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* clocksource/drivers/pistachio: Fix wrong calculated clocksource read valueJisheng Zhang2015-12-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | Let's assume the counter value is 0xf0000000, the pistachio clocksource read cycles function should return ~0x0fffffff but actually it returns 0xffffffff0fffffff. That occurs because: ~(cycle_t)value is different from (cycle_t)~value. unsigned long val = ~(unsigned long)0xf0000000; 40049a: 48 b8 ff ff ff 0f ff movabs $0xffffffff0fffffff,%rax unsigned long val = (unsigned long)~0xf0000000; 40049a: 48 c7 45 f8 ff ff ff movq $0xfffffff,-0x8(%rbp) We fix this issue by calculating bitwise-not counter, then cast to cycle_t. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
* clocksource/drivers/pistachio: Prevent ftrace recursionJisheng Zhang2015-10-271-1/+2
| | | | | | | | | | | | | | | Currently pistachio can be used as a scheduler clock. We properly marked pistachio_read_sched_clock() as notrace but we then call another function pistachio_clocksource_read_cycles() that _wasn't_ notrace. Having a traceable function in the sched_clock() path leads to a recursion within ftrace and a kernel crash. Fix this by adding notrace attribute to the pistachio_clocksource_read_cycles() function. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
* CLOCKSOURCE: Add Pistachio clocksource-only driverEzequiel Garcia2015-09-031-0/+217
The Pistachio SoC provides four general purpose timers, and allow to implement a clocksource driver. This driver can be used as a replacement for the MIPS GIC and MIPS R4K clocksources and sched clocks, which are clocked from the CPU clock. Given the general purpose timers are clocked from an independent clock, this new clocksource driver will be useful to introduce CPUFreq support for Pistachio machines. Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com> Signed-off-by: Govindraj Raja <govindraj.raja@imgtec.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: devicetree@vger.kernel.org Cc: Andrew Bresticker <abrestic@chromium.org> Cc: James Hartley <James.Hartley@imgtec.com> Cc: Damien Horsley <Damien.Horsley@imgtec.com> Cc: James Hogan <James.Hogan@imgtec.com> Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com> Patchwork: https://patchwork.linux-mips.org/patch/10899/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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