// SPDX-License-Identifier: GPL-2.0+ /* * (C) Copyright 2013 * David Feng */ #include #include #include #include #include #include #include DECLARE_GLOBAL_DATA_PTR; /* * Generic timer implementation of get_tbclk() */ unsigned long notrace get_tbclk(void) { unsigned long cntfrq; asm volatile("mrs %0, cntfrq_el0" : "=r" (cntfrq)); return cntfrq; } #ifdef CONFIG_SYS_FSL_ERRATUM_A008585 /* * FSL erratum A-008585 says that the ARM generic timer counter "has the * potential to contain an erroneous value for a small number of core * clock cycles every time the timer value changes". * This sometimes leads to a consecutive counter read returning a lower * value than the previous one, thus reporting the time to go backwards. * The workaround is to read the counter twice and only return when the value * was the same in both reads. * Assumes that the CPU runs in much higher frequency than the timer. */ unsigned long timer_read_counter(void) { unsigned long cntpct; unsigned long temp; isb(); asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct)); asm volatile("mrs %0, cntpct_el0" : "=r" (temp)); while (temp != cntpct) { asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct)); asm volatile("mrs %0, cntpct_el0" : "=r" (temp)); } return cntpct; } #elif CONFIG_SUNXI_A64_TIMER_ERRATUM /* * This erratum sometimes flips the lower 11 bits of the counter value * to all 0's or all 1's, leading to jumps forwards or backwards. * Backwards jumps might be interpreted all roll-overs and be treated as * huge jumps forward. * The workaround is to check whether the lower 11 bits of the counter are * all 0 or all 1, then discard this value and read again. * This occasionally discards valid values, but will catch all erroneous * reads and fixes the problem reliably. Also this mostly requires only a * single read, so does not have any significant overhead. * The algorithm was conceived by Samuel Holland. */ unsigned long timer_read_counter(void) { unsigned long cntpct; isb(); do { asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct)); } while (((cntpct + 1) & GENMASK(10, 0)) <= 1); return cntpct; } #else /* * timer_read_counter() using the Arm Generic Timer (aka arch timer). */ unsigned long notrace timer_read_counter(void) { unsigned long cntpct; isb(); asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct)); return cntpct; } #endif uint64_t notrace get_ticks(void) { unsigned long ticks = timer_read_counter(); gd->arch.tbl = ticks; return ticks; } unsigned long usec2ticks(unsigned long usec) { ulong ticks; if (usec < 1000) ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000; else ticks = ((usec / 10) * (get_tbclk() / 100000)); return ticks; } ulong timer_get_boot_us(void) { u64 val = get_ticks() * 1000000; return val / get_tbclk(); }