On 17.08.21 12:10, Antony Pavlov wrote: > barebox timer-riscv driver supports one of user counters: > > * 'cycle', counter for RDCYCLE instruction (CSR 0xc00); > * 'time', timer for RDTIME instruction (CSR 0xc01). > > At the moment in M-mode timer-riscv uses the 'cycle' counter, > and in S-mode timer-riscv uses the 'time' timer. > > Alas picorv32 CPU core supports only the 'cycle' counter. > VexRiscV CPU core in M-mode supports only the 'time' timer. > > This patch makes it possible to use the 'time' timer > for VexRiscV CPU in M-mode. > > See also http://lists.infradead.org/pipermail/barebox/2021-May/036067.html
Comment from earlier series: "It also changes the default for M-Mode from cycle to time. I can't comment on whether this is ok, I just copied the logic from Linux." Can you say why this is ok? > > Signed-off-by: Antony Pavlov <[email protected]> > --- > arch/riscv/dts/erizo.dtsi | 2 ++ > drivers/clocksource/timer-riscv.c | 24 ++++++++++++------------ > 2 files changed, 14 insertions(+), 12 deletions(-) > > diff --git a/arch/riscv/dts/erizo.dtsi b/arch/riscv/dts/erizo.dtsi > index 228711bd69..4eb92ae6f1 100644 > --- a/arch/riscv/dts/erizo.dtsi > +++ b/arch/riscv/dts/erizo.dtsi > @@ -22,6 +22,8 @@ > > timebase-frequency = <24000000>; > > + barebox,csr-cycle; > + > cpu@0 { > device_type = "cpu"; > compatible = "cliffordwolf,picorv32", "riscv"; > diff --git a/drivers/clocksource/timer-riscv.c > b/drivers/clocksource/timer-riscv.c > index 5a517fe6b4..96637f988a 100644 > --- a/drivers/clocksource/timer-riscv.c > +++ b/drivers/clocksource/timer-riscv.c > @@ -12,9 +12,8 @@ > #include <clock.h> > #include <asm/timer.h> > #include <asm/csr.h> > -#include <asm/system.h> > > -static u64 notrace riscv_timer_get_count_sbi(void) > +static u64 notrace riscv_timer_get_count_time(void) > { > __maybe_unused u32 hi, lo; > > @@ -29,7 +28,7 @@ static u64 notrace riscv_timer_get_count_sbi(void) > return ((u64)hi << 32) | lo; > } > > -static u64 notrace riscv_timer_get_count_rdcycle(void) > +static u64 notrace riscv_timer_get_count_cycle(void) > { > __maybe_unused u32 hi, lo; > > @@ -44,24 +43,25 @@ static u64 notrace riscv_timer_get_count_rdcycle(void) > return ((u64)hi << 32) | lo; > } > > -static u64 notrace riscv_timer_get_count(void) > -{ > - if (riscv_mode() == RISCV_S_MODE) > - return riscv_timer_get_count_sbi(); > - else > - return riscv_timer_get_count_rdcycle(); > -} > - > static struct clocksource riscv_clocksource = { > - .read = riscv_timer_get_count, > .mask = CLOCKSOURCE_MASK(64), > .priority = 100, > }; > > static int riscv_timer_init(struct device_d* dev) > { > + struct device_node *cpu; > + > dev_dbg(dev, "running at %lu Hz\n", riscv_timebase); > > + cpu = of_find_node_by_path("/cpus"); > + > + if (of_property_read_bool(cpu, "barebox,csr-cycle")) { > + riscv_clocksource.read = riscv_timer_get_count_cycle; > + } else { > + riscv_clocksource.read = riscv_timer_get_count_time; > + } > + > riscv_clocksource.mult = clocksource_hz2mult(riscv_timebase, > riscv_clocksource.shift); > > return init_clock(&riscv_clocksource); > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
