42d331a279
[ Upstream commit bceaae3bac0ce27c549bb050336d8d08abc2ee54 ]
The existing fix for errata i940 causes a conflict for IPU2 which is
using timer 3 and 4. From arch/arm/boot/dts/dra7-ipu-dsp-common.dtsi:
&ipu2 {
mboxes = <&mailbox6 &mbox_ipu2_ipc3x>;
ti,timers = <&timer3>;
ti,watchdog-timers = <&timer4>, <&timer9>;
};
The conflict was noticed when booting mainline on the BeagleBoard X15
which has a TI AM5728 SoC:
remoteproc remoteproc1: 55020000.ipu is available
remoteproc remoteproc1: powering up 55020000.ipu
remoteproc remoteproc1: Booting fw image dra7-ipu2-fw.xem4
omap-rproc 55020000.ipu: could not get timer platform device
omap-rproc 55020000.ipu: omap_rproc_enable_timers failed: -19
remoteproc remoteproc1: can't start rproc 55020000.ipu: -19
This change modifies the errata fix to instead use timer 15 and 16 which
resolves the timer conflict.
It does not appear to introduce any latency regression. Results from
cyclictest with original errata fix using dmtimer 3 and 4:
# cyclictest --mlockall --smp --priority=80 --interval=200 --distance=0
policy: fifo: loadavg: 0.02 0.03 0.05
T: 0 ( 1449) P:80 I:200 C: 800368 Min: 0 Act: 32 Avg: 22 Max: 128
T: 1 ( 1450) P:80 I:200 C: 800301 Min: 0 Act: 12 Avg: 23 Max: 70
The results after the change to dmtimer 15 and 16:
# cyclictest --mlockall --smp --priority=80 --interval=200 --distance=0
policy: fifo: loadavg: 0.36 0.19 0.07
T: 0 ( 1711) P:80 I:200 C: 759599 Min: 0 Act: 6 Avg: 22 Max: 108
T: 1 ( 1712) P:80 I:200 C: 759539 Min: 0 Act: 19 Avg: 23 Max: 79
Fixes: 25de4ce5ed02 ("clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940")
Link: https://lore.kernel.org/linux-omap/YfWsG0p6to3IJuvE@x1/
Suggested-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Drew Fustini <dfustini@baylibre.com>
Link: https://lore.kernel.org/r/20220204053503.1409162-1-dfustini@baylibre.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.