The beginnings of a new parameter system.

apps/px4/tests/tests.h

@@ -95,5 +95,6 @@ extern int	test_sleep(int argc, char *argv[]);
 extern int	test_time(int argc, char *argv[]);
 extern int	test_uart_console(int argc, char *argv[]);
 extern int	test_jig_voltages(int argc, char *argv[]);
+extern int	test_param(int argc, char *argv[]);
 
 #endif /* __APPS_PX4_TESTS_H */

apps/px4/tests/tests_main.c

@@ -108,6 +108,7 @@ struct {
 	{"perf",		test_perf,	OPT_NOJIGTEST, 0},
 	{"all",			test_all,	OPT_NOALLTEST | OPT_NOJIGTEST, 0},
 	{"jig",			test_jig,	OPT_NOJIGTEST | OPT_NOALLTEST, 0},
+	{"param",		test_param,	0, 0},
 	{"help",		test_help,	OPT_NOALLTEST | OPT_NOHELP | OPT_NOJIGTEST, 0},
 	{NULL,			NULL, 		0, 0}
 };

apps/px4/tests/tests_param.c

@@ -0,0 +1,70 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Author: @author Lorenz Meier <lm@inf.ethz.ch>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file tests_param.c
+ *
+ * Tests related to the parameter system.
+ */
+
+#include <stdio.h>
+#include "systemlib/err.h"
+
+#include "systemlib/param/param.h"
+
+PARAM_DEFINE_INT32(test, 0x12345678);
+
+int
+test_param(int argc, char *argv[])
+{
+	param_t		p;
+
+	p = param_find("test");
+	if (p == PARAM_INVALID)
+		errx(1, "test parameter not found\n");
+
+	param_type_t t = param_type(p);
+	if (t != PARAM_TYPE_INT32)
+		errx(1, "test parameter type mismatch (got %u)\n", (unsigned)t);
+
+	int32_t	val;
+	if (param_get(p, &val) != 0)
+		errx(1, "failed to read test parameter\n");
+	if (val != 0x12345678)
+		errx(1, "parameter value mismatch\n");
+
+	warnx("parameter test PASS\n");
+
+	return 0;
+}

apps/systemlib/Makefile

@@ -37,7 +37,8 @@
 
 CSRCS		 = err.c \
 		   hx_stream.c \
-		   perf_counter.c
+		   perf_counter.c \
+		   param/param.c
 
 #
 # XXX this really should be a CONFIG_* test

apps/systemlib/param/param.c

@@ -0,0 +1,110 @@
+/**
+ * @file param.c
+ *
+ * Global parameter store.
+ */
+
+#include <string.h>
+#include <stdbool.h>
+
+#include <unistd.h>
+
+#include "param.h"
+
+/**
+ * Array of static parameter info.
+ */
+extern char __param_start, __param_end;
+static const struct param_info_s	*param_info_base = (struct param_info_s *)&__param_start;
+static const struct param_info_s	*param_info_limit = (struct param_info_s *)&__param_end;
+#define	param_info_count		((unsigned)(param_info_limit - param_info_base))
+
+static bool
+handle_in_range(param_t handle) 
+{
+	return (handle < param_info_count);
+}
+
+param_t
+param_find(const char *name)
+{
+	param_t param;
+
+	for (param = 0; handle_in_range(param); param++) {
+		if (!strcmp(param_info_base[param].name, name))
+			return param;
+	}
+
+	/* not found */
+	return PARAM_INVALID;
+}
+
+enum
+param_type_e param_type(param_t param)
+{
+	if (handle_in_range(param))
+		return param_info_base[param].type;
+
+	return PARAM_TYPE_UNKNOWN;
+}
+
+size_t
+param_size(param_t param)
+{
+
+	if (handle_in_range(param)) {
+		switch (param_info_base[param].type) {
+		case PARAM_TYPE_INT32:
+		case PARAM_TYPE_FLOAT:
+			return 4;
+
+		case PARAM_TYPE_STRUCT ... PARAM_TYPE_STRUCT_MAX:
+			return param_info_base[param].type - PARAM_TYPE_STRUCT;
+
+		default:
+			return 0;
+		}
+	}
+
+	return 0;
+}
+
+int
+param_get(param_t param, void *val)
+{
+	if (handle_in_range(param)) {
+
+		/* XXX look for updated value stored elsewhere */
+
+		switch (param_info_base[param].type) {
+		case PARAM_TYPE_INT32:
+			*(int32_t *)val = param_info_base[param].i;
+			return 0;
+
+		case PARAM_TYPE_FLOAT:
+			*(float *)val = param_info_base[param].f;
+			return 0;
+
+		case PARAM_TYPE_STRUCT ... PARAM_TYPE_STRUCT_MAX:
+			memcpy(val, param_info_base[param].p, param_size(param));
+			return 0;
+
+		default:
+			return -1;
+		}
+	}
+	return -1;
+}
+
+int
+param_set(param_t param, void *val)
+{
+	if (handle_in_range(param)) {
+
+		/* XXX maintain list of changed values */
+
+	}
+	return -1;
+
+}
+

apps/systemlib/param/param.h

@@ -0,0 +1,140 @@
+/**
+ * @file param.h
+ *
+ * Global parameter store.
+ */
+
+#ifndef _SYSTEMLIB_PARAM_PARAM_H
+#define _SYSTEMLIB_PARAM_PARAM_H
+
+#include <stdint.h>
+
+/**
+ * Parameter types.
+ */
+typedef enum param_type_e
+{
+	/* globally-known parameter types */
+	PARAM_TYPE_INT32 = 0,
+	PARAM_TYPE_FLOAT,
+
+	/* structure parameters; these are expected to be identified by name */
+	PARAM_TYPE_STRUCT = 100,
+	PARAM_TYPE_STRUCT_MAX = 16384 + PARAM_TYPE_STRUCT,
+
+	PARAM_TYPE_UNKNOWN = 0xffff
+} param_type_t;
+
+/**
+ * Parameter handle.
+ *
+ * Parameters are represented by parameter handles, which can
+ * be obtained by looking up (or creating?) parameters.
+ */
+typedef uintptr_t	param_t;
+
+/**
+ * Handle returned when a parameter cannot be found.
+ */
+#define PARAM_INVALID	((uintptr_t)0xffffffff)
+
+/**
+ * Look up a parameter by name.
+ *
+ * @param name		The canonical name of the parameter being looked up.
+ * @return		A handle to the parameter, or PARAM_INVALID if the parameter does not exist.
+ */
+__EXPORT param_t	param_find(const char *name);
+
+/**
+ * Obtain the type of a parameter.
+ *
+ * @param param		A handle returned by param_find.
+ * @return		The type assigned to the parameter.
+ */
+__EXPORT param_type_t	param_type(param_t param);
+
+/**
+ * Determine the size of a parameter.
+ *
+ * @param param		A handle returned by param_find.
+ * @return		The size of the parameter's value.
+ */
+__EXPORT size_t		param_size(param_t param);
+
+/**
+ * Obtain the scalar value of a parameter.
+ *
+ * @param param		A handle returned by param_find.
+ * @param val		Where to return the value, assumed to point to suitable storage for the parameter type.
+ *			For structures, a pointer to the structure is returned.
+ * @return		Zero if the parameter's value could be returned as a scalar, nonzero otherwise.
+ */
+__EXPORT int		param_get(param_t param, void *val);
+
+/**
+ * Set the scalar value of a parameter.
+ *
+ * @param param		A handle returned by param_find.
+ * @param val		The value to set; assumed to point to a variable of the parameter type.
+ *			For structures, the pointer is assumed to point to a copy of the structure.
+ * @return		Zero if the parameter's value could be set from a scalar, nonzero otherwise.
+ */
+__EXPORT int		param_set(param_t param, void *val);
+
+/*
+ * Macros creating static parameter definitions.
+ *
+ * Note that these structures are not known by name; they are 
+ * collected into a section that is iterated by the parameter
+ * code.
+ */
+
+/** define an int32 parameter */
+#define PARAM_DEFINE_INT32(_name, _default)		\
+	static const					\
+	__attribute__((used, section("__param")))	\
+	struct param_info_s __param__##_name = {	\
+		.name = #_name,				\
+		.type = PARAM_TYPE_INT32,		\
+		.i = _default				\
+	}
+
+/** define a float parameter */
+#define PARAM_DEFINE_FLOAT(_name, _default)		\
+	static const					\
+	__attribute__((used, section("__param")))	\
+	struct param_info_s __param__##_name = {	\
+		.name = #_name,				\
+		.type = PARAM_TYPE_FLOAT,		\
+		.f = _default				\
+	}
+
+/** define a parameter that points to a structure */
+#define PARAM_DEFINE_STRUCT(_name, _default)		\
+	static const					\
+	__attribute__((used, section("__param")))	\
+	struct param_info_s __param__##_name = {	\
+		.name = #_name,				\
+		.type = PARAM_TYPE_STRUCT + sizeof(_default), \
+		.p = &_default;				\
+	}
+
+/**
+ * Static parameter definition structure.
+ *
+ * This is normally not used by user code; see the PARAM_DEFINE macros
+ * instead.
+ */
+struct param_info_s
+{
+	const char	*name;
+	param_type_t	type;
+	union {
+		void		*p;
+		int32_t		i;
+		float		f;
+	};
+};
+
+#endif