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 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); -- 2.32.0 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
