Current ARM MPTimer implementation uses QEMUTimer for the actual timer,
this implementation isn't complete and mostly tries to duplicate of what
generic ptimer is already doing fine.
Conversion to ptimer brings the following benefits and fixes:
- Simple timer pausing implementation
- Fixes counter value preservation after stopping the timer
- Properly handles prescaler != 0 / counter = 0 / load = 0 cases
- Code simplification and reduction
Bump VMSD to version 3, since VMState is changed and is not compatible
with the previous implementation.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Message-id: 37f378c33bb5a28d5cd71167a6bd5bff5e59cbc3.1475421224.git.digetx@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
For most of the timers counter starts to decrement after first period
expires. Due to rounding down performed by the ptimer_get_count, it returns
counter - 1 for the running timer, so that for the ptimer user it looks
like counter gets decremented immediately after running the timer. Add "no
counter round down" policy that provides correct behaviour for those timers.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Message-id: ef39622d0ebfdc32a0877e59ffdf6910dc3db688.1475421224.git.digetx@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Currently, periodic counter wraps around immediately once counter reaches
"0", this is wrong behaviour for some of the timers, resulting in one period
being lost. Add new ptimer policy that provides correct behaviour for such
timers, so that counter stays with "0" for a one period before wrapping
around.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Message-id: f22a670cf1f4be298b31640cb5f4be1df0f20ab6.1475421224.git.digetx@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Software should see timer counter wraparound only after IRQ being triggered.
This fixes regression introduced by the commit 5a50307 ("hw/ptimer: Perform
counter wrap around if timer already expired"), resulting in monotonic timer
jumping backwards on SPARC emulated machine running NetBSD guest OS, as
reported by Mark Cave-Ayland.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Message-id: 20160708132206.2080-1-digetx@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Delta value must be updated on period/freq change, otherwise running timer
would be restarted (counter reloaded with old delta). Only m68k/mcf520x
and arm/arm_timer devices are currently doing freq change correctly, i.e.
stopping the timer. Perform delta update to fix affected devices and
eliminate potential further mistakes.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Message-id: 4987ef5fdc128bb9a744fd794d3f609135c6a39c.1464367869.git.digetx@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
ptimer_get_count() might be called while QEMU timer already been expired.
In that case ptimer would return counter = 0, which might be undesirable
in case of polled timer. Do counter wrap around for periodic timer to keep
it distributed. In order to achieve more accurate emulation behaviour of
certain hardware, don't perform wrap around when in icount mode and return
counter = 0 in that case (that doesn't affect polled counter distribution).
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Message-id: 4ce381c7d24d85d165ff251d2875d16a4b6a5c04.1464367869.git.digetx@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Multiple issues here related to the timer with a adjusted .limit value:
1) ptimer_get_count() returns incorrect counter value for the disabled
timer after loading the counter with a small value, because adjusted limit
value is used instead of the original.
For instance:
1) ptimer_stop(t)
2) ptimer_set_period(t, 1)
3) ptimer_set_limit(t, 0, 1)
4) ptimer_get_count(t) <-- would return 10000 instead of 0
2) ptimer_get_count() might return incorrect value for the timer running
with a adjusted limit value.
For instance:
1) ptimer_stop(t)
2) ptimer_set_period(t, 1)
3) ptimer_set_limit(t, 10, 1)
4) ptimer_run(t)
5) ptimer_get_count(t) <-- might return value > 10
3) Neither ptimer_set_period() nor ptimer_set_freq() are adjusting the
limit value, so it is still possible to make timer timeout value
arbitrary small.
For instance:
1) ptimer_set_period(t, 10000)
2) ptimer_set_limit(t, 1, 0)
3) ptimer_set_period(t, 1) <-- bypass limit correction
Fix all of the above issues by adjusting timer period instead of the limit.
Perform the adjustment for periodic timer only. Use the delta value instead
of the limit to make decision whether adjustment is required, as limit could
be altered while timer is running, resulting in incorrect value returned by
ptimer_get_count.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Message-id: cd141f74f5737480ec586b9c7d18cce1d69884e2.1464367869.git.digetx@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The timer should fire the interrupt only if the IT (interrupt enable) bit
state of the control register is enabled.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The running timer can't be stopped because timer control code just
doesn't handle disabling the timer. Fix it by deleting the timer if
the enable bit is cleared.
The timer won't start periodic ticking if a ONE-SHOT -> PERIODIC mode
change happens after a one-shot tick was completed. Fix it by
re-starting ticking if the timer isn't ticking right now.
To avoid code churning, these two fixes are squashed in one commit.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Dmitry Osipenko