From: Guiding Li <[email protected]> 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 <[email protected]> --- 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 <[email protected]>"); +MODULE_DESCRIPTION("rpmsg syslog redirection driver"); +MODULE_LICENSE("GPL v2"); -- 2.7.4
