clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940
There is a timer wrap issue on dra7 for the ARM architected timer. In a typical clock configuration the timer fails to wrap after 388 days. To work around the issue, we need to use timer-ti-dm percpu timers instead. Let's configure dmtimer3 and 4 as percpu timers by default, and warn about the issue if the dtb is not configured properly. Let's do this as a single patch so it can be backported to v5.8 and later kernels easily. Note that this patch depends on earlier timer-ti-dm systimer posted mode fixes, and a preparatory clockevent patch "clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue". For more information, please see the errata for "AM572x Sitara Processors Silicon Revisions 1.1, 2.0": https://www.ti.com/lit/er/sprz429m/sprz429m.pdf The concept is based on earlier reference patches done by Tero Kristo and Keerthy. Cc: Keerthy <j-keerthy@ti.com> Cc: Tero Kristo <kristo@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20210323074326.28302-3-tony@atomide.com
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