diff options
Diffstat (limited to 'arch/riscv64')
| -rw-r--r-- | arch/riscv64/include/csr.h | 4 | ||||
| -rw-r--r-- | arch/riscv64/kernel/timer.c | 35 |
2 files changed, 34 insertions, 5 deletions
diff --git a/arch/riscv64/include/csr.h b/arch/riscv64/include/csr.h index 39e8dc9..ae0763b 100644 --- a/arch/riscv64/include/csr.h +++ b/arch/riscv64/include/csr.h @@ -5,6 +5,10 @@ #define SATP_MODE_Sv39 0x8000000000000000 #define SATP_MODE_Sv48 0x9000000000000000 +/* unprivileged CSR registers */ +#define CSR_TIME 0xc01 +#define CSR_TIMEH 0xc81 + /* supervisor CSR registers */ #define CSR_SSTATUS 0x100 #define CSR_SIE 0x104 diff --git a/arch/riscv64/kernel/timer.c b/arch/riscv64/kernel/timer.c index 02f080c..1f79c5b 100644 --- a/arch/riscv64/kernel/timer.c +++ b/arch/riscv64/kernel/timer.c @@ -1,20 +1,45 @@ #include <arch/timer.h> +#include <libfdt.h> +#include <csr.h> #include <sbi.h> ticks_t stat_timer(const void *fdt) { - /* TODO: read from fdt */ - return 0; + int cpu_offset = fdt_path_offset(fdt, "/cpus"); + uint8_t *tf_reg = (uint8_t *)fdt_getprop(fdt, cpu_offset, + "timebase-frequency", NULL); + return (ticks_t)fdt_load_int32_ptr(tf_reg); } void set_timer(ticks_t ticks) { - /* TODO */ sbi_set_timer(ticks); } +#if __riscv_xlen == 64 +static ticks_t get_ticks64() +{ + ticks_t ticks = 0; + csr_read(CSR_TIME, ticks); + return ticks; +} +#else +static ticks_t get_ticks64() +{ + ticks_t ticksh, ticksl, check; + + /* avoid overflow between reading high and low */ + do { + csr_read(CSR_TIMEH, ticksh); + csr_read(CSR_TIME, ticksl); + csr_read(CSR_TIMEH, check); + } while (ticksh != check); + + return (ticksh << 32) | ticksl; +} +#endif + ticks_t current_ticks() { - /* TODO */ - return 0; + return get_ticks64(); } |