diff options
| author | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-09-14 09:56:30 -0700 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-09-19 13:21:11 -0700 |
| commit | d5be89a8d118a8e8d09cd74a921a808f17fbdd09 (patch) | |
| tree | 23ca84b9c2f1ae9f5f1ac483bf72c60e9934786b /drivers/clocksource/timer-clint.c | |
| parent | f025d9d9934b84cd03b7796072d10686029c408e (diff) | |
RISC-V: Resurrect the MMIO timer implementation for M-mode systems
The K210 doesn't implement rdtime in M-mode, and since that's where Linux runs
in the NOMMU systems that means we can't use rdtime. The K210 is the only
system that anyone is currently running NOMMU or M-mode on, so here we're just
inlining the timer read directly.
This also adds the CLINT driver as an !MMU dependency, as it's currently the
only timer driver availiable for these systems and without it we get a build
failure for some configurations.
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'drivers/clocksource/timer-clint.c')
| -rw-r--r-- | drivers/clocksource/timer-clint.c | 17 |
1 files changed, 17 insertions, 0 deletions
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); |