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2012-10-09ARM: export default read_current_timerArnd Bergmann1-0/+1
read_current_timer is used by get_cycles since "ARM: 7538/1: delay: add registration mechanism for delay timer sources", and get_cycles can be used by device drivers in loadable modules, so it has to be exported. Without this patch, building imote2_defconfig fails with ERROR: "read_current_timer" [crypto/tcrypt.ko] undefined! Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Jonathan Austin <jonathan.austin@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk>
2012-09-26ARM: 7538/1: delay: add registration mechanism for delay timer sourcesJonathan Austin1-8/+26
The current timer-based delay loop relies on the architected timer to initiate the switch away from the polling-based implementation. This is unfortunate for platforms without the architected timers but with a suitable delay source (that is, constant frequency, always powered-up and ticking as long as the CPUs are online). This patch introduces a registration mechanism for the delay timer (which provides an unconditional read_current_timer implementation) and updates the architected timer code to use the new interface. Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Jonathan Austin <jonathan.austin@arm.com> 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 Deacon1-0/+71
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>