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2012-09-09ARM: 7529/1: delay: set loops_per_jiffy when moving to timer-based loopWill Deacon
The delay functions may be called by some platforms between switching to the timer-based delay loop but before calibration. In this case, the initial loops_per_jiffy may not be suitable for the timer (although a compromise may be achievable) and delay times may be considered too inaccurate. This patch updates loops_per_jiffy when switching to the timer-based delay loop so that delays are consistent prior to calibration. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-07-09ARM: 7452/1: delay: allow timer-based delay implementation to be selectedWill Deacon
This patch allows a timer-based delay implementation to be selected by switching the delay routines over to use get_cycles, which is implemented in terms of read_current_timer. This further allows us to skip the loop calibration and have a consistent delay function in the face of core frequency scaling. To avoid the pain of dealing with memory-mapped counters, this implementation uses the co-processor interface to the architected timers when they are available. The previous loop-based implementation is kept around for CPUs without the architected timers and we retain both the maximum delay (2ms) and the corresponding conversion factors for determining the number of loops required for a given interval. Since the indirection of the timer routines will only work when called from C, the sa1100 sleep routines are modified to branch to the loop-based delay functions directly. Tested-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>