rmtfs: Sync rmtfs server with rproc instance

Add sigterm/sigint handlers to enable graceful rmtfs server
bringdown on first instance of SIGINT/SIGTERM. Start/Stop the
remoteproc instance on RMTFS service up and SIGINT/SIGTERM
respectively. Force quit on second instance of SIGINT/SIGTERM.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
[bjorn: Pipe for event loop signaling, reworked /sys traversal]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Makefile

@@ -1,10 +1,10 @@
 OUT := rmtfs
 
 CFLAGS += -Wall -g -O2
-LDFLAGS += -lqrtr -ludev
+LDFLAGS += -lqrtr -ludev -lpthread
 prefix = /usr/local
 
-SRCS := qmi_rmtfs.c rmtfs.c sharedmem.c storage.c util.c
+SRCS := qmi_rmtfs.c rmtfs.c rproc.c sharedmem.c storage.c util.c
 OBJS := $(SRCS:.c=.o)
 
 $(OUT): $(OBJS)

rmtfs.c

@@ -2,14 +2,18 @@
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <ctype.h>
+#include <dirent.h>
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <libqrtr.h>
+#include <limits.h>
+#include <signal.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -22,6 +26,7 @@
 #define RMTFS_QMI_INSTANCE	0
 
 static struct rmtfs_mem *rmem;
+static sig_atomic_t sig_int_count;
 
 static bool dbgprintf_enabled;
 static void dbgprintf(const char *fmt, ...)
@@ -410,9 +415,15 @@ static int handle_rmtfs(int sock)
 	return ret;
 }
 
-static int run_rmtfs(void)
+static int sig_int_count;
+
+static int run_rmtfs(int rprocfd)
 {
+	bool sig_int_handled = false;
 	int rmtfs_fd;
+	fd_set rfds;
+	char done;
+	int nfds;
 	int ret;
 
 	rmtfs_fd = qrtr_open(RMTFS_QMI_SERVICE);
@@ -430,32 +441,63 @@ static int run_rmtfs(void)
 		return ret;
 	}
 
+	if (rprocfd >= 0)
+		rproc_start();
+
 	for (;;) {
-		ret = qrtr_poll(rmtfs_fd, -1);
+		if (rprocfd >= 0 && sig_int_count == 1 && !sig_int_handled) {
+			rproc_stop();
+			sig_int_handled = true;
+		} else if (sig_int_count > 1) {
+			break;
+		}
+
+		FD_ZERO(&rfds);
+		FD_SET(rmtfs_fd, &rfds);
+		if (rprocfd >= 0)
+			FD_SET(rprocfd, &rfds);
+		nfds = MAX(rmtfs_fd, rprocfd) + 1;
+
+		ret = select(nfds, &rfds, NULL, NULL, NULL);
 		if (ret < 0 && errno != EINTR)
 			break;
 		else if (ret < 0 && errno == EINTR)
 			continue;
 
+		if (rprocfd >= 0 && FD_ISSET(rprocfd, &rfds)) {
+			ret = read(rprocfd, &done, 1);
+			if (!ret || done == 'Y')
+				break;
+		}
+
+		if (FD_ISSET(rmtfs_fd, &rfds)) {
 			ret = handle_rmtfs(rmtfs_fd);
 			if (ret == -ENETRESET)
 				break;
 		}
+	}
 
 	close(rmtfs_fd);
 
 	return ret;
 }
 
+static void sig_int_handler(int signo)
+{
+	sig_int_count++;
+}
+
 int main(int argc, char **argv)
 {
+	struct sigaction action;
 	bool use_partitions = false;
 	bool read_only = false;
+	int rprocfd = -1;
 	int ret;
 	int option;
 	const char *storage_root = NULL;
 
-	while ((option = getopt(argc, argv, "o:Prv")) != -1) {
+	while ((option = getopt(argc, argv, "o:Prsv")) != -1) {
 		switch (option) {
 		/* -o sets the directory where EFS images are stored. */
 		case 'o':
@@ -472,6 +514,11 @@ int main(int argc, char **argv)
 			read_only = true;
 			break;
 
+		/* enable sync for the mss rproc instance */
+		case 's':
+			rprocfd = rproc_init();
+			break;
+
 		/* -v is for verbose */
 		case 'v':
 			dbgprintf_enabled = 1;
@@ -483,6 +530,13 @@ int main(int argc, char **argv)
 		}
 	}
 
+	sigemptyset(&action.sa_mask);
+	action.sa_handler = sig_int_handler;
+	action.sa_flags = 0;
+
+	sigaction(SIGINT, &action, NULL);
+	sigaction(SIGTERM, &action, NULL);
+
 	rmem = rmtfs_mem_open();
 	if (!rmem)
 		return 1;
@@ -493,15 +547,8 @@ int main(int argc, char **argv)
 		goto close_rmtfs_mem;
 	}
 
-	for (;;) {
-		ret = run_rmtfs();
-
-		if (ret <= 0 && ret != -ENETRESET)
-			break;
-	}
-
 	do {
-		ret = run_rmtfs();
+		ret = run_rmtfs(rprocfd);
 	} while (ret == -ENETRESET);
 
 	storage_exit();

rmtfs.h

@@ -35,4 +35,8 @@ void storage_exit(void);
 ssize_t storage_pread(const struct rmtfd *rmtfd, void *buf, size_t nbyte, off_t offset);
 ssize_t storage_pwrite(struct rmtfd *rmtfd, const void *buf, size_t nbyte, off_t offset);
 
+int rproc_init(void);
+int rproc_start(void);
+int rproc_stop(void);
+
 #endif

rproc.c

@@ -0,0 +1,137 @@
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "rmtfs.h"
+
+#define RPROC_BASE_PATH		"/sys/bus/platform/drivers/qcom-q6v5-mss/"
+
+static pthread_t start_thread;
+static pthread_t stop_thread;
+static int rproc_state_fd;
+static int rproc_pipe[2];
+
+int rproc_init(void)
+{
+	struct dirent *device_de;
+	struct dirent *rproc_de;
+	int rproc_base_fd;
+	DIR *rproc_dir;
+	DIR *base_dir;
+	int device_fd;
+	int rproc_fd;
+	int base_fd;
+	int ret;
+
+	rproc_state_fd = -1;
+
+	base_fd = open(RPROC_BASE_PATH, O_RDONLY | O_DIRECTORY);
+	if (base_fd < 0)
+		return -1;
+
+	base_dir = fdopendir(base_fd);
+	if (!base_dir) {
+		fprintf(stderr, "failed to open mss driver path\n");
+		close(base_fd);
+		return -1;
+	}
+
+	while (rproc_state_fd < 0 && (device_de = readdir(base_dir)) != NULL) {
+		if (!strcmp(device_de->d_name, ".") ||
+		    !strcmp(device_de->d_name, ".."))
+			continue;
+
+		device_fd = openat(base_fd, device_de->d_name, O_RDONLY | O_DIRECTORY);
+		if (device_fd < 0)
+			continue;
+
+		rproc_base_fd = openat(device_fd, "remoteproc", O_RDONLY | O_DIRECTORY);
+		if (rproc_base_fd < 0) {
+			close(device_fd);
+			continue;
+		}
+
+		rproc_dir = fdopendir(rproc_base_fd);
+		while (rproc_state_fd < 0 && (rproc_de = readdir(rproc_dir)) != NULL) {
+			if (!strcmp(rproc_de->d_name, ".") ||
+			    !strcmp(rproc_de->d_name, ".."))
+				continue;
+
+			rproc_fd = openat(rproc_base_fd, rproc_de->d_name, O_RDONLY | O_DIRECTORY);
+			if (rproc_fd < 0)
+				continue;
+
+			rproc_state_fd = openat(rproc_fd, "state", O_WRONLY);
+			if (rproc_state_fd < 0) {
+				fprintf(stderr,
+					"unable to open remoteproc \"state\" control file of %s\n",
+					device_de->d_name);
+			}
+
+			close(rproc_fd);
+
+		}
+		closedir(rproc_dir);
+		close(rproc_base_fd);
+		close(device_fd);
+	}
+	closedir(base_dir);
+	close(base_fd);
+
+	if (rproc_state_fd < 0)
+		return -1;
+
+	ret = pipe(rproc_pipe);
+	if (ret < 0) {
+		close(rproc_state_fd);
+		return -1;
+	}
+
+	return rproc_pipe[0];
+}
+
+static void *do_rproc_start(void *unused)
+{
+	ssize_t ret;
+
+	ret = pwrite(rproc_state_fd, "start", 5, 0);
+	if (ret < 4)
+		fprintf(stderr, "failed to update start state\n");
+
+	return NULL;
+}
+
+int rproc_start()
+{
+	return pthread_create(&start_thread, NULL, do_rproc_start, NULL);
+}
+
+static void *do_rproc_stop(void *unused)
+{
+	ssize_t ret;
+
+	ret = pwrite(rproc_state_fd, "stop", 4, 0);
+	if (ret < 4)
+		fprintf(stderr, "failed to update stop state\n");
+
+	ret = write(rproc_pipe[1], "Y", 1);
+	if (ret != 1) {
+		fprintf(stderr, "failed to signal event loop about exit\n");
+		exit(0);
+	}
+
+	return NULL;
+}
+
+int rproc_stop(void)
+{
+	return pthread_create(&stop_thread, NULL, do_rproc_stop, NULL);
+}