@@ -15,6 +15,18 @@ config RPMSG_CHAR
in /dev. They make it possible for user-space programs to send and
receive rpmsg packets.
+config RPMSG_SYSLOG
+ tristate "RPMSG syslog redirection"
+ depends on RPMSG
+ help
+ Say Y here to redirect the syslog/printf from remote processor into
+ the kernel log which is very useful to see what happened in the remote
+ side.
+
+ If the remote processor hangs during bootup or panics during runtime,
+ we can even cat /sys/kernel/debug/remoteproc/remoteprocX/trace0 to
+ get the last log which hasn't been output yet.
+
config RPMSG_QCOM_GLINK_NATIVE
tristate
select RPMSG
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_RPMSG) += rpmsg_core.o
obj-$(CONFIG_RPMSG_CHAR) += rpmsg_char.o
+obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_NATIVE) += qcom_glink_native.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
new file mode 100644
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Pinecone Inc.
+ *
+ * redirect syslog/printf from remote to the kernel.
+ */
+
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+
+#define RPMSG_SYSLOG_TRANSFER 0
+#define RPMSG_SYSLOG_TRANSFER_DONE 1
+#define RPMSG_SYSLOG_SUSPEND 2
+#define RPMSG_SYSLOG_RESUME 3
+
+struct rpmsg_syslog_header {
+ u32 command;
+ s32 result;
+} __packed;
+
+struct rpmsg_syslog_transfer {
+ struct rpmsg_syslog_header header;
+ u32 count;
+ char data[0];
+} __packed;
+
+#define rpmsg_syslog_suspend rpmsg_syslog_header
+#define rpmsg_syslog_resume rpmsg_syslog_header
+#define rpmsg_syslog_transfer_done rpmsg_syslog_header
+
+struct rpmsg_syslog {
+ char *buf;
+ unsigned int next;
+ unsigned int size;
+};
+
+static int rpmsg_syslog_callback(struct rpmsg_device *rpdev,
+ void *data, int len, void *priv_, u32 src)
+{
+ struct rpmsg_syslog *priv = dev_get_drvdata(&rpdev->dev);
+ struct rpmsg_syslog_transfer *msg = data;
+ struct rpmsg_syslog_transfer_done done;
+ char *s, *e, *nl;
+
+ if (msg->header.command != RPMSG_SYSLOG_TRANSFER)
+ return -EINVAL;
+
+ s = msg->data;
+ e = s + msg->count;
+
+ /* redirect the message to kernel log line by line */
+ while ((nl = strnchr(s, e - s, '\n')) != NULL) {
+ *nl = '\0';
+ if (priv->next) {
+ pr_info("%.*s%s\n", priv->next, priv->buf, s);
+ priv->next = 0;
+ } else {
+ pr_info("%s\n", s);
+ }
+ s = nl + 1;
+ }
+
+ /* append the remain to the buffer */
+ if (s != e) {
+ unsigned int size = e - s;
+ unsigned int newsize = priv->next + size;
+
+ if (newsize > priv->size) {
+ char *newbuf;
+
+ newbuf = krealloc(priv->buf, newsize, GFP_KERNEL);
+ if (newbuf) {
+ priv->buf = newbuf;
+ priv->size = newsize;
+ } else {
+ size = priv->size - priv->next;
+ }
+ }
+
+ strncpy(priv->buf + priv->next, s, size);
+ priv->next += size;
+ s += size;
+ }
+
+ done.command = RPMSG_SYSLOG_TRANSFER_DONE;
+ done.result = s - msg->data;
+ return rpmsg_send(rpdev->ept, &done, sizeof(done));
+}
+
+static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_syslog *priv;
+
+ priv = devm_kzalloc(&rpdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ dev_set_drvdata(&rpdev->dev, priv);
+ return 0;
+}
+
+static void rpmsg_syslog_remove(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_syslog *priv = dev_get_drvdata(&rpdev->dev);
+
+ /* flush the buffered log if need */
+ if (priv->next)
+ pr_info("%.*s\n", priv->next, priv->buf);
+ kfree(priv->buf);
+}
+
+static int __maybe_unused rpmsg_syslog_dev_suspend(struct device *dev)
+{
+ struct rpmsg_device *rpdev = dev_get_drvdata(dev);
+ struct rpmsg_syslog_suspend msg = {
+ .command = RPMSG_SYSLOG_SUSPEND,
+ };
+
+ return rpmsg_send(rpdev->ept, &msg, sizeof(msg));
+}
+
+static int __maybe_unused rpmsg_syslog_dev_resume(struct device *dev)
+{
+ struct rpmsg_device *rpdev = dev_get_drvdata(dev);
+ struct rpmsg_syslog_resume msg = {
+ .command = RPMSG_SYSLOG_RESUME,
+ };
+
+ return rpmsg_send(rpdev->ept, &msg, sizeof(msg));
+}
+
+static SIMPLE_DEV_PM_OPS(rpmsg_syslog_pm,
+ rpmsg_syslog_dev_suspend,
+ rpmsg_syslog_dev_resume);
+
+static const struct rpmsg_device_id rpmsg_syslog_id_table[] = {
+ { .name = "rpmsg-syslog" },
+ { }
+};
+MODULE_DEVICE_TABLE(rpmsg, rpmsg_syslog_id_table);
+
+static struct rpmsg_driver rpmsg_syslog_driver = {
+ .drv = {
+ .name = "rpmsg_syslog",
+ .owner = THIS_MODULE,
+ .pm = &rpmsg_syslog_pm,
+ },
+
+ .id_table = rpmsg_syslog_id_table,
+ .probe = rpmsg_syslog_probe,
+ .callback = rpmsg_syslog_callback,
+ .remove = rpmsg_syslog_remove,
+};
+
+module_rpmsg_driver(rpmsg_syslog_driver);
+
+MODULE_ALIAS("rpmsg:rpmsg_syslog");
+MODULE_AUTHOR("Guiding Li <liguiding@pinecone.net>");
+MODULE_DESCRIPTION("rpmsg syslog redirection driver");
+MODULE_LICENSE("GPL v2");