From: Guiding Li <liguiding@xxxxxxxxxxxx>
This driver allows the remote processor redirect the output of
syslog/printf into the kernel log, which is very useful to see
what happen in the remote side.
Signed-off-by: Guiding Li <liguiding@xxxxxxxxxxxx>
---
drivers/rpmsg/Kconfig | 12 ++++
drivers/rpmsg/Makefile | 1 +
drivers/rpmsg/rpmsg_syslog.c | 163 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 176 insertions(+)
create mode 100644 drivers/rpmsg/rpmsg_syslog.c
diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index d0322b4..d701614 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -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 happen in the remote
+ side.
+
+ If the remote processor hang during bootup or panic at the runtime,
+ We can even cat /sys/kernel/debug/remoteproc/remoteprocX/trace0 to
+ get the last log which doesn't output yet.
+
config RPMSG_QCOM_GLINK_NATIVE
tristate
select RPMSG
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index 9aa8595..bfd22df 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -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
diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
new file mode 100644
index 0000000..b7a0d27
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_syslog.c
@@ -0,0 +1,163 @@
+// 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;
+ unsigned int copied = msg->count;
+ unsigned int printed = 0;
+ const char *nl;
+
+ if (msg->header.command != RPMSG_SYSLOG_TRANSFER)
+ return -EINVAL;
+
+ /* output the message before '\n' to the kernel log */
+ nl = memrchr(msg->data, '\n', msg->count);
+ if (nl) {
+ printed = nl + 1 - msg->data;
+ copied = msg->count - printed;
+
+ if (priv->next) {
+ pr_info("%.*s%.*s", priv->next,
+ priv->buf, printed, msg->data);
+ priv->next = 0;
+ } else {
+ pr_info("%.*s", printed, msg->data);
+ }
+ }
+
+ /* append the message after '\n' to the buffer */
+ if (copied != 0) {
+ unsigned int newsize = priv->next + copied;
+
+ if (newsize > priv->size) {
+ char *newbuf;
+
+ newbuf = krealloc(priv->buf, newsize, GFP_KERNEL);
+ if (newbuf) {
+ priv->buf = newbuf;
+ priv->size = newsize;
+ } else {
+ copied = priv->size - priv->next;
+ }
+ }
+
+ strncpy(priv->buf + priv->next, msg->data + printed, copied);
+ priv->next += copied;
+ }
+
+ done.command = RPMSG_SYSLOG_TRANSFER_DONE;
+ done.result = printed + copied;
+ 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);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int 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 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));
+}
+#endif
+
+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@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("rpmsg syslog redirection driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
