Allows the remote firmware to log into syslog.
Signed-off-by: Christian Gmeiner <[email protected]>
---
drivers/rpmsg/Kconfig | 8 +++++
drivers/rpmsg/Makefile | 1 +
drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
3 files changed, 74 insertions(+)
create mode 100644 drivers/rpmsg/rpmsg_syslog.c
diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index 0b4407abdf13..801f9956ec21 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -73,4 +73,12 @@ config RPMSG_VIRTIO
select RPMSG_NS
select VIRTIO
+config RPMSG_SYSLOG
+ tristate "SYSLOG device interface"
+ depends on RPMSG
+ help
+ Say Y here to export rpmsg endpoints as device files, usually found
+ in /dev. They make it possible for user-space programs to send and
+ receive rpmsg packets.
+
endmenu
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index 8d452656f0ee..75b2ec7133a5 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
+obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
new file mode 100644
index 000000000000..b3fdae495fd9
--- /dev/null
+++ b/drivers/rpmsg/rpmsg_syslog.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+
+static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
+ void *priv, u32 src)
+{
+ const char *buffer = data;
+
+ switch (buffer[0]) {
+ case 'e':
+ dev_err(&rpdev->dev, "%s", buffer + 1);
+ break;
+ case 'w':
+ dev_warn(&rpdev->dev, "%s", buffer + 1);
+ break;
+ case 'i':
+ dev_info(&rpdev->dev, "%s", buffer + 1);
+ break;
+ default:
+ dev_info(&rpdev->dev, "%s", buffer);
+ break;
+ }
+
+ return 0;
+}
+
+static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
+{
+ struct rpmsg_endpoint *syslog_ept;
+ struct rpmsg_channel_info syslog_chinfo = {
+ .src = 42,
+ .dst = 42,
+ .name = "syslog",
+ };
+
+ /*
+ * Create the syslog service endpoint associated to the RPMsg
+ * device. The endpoint will be automatically destroyed when the RPMsg
+ * device will be deleted.
+ */
+ syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
+ if (!syslog_ept) {
+ dev_err(&rpdev->dev, "failed to create the syslog ept\n");
+ return -ENOMEM;
+ }
+ rpdev->ept = syslog_ept;
+
+ return 0;
+}
+
+static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
+ { .name = "syslog" },
+ { },
+};
+MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
+
+static struct rpmsg_driver rpmsg_syslog_client = {
+ .drv.name = KBUILD_MODNAME,
+ .id_table = rpmsg_driver_syslog_id_table,
+ .probe = rpmsg_syslog_probe,
+};
+module_rpmsg_driver(rpmsg_syslog_client);
--
2.33.1
On Tue 09 Nov 00:39 PST 2021, Christian Gmeiner wrote:
> Allows the remote firmware to log into syslog.
>
This allows the remote firmware to print log messages in the kernel log,
not the syslog (although your system might inject the kernel log into
the syslog as well)
> Signed-off-by: Christian Gmeiner <[email protected]>
> ---
> drivers/rpmsg/Kconfig | 8 +++++
> drivers/rpmsg/Makefile | 1 +
> drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
drivers/rpmsg is for rpmsg bus and transport drivers. Client drivers
should live elsewhere.
But perhaps, rather than having a driver for this, you could simply use
rpmsg_char and a userspace tool; if you want to get the remote processor
logs into syslog, instead of the kernel log?
> 3 files changed, 74 insertions(+)
> create mode 100644 drivers/rpmsg/rpmsg_syslog.c
>
> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> index 0b4407abdf13..801f9956ec21 100644
> --- a/drivers/rpmsg/Kconfig
> +++ b/drivers/rpmsg/Kconfig
> @@ -73,4 +73,12 @@ config RPMSG_VIRTIO
> select RPMSG_NS
> select VIRTIO
>
> +config RPMSG_SYSLOG
> + tristate "SYSLOG device interface"
> + depends on RPMSG
> + help
> + Say Y here to export rpmsg endpoints as device files, usually found
> + in /dev. They make it possible for user-space programs to send and
> + receive rpmsg packets.
> +
> endmenu
> diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
> index 8d452656f0ee..75b2ec7133a5 100644
> --- a/drivers/rpmsg/Makefile
> +++ b/drivers/rpmsg/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
> obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
> obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
> obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
> +obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
> diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
> new file mode 100644
> index 000000000000..b3fdae495fd9
> --- /dev/null
> +++ b/drivers/rpmsg/rpmsg_syslog.c
> @@ -0,0 +1,65 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/rpmsg.h>
> +
> +static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
> + void *priv, u32 src)
> +{
> + const char *buffer = data;
> +
> + switch (buffer[0]) {
> + case 'e':
> + dev_err(&rpdev->dev, "%s", buffer + 1);
> + break;
> + case 'w':
> + dev_warn(&rpdev->dev, "%s", buffer + 1);
> + break;
> + case 'i':
> + dev_info(&rpdev->dev, "%s", buffer + 1);
> + break;
> + default:
> + dev_info(&rpdev->dev, "%s", buffer);
> + break;
> + }
> +
> + return 0;
> +}
> +
> +static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
> +{
> + struct rpmsg_endpoint *syslog_ept;
> + struct rpmsg_channel_info syslog_chinfo = {
> + .src = 42,
> + .dst = 42,
> + .name = "syslog",
> + };
> +
> + /*
> + * Create the syslog service endpoint associated to the RPMsg
> + * device. The endpoint will be automatically destroyed when the RPMsg
> + * device will be deleted.
> + */
> + syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
The rpmsg_device_id below should cause the device to probe on the
presence of a "syslog" channel announcement, so why are you creating a
new endpoint with the same here?
Why aren't you just specifying the callback of the driver?
> + if (!syslog_ept) {
> + dev_err(&rpdev->dev, "failed to create the syslog ept\n");
> + return -ENOMEM;
> + }
> + rpdev->ept = syslog_ept;
> +
> + return 0;
> +}
> +
> +static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
> + { .name = "syslog" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
> +
> +static struct rpmsg_driver rpmsg_syslog_client = {
> + .drv.name = KBUILD_MODNAME,
> + .id_table = rpmsg_driver_syslog_id_table,
> + .probe = rpmsg_syslog_probe,
> +};
> +module_rpmsg_driver(rpmsg_syslog_client);
I would expect that building this as a module gives you complaints about
lacking MODULE_LICENSE().
Regards,
Bjorn
> --
> 2.33.1
>
Hi Christian,
On 11/9/21 7:06 PM, Bjorn Andersson wrote:
> On Tue 09 Nov 00:39 PST 2021, Christian Gmeiner wrote:
>
>> Allows the remote firmware to log into syslog.
>>
For you information a similar patch has been sent few years ago:
https://www.spinics.net/lists/kernel/msg3045824.html
The suspend /resume mechanism seems interesting to manage the low power use case.
>
> This allows the remote firmware to print log messages in the kernel log,
> not the syslog (although your system might inject the kernel log into
> the syslog as well)
>
>> Signed-off-by: Christian Gmeiner <[email protected]>
>> ---
>> drivers/rpmsg/Kconfig | 8 +++++
>> drivers/rpmsg/Makefile | 1 +
>> drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
>
> drivers/rpmsg is for rpmsg bus and transport drivers. Client drivers
> should live elsewhere.
>
> But perhaps, rather than having a driver for this, you could simply use
> rpmsg_char and a userspace tool; if you want to get the remote processor
> logs into syslog, instead of the kernel log?
This is also a question that comes to me while looking at the patch.
rpmsg_tty service (if available in 5.16) could be another alternative.
Regards,
Arnaud
>
>> 3 files changed, 74 insertions(+)
>> create mode 100644 drivers/rpmsg/rpmsg_syslog.c
>>
>> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
>> index 0b4407abdf13..801f9956ec21 100644
>> --- a/drivers/rpmsg/Kconfig
>> +++ b/drivers/rpmsg/Kconfig
>> @@ -73,4 +73,12 @@ config RPMSG_VIRTIO
>> select RPMSG_NS
>> select VIRTIO
>>
>> +config RPMSG_SYSLOG
>> + tristate "SYSLOG device interface"
>> + depends on RPMSG
>> + help
>> + Say Y here to export rpmsg endpoints as device files, usually found
>> + in /dev. They make it possible for user-space programs to send and
>> + receive rpmsg packets.
>> +
>> endmenu
>> diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
>> index 8d452656f0ee..75b2ec7133a5 100644
>> --- a/drivers/rpmsg/Makefile
>> +++ b/drivers/rpmsg/Makefile
>> @@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
>> obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
>> obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
>> obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
>> +obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
>> diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
>> new file mode 100644
>> index 000000000000..b3fdae495fd9
>> --- /dev/null
>> +++ b/drivers/rpmsg/rpmsg_syslog.c
>> @@ -0,0 +1,65 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/rpmsg.h>
>> +
>> +static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
>> + void *priv, u32 src)
>> +{
>> + const char *buffer = data;
>> +
>> + switch (buffer[0]) {
>> + case 'e':
>> + dev_err(&rpdev->dev, "%s", buffer + 1);
>> + break;
>> + case 'w':
>> + dev_warn(&rpdev->dev, "%s", buffer + 1);
>> + break;
>> + case 'i':
>> + dev_info(&rpdev->dev, "%s", buffer + 1);
>> + break;
>> + default:
>> + dev_info(&rpdev->dev, "%s", buffer);
>> + break;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
>> +{
>> + struct rpmsg_endpoint *syslog_ept;
>> + struct rpmsg_channel_info syslog_chinfo = {
>> + .src = 42,
>> + .dst = 42,
>> + .name = "syslog",
>> + };
>> +
>> + /*
>> + * Create the syslog service endpoint associated to the RPMsg
>> + * device. The endpoint will be automatically destroyed when the RPMsg
>> + * device will be deleted.
>> + */
>> + syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
>
> The rpmsg_device_id below should cause the device to probe on the
> presence of a "syslog" channel announcement, so why are you creating a
> new endpoint with the same here?
>
> Why aren't you just specifying the callback of the driver?
>
>> + if (!syslog_ept) {
>> + dev_err(&rpdev->dev, "failed to create the syslog ept\n");
>> + return -ENOMEM;
>> + }
>> + rpdev->ept = syslog_ept;
>> +
>> + return 0;
>> +}
>> +
>> +static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
>> + { .name = "syslog" },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
>> +
>> +static struct rpmsg_driver rpmsg_syslog_client = {
>> + .drv.name = KBUILD_MODNAME,
>> + .id_table = rpmsg_driver_syslog_id_table,
>> + .probe = rpmsg_syslog_probe,
>> +};
>> +module_rpmsg_driver(rpmsg_syslog_client);
>
> I would expect that building this as a module gives you complaints about
> lacking MODULE_LICENSE().
>
> Regards,
> Bjorn
>
>> --
>> 2.33.1
>>
Hi Arnaud
>
> On 11/9/21 7:06 PM, Bjorn Andersson wrote:
> > On Tue 09 Nov 00:39 PST 2021, Christian Gmeiner wrote:
> >
> >> Allows the remote firmware to log into syslog.
> >>
>
> For you information a similar patch has been sent few years ago:
> https://www.spinics.net/lists/kernel/msg3045824.html
>
Interesting - do you know why the patch was not taken?
> The suspend /resume mechanism seems interesting to manage the low power use case.
>
Yeah .. nothing I thought about.
> >
> > This allows the remote firmware to print log messages in the kernel log,
> > not the syslog (although your system might inject the kernel log into
> > the syslog as well)
> >
> >> Signed-off-by: Christian Gmeiner <[email protected]>
> >> ---
> >> drivers/rpmsg/Kconfig | 8 +++++
> >> drivers/rpmsg/Makefile | 1 +
> >> drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
> >
> > drivers/rpmsg is for rpmsg bus and transport drivers. Client drivers
> > should live elsewhere.
> >
> > But perhaps, rather than having a driver for this, you could simply use
> > rpmsg_char and a userspace tool; if you want to get the remote processor
> > logs into syslog, instead of the kernel log?
>
> This is also a question that comes to me while looking at the patch.
> rpmsg_tty service (if available in 5.16) could be another alternative.
>
I thought about it too but I do not see how the syslog/journald can read the log
messages from this tty device without an extra user space component.
With a syslog redirection rpmsg service this happens automatically without any
extra user space daemon that reads from tty and writes to syslog.
Maybe I am missing something.
> Regards,
> Arnaud
>
> >
> >> 3 files changed, 74 insertions(+)
> >> create mode 100644 drivers/rpmsg/rpmsg_syslog.c
> >>
> >> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> >> index 0b4407abdf13..801f9956ec21 100644
> >> --- a/drivers/rpmsg/Kconfig
> >> +++ b/drivers/rpmsg/Kconfig
> >> @@ -73,4 +73,12 @@ config RPMSG_VIRTIO
> >> select RPMSG_NS
> >> select VIRTIO
> >>
> >> +config RPMSG_SYSLOG
> >> + tristate "SYSLOG device interface"
> >> + depends on RPMSG
> >> + help
> >> + Say Y here to export rpmsg endpoints as device files, usually found
> >> + in /dev. They make it possible for user-space programs to send and
> >> + receive rpmsg packets.
> >> +
> >> endmenu
> >> diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
> >> index 8d452656f0ee..75b2ec7133a5 100644
> >> --- a/drivers/rpmsg/Makefile
> >> +++ b/drivers/rpmsg/Makefile
> >> @@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
> >> obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
> >> obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
> >> obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
> >> +obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
> >> diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
> >> new file mode 100644
> >> index 000000000000..b3fdae495fd9
> >> --- /dev/null
> >> +++ b/drivers/rpmsg/rpmsg_syslog.c
> >> @@ -0,0 +1,65 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +
> >> +#include <linux/kernel.h>
> >> +#include <linux/module.h>
> >> +#include <linux/rpmsg.h>
> >> +
> >> +static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
> >> + void *priv, u32 src)
> >> +{
> >> + const char *buffer = data;
> >> +
> >> + switch (buffer[0]) {
> >> + case 'e':
> >> + dev_err(&rpdev->dev, "%s", buffer + 1);
> >> + break;
> >> + case 'w':
> >> + dev_warn(&rpdev->dev, "%s", buffer + 1);
> >> + break;
> >> + case 'i':
> >> + dev_info(&rpdev->dev, "%s", buffer + 1);
> >> + break;
> >> + default:
> >> + dev_info(&rpdev->dev, "%s", buffer);
> >> + break;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
> >> +{
> >> + struct rpmsg_endpoint *syslog_ept;
> >> + struct rpmsg_channel_info syslog_chinfo = {
> >> + .src = 42,
> >> + .dst = 42,
> >> + .name = "syslog",
> >> + };
> >> +
> >> + /*
> >> + * Create the syslog service endpoint associated to the RPMsg
> >> + * device. The endpoint will be automatically destroyed when the RPMsg
> >> + * device will be deleted.
> >> + */
> >> + syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
> >
> > The rpmsg_device_id below should cause the device to probe on the
> > presence of a "syslog" channel announcement, so why are you creating a
> > new endpoint with the same here?
> >
> > Why aren't you just specifying the callback of the driver?
> >
> >> + if (!syslog_ept) {
> >> + dev_err(&rpdev->dev, "failed to create the syslog ept\n");
> >> + return -ENOMEM;
> >> + }
> >> + rpdev->ept = syslog_ept;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
> >> + { .name = "syslog" },
> >> + { },
> >> +};
> >> +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
> >> +
> >> +static struct rpmsg_driver rpmsg_syslog_client = {
> >> + .drv.name = KBUILD_MODNAME,
> >> + .id_table = rpmsg_driver_syslog_id_table,
> >> + .probe = rpmsg_syslog_probe,
> >> +};
> >> +module_rpmsg_driver(rpmsg_syslog_client);
> >
> > I would expect that building this as a module gives you complaints about
> > lacking MODULE_LICENSE().
> >
> > Regards,
> > Bjorn
> >
> >> --
> >> 2.33.1
> >>
--
greets
--
Christian Gmeiner, MSc
https://christian-gmeiner.info/privacypolicy
Hi Bjorn
> > Allows the remote firmware to log into syslog.
> >
>
> This allows the remote firmware to print log messages in the kernel log,
> not the syslog (although your system might inject the kernel log into
> the syslog as well)
>
Correct.
> > Signed-off-by: Christian Gmeiner <[email protected]>
> > ---
> > drivers/rpmsg/Kconfig | 8 +++++
> > drivers/rpmsg/Makefile | 1 +
> > drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
>
> drivers/rpmsg is for rpmsg bus and transport drivers. Client drivers
> should live elsewhere.
>
Ahh .. yes.
> But perhaps, rather than having a driver for this, you could simply use
> rpmsg_char and a userspace tool; if you want to get the remote processor
> logs into syslog, instead of the kernel log?
>
I thought about that too (also regarding the rpmsg tty driver) but that means I
need to start/supervise a user space tool.
> > 3 files changed, 74 insertions(+)
> > create mode 100644 drivers/rpmsg/rpmsg_syslog.c
> >
> > diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> > index 0b4407abdf13..801f9956ec21 100644
> > --- a/drivers/rpmsg/Kconfig
> > +++ b/drivers/rpmsg/Kconfig
> > @@ -73,4 +73,12 @@ config RPMSG_VIRTIO
> > select RPMSG_NS
> > select VIRTIO
> >
> > +config RPMSG_SYSLOG
> > + tristate "SYSLOG device interface"
> > + depends on RPMSG
> > + help
> > + Say Y here to export rpmsg endpoints as device files, usually found
> > + in /dev. They make it possible for user-space programs to send and
> > + receive rpmsg packets.
> > +
> > endmenu
> > diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
> > index 8d452656f0ee..75b2ec7133a5 100644
> > --- a/drivers/rpmsg/Makefile
> > +++ b/drivers/rpmsg/Makefile
> > @@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
> > obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
> > obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
> > obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
> > +obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
> > diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
> > new file mode 100644
> > index 000000000000..b3fdae495fd9
> > --- /dev/null
> > +++ b/drivers/rpmsg/rpmsg_syslog.c
> > @@ -0,0 +1,65 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/rpmsg.h>
> > +
> > +static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
> > + void *priv, u32 src)
> > +{
> > + const char *buffer = data;
> > +
> > + switch (buffer[0]) {
> > + case 'e':
> > + dev_err(&rpdev->dev, "%s", buffer + 1);
> > + break;
> > + case 'w':
> > + dev_warn(&rpdev->dev, "%s", buffer + 1);
> > + break;
> > + case 'i':
> > + dev_info(&rpdev->dev, "%s", buffer + 1);
> > + break;
> > + default:
> > + dev_info(&rpdev->dev, "%s", buffer);
> > + break;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
> > +{
> > + struct rpmsg_endpoint *syslog_ept;
> > + struct rpmsg_channel_info syslog_chinfo = {
> > + .src = 42,
> > + .dst = 42,
> > + .name = "syslog",
> > + };
> > +
> > + /*
> > + * Create the syslog service endpoint associated to the RPMsg
> > + * device. The endpoint will be automatically destroyed when the RPMsg
> > + * device will be deleted.
> > + */
> > + syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
>
> The rpmsg_device_id below should cause the device to probe on the
> presence of a "syslog" channel announcement, so why are you creating a
> new endpoint with the same here?
>
> Why aren't you just specifying the callback of the driver?
>
Good question. I think I was happy that I got work working somehow. I
also want to send out
a documentation update as it is not up to date with the current API.
> > + if (!syslog_ept) {
> > + dev_err(&rpdev->dev, "failed to create the syslog ept\n");
> > + return -ENOMEM;
> > + }
> > + rpdev->ept = syslog_ept;
> > +
> > + return 0;
> > +}
> > +
> > +static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
> > + { .name = "syslog" },
> > + { },
> > +};
> > +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
> > +
> > +static struct rpmsg_driver rpmsg_syslog_client = {
> > + .drv.name = KBUILD_MODNAME,
> > + .id_table = rpmsg_driver_syslog_id_table,
> > + .probe = rpmsg_syslog_probe,
> > +};
> > +module_rpmsg_driver(rpmsg_syslog_client);
>
> I would expect that building this as a module gives you complaints about
> lacking MODULE_LICENSE().
>
Yeah .. I never built it as a module.
The biggest question I have: do you see any possibility to get such a
redirection
driver into mainline? At the moment I have not heard a big no.
--
greets
--
Christian Gmeiner, MSc
https://christian-gmeiner.info/privacypolicy
On Thu 11 Nov 04:36 CST 2021, Christian Gmeiner wrote:
> Hi Bjorn
>
>
> > > Allows the remote firmware to log into syslog.
> > >
> >
> > This allows the remote firmware to print log messages in the kernel log,
> > not the syslog (although your system might inject the kernel log into
> > the syslog as well)
> >
>
> Correct.
>
> > > Signed-off-by: Christian Gmeiner <[email protected]>
> > > ---
> > > drivers/rpmsg/Kconfig | 8 +++++
> > > drivers/rpmsg/Makefile | 1 +
> > > drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
> >
> > drivers/rpmsg is for rpmsg bus and transport drivers. Client drivers
> > should live elsewhere.
> >
>
> Ahh .. yes.
>
> > But perhaps, rather than having a driver for this, you could simply use
> > rpmsg_char and a userspace tool; if you want to get the remote processor
> > logs into syslog, instead of the kernel log?
> >
>
> I thought about that too (also regarding the rpmsg tty driver) but that means I
> need to start/supervise a user space tool.
>
> > > 3 files changed, 74 insertions(+)
> > > create mode 100644 drivers/rpmsg/rpmsg_syslog.c
> > >
> > > diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
> > > index 0b4407abdf13..801f9956ec21 100644
> > > --- a/drivers/rpmsg/Kconfig
> > > +++ b/drivers/rpmsg/Kconfig
> > > @@ -73,4 +73,12 @@ config RPMSG_VIRTIO
> > > select RPMSG_NS
> > > select VIRTIO
> > >
> > > +config RPMSG_SYSLOG
> > > + tristate "SYSLOG device interface"
> > > + depends on RPMSG
> > > + help
> > > + Say Y here to export rpmsg endpoints as device files, usually found
> > > + in /dev. They make it possible for user-space programs to send and
> > > + receive rpmsg packets.
> > > +
> > > endmenu
> > > diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
> > > index 8d452656f0ee..75b2ec7133a5 100644
> > > --- a/drivers/rpmsg/Makefile
> > > +++ b/drivers/rpmsg/Makefile
> > > @@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
> > > obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
> > > obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
> > > obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
> > > +obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
> > > diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
> > > new file mode 100644
> > > index 000000000000..b3fdae495fd9
> > > --- /dev/null
> > > +++ b/drivers/rpmsg/rpmsg_syslog.c
> > > @@ -0,0 +1,65 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +
> > > +#include <linux/kernel.h>
> > > +#include <linux/module.h>
> > > +#include <linux/rpmsg.h>
> > > +
> > > +static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
> > > + void *priv, u32 src)
> > > +{
> > > + const char *buffer = data;
> > > +
> > > + switch (buffer[0]) {
> > > + case 'e':
> > > + dev_err(&rpdev->dev, "%s", buffer + 1);
> > > + break;
> > > + case 'w':
> > > + dev_warn(&rpdev->dev, "%s", buffer + 1);
> > > + break;
> > > + case 'i':
> > > + dev_info(&rpdev->dev, "%s", buffer + 1);
> > > + break;
> > > + default:
> > > + dev_info(&rpdev->dev, "%s", buffer);
> > > + break;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
> > > +{
> > > + struct rpmsg_endpoint *syslog_ept;
> > > + struct rpmsg_channel_info syslog_chinfo = {
> > > + .src = 42,
> > > + .dst = 42,
> > > + .name = "syslog",
> > > + };
> > > +
> > > + /*
> > > + * Create the syslog service endpoint associated to the RPMsg
> > > + * device. The endpoint will be automatically destroyed when the RPMsg
> > > + * device will be deleted.
> > > + */
> > > + syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
> >
> > The rpmsg_device_id below should cause the device to probe on the
> > presence of a "syslog" channel announcement, so why are you creating a
> > new endpoint with the same here?
> >
> > Why aren't you just specifying the callback of the driver?
> >
>
> Good question. I think I was happy that I got work working somehow. I
> also want to send out
> a documentation update as it is not up to date with the current API.
>
I'd be happy to take any documentation updates - or perhaps we should
reduce the duplication between the kerneldoc and Documentation/*...
> > > + if (!syslog_ept) {
> > > + dev_err(&rpdev->dev, "failed to create the syslog ept\n");
> > > + return -ENOMEM;
> > > + }
> > > + rpdev->ept = syslog_ept;
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
> > > + { .name = "syslog" },
> > > + { },
> > > +};
> > > +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
> > > +
> > > +static struct rpmsg_driver rpmsg_syslog_client = {
> > > + .drv.name = KBUILD_MODNAME,
> > > + .id_table = rpmsg_driver_syslog_id_table,
> > > + .probe = rpmsg_syslog_probe,
> > > +};
> > > +module_rpmsg_driver(rpmsg_syslog_client);
> >
> > I would expect that building this as a module gives you complaints about
> > lacking MODULE_LICENSE().
> >
>
> Yeah .. I never built it as a module.
>
> The biggest question I have: do you see any possibility to get such a
> redirection
> driver into mainline? At the moment I have not heard a big no.
>
My feeling is "do we really need a dedicated driver for it", but I do
recognize that it solves a problem for you.
The only "objection" I have is that I personally wouldn't want all the
firmware logs mixed up with the kernel logs. Somehow getting this into
journald separately seems more useful.
Regards,
Bjorn
> --
> greets
> --
> Christian Gmeiner, MSc
>
> https://christian-gmeiner.info/privacypolicy
Hi Christian,
On 11/11/21 11:29 AM, Christian Gmeiner wrote:
> Hi Arnaud
>
>>
>> On 11/9/21 7:06 PM, Bjorn Andersson wrote:
>>> On Tue 09 Nov 00:39 PST 2021, Christian Gmeiner wrote:
>>>
>>>> Allows the remote firmware to log into syslog.
>>>>
>>
>> For you information a similar patch has been sent few years ago:
>> https://www.spinics.net/lists/kernel/msg3045824.html
>>
>
> Interesting - do you know why the patch was not taken?
I don't know. It might be worthwhile to contact Xiang Xiao for more details.
>
>> The suspend /resume mechanism seems interesting to manage the low power use case.
>>
>
> Yeah .. nothing I thought about.
>
>>>
>>> This allows the remote firmware to print log messages in the kernel log,
>>> not the syslog (although your system might inject the kernel log into
>>> the syslog as well)
>>>
>>>> Signed-off-by: Christian Gmeiner <[email protected]>
>>>> ---
>>>> drivers/rpmsg/Kconfig | 8 +++++
>>>> drivers/rpmsg/Makefile | 1 +
>>>> drivers/rpmsg/rpmsg_syslog.c | 65 ++++++++++++++++++++++++++++++++++++
>>>
>>> drivers/rpmsg is for rpmsg bus and transport drivers. Client drivers
>>> should live elsewhere.
>>>
>>> But perhaps, rather than having a driver for this, you could simply use
>>> rpmsg_char and a userspace tool; if you want to get the remote processor
>>> logs into syslog, instead of the kernel log?
>>
>> This is also a question that comes to me while looking at the patch.
>> rpmsg_tty service (if available in 5.16) could be another alternative.
>>
>
> I thought about it too but I do not see how the syslog/journald can read the log
> messages from this tty device without an extra user space component.
>
> With a syslog redirection rpmsg service this happens automatically without any
> extra user space daemon that reads from tty and writes to syslog.
>
> Maybe I am missing something.
That's true, this is one constraint. I suppose that you already have user code
to start the remoteproc. In this case it could also launch a deamon which could
redirects and/or perhaps analyzes traces to detect errors...
That said it is my point of view, working on a general purpose platform
(stm32mp15), I guess other people have other feedbacks.
A last question: Do you manage the traces enable/disable and trace level during
runtime?
Regards,
Arnaud
>
>> Regards,
>> Arnaud
>>
>>>
>>>> 3 files changed, 74 insertions(+)
>>>> create mode 100644 drivers/rpmsg/rpmsg_syslog.c
>>>>
>>>> diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
>>>> index 0b4407abdf13..801f9956ec21 100644
>>>> --- a/drivers/rpmsg/Kconfig
>>>> +++ b/drivers/rpmsg/Kconfig
>>>> @@ -73,4 +73,12 @@ config RPMSG_VIRTIO
>>>> select RPMSG_NS
>>>> select VIRTIO
>>>>
>>>> +config RPMSG_SYSLOG
>>>> + tristate "SYSLOG device interface"
>>>> + depends on RPMSG
>>>> + help
>>>> + Say Y here to export rpmsg endpoints as device files, usually found
>>>> + in /dev. They make it possible for user-space programs to send and
>>>> + receive rpmsg packets.
>>>> +
>>>> endmenu
>>>> diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
>>>> index 8d452656f0ee..75b2ec7133a5 100644
>>>> --- a/drivers/rpmsg/Makefile
>>>> +++ b/drivers/rpmsg/Makefile
>>>> @@ -9,3 +9,4 @@ obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
>>>> obj-$(CONFIG_RPMSG_QCOM_GLINK_SMEM) += qcom_glink_smem.o
>>>> obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
>>>> obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
>>>> +obj-$(CONFIG_RPMSG_SYSLOG) += rpmsg_syslog.o
>>>> diff --git a/drivers/rpmsg/rpmsg_syslog.c b/drivers/rpmsg/rpmsg_syslog.c
>>>> new file mode 100644
>>>> index 000000000000..b3fdae495fd9
>>>> --- /dev/null
>>>> +++ b/drivers/rpmsg/rpmsg_syslog.c
>>>> @@ -0,0 +1,65 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +
>>>> +#include <linux/kernel.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/rpmsg.h>
>>>> +
>>>> +static int rpmsg_syslog_cb(struct rpmsg_device *rpdev, void *data, int len,
>>>> + void *priv, u32 src)
>>>> +{
>>>> + const char *buffer = data;
>>>> +
>>>> + switch (buffer[0]) {
>>>> + case 'e':
>>>> + dev_err(&rpdev->dev, "%s", buffer + 1);
>>>> + break;
>>>> + case 'w':
>>>> + dev_warn(&rpdev->dev, "%s", buffer + 1);
>>>> + break;
>>>> + case 'i':
>>>> + dev_info(&rpdev->dev, "%s", buffer + 1);
>>>> + break;
>>>> + default:
>>>> + dev_info(&rpdev->dev, "%s", buffer);
>>>> + break;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int rpmsg_syslog_probe(struct rpmsg_device *rpdev)
>>>> +{
>>>> + struct rpmsg_endpoint *syslog_ept;
>>>> + struct rpmsg_channel_info syslog_chinfo = {
>>>> + .src = 42,
>>>> + .dst = 42,
>>>> + .name = "syslog",
>>>> + };
>>>> +
>>>> + /*
>>>> + * Create the syslog service endpoint associated to the RPMsg
>>>> + * device. The endpoint will be automatically destroyed when the RPMsg
>>>> + * device will be deleted.
>>>> + */
>>>> + syslog_ept = rpmsg_create_ept(rpdev, rpmsg_syslog_cb, NULL, syslog_chinfo);
>>>
>>> The rpmsg_device_id below should cause the device to probe on the
>>> presence of a "syslog" channel announcement, so why are you creating a
>>> new endpoint with the same here?
>>>
>>> Why aren't you just specifying the callback of the driver?
>>>
>>>> + if (!syslog_ept) {
>>>> + dev_err(&rpdev->dev, "failed to create the syslog ept\n");
>>>> + return -ENOMEM;
>>>> + }
>>>> + rpdev->ept = syslog_ept;
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static struct rpmsg_device_id rpmsg_driver_syslog_id_table[] = {
>>>> + { .name = "syslog" },
>>>> + { },
>>>> +};
>>>> +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_syslog_id_table);
>>>> +
>>>> +static struct rpmsg_driver rpmsg_syslog_client = {
>>>> + .drv.name = KBUILD_MODNAME,
>>>> + .id_table = rpmsg_driver_syslog_id_table,
>>>> + .probe = rpmsg_syslog_probe,
>>>> +};
>>>> +module_rpmsg_driver(rpmsg_syslog_client);
>>>
>>> I would expect that building this as a module gives you complaints about
>>> lacking MODULE_LICENSE().
>>>
>>> Regards,
>>> Bjorn
>>>
>>>> --
>>>> 2.33.1
>>>>
>
>
>