Add a delay method that would allow tests to wait for some specified number of cycles. Also add a conversion helper method between microseconds and cycles. This conversion is done by using the timebase frequency, which is obtained during setup via the device tree. Signed-off-by: James Raphael Tiovalen <jamestiotio@xxxxxxxxx> --- riscv/Makefile | 2 ++ lib/riscv/asm/csr.h | 1 + lib/riscv/asm/delay.h | 15 +++++++++++++++ lib/riscv/asm/setup.h | 1 + lib/riscv/asm/timer.h | 14 ++++++++++++++ lib/riscv/delay.c | 16 ++++++++++++++++ lib/riscv/setup.c | 4 ++++ lib/riscv/timer.c | 26 ++++++++++++++++++++++++++ 8 files changed, 79 insertions(+) create mode 100644 lib/riscv/asm/delay.h create mode 100644 lib/riscv/asm/timer.h create mode 100644 lib/riscv/delay.c create mode 100644 lib/riscv/timer.c diff --git a/riscv/Makefile b/riscv/Makefile index 919a3ebb..b0cd613f 100644 --- a/riscv/Makefile +++ b/riscv/Makefile @@ -30,6 +30,7 @@ cflatobjs += lib/memregions.o cflatobjs += lib/on-cpus.o cflatobjs += lib/vmalloc.o cflatobjs += lib/riscv/bitops.o +cflatobjs += lib/riscv/delay.o cflatobjs += lib/riscv/io.o cflatobjs += lib/riscv/isa.o cflatobjs += lib/riscv/mmu.o @@ -38,6 +39,7 @@ cflatobjs += lib/riscv/sbi.o cflatobjs += lib/riscv/setup.o cflatobjs += lib/riscv/smp.o cflatobjs += lib/riscv/stack.o +cflatobjs += lib/riscv/timer.o ifeq ($(ARCH),riscv32) cflatobjs += lib/ldiv32.o endif diff --git a/lib/riscv/asm/csr.h b/lib/riscv/asm/csr.h index ba810c9f..a9b1bd42 100644 --- a/lib/riscv/asm/csr.h +++ b/lib/riscv/asm/csr.h @@ -10,6 +10,7 @@ #define CSR_SCAUSE 0x142 #define CSR_STVAL 0x143 #define CSR_SATP 0x180 +#define CSR_TIME 0xc01 #define SR_SIE _AC(0x00000002, UL) diff --git a/lib/riscv/asm/delay.h b/lib/riscv/asm/delay.h new file mode 100644 index 00000000..ce540f4c --- /dev/null +++ b/lib/riscv/asm/delay.h @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASMRISCV_DELAY_H_ +#define _ASMRISCV_DELAY_H_ + +#include <libcflat.h> +#include <asm/setup.h> + +extern void delay(u64 cycles); + +static inline uint64_t usec_to_cycles(uint64_t usec) +{ + return (timebase_frequency * usec) / 1000000; +} + +#endif /* _ASMRISCV_DELAY_H_ */ diff --git a/lib/riscv/asm/setup.h b/lib/riscv/asm/setup.h index 7f81a705..a13159bf 100644 --- a/lib/riscv/asm/setup.h +++ b/lib/riscv/asm/setup.h @@ -7,6 +7,7 @@ #define NR_CPUS 16 extern struct thread_info cpus[NR_CPUS]; extern int nr_cpus; +extern uint64_t timebase_frequency; int hartid_to_cpu(unsigned long hartid); void io_init(void); diff --git a/lib/riscv/asm/timer.h b/lib/riscv/asm/timer.h new file mode 100644 index 00000000..2e319391 --- /dev/null +++ b/lib/riscv/asm/timer.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASMRISCV_TIMER_H_ +#define _ASMRISCV_TIMER_H_ + +#include <asm/csr.h> + +extern void timer_get_frequency(const void *fdt); + +static inline uint64_t timer_get_cycles(void) +{ + return csr_read(CSR_TIME); +} + +#endif /* _ASMRISCV_TIMER_H_ */ diff --git a/lib/riscv/delay.c b/lib/riscv/delay.c new file mode 100644 index 00000000..6b5c78da --- /dev/null +++ b/lib/riscv/delay.c @@ -0,0 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024, James Raphael Tiovalen <jamestiotio@xxxxxxxxx> + */ +#include <libcflat.h> +#include <asm/barrier.h> +#include <asm/delay.h> +#include <asm/timer.h> + +void delay(uint64_t cycles) +{ + uint64_t start = timer_get_cycles(); + + while ((timer_get_cycles() - start) < cycles) + cpu_relax(); +} diff --git a/lib/riscv/setup.c b/lib/riscv/setup.c index 50ffb0d0..905ea708 100644 --- a/lib/riscv/setup.c +++ b/lib/riscv/setup.c @@ -20,6 +20,7 @@ #include <asm/page.h> #include <asm/processor.h> #include <asm/setup.h> +#include <asm/timer.h> #define VA_BASE ((phys_addr_t)3 * SZ_1G) #if __riscv_xlen == 64 @@ -38,6 +39,7 @@ u32 initrd_size; struct thread_info cpus[NR_CPUS]; int nr_cpus; +uint64_t timebase_frequency; static struct mem_region riscv_mem_regions[NR_MEM_REGIONS + 1]; @@ -199,6 +201,7 @@ void setup(const void *fdt, phys_addr_t freemem_start) mem_init(PAGE_ALIGN(__pa(freemem))); cpu_init(); + timer_get_frequency(dt_fdt()); thread_info_init(); io_init(); @@ -264,6 +267,7 @@ efi_status_t setup_efi(efi_bootinfo_t *efi_bootinfo) } cpu_init(); + timer_get_frequency(dt_fdt()); thread_info_init(); io_init(); initrd_setup(); diff --git a/lib/riscv/timer.c b/lib/riscv/timer.c new file mode 100644 index 00000000..db8dbb36 --- /dev/null +++ b/lib/riscv/timer.c @@ -0,0 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2024, James Raphael Tiovalen <jamestiotio@xxxxxxxxx> + */ +#include <libcflat.h> +#include <devicetree.h> +#include <asm/setup.h> +#include <asm/timer.h> + +void timer_get_frequency(const void *fdt) +{ + const struct fdt_property *prop; + u32 *data; + int cpus; + + assert_msg(dt_available(), "ACPI not yet supported"); + + cpus = fdt_path_offset(fdt, "/cpus"); + assert(cpus >= 0); + + prop = fdt_get_property(fdt, cpus, "timebase-frequency", NULL); + assert(prop != NULL); + + data = (u32 *)prop->data; + timebase_frequency = fdt32_to_cpu(*data); +} -- 2.43.0