This peripheral has 1 free-running timer and 4 compare registers.
Only the free-running timer is implemented. Add support the
COMPARE registers (each register is wired to an IRQ).
Reference: "BCM2835 ARM Peripherals" datasheet [*]
chapter 12 "System Timer":
The System Timer peripheral provides four 32-bit timer channels
and a single 64-bit free running counter. Each channel has an
output compare register, which is compared against the 32 least
significant bits of the free running counter values. When the
two values match, the system timer peripheral generates a signal
to indicate a match for the appropriate channel. The match signal
is then fed into the interrupt controller.
This peripheral is used since Linux 3.7, commit ee4af5696720
("ARM: bcm2835: add system timer").
[*] https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Message-id: 20201010203709.3116542-4-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The variable holding the CTRL_STATUS register is misnamed
'status'. Rename it 'ctrl_status' to make it more obvious
this register is also used to control the peripheral.
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20201010203709.3116542-3-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Use the BCM2835_SYSTIMER_COUNT definition instead of the
magic '4' value.
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20201010203709.3116542-2-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
