Many PTP drivers required to perform some asynchronous or periodic work,
like periodically handling PHC counter overflow or handle delayed timestamp
for RX/TX network packets. In most of the cases, such work is implemented
using workqueues. Unfortunately, Kernel workqueues might introduce
significant delay in work scheduling under high system load and on -RT,
which could cause misbehavior of PTP drivers due to internal counter
overflow, for example, and there is no way to tune its execution policy and
priority manuallly.
Hence, The kthread_worker can be used insted of workqueues, as it create
separte named kthread for each worker and its its execution policy and
priority can be configured using chrt tool.
This prblem was reported for two drivers TI CPSW CPTS and dp83640, so
instead of modifying each of these driver it was proposed to add PTP
auxiliary worker to the PHC subsystem.
The patch adds PTP auxiliary worker in PHC subsystem using kthread_worker
and kthread_delayed_work and introduces two new PHC subsystem APIs:
- long (*do_aux_work)(struct ptp_clock_info *ptp) callback in
ptp_clock_info structure, which driver should assign if it require to
perform asynchronous or periodic work. Driver should return the delay of
the PTP next auxiliary work scheduling time (>=0) or negative value in case
further scheduling is not required.
- int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay) which
allows schedule PTP auxiliary work.
The name of kthread_worker thread corresponds PTP PHC device name "ptp%d".
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Let's switch to using device_create_with_groups(), which will allow us to
create "pins" attribute group together with the rest of ptp device
attributes, and before userspace gets notified about ptp device creation.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the sysfs hooks needed in order to get and set the
programmable pin settings.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a pair of new ioctls to the PTP Hardware Clock device
interface. Using the ioctls, user space programs can query each pin to
find out its current function and also reprogram a different function
if desired.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The dev_attrs field of struct class is going away soon, dev_groups
should be used instead. This converts the ptp class code to use the
correct field.
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds a field to the representation of a PTP hardware clock in
order to remember the frequency adjustment value dialed by the user.
Adding this field will let us answer queries in the manner of adjtimex
in a follow on patch.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds an infrastructure for hardware clocks that implement
IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a
registration method to particular hardware clock drivers. Each clock is
presented as a standard POSIX clock.
The ancillary clock features are exposed in two different ways, via
the sysfs and by a character device.
Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John Stultz <john.stultz@linaro.org>
