On secondary CPUs, the Timer Control Register is not reset
to a sane value before the timer is registered, and the TRM
doesn't seem to indicate any reset value either. In some cases,
the kernel will take an interrupt too early, depending on what
junk was present in the registers at reset time.
The fix is to set the Timer Control Register to 0 before
registering the clock_event_device and enabling the interrupt.
Problem seen on VE (Cortex A5) and Tegra.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The smp_twd clockevents driver currently enables the local timer PPI
before the clockevents device is registered. This can lead to a kernel
panic if a spurious timer interrupt is generated before registration
has completed since the kernel will treat it as an IPI timer.
This patch moves the clockevents device registration before the IRQ
unmasking so that we can always handle timer interrupts once they can
occur.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
clockevents_reconfigure was an older api that doesn't handle
updating the max time between ticks when the frequency changes.
Under some conditions, the boot value of max_delta_ns scaled
by the mult/shift values for the current frequency can result
in a value of 0x200000004 selected as the number of cycles to
program for a long tick, which gets wrapped to 0x4.
Also switch to the matching clockevents_config_and_register
function to register the clockevent, which handles converting
the min/max ticks to ns during init.
Change-Id: I6ca659c309e7bb031cdb1954767b5aa7a022ff44
Signed-off-by: Colin Cross <ccross@android.com>
The localtimer's clock changes with the cpu clock. After a
cpufreq transition, update the clockevent's frequency and
reprogram the next clock event.
Adds a clock called "smp_twd" that is used to determine the
twd frequency, which can also be used at init time to
avoid calibrating the twd frequency.
Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rob Herring <robherring2@gmail.com>
