Messages in this thread Patch in this message | | | From | Atish Patra <> | Subject | [RFC 2/3] RISC-V:Support per-hart timebase-frequency | Date | Fri, 14 Sep 2018 14:54:55 -0700 |
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Follow the updated DT specs and read the timebase-frequency from the boot cpu. Keep the old DT reading as well for backward compatibility. This patch is rework of old patch from Palmer.
Signed-off-by: Atish Patra <atish.patra@wdc.com> --- arch/riscv/kernel/time.c | 9 +-------- drivers/clocksource/riscv_timer.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c index 1911c8f6..225fe743 100644 --- a/arch/riscv/kernel/time.c +++ b/arch/riscv/kernel/time.c @@ -20,14 +20,7 @@ unsigned long riscv_timebase; void __init time_init(void) { - struct device_node *cpu; - u32 prop; - - cpu = of_find_node_by_path("/cpus"); - if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop)) - panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n"); - riscv_timebase = prop; + timer_probe(); lpj_fine = riscv_timebase / HZ; - timer_probe(); } diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c index 084e97dc..335bdb91 100644 --- a/drivers/clocksource/riscv_timer.c +++ b/drivers/clocksource/riscv_timer.c @@ -83,6 +83,21 @@ void riscv_timer_interrupt(void) evdev->event_handler(evdev); } +static long __init riscv_timebase_frequency(struct device_node *node) +{ + u32 timebase; + + if (!of_property_read_u32(node, "timebase-frequency", &timebase)) + return timebase; + + /* check under parent "cpus" node */ + if (!of_property_read_u32(node->parent, "timebase-frequency", + &timebase)) + return timebase; + + panic("RISC-V system with no 'timebase-frequency' in DTS\n"); +} + static int __init riscv_timer_init_dt(struct device_node *n) { int cpuid, hartid, error; @@ -94,6 +109,7 @@ static int __init riscv_timer_init_dt(struct device_node *n) if (cpuid != smp_processor_id()) return 0; + riscv_timebase = riscv_timebase_frequency(n); cs = per_cpu_ptr(&riscv_clocksource, cpuid); clocksource_register_hz(cs, riscv_timebase); -- 2.7.4
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