system/riscv64: Use dtb-based time cv for system_time

* Fixes speedy-system_time in qemu

Change-Id: I07ae4d984c09f2f2503bd45acc415c219f3b3f11
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5327
Reviewed-by: waddlesplash <[email protected]>

src/system/kernel/arch/riscv64/arch_cpu.cpp

@@ -59,12 +59,11 @@ arch_cpu_init(kernel_args *args)
 			cpu->cache_id[i] = -1;
 	}
 
-/*
 	uint64 conversionFactor
 		= (1LL << 32) * 1000000LL / args->arch_args.timerFrequency;
 
 	__riscv64_setup_system_time(conversionFactor);
-*/
+
 	return B_OK;
 }
 

src/system/kernel/arch/riscv64/arch_real_time_clock.cpp

@@ -15,15 +15,12 @@
 status_t
 arch_rtc_init(kernel_args *args, struct real_time_data *data)
 {
-/*
 	data->arch_data.system_time_conversion_factor
 		= (1LL << 32) * 1000000LL / args->arch_args.timerFrequency;
-
 	dprintf("timerFrequency: %" B_PRIu64 "\n",
 		args->arch_args.timerFrequency);
 	dprintf("system_time_conversion_factor: %" B_PRIu64 "\n",
 		data->arch_data.system_time_conversion_factor);
-*/
 	return B_OK;
 }
 

src/system/libroot/os/arch/riscv64/system_time.cpp

@@ -31,17 +31,6 @@ __riscv64_setup_system_time(uint64 cv)
 [[gnu::optimize("omit-frame-pointer")]] bigtime_t
 system_time()
 {
-	// TODO: Timer unit conversion needs fixed here
-	// QEMU and SiFive boards use diferent timer frequencies
-	return CpuTime();
-/*
-	uint64 time = CpuTime();
-	uint64 lo = (uint32)time;
-	uint64 hi = time >> 32;
-	return ((lo * cv_factor) >> 32) + hi * cv_factor;
-*/
-/*
 	__uint128_t time = static_cast<__uint128_t>(CpuTime()) * cv_factor;
 	return time >> 32;
-*/
 }