On 31.08.21 06:07, Antony Pavlov wrote: > On Mon, 23 Aug 2021 14:08:52 +0200 > Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> wrote: > > Hi Ahmad! > >> 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? > > v4 patch removes riscv_mode() mention from timer-riscv code > so timer-riscv uses the 'time' timer by default disregarding > M-mode or S-mode is used. > > I suppose that the 'time' timer is "more popular" than > the 'cycle' counter. > So IMHO it is ok to use "more popular" feature by default. Ok. We'll see if something breaks. >>> Signed-off-by: Antony Pavlov <antonynpavlov@xxxxxxxxx> Acked-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> >>> --- >>> 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 | > > -- 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 barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
