Register a valid read_current_timer() function for the
SP804 timer on ARM32.

On ARM32 platforms, when the SP804 timer is selected as the clocksource,
the driver does not register a valid read_current_timer() function.
As a result, features that rely on this API—such as rdseed—consistently
return incorrect values.

To fix this, a delay_timer structure is registered during the SP804
driver's initialization. The read_current_timer() function is implemented
using the existing sp804_read() logic, and the timer frequency is reused
from the already-initialized clocksource.

Signed-off-by: Stephen Eta Zhou <stephen.eta.zhou@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20250525-sp804-fix-read_current_timer-v4-1-87a9201fa4ec@gmail.com

A new "shutdown" timer state is being added to the generic timer code. One
of the functions to change the timer into the state is called
"timer_shutdown()". This means that there can not be other functions
called "timer_shutdown()" as the timer code owns the "timer_*" name space.

Rename timer_shutdown() to evt_timer_shutdown() to avoid this conflict.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Link: https://lkml.kernel.org/r/20221106212702.182883323@goodmis.org
Link: https://lore.kernel.org/all/20221105060155.592778858@goodmis.org/
Link: https://lore.kernel.org/r/20221110064147.158230501@goodmis.org
Link: https://lore.kernel.org/r/20221123201624.634354813@linutronix.de

When a machine sports more than one SP804 timer instance, we only bring
up the first one, since multiple timers of the same kind are not useful
to Linux. As this is intentional behaviour, we should not return an
error message, as we do today:
===============
[    0.000800] Failed to initialize '/bus@8000000/motherboard-bus@8000000/iofpga-bus@300000000/timer@120000': -22
===============

Replace the -EINVAL return with a debug message and return 0 instead.

Also we do not reach the init function anymore if the DT node is
disabled (as this is now handled by OF_DECLARE), so remove the explicit
check for that case.

This fixes a long standing bogus error when booting ARM's fastmodels.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20220506162522.3675399-1-andre.przywara@arm.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Add pr_fmt to prefix pr_<level> output.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201029123317.90286-5-wangkefeng.wang@huawei.com

clk_get_rate won't return negative value, correct clk_get_rate handle.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201029123317.90286-4-wangkefeng.wang@huawei.com

Directly use clk_prepare_enable and clk_disable_unprepare.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201029123317.90286-3-wangkefeng.wang@huawei.com

drivers/clocksource/timer-sp804.c:38:31: warning: symbol 'arm_sp804_timer' was not declared. Should it be static?
drivers/clocksource/timer-sp804.c:47:31: warning: symbol 'hisi_sp804_timer' was not declared. Should it be static?
drivers/clocksource/timer-sp804.c:120:12: warning: symbol 'sp804_clocksource_and_sched_clock_init' was not declared. Should it be static?
drivers/clocksource/timer-sp804.c:219:12: warning: symbol 'sp804_clockevents_init' was not declared. Should it be static?

And move __initdata after the variables.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201029123317.90286-2-wangkefeng.wang@huawei.com

Add static for sp804_clocksource_and_sched_clock_init() and
sp804_clockevents_init(), they are only used in timer-sp804.c now.
Otherwise, the following warning will be reported:

drivers/clocksource/timer-sp804.c:68:12: warning: no previous prototype \
for 'sp804_clocksource_and_sched_clock_init' [-Wmissing-prototypes]
drivers/clocksource/timer-sp804.c:162:12: warning: no previous prototype \
for 'sp804_clockevents_init' [-Wmissing-prototypes]

Fixes: 975434f8b24a ("clocksource/drivers/sp804: Delete the leading "__" of some functions")
Fixes: 65f4d7ddc7b6 ("clocksource/drivers/sp804: Remove unused sp804_timer_disable() and timer-sp804.h")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201021012259.2067-2-thunder.leizhen@huawei.com

A 100MHZ 32-bit timer will be wrapped up less than 43s. Although the
kernel maintains a software high 32-bit count in the tick IRQ. But it's
not applicable to the user mode APPs.

Note: The kernel still uses the lower 32 bits of the timer.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200918132237.3552-9-thunder.leizhen@huawei.com

The ARM SP804 supports a maximum of 32-bit counter, but Hisilicon extends
it to 64-bit. That means, the registers: TimerXload, TimerXValue and
TimerXBGLoad are 64bits, all other registers are the same as those in the
SP804. The driver code can be completely reused except that the register
offset is different.

Use compatible = "hisilicon,sp804" mark as Hisilicon sp804 timer.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200918132237.3552-8-thunder.leizhen@huawei.com