mode 100644
index 0000000..257c1f7
--- /dev/null
+++ b/include/iomux.h
@@ -0,0 +1,48 @@
+/*
+ * (C) Copyright 2008
+ * Gary Jennejohn, DENX Software Engineering GmbH, garyj@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ *This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _IO_MUX_H
+#define _IO_MUX_H
+
+#include <devices.h>
+
+/*
+ * Stuff required to support console multiplexing.
+ */
+
+/*
+ * Pointers to devices used for each file type.  Defined in console.c
+ * but storage is allocated in iomux.c.
+ */
+extern device_t **console_devices[MAX_FILES];
+/*
+ * The count of devices assigned to each FILE.  Defined in console.c
+ * and populated in iomux.c.
+ */
+extern int cd_count[MAX_FILES];
+
+int iomux_doenv(const int, const char *);
+void iomux_printdevs(const int);
+device_t *search_device(int, char *);
+
+#endif /* _IO_MUX_H */