diff options
| -rw-r--r-- | arch/riscv/Kconfig | 1 | ||||
| -rw-r--r-- | arch/riscv/include/asm/clint.h | 26 | ||||
| -rw-r--r-- | arch/riscv/include/asm/timex.h | 27 | ||||
| -rw-r--r-- | drivers/clocksource/timer-clint.c | 17 |
4 files changed, 71 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index df18372861d8..7766e1289468 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -32,6 +32,7 @@ config RISCV select ARCH_WANT_FRAME_POINTERS select ARCH_WANT_HUGE_PMD_SHARE if 64BIT select CLONE_BACKWARDS + select CLINT_TIMER if !MMU select COMMON_CLK select EDAC_SUPPORT select GENERIC_ARCH_TOPOLOGY if SMP diff --git a/arch/riscv/include/asm/clint.h b/arch/riscv/include/asm/clint.h new file mode 100644 index 000000000000..0789fd37b40a --- /dev/null +++ b/arch/riscv/include/asm/clint.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2020 Google, Inc + */ + +#ifndef _ASM_RISCV_CLINT_H +#define _ASM_RISCV_CLINT_H + +#include <linux/types.h> +#include <asm/mmio.h> + +#ifdef CONFIG_RISCV_M_MODE +/* + * This lives in the CLINT driver, but is accessed directly by timex.h to avoid + * any overhead when accessing the MMIO timer. + * + * The ISA defines mtime as a 64-bit memory-mapped register that increments at + * a constant frequency, but it doesn't define some other constraints we depend + * on (most notably ordering constraints, but also some simpler stuff like the + * memory layout). Thus, this is called "clint_time_val" instead of something + * like "riscv_mtime", to signify that these non-ISA assumptions must hold. + */ +extern u64 __iomem *clint_time_val; +#endif + +#endif diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h index a3fb85d505d4..7f659dda0032 100644 --- a/arch/riscv/include/asm/timex.h +++ b/arch/riscv/include/asm/timex.h @@ -10,6 +10,31 @@ typedef unsigned long cycles_t; +#ifdef CONFIG_RISCV_M_MODE + +#include <asm/clint.h> + +#ifdef CONFIG_64BIT +static inline cycles_t get_cycles(void) +{ + return readq_relaxed(clint_time_val); +} +#else /* !CONFIG_64BIT */ +static inline u32 get_cycles(void) +{ + return readl_relaxed(((u32 *)clint_time_val)); +} +#define get_cycles get_cycles + +static inline u32 get_cycles_hi(void) +{ + return readl_relaxed(((u32 *)clint_time_val) + 1); +} +#define get_cycles_hi get_cycles_hi +#endif /* CONFIG_64BIT */ + +#else /* CONFIG_RISCV_M_MODE */ + static inline cycles_t get_cycles(void) { return csr_read(CSR_TIME); @@ -41,6 +66,8 @@ static inline u64 get_cycles64(void) } #endif /* CONFIG_64BIT */ +#endif /* !CONFIG_RISCV_M_MODE */ + #define ARCH_HAS_READ_CURRENT_TIMER static inline int read_current_timer(unsigned long *timer_val) { diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c index 8eeafa82c03d..d17367dee02c 100644 --- a/drivers/clocksource/timer-clint.c +++ b/drivers/clocksource/timer-clint.c @@ -19,6 +19,11 @@ #include <linux/interrupt.h> #include <linux/of_irq.h> #include <linux/smp.h> +#include <linux/timex.h> + +#ifndef CONFIG_RISCV_M_MODE +#include <asm/clint.h> +#endif #define CLINT_IPI_OFF 0 #define CLINT_TIMER_CMP_OFF 0x4000 @@ -31,6 +36,10 @@ static u64 __iomem *clint_timer_val; static unsigned long clint_timer_freq; static unsigned int clint_timer_irq; +#ifdef CONFIG_RISCV_M_MODE +u64 __iomem *clint_time_val; +#endif + static void clint_send_ipi(const struct cpumask *target) { unsigned int cpu; @@ -184,6 +193,14 @@ static int __init clint_timer_init_dt(struct device_node *np) clint_timer_val = base + CLINT_TIMER_VAL_OFF; clint_timer_freq = riscv_timebase; +#ifdef CONFIG_RISCV_M_MODE + /* + * Yes, that's an odd naming scheme. time_val is public, but hopefully + * will die in favor of something cleaner. + */ + clint_time_val = clint_timer_val; +#endif + pr_info("%pOFP: timer running at %ld Hz\n", np, clint_timer_freq); rc = clocksource_register_hz(&clint_clocksource, clint_timer_freq); |