diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 55 |
2 files changed, 65 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index a9e26f6a81a1..8dfd3bc448d0 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -360,6 +360,16 @@ config ARM64_ERRATUM_858921 The workaround will be dynamically enabled when an affected core is detected. +config SUN50I_ERRATUM_UNKNOWN1 + bool "Workaround for Allwinner A64 erratum UNKNOWN1" + default y + depends on ARM_ARCH_TIMER && ARM64 && ARCH_SUNXI + select ARM_ARCH_TIMER_OOL_WORKAROUND + help + This option enables a workaround for instability in the timer on + the Allwinner A64 SoC. The workaround will only be active if the + allwinner,erratum-unknown1 property is found in the timer node. + config ARM_GLOBAL_TIMER bool "Support for the ARM global timer" if COMPILE_TEST select TIMER_OF if OF diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 9a7d4dc00b6e..a8b20b65bd4b 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -326,6 +326,48 @@ static u64 notrace arm64_1188873_read_cntvct_el0(void) } #endif +#ifdef CONFIG_SUN50I_ERRATUM_UNKNOWN1 +/* + * The low bits of the counter registers are indeterminate while bit 10 or + * greater is rolling over. Since the counter value can jump both backward + * (7ff -> 000 -> 800) and forward (7ff -> fff -> 800), ignore register values + * with all ones or all zeros in the low bits. Bound the loop by the maximum + * number of CPU cycles in 3 consecutive 24 MHz counter periods. + */ +#define __sun50i_a64_read_reg(reg) ({ \ + u64 _val; \ + int _retries = 150; \ + \ + do { \ + _val = read_sysreg(reg); \ + _retries--; \ + } while (((_val + 1) & GENMASK(9, 0)) <= 1 && _retries); \ + \ + WARN_ON_ONCE(!_retries); \ + _val; \ +}) + +static u64 notrace sun50i_a64_read_cntpct_el0(void) +{ + return __sun50i_a64_read_reg(cntpct_el0); +} + +static u64 notrace sun50i_a64_read_cntvct_el0(void) +{ + return __sun50i_a64_read_reg(cntvct_el0); +} + +static u32 notrace sun50i_a64_read_cntp_tval_el0(void) +{ + return read_sysreg(cntp_cval_el0) - sun50i_a64_read_cntpct_el0(); +} + +static u32 notrace sun50i_a64_read_cntv_tval_el0(void) +{ + return read_sysreg(cntv_cval_el0) - sun50i_a64_read_cntvct_el0(); +} +#endif + #ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround); EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround); @@ -423,6 +465,19 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = { .read_cntvct_el0 = arm64_1188873_read_cntvct_el0, }, #endif +#ifdef CONFIG_SUN50I_ERRATUM_UNKNOWN1 + { + .match_type = ate_match_dt, + .id = "allwinner,erratum-unknown1", + .desc = "Allwinner erratum UNKNOWN1", + .read_cntp_tval_el0 = sun50i_a64_read_cntp_tval_el0, + .read_cntv_tval_el0 = sun50i_a64_read_cntv_tval_el0, + .read_cntpct_el0 = sun50i_a64_read_cntpct_el0, + .read_cntvct_el0 = sun50i_a64_read_cntvct_el0, + .set_next_event_phys = erratum_set_next_event_tval_phys, + .set_next_event_virt = erratum_set_next_event_tval_virt, + }, +#endif }; typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *, |