diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/arch_timer.h | 47 |
1 files changed, 44 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index 7ff386c15539..eaa5bbe3fa87 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -24,10 +24,51 @@ #include <linux/bug.h> #include <linux/init.h> +#include <linux/jump_label.h> #include <linux/types.h> #include <clocksource/arm_arch_timer.h> +#if IS_ENABLED(CONFIG_FSL_ERRATUM_A008585) +extern struct static_key_false arch_timer_read_ool_enabled; +#define needs_fsl_a008585_workaround() \ + static_branch_unlikely(&arch_timer_read_ool_enabled) +#else +#define needs_fsl_a008585_workaround() false +#endif + +u32 __fsl_a008585_read_cntp_tval_el0(void); +u32 __fsl_a008585_read_cntv_tval_el0(void); +u64 __fsl_a008585_read_cntvct_el0(void); + +/* + * The number of retries is an arbitrary value well beyond the highest number + * of iterations the loop has been observed to take. + */ +#define __fsl_a008585_read_reg(reg) ({ \ + u64 _old, _new; \ + int _retries = 200; \ + \ + do { \ + _old = read_sysreg(reg); \ + _new = read_sysreg(reg); \ + _retries--; \ + } while (unlikely(_old != _new) && _retries); \ + \ + WARN_ON_ONCE(!_retries); \ + _new; \ +}) + +#define arch_timer_reg_read_stable(reg) \ +({ \ + u64 _val; \ + if (needs_fsl_a008585_workaround()) \ + _val = __fsl_a008585_read_##reg(); \ + else \ + _val = read_sysreg(reg); \ + _val; \ +}) + /* * These register accessors are marked inline so the compiler can * nicely work out which register we want, and chuck away the rest of @@ -67,14 +108,14 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg) case ARCH_TIMER_REG_CTRL: return read_sysreg(cntp_ctl_el0); case ARCH_TIMER_REG_TVAL: - return read_sysreg(cntp_tval_el0); + return arch_timer_reg_read_stable(cntp_tval_el0); } } else if (access == ARCH_TIMER_VIRT_ACCESS) { switch (reg) { case ARCH_TIMER_REG_CTRL: return read_sysreg(cntv_ctl_el0); case ARCH_TIMER_REG_TVAL: - return read_sysreg(cntv_tval_el0); + return arch_timer_reg_read_stable(cntv_tval_el0); } } @@ -108,7 +149,7 @@ static inline u64 arch_counter_get_cntpct(void) static inline u64 arch_counter_get_cntvct(void) { isb(); - return read_sysreg(cntvct_el0); + return arch_timer_reg_read_stable(cntvct_el0); } static inline int arch_timer_arch_init(void) |