rpmsgexport implementation

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

.gitignore

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+*.o
+rpmsgexport

Makefile

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+OUT := rpmsgexport
+
+CFLAGS := -Wall -g -O2
+LDFLAGS := 
+prefix := /usr/local
+
+SRCS := rpmsgexport.c
+OBJS := $(SRCS:.c=.o)
+
+$(OUT): $(OBJS)
+	$(CC) $(LDFLAGS) -o $@ $^
+
+install: $(OUT)
+	install -D -m 755 $< $(DESTDIR)$(prefix)/bin/$<
+
+clean:
+	rm -f $(OUT) $(OBJS)

README

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+rpmsgexport
+===========
+
+rpmsgexport implements RPMSG_CREATE_EPT_IOCTL for usage in udev rules to
+automatically create endpoint devices as remoteproc devices are booted.
+
+An example of udev-rule that automatically exposes the APPS_RIVA_CTRL channel
+to user space as the pronto core comes up:
+
+ACTION=="add", SUBSYSTEM=="rpmsg", \
+	       KERNEL=="rpmsg_ctrl[0-9]*", \
+	       ATTRS{rpmsg_name}=="pronto", \
+	       RUN+="rpmsgexport /dev/$name APPS_RIVA_CTRL"
+
+Which together with the following two udev rules creates a nice directory
+structure of rpmsg endpoint devices under /dev/rpmsg:
+
+SUBSYSTEM=="rpmsg", KERNEL=="rpmsg_ctrl[0-9]*", \
+		    ATTRS{rpmsg_name}=="?*", \
+		    SYMLINK+="rpmsg/$attr{rpmsg_name}/ctrl"
+SUBSYSTEM=="rpmsg", KERNEL=="rpmsg[0-9]*", \
+		    ATTR{name}=="?*", \
+		    ATTRS{rpmsg_name}=="?*", \
+		    SYMLINK+="rpmsg/$attr{rpmsg_name}/$attr{name}"

rpmsgexport.c

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+/*
+ * Copyright (c) 2016, Linaro Ltd.
+ * All rights reserved.
+ *
+ * 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 of the copyright holder 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 HOLDER 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.
+ */
+#include <sys/ioctl.h>
+
+#include <err.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+struct rpmsg_endpoint_info {
+	char name[32];
+	uint32_t src;
+	uint32_t dst;
+};
+
+#define RPMSG_CREATE_EPT_IOCTL  _IOW(0xb5, 0x1, struct rpmsg_endpoint_info)
+
+static void usage(void)
+{
+	extern char *__progname;
+
+	fprintf(stderr, "%s <ctrl> <name> [<src> <dst>]\n", __progname);
+	exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	struct rpmsg_endpoint_info ept;
+	int ret;
+	int fd;
+
+	if (argc != 3 && argc != 5)
+		usage();
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0)
+		err(1, "failed to open %s\n", argv[1]);
+
+	strncpy(ept.name, argv[2], sizeof(ept.name));
+	ept.name[sizeof(ept.name)-1] = '\0';
+
+	if (argc == 4) {
+		ept.src = atoi(argv[3]);
+		ept.dst = atoi(argv[4]);
+
+		if (!ept.src || !ept.dst)
+			usage();
+	}
+
+	ret = ioctl(fd, RPMSG_CREATE_EPT_IOCTL, &ept);
+	if (ret < 0) {
+		fprintf(stderr, "failed to create endpoint");
+		exit(1);
+	}
+
+	close(fd);
+	return 0;
+}