[U-Boot] [PATCH 1/2 V3] IOMUX: Add console multiplexing support.
Gary Jennejohn
garyj at denx.de
Thu Nov 6 15:04:23 CET 2008
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 at denx.de>
---
V3
- handle comments from the ML
- iomux_doenv() now removes repeated device entries
common/Makefile | 1 +
common/cmd_nvedit.c | 6 ++
common/console.c | 156 +++++++++++++++++++++++++++++++++++++++++++++-
common/iomux.c | 175 +++++++++++++++++++++++++++++++++++++++++++++++++++
doc/README.iomux | 106 +++++++++++++++++++++++++++++++
include/common.h | 7 ++
include/iomux.h | 48 ++++++++++++++
7 files changed, 498 insertions(+), 1 deletions(-)
create mode 100644 common/iomux.c
create mode 100644 doc/README.iomux
create mode 100644 include/iomux.h
diff --git a/common/Makefile b/common/Makefile
index f00cbd9..b1d2297 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -149,6 +149,7 @@ COBJS-$(CONFIG_CMD_XIMG) += cmd_ximg.o
COBJS-$(CONFIG_YAFFS2) += cmd_yaffs2.o
COBJS-$(CONFIG_VFD) += cmd_vfd.o
COBJS-$(CONFIG_CMD_DOC) += docecc.o
+COBJS-$(CONFIG_CONSOLE_MUX) += iomux.o
COBJS-y += flash.o
COBJS-y += kgdb.o
COBJS-$(CONFIG_LCD) += lcd.o
diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
index d280cb0..85025da 100644
--- a/common/cmd_nvedit.c
+++ b/common/cmd_nvedit.c
@@ -213,6 +213,11 @@ int _do_setenv (int flag, int argc, char *argv[])
return 1;
}
+#ifdef CONFIG_CONSOLE_MUX
+ i = iomux_doenv(console, argv[2]);
+ if (i)
+ return i;
+#else
/* Try assigning specified device */
if (console_assign (console, argv[2]) < 0)
return 1;
@@ -221,6 +226,7 @@ int _do_setenv (int flag, int argc, char *argv[])
if (serial_assign (argv[2]) < 0)
return 1;
#endif
+#endif /* CONFIG_CONSOLE_MUX */
}
/*
diff --git a/common/console.c b/common/console.c
index 6f0846f..89aeab6 100644
--- a/common/console.c
+++ b/common/console.c
@@ -93,6 +93,76 @@ static int console_setfile (int file, device_t * dev)
return error;
}
+#if defined(CONFIG_CONSOLE_MUX)
+/** Console I/O multiplexing *******************************************/
+
+static device_t *tstcdev;
+device_t **console_devices[MAX_FILES];
+int cd_count[MAX_FILES];
+
+/*
+ * This depends on tstc() always being called before getc().
+ * This is guaranteed to be true because this routine is called
+ * only from fgetc() which assures it.
+ * No attempt is made to demultiplex multiple input sources.
+ */
+static int iomux_getc(void)
+{
+ unsigned char ret;
+
+ /* This is never called with testcdev == NULL */
+ ret = tstcdev->getc();
+ tstcdev = NULL;
+ return ret;
+}
+
+static int iomux_tstc(int file)
+{
+ int i, ret;
+ device_t *dev;
+
+ disable_ctrlc(1);
+ for (i = 0; i < cd_count[file]; i++) {
+ dev = console_devices[file][i];
+ if (dev->tstc != NULL) {
+ ret = dev->tstc();
+ if (ret > 0) {
+ tstcdev = dev;
+ disable_ctrlc(0);
+ return ret;
+ }
+ }
+ }
+ disable_ctrlc(0);
+
+ return 0;
+}
+
+static void iomux_putc(int file, const char c)
+{
+ int i;
+ device_t *dev;
+
+ for (i = 0; i < cd_count[file]; i++) {
+ dev = console_devices[file][i];
+ if (dev->putc != NULL)
+ dev->putc(c);
+ }
+}
+
+static void iomux_puts(int file, const char *s)
+{
+ int i;
+ device_t *dev;
+
+ for (i = 0; i < cd_count[file]; i++) {
+ dev = console_devices[file][i];
+ if (dev->puts != NULL)
+ dev->puts(s);
+ }
+}
+#endif /* defined(CONFIG_CONSOLE_MUX) */
+
/** U-Boot INITIAL CONSOLE-NOT COMPATIBLE FUNCTIONS *************************/
void serial_printf (const char *fmt, ...)
@@ -114,8 +184,31 @@ void serial_printf (const char *fmt, ...)
int fgetc (int file)
{
- if (file < MAX_FILES)
+ if (file < MAX_FILES) {
+#if defined(CONFIG_CONSOLE_MUX)
+ /*
+ * Effectively poll for input wherever it may be available.
+ */
+ for (;;) {
+ /*
+ * Upper layer may have already called tstc() so
+ * check for that first.
+ */
+ if (tstcdev != NULL)
+ return iomux_getc();
+ iomux_tstc(file);
+#ifdef CONFIG_WATCHDOG
+ /*
+ * If the watchdog must be rate-limited then it should
+ * already be handled in board-specific code.
+ */
+ udelay(1);
+#endif
+ }
+#else
return stdio_devices[file]->getc ();
+#endif
+ }
return -1;
}
@@ -123,7 +216,11 @@ int fgetc (int file)
int ftstc (int file)
{
if (file < MAX_FILES)
+#if defined(CONFIG_CONSOLE_MUX)
+ return iomux_tstc(file);
+#else
return stdio_devices[file]->tstc ();
+#endif
return -1;
}
@@ -131,13 +228,21 @@ int ftstc (int file)
void fputc (int file, const char c)
{
if (file < MAX_FILES)
+#if defined(CONFIG_CONSOLE_MUX)
+ iomux_putc(file, c);
+#else
stdio_devices[file]->putc (c);
+#endif
}
void fputs (int file, const char *s)
{
if (file < MAX_FILES)
+#if defined(CONFIG_CONSOLE_MUX)
+ iomux_puts(file, s);
+#else
stdio_devices[file]->puts (s);
+#endif
}
void fprintf (int file, const char *fmt, ...)
@@ -407,6 +512,9 @@ int console_init_r (void)
#ifdef CONFIG_SYS_CONSOLE_ENV_OVERWRITE
int i;
#endif /* CONFIG_SYS_CONSOLE_ENV_OVERWRITE */
+#ifdef CONFIG_CONSOLE_MUX
+ int iomux_err = 0;
+#endif
/* set default handlers at first */
gd->jt[XF_getc] = serial_getc;
@@ -425,6 +533,14 @@ int console_init_r (void)
inputdev = search_device (DEV_FLAGS_INPUT, stdinname);
outputdev = search_device (DEV_FLAGS_OUTPUT, stdoutname);
errdev = search_device (DEV_FLAGS_OUTPUT, stderrname);
+#ifdef CONFIG_CONSOLE_MUX
+ iomux_err = iomux_doenv(stdin, stdinname);
+ iomux_err += iomux_doenv(stdout, stdoutname);
+ iomux_err += iomux_doenv(stderr, stderrname);
+ if (!iomux_err)
+ /* Successful, so skip all the code below. */
+ goto done;
+#endif
}
/* if the devices are overwritten or not found, use default device */
if (inputdev == NULL) {
@@ -438,15 +554,34 @@ int console_init_r (void)
}
/* Initializes output console first */
if (outputdev != NULL) {
+#ifdef CONFIG_CONSOLE_MUX
+ /* need to set a console if not done above. */
+ iomux_doenv(stdout, outputdev->name);
+#else
console_setfile (stdout, outputdev);
+#endif
}
if (errdev != NULL) {
+#ifdef CONFIG_CONSOLE_MUX
+ /* need to set a console if not done above. */
+ iomux_doenv(stderr, errdev->name);
+#else
console_setfile (stderr, errdev);
+#endif
}
if (inputdev != NULL) {
+#ifdef CONFIG_CONSOLE_MUX
+ /* need to set a console if not done above. */
+ iomux_doenv(stdin, inputdev->name);
+#else
console_setfile (stdin, inputdev);
+#endif
}
+#ifdef CONFIG_CONSOLE_MUX
+done:
+#endif
+
gd->flags |= GD_FLG_DEVINIT; /* device initialization completed */
#ifndef CONFIG_SYS_CONSOLE_INFO_QUIET
@@ -455,21 +590,33 @@ int console_init_r (void)
if (stdio_devices[stdin] == NULL) {
puts ("No input devices available!\n");
} else {
+#ifdef CONFIG_CONSOLE_MUX
+ iomux_printdevs(stdin);
+#else
printf ("%s\n", stdio_devices[stdin]->name);
+#endif
}
puts ("Out: ");
if (stdio_devices[stdout] == NULL) {
puts ("No output devices available!\n");
} else {
+#ifdef CONFIG_CONSOLE_MUX
+ iomux_printdevs(stdout);
+#else
printf ("%s\n", stdio_devices[stdout]->name);
+#endif
}
puts ("Err: ");
if (stdio_devices[stderr] == NULL) {
puts ("No error devices available!\n");
} else {
+#ifdef CONFIG_CONSOLE_MUX
+ iomux_printdevs(stderr);
+#else
printf ("%s\n", stdio_devices[stderr]->name);
+#endif
}
#endif /* CONFIG_SYS_CONSOLE_INFO_QUIET */
@@ -524,11 +671,18 @@ int console_init_r (void)
if (outputdev != NULL) {
console_setfile (stdout, outputdev);
console_setfile (stderr, outputdev);
+#ifdef CONFIG_CONSOLE_MUX
+ console_devices[stdout][0] = outputdev;
+ console_devices[stderr][0] = outputdev;
+#endif
}
/* Initializes input console */
if (inputdev != NULL) {
console_setfile (stdin, inputdev);
+#ifdef CONFIG_CONSOLE_MUX
+ console_devices[stdin][0] = inputdev;
+#endif
}
gd->flags |= GD_FLG_DEVINIT; /* device initialization completed */
diff --git a/common/iomux.c b/common/iomux.c
new file mode 100644
index 0000000..bdcc853
--- /dev/null
+++ b/common/iomux.c
@@ -0,0 +1,175 @@
+/*
+ * (C) Copyright 2008
+ * Gary Jennejohn, DENX Software Engineering GmbH, garyj at 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
+ */
+
+#include <common.h>
+#include <serial.h>
+#include <malloc.h>
+
+#ifdef CONFIG_CONSOLE_MUX
+void iomux_printdevs(const int console)
+{
+ int i;
+ device_t *dev;
+
+ for (i = 0; i < cd_count[console]; i++) {
+ dev = console_devices[console][i];
+ printf("%s ", dev->name);
+ }
+ printf("\n");
+}
+
+/* This tries to preserve the old list if an error occurs. */
+int iomux_doenv(const int console, const char *arg)
+{
+ char *console_args, *temp, **start;
+ int i, j, k, io_flag, cs_idx, repeat;
+ device_t *dev;
+ device_t **cons_set;
+
+ console_args = strdup(arg);
+ if (console_args == NULL)
+ return 1;
+ /*
+ * Check whether a comma separated list of devices was
+ * entered and count how many devices were entered.
+ * The array start[] has pointers to the beginning of
+ * each device name (up to MAX_CONSARGS devices).
+ *
+ * Have to do this twice - once to count the number of
+ * commas and then again to populate start.
+ */
+ i = 0;
+ temp = console_args;
+ for (;;) {
+ temp = strchr(temp, ',');
+ if (temp != NULL) {
+ i++;
+ temp++;
+ continue;
+ }
+ /* There's always one entry more than the number of commas. */
+ i++;
+ break;
+ }
+ start = (char **)malloc(i * sizeof(char *));
+ if (start == NULL) {
+ free(console_args);
+ return 1;
+ }
+ i = 0;
+ start[0] = console_args;
+ for (;;) {
+ temp = strchr(start[i++], ',');
+ if (temp == NULL)
+ break;
+ *temp = '\0';
+ start[i] = temp + 1;
+ }
+ cons_set = (device_t **)calloc(i, sizeof(device_t *));
+ if (cons_set == NULL) {
+ free(start);
+ free(console_args);
+ return 1;
+ }
+
+ switch (console) {
+ case stdin:
+ io_flag = DEV_FLAGS_INPUT;
+ break;
+ case stdout:
+ case stderr:
+ io_flag = DEV_FLAGS_OUTPUT;
+ break;
+ default:
+ free(start);
+ free(console_args);
+ free(cons_set);
+ return 1;
+ }
+
+ cs_idx = 0;
+ for (j = 0; j < i; j++) {
+ /*
+ * Check whether the device exists and is valid.
+ * console_assign() also calls search_device(),
+ * but I need the pointer to the device.
+ */
+ dev = search_device(io_flag, start[j]);
+ if (dev == NULL)
+ continue;
+ /*
+ * Prevent multiple entries for a device.
+ */
+ repeat = 0;
+ for (k = 0; k < cs_idx; k++) {
+ if (dev == cons_set[k]) {
+ repeat++;
+ break;
+ }
+ }
+ if (repeat)
+ continue;
+ /*
+ * Try assigning the specified device.
+ * This could screw up the console settings for apps.
+ */
+ if (console_assign(console, start[j]) < 0)
+ continue;
+#ifdef CONFIG_SERIAL_MULTI
+ /*
+ * This was taken from common/cmd_nvedit.c.
+ * This will never work because serial_assign() returns
+ * 1 upon error, not -1.
+ * This would almost always return an error anyway because
+ * serial_assign() expects the name of a serial device, like
+ * serial_smc, but the user generally only wants to set serial.
+ */
+ if (serial_assign(start[j]) < 0)
+ continue;
+#endif
+ cons_set[cs_idx++] = dev;
+ }
+ free(console_args);
+ free(start);
+ /* failed to set any console */
+ if (cs_idx == 0) {
+ free(cons_set);
+ return 1;
+ } else {
+ /* Works even if console_devices[console] is NULL. */
+ console_devices[console] =
+ (device_t **)realloc(console_devices[console],
+ cs_idx * sizeof(device_t *));
+ if (console_devices[console] == NULL) {
+ free(cons_set);
+ return 1;
+ }
+ memcpy(console_devices[console], cons_set, cs_idx *
+ sizeof(device_t *));
+
+ cd_count[console] = cs_idx;
+ }
+ free(cons_set);
+ return 0;
+}
+#endif /* CONFIG_CONSOLE_MUX */
diff --git a/doc/README.iomux b/doc/README.iomux
new file mode 100644
index 0000000..5b82a86
--- /dev/null
+++ b/doc/README.iomux
@@ -0,0 +1,106 @@
+/*
+ * (C) Copyright 2008
+ * Gary Jennejohn, DENX Software Engineering GmbH <garyj at 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
+ */
+
+U-Boot console multiplexing
+===========================
+
+HOW CONSOLE MULTIPLEXING WORKS
+------------------------------
+
+This functionality is controlled with CONFIG_CONSOLE_MUX in the board
+configuration file.
+
+Two new files, common/iomux.c and include/iomux.h, contain the heart
+(iomux_doenv()) of the environment setting implementation.
+
+iomux_doenv() is called in common/cmd_nvedit.c to handle setenv and in
+common/console.c in console_init_r() during bootup to initialize
+stdio_devices[].
+
+A user can use a comma-separated list of devices to set stdin, stdout
+and stderr. For example: "setenv stdin serial,nc". NOTE: No spaces
+are allowed around the comma(s)!
+
+The length of the list is limited by malloc(), since the array used
+is allocated and freed dynamically.
+
+It should be possible to specify any device which console_assign()
+finds acceptable, but the code has only been tested with serial and
+nc.
+
+iomux_doenv() prevents multiple use of the same device, e.g. "setenv
+stdin nc,nc,serial" will discard the second nc. iomux_doenv() is
+not able to modify the environment, however, so that "pri stdin" still
+shows "nc,nc,serial".
+
+The major change in common/console.c was to modify fgetc() to call
+the iomux_tstc() routine in a for-loop. iomux_tstc() in turn calls
+the tstc() routine for every registered device, but exits immediately
+when one of them returns true. fgetc() then calls iomux_getc(),
+which calls the corresponding getc() routine. fgetc() hangs in
+the for-loop until iomux_tstc() returns true and the input can be
+retrieved.
+
+Thus, a user can type into any device registered for stdin. No effort
+has been made to demulitplex simultaneous input from multiple stdin
+devices.
+
+fputc() and fputs() have been modified to call iomux_putc() and
+iomux_puts() respectively, which call the corresponding output
+routines for every registered device.
+
+Thus, a user can see the ouput for any device registered for stdout
+or stderr on all devices registered for stdout or stderr. As an
+example, if stdin=serial,nc and stdout=serial,nc then all output
+for serial, e.g. echos of input on serial, will appear on serial and nc.
+
+Just as with the old console code, this statement is still true:
+If not defined in the environment, the first input device is assigned
+to the 'stdin' file, the first output one to 'stdout' and 'stderr'.
+
+If CONFIG_SYS_CONSOLE_IS_IN_ENV is defined then multiple input/output
+devices can be set at boot time if defined in the environment.
+
+CAVEATS
+-------
+
+Note that common/iomux.c calls console_assign() for every registered
+device as it is discovered. This means that the environment settings
+for application consoles will be set to the last device in the list.
+
+On a slow machine, such as MPC852T clocked at 66MHz, the overhead associated
+with calling tstc() and then getc() means that copy&paste will normally not
+work, even when stdin=stdout=stderr=serial.
+On a faster machine, such as a sequoia, cut&paste of longer (about 80
+characters) lines works fine when serial is the only device used.
+
+Using nc as a stdin device results in even more overhead because nc_tstc()
+is quite slow. Even on a sequoia cut&paste does not work on the serial
+interface when nc is added to stdin, although there is no character loss using
+the ethernet interface for input. In this test case stdin=serial,nc and
+stdout=serial.
+
+In addition, the overhead associated with sending to two devices, when one of
+them is nc, also causes problems. Even on a sequoia cut&paste does not work
+on the serial interface (stdin=serial) when nc is added to stdout (stdout=
+serial,nc).
diff --git a/include/common.h b/include/common.h
index b8a654a..a005bb7 100644
--- a/include/common.h
+++ b/include/common.h
@@ -675,6 +675,13 @@ void fputc(int file, const char c);
int ftstc(int file);
int fgetc(int file);
+/*
+ * CONSOLE multiplexing.
+ */
+#ifdef CONFIG_CONSOLE_MUX
+#include <iomux.h>
+#endif
+
int pcmcia_init (void);
#ifdef CONFIG_STATUS_LED
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 at 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 */
--
1.5.4.3
---
Gary Jennejohn
*********************************************************************
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office at denx.de
*********************************************************************
More information about the U-Boot
mailing list