+int timer_init(void) +{
- u32 __iomem *cntcr = (u32 *)CONFIG_SYS_FSL_TIMER_ADDR;
- u32 __iomem *cltbenr = (u32 *)CONFIG_SYS_FSL_PMU_CLTBENR;
+#ifdef COUNTER_FREQUENCY_REAL
- unsigned long cntfrq = COUNTER_FREQUENCY_REAL;
- /* Update with accurate clock frequency */
- asm volatile("msr cntfrq_el0, %0" : : "r" (cntfrq) : "memory");
The commit message says that this can only be determined at runtime, but this looks like we're writing a compile-time static value.
The macro COUNTER_FREQUENCY_REA is (CONFIG_SYS_CLK_FREQ/4), where CONFIG_SYS_CLK_FREQ is a function call get_board_sys_clk().
Ah, that sounds fine to me then.
- __real_cntfrq = cntfrq; /* update for secondary cores */
Do we need anything in the way or barriers and/or cache flushing to ensure that this is visible to the secondary CPUs? Or is the MMU off at this point?
It is flushed before booting secondary cores. But I am relying on the trick of enabling cache on flash. It may not be as reliable if someone decide to disable the cache to begin with. I will move the code to somewhere safe in next version.
Ok.
- .global __real_cntfrq
+__real_cntfrq:
- .quad 0x17d7840 /* 25MHz */
I think this would be better as COUNTER_FREQUENCY, so as to avoid duplicating the value.
Good idea. Will fix in next version.
Great!
Mark.