BSL entry via GPIO toggling.

AUTHORS

@@ -83,3 +83,4 @@ Jose Angel Caso Sanchez <altomaltes@gmail.com>:
 
 Paolo Zebelloni <p.zebelloni@c-labs.it>:
 	* Testing, debugging and research for the ROM BSL driver.
+	* BSL entry via GPIOs.

Makefile

@@ -121,6 +121,7 @@ OBJ=\
     util/powerbuf.o \
     util/ctrlc.o \
     util/chipinfo.o \
+    util/gpio.o \
     transport/cp210x.o \
     transport/cdc_acm.o \
     transport/ftdi.o \

drivers/bsllib.c

@@ -18,6 +18,7 @@
 
 #include "util/util.h"
 #include "bsllib.h"
+#include "gpio.h"
 
 int bsllib_seq_do(sport_t fd, const char *seq)
 {
@@ -58,6 +59,48 @@ int bsllib_seq_do(sport_t fd, const char *seq)
 	return 0;
 }
 
+int bsllib_seq_do_gpio(int rts, int dtr, const char *seq)
+{
+	gpio_export ( rts );
+	gpio_set_dir ( rts, 1 );
+	gpio_export ( dtr );
+	gpio_set_dir ( dtr, 1 );
+
+	while (*seq && *seq != ':') {
+		const char c = *(seq++);
+
+		// Logic is reversed!
+		switch (c) {
+			case 'R':
+				gpio_set_value ( rts, 0 );
+				break;
+
+			case 'r':
+				gpio_set_value ( rts, 1 );
+				break;
+
+			case 'D':
+				gpio_set_value ( dtr, 0 );
+				break;
+
+			case 'd':
+				gpio_set_value ( dtr, 1 );
+				break;
+
+			case ',':
+				delay_ms(50);
+				break;
+		}
+	}
+
+	gpio_unexport ( rts );
+	gpio_unexport ( dtr );
+
+	delay_ms(50);
+
+	return 0;
+}
+
 const char *bsllib_seq_next(const char *seq)
 {
 	while (*seq && *seq != ':')

drivers/bsllib.h

@@ -23,6 +23,7 @@
 
 /* Execute the given sequence specifier with the modem control lines */
 int bsllib_seq_do(sport_t sport, const char *seq);
+int bsllib_seq_do_gpio(int rts, int dtr, const char *seq);
 
 /* Skip to the next part of a sequence specified */
 const char *bsllib_seq_next(const char *seq);

drivers/device.h

@@ -81,6 +81,9 @@ struct device_args {
 	const char		*requested_serial;
 	const char		*require_fwupdate;
 	const char		*bsl_entry_seq;
+	int			bsl_gpio_used;
+	int			bsl_gpio_rts;
+	int			bsl_gpio_dtr;
 };
 
 struct device_class {

drivers/rom_bsl.c

@@ -425,10 +425,20 @@ static device_t rom_bsl_open(const struct device_args *args)
 	if (!dev->seq)
 		dev->seq = "DR,r,R,r,d,R:DR,r";
 
+	if ( args->bsl_gpio_used )
+	{
+		if (bsllib_seq_do_gpio(args->bsl_gpio_rts, args->bsl_gpio_dtr, dev->seq) < 0) {
+			pr_error("rom_bsl: entry sequence failed");
+			goto fail;
+		}
+	}
+	else
+	{
 		if (bsllib_seq_do(dev->fd, dev->seq) < 0) {
 			pr_error("rom_bsl: entry sequence failed");
 			goto fail;
 		}
+	}
 
 	delay_ms(500);
 

ui/main.c

@@ -148,6 +148,10 @@ static void usage(const char *progname)
 "        Specify a BSL entry sequence. Each character specifies a modem\n"
 "        control line transition (R: RTS on, r: RTS off, D: DTR on, \n"
 "        d: DTR off).\n"
+"    --bsl-gpio-rts\n"
+"        On some host (say RaspberryPi) defines a GPIO pin# to be used as RTS\n"
+"    --bsl-gpio-dtr\n"
+"        On some host (say RaspberryPi) defines a GPIO pin# to be used as DTR\n"
 "\n"
 "Most drivers connect by default via USB, unless told otherwise via the\n"
 "-d option. By default, the first USB device found is opened.\n"
@@ -247,6 +251,8 @@ static int parse_cmdline_args(int argc, char **argv,
 		LOPT_REQUIRE_FW_UPDATE,
 		LOPT_EMBEDDED,
 		LOPT_BSL_ENTRY_SEQUENCE,
+		LOPT_BSL_GPIO_RTS,
+		LOPT_BSL_GPIO_DTR,
 	};
 
 	static const struct option longopts[] = {
@@ -262,6 +268,8 @@ static int parse_cmdline_args(int argc, char **argv,
 		{"require-fw-update",	1, 0, LOPT_REQUIRE_FW_UPDATE},
 		{"embedded",		0, 0, LOPT_EMBEDDED},
 		{"bsl-entry-sequence",	1, 0, LOPT_BSL_ENTRY_SEQUENCE},
+		{"bsl-gpio-rts",	1, 0, LOPT_BSL_GPIO_RTS},
+		{"bsl-gpio-dtr",	1, 0, LOPT_BSL_GPIO_DTR},
 		{NULL, 0, 0, 0}
 	};
 
@@ -289,6 +297,15 @@ static int parse_cmdline_args(int argc, char **argv,
 			args->devarg.bsl_entry_seq = optarg;
 			break;
 
+		case LOPT_BSL_GPIO_RTS:
+			args->devarg.bsl_gpio_used = 1;
+			args->devarg.bsl_gpio_rts = atoi ( optarg );
+			break;
+		case LOPT_BSL_GPIO_DTR:
+			args->devarg.bsl_gpio_used = 1;
+			args->devarg.bsl_gpio_dtr = atoi ( optarg );
+			break;
+
 		case LOPT_EMBEDDED:
 			args->flags |= OPT_EMBEDDED;
 			break;

util/gpio.c

@@ -0,0 +1,161 @@
+/*
+*  C Implementation: gpio
+*
+* Description: 
+*
+*
+* Author: Paolo Zebelloni <p.zebelloni@c-labs-wt.com>, (C) 2014
+*
+* Copyright: See COPYING file that comes with this distribution
+*
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/signal.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include "gpio.h"
+
+#define SYSFS_GPIO_DIR		"/sys/class/gpio"
+#define MAX_BUF 64
+
+/**
+ * Before a Linux application can configure and use a GPIO, the GPIO first has to be exported to user.
+ * Each GPIO is not accessible from user space until the GPIO has been exported. 
+ * You can only export a GPIO that isn't owned by a Linux kernel driver 
+ * @param gpio GPIO number
+ * @return 0 if OK, -1 if fails
+ */
+int gpio_export ( unsigned int gpio )
+{
+	int fd, len;
+	char buf[MAX_BUF];
+
+	fd = open ( SYSFS_GPIO_DIR "/export", O_WRONLY );
+	if ( fd < 0 )
+	{
+		perror ( "gpio/export" );
+		return -1;
+	}
+
+	len = snprintf ( buf, sizeof ( buf ), "%d", gpio );
+	write ( fd, buf, len );
+	close ( fd );
+
+	return 0;
+}
+
+/**
+ * Complement of gpio_export().
+ * @param gpio  GPIO number
+ * @return 0 if OK, -1 if fails
+ */
+int gpio_unexport ( unsigned int gpio )
+{
+	int fd, len;
+	char buf[MAX_BUF];
+
+	fd = open ( SYSFS_GPIO_DIR "/unexport", O_WRONLY );
+	if ( fd < 0 )
+	{
+		perror ( "gpio/unexport" );
+		return -1;
+	}
+
+	len = snprintf ( buf, sizeof ( buf ), "%d", gpio );
+	write ( fd, buf, len );
+	close ( fd );
+
+	return 0;
+}
+
+/**
+ * To avoid hardware issues where two devices are driving the same signal, GPIOs default to be configured as an input.
+ * If you want to use the GPIO as an output, you need to change the configuration 
+ * @param gpio GPIO number
+ * @param out_flag TRUE means OUT, FALSE means IN
+ * @return 0 if OK, -1 if fails
+ */
+int gpio_set_dir ( unsigned int gpio, unsigned int out_flag )
+{
+	int fd;
+	char buf[MAX_BUF];
+
+	snprintf ( buf, MAX_BUF, SYSFS_GPIO_DIR  "/gpio%d/direction", gpio );
+
+	fd = open ( buf, O_WRONLY );
+	if ( fd < 0 )
+	{
+		perror ( "gpio/direction" );
+		return -1;
+	}
+
+	if ( out_flag )
+		write ( fd, "out", 4 );
+	else
+		write ( fd, "in", 3 );
+
+	close ( fd );
+
+	return 0;
+}
+
+/**
+ * Set HI or LO state to GPIO (output) pin.
+ * @param gpio GPIO number
+ * @param value TRUE means HI, FALSE means LO
+ * @return 0 if OK, -1 if fails
+ */
+int gpio_set_value ( unsigned int gpio, unsigned int value )
+{
+	int fd;
+	char buf[MAX_BUF];
+
+	snprintf ( buf, MAX_BUF, SYSFS_GPIO_DIR "/gpio%d/value", gpio );
+
+	fd = open ( buf, O_WRONLY );
+	if ( fd < 0 )
+	{
+		perror ( "gpio/set-value" );
+		return -1;
+	}
+
+	write ( fd, value ? "1" : "0", 2 );
+
+	close ( fd );
+
+	return 0;
+}
+
+/**
+ * Read state of GPIO (input) pin.
+ * @param gpio GPIO number
+ * @return 0 if LO, 1 if HI, -1 if fails
+ */
+int gpio_get_value ( unsigned int gpio )
+{
+	int fd;
+	char buf[MAX_BUF];
+	char ch;
+
+	snprintf ( buf, MAX_BUF, SYSFS_GPIO_DIR "/gpio%d/value", gpio );
+
+	fd = open ( buf, O_RDONLY );
+	if ( fd < 0 )
+	{
+		perror ( "gpio/get-value" );
+		return -1;
+	}
+
+	read ( fd, &ch, 1 );
+
+	close ( fd );
+
+	return ( ch != '0' );
+}
+

util/gpio.h

@@ -0,0 +1,22 @@
+//
+// C++ Interface: gpio
+//
+// Description: 
+//
+//
+// Author: Paolo Zebelloni <p.zebelloni@c-labs-wt.com>, (C) 2014
+//
+// Copyright: See COPYING file that comes with this distribution
+//
+//
+
+#ifndef _GPIO_H
+#define _GPIO_H
+
+int gpio_export ( unsigned int gpio );
+int gpio_unexport ( unsigned int gpio );
+int gpio_set_dir ( unsigned int gpio, unsigned int out_flag );
+int gpio_set_value ( unsigned int gpio, unsigned int value );
+int gpio_get_value ( unsigned int gpio );
+
+#endif