Add a test for the set_timer function of the time extension. The test checks that: - The time extension is available - The time counter monotonically increases - The installed timer interrupt handler is called - The timer interrupt is received within a reasonable time interval - The timer interrupt pending bit is cleared after the set_timer SBI call is made - The timer interrupt can be cleared either by requesting a timer interrupt infinitely far into the future or by masking the timer interrupt The timer interrupt delay can be set using the TIMER_DELAY environment variable in microseconds. The default delay value is 1 second. Since the interrupt can arrive a little later than the specified delay, allow some margin of error. This margin of error can be specified via the TIMER_MARGIN environment variable in microseconds. The default margin of error is 1 second. This test has been verified on RV32 and RV64 with OpenSBI using QEMU. Signed-off-by: James Raphael Tiovalen <jamestiotio@xxxxxxxxx> --- lib/riscv/asm/csr.h | 7 +++ lib/riscv/asm/sbi.h | 5 ++ lib/riscv/asm/setup.h | 1 + lib/riscv/asm/timer.h | 30 ++++++++++++ lib/riscv/processor.c | 6 +++ lib/riscv/setup.c | 24 ++++++++++ riscv/sbi.c | 108 ++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 181 insertions(+) create mode 100644 lib/riscv/asm/timer.h diff --git a/lib/riscv/asm/csr.h b/lib/riscv/asm/csr.h index b3c48e8e..dc05bfc9 100644 --- a/lib/riscv/asm/csr.h +++ b/lib/riscv/asm/csr.h @@ -4,12 +4,15 @@ #include <linux/const.h> #define CSR_SSTATUS 0x100 +#define CSR_SIE 0x104 #define CSR_STVEC 0x105 #define CSR_SSCRATCH 0x140 #define CSR_SEPC 0x141 #define CSR_SCAUSE 0x142 #define CSR_STVAL 0x143 +#define CSR_SIP 0x144 #define CSR_SATP 0x180 +#define CSR_TIME 0xc01 #define SR_SIE _AC(0x00000002, UL) @@ -50,6 +53,10 @@ #define IRQ_S_GEXT 12 #define IRQ_PMU_OVF 13 +#define IE_TIE (_AC(0x1, UL) << IRQ_S_TIMER) + +#define IP_TIP IE_TIE + #ifndef __ASSEMBLY__ #define csr_swap(csr, val) \ diff --git a/lib/riscv/asm/sbi.h b/lib/riscv/asm/sbi.h index d82a384d..84ce1bff 100644 --- a/lib/riscv/asm/sbi.h +++ b/lib/riscv/asm/sbi.h @@ -16,6 +16,7 @@ enum sbi_ext_id { SBI_EXT_BASE = 0x10, + SBI_EXT_TIME = 0x54494d45, SBI_EXT_HSM = 0x48534d, SBI_EXT_SRST = 0x53525354, }; @@ -37,6 +38,10 @@ enum sbi_ext_hsm_fid { SBI_EXT_HSM_HART_SUSPEND, }; +enum sbi_ext_time_fid { + SBI_EXT_TIME_SET_TIMER = 0, +}; + struct sbiret { long error; long value; diff --git a/lib/riscv/asm/setup.h b/lib/riscv/asm/setup.h index 7f81a705..5be252df 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 tb_hz; 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..3eeb8344 --- /dev/null +++ b/lib/riscv/asm/timer.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASMRISCV_TIMER_H_ +#define _ASMRISCV_TIMER_H_ + +#include <asm/csr.h> +#include <asm/processor.h> + +extern uint64_t usec_to_cycles(uint64_t usec); + +static inline void timer_irq_enable(void) +{ + csr_set(CSR_SIE, IE_TIE); +} + +static inline void timer_irq_disable(void) +{ + csr_clear(CSR_SIE, IE_TIE); +} + +static inline uint64_t timer_get_cycles(void) +{ + return csr_read(CSR_TIME); +} + +static inline bool timer_irq_pending(void) +{ + return csr_read(CSR_SIP) & IP_TIP; +} + +#endif /* _ASMRISCV_TIMER_H_ */ diff --git a/lib/riscv/processor.c b/lib/riscv/processor.c index 0dffadc7..082b9d80 100644 --- a/lib/riscv/processor.c +++ b/lib/riscv/processor.c @@ -7,6 +7,7 @@ #include <asm/isa.h> #include <asm/processor.h> #include <asm/setup.h> +#include <asm/timer.h> extern unsigned long ImageBase; @@ -82,3 +83,8 @@ void thread_info_init(void) isa_init(&cpus[cpu]); csr_write(CSR_SSCRATCH, &cpus[cpu]); } + +uint64_t usec_to_cycles(uint64_t usec) +{ + return (tb_hz * usec) / 1000000; +} diff --git a/lib/riscv/setup.c b/lib/riscv/setup.c index 50ffb0d0..b659c14e 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 tb_hz; static struct mem_region riscv_mem_regions[NR_MEM_REGIONS + 1]; @@ -67,6 +69,26 @@ static void cpu_init_acpi(void) assert_msg(false, "ACPI not available"); } +static int cpu_init_timer(const void *fdt) +{ + const struct fdt_property *prop; + u32 *data; + int cpus; + + cpus = fdt_path_offset(fdt, "/cpus"); + if (cpus < 0) + return cpus; + + prop = fdt_get_property(fdt, cpus, "timebase-frequency", NULL); + if (prop == NULL) + return -1; + + data = (u32 *)prop->data; + tb_hz = fdt32_to_cpu(*data); + + return 0; +} + static void cpu_init(void) { int ret; @@ -75,6 +97,8 @@ static void cpu_init(void) if (dt_available()) { ret = dt_for_each_cpu_node(cpu_set_fdt, NULL); assert(ret == 0); + ret = cpu_init_timer(dt_fdt()); + assert(ret == 0); } else { cpu_init_acpi(); } diff --git a/riscv/sbi.c b/riscv/sbi.c index 762e9711..a1a9ce84 100644 --- a/riscv/sbi.c +++ b/riscv/sbi.c @@ -6,7 +6,14 @@ */ #include <libcflat.h> #include <stdlib.h> +#include <asm/barrier.h> +#include <asm/csr.h> +#include <asm/processor.h> #include <asm/sbi.h> +#include <asm/timer.h> + +static bool timer_works; +static bool mask_timer_irq; static void help(void) { @@ -19,6 +26,27 @@ static struct sbiret __base_sbi_ecall(int fid, unsigned long arg0) return sbi_ecall(SBI_EXT_BASE, fid, arg0, 0, 0, 0, 0, 0); } +static struct sbiret __time_sbi_ecall(unsigned long stime_value) +{ + return sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value, 0, 0, 0, 0, 0); +} + +static void timer_irq_handler(struct pt_regs *regs) +{ + if (timer_works) + report_abort("timer interrupt received multiple times"); + + timer_works = true; + report(timer_irq_pending(), "pending timer interrupt bit set"); + + if (mask_timer_irq) + timer_irq_disable(); + else { + __time_sbi_ecall(-1); + report(!timer_irq_pending(), "pending timer interrupt bit cleared"); + } +} + static bool env_or_skip(const char *env) { if (!getenv(env)) { @@ -112,6 +140,85 @@ static void check_base(void) report_prefix_pop(); } +static void check_time(void) +{ + struct sbiret ret; + unsigned long begin, end, duration; + unsigned long delay = getenv("TIMER_DELAY") + ? strtol(getenv("TIMER_DELAY"), NULL, 0) + : 1000000; + unsigned long margin = getenv("TIMER_MARGIN") + ? strtol(getenv("TIMER_MARGIN"), NULL, 0) + : 1000000; + + delay = usec_to_cycles(delay); + margin = usec_to_cycles(margin); + + report_prefix_push("time"); + + ret = __base_sbi_ecall(SBI_EXT_BASE_PROBE_EXT, SBI_EXT_TIME); + + if (ret.error) { + report_fail("probing for time extension failed"); + report_prefix_pop(); + return; + } + + if (!ret.value) { + report_skip("time extension not available"); + report_prefix_pop(); + return; + } + + begin = timer_get_cycles(); + while ((end = timer_get_cycles()) <= begin) + cpu_relax(); + assert(begin < end); + + report_prefix_push("set_timer"); + + install_irq_handler(IRQ_S_TIMER, timer_irq_handler); + local_irq_enable(); + timer_irq_enable(); + + begin = timer_get_cycles(); + ret = __time_sbi_ecall(begin + delay); + + if (ret.error) + report_fail("setting timer failed"); + + report(!timer_irq_pending(), "pending timer interrupt bit cleared"); + + while ((end = timer_get_cycles()) <= (begin + delay + margin) && !timer_works) + cpu_relax(); + + report(timer_works, "timer interrupt received"); + + if (timer_works) { + duration = end - begin; + report(duration >= delay && duration <= (delay + margin), "timer delay honored"); + } + + timer_works = false; + mask_timer_irq = true; + begin = timer_get_cycles(); + ret = __time_sbi_ecall(begin + delay); + + if (ret.error) + report_fail("setting timer failed"); + + while ((end = timer_get_cycles()) <= (begin + delay + margin) && !timer_works) + cpu_relax(); + + report(timer_works, "timer interrupt received"); + + local_irq_disable(); + install_irq_handler(IRQ_S_TIMER, NULL); + + report_prefix_pop(); + report_prefix_pop(); +} + int main(int argc, char **argv) { @@ -122,6 +229,7 @@ int main(int argc, char **argv) report_prefix_push("sbi"); check_base(); + check_time(); return report_summary(); } -- 2.43.0