Commit Graph

4 Commits

Author SHA1 Message Date
Vladimir Zapolskiy b7c8b4aac6 clocksource/drivers/pistachio: Correct output format of PTR_ERR()
Use signed integer output in the pr_err() string format, here PTR_ERR() value
is negative and it should be reported in human readable way.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1458603727-4446-1-git-send-email-vz@mleia.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-03-23 12:30:40 +01:00
Jisheng Zhang 272a25a247 clocksource/drivers/pistachio: Fix wrong calculated clocksource read value
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>
2015-12-16 09:45:10 +01:00
Jisheng Zhang f8af0e9c64 clocksource/drivers/pistachio: Prevent ftrace recursion
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>
2015-10-27 01:33:18 +01:00
Ezequiel Garcia 84583983c3 CLOCKSOURCE: Add Pistachio clocksource-only driver
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>
2015-09-03 12:08:07 +02:00