// SPDX-License-Identifier: GPL-2.0+ /* * (C) Copyright 2008 - 2013 Tensilica Inc. */ #include <common.h> #include <clock_legacy.h> #include <time.h> #include <asm/global_data.h> #include <linux/delay.h> #include <linux/stringify.h> DECLARE_GLOBAL_DATA_PTR; #if XCHAL_HAVE_CCOUNT static ulong get_ccount(void) { ulong ccount; asm volatile ("rsr %0,"__stringify(CCOUNT) : "=a" (ccount)); return ccount; } #else static ulong fake_ccount; #define get_ccount() fake_ccount #endif static void delay_cycles(unsigned cycles) { #if XCHAL_HAVE_CCOUNT unsigned expiry = get_ccount() + cycles; while ((signed)(expiry - get_ccount()) > 0) ; #else #warning "Without Xtensa timer option, timing will not be accurate." /* * Approximate the cycle count by a loop iteration count. * This is highly dependent on config and optimization. */ volatile unsigned i; for (i = cycles >> 4U; i > 0; --i) ; fake_ccount += cycles; #endif } /* * Delay (busy-wait) for a number of microseconds. */ void __udelay(unsigned long usec) { ulong lo, hi, i; ulong mhz = get_board_sys_clk() / 1000000; /* Scale to support full 32-bit usec range */ lo = usec & ((1<<22)-1); hi = usec >> 22UL; for (i = 0; i < hi; ++i) delay_cycles(mhz << 22); delay_cycles(mhz * lo); } /* * Return the elapsed time (ticks) since 'base'. */ ulong get_timer(ulong base) { /* Don't tie up a timer; use cycle counter if available (or fake it) */ #if XCHAL_HAVE_CCOUNT register ulong ccount; __asm__ volatile ("rsr %0, CCOUNT" : "=a"(ccount)); return ccount / (get_board_sys_clk() / CONFIG_SYS_HZ) - base; #else /* * Add at least the overhead of this call (in cycles). * Avoids hanging in case caller doesn't use udelay(). * Note that functions that don't call udelay() (such as * the "sleep" command) will not get a significant delay * because there is no time reference. */ fake_ccount += 20; return fake_ccount / (get_board_sys_clk() / CONFIG_SYS_HZ) - base; #endif } /* * This function is derived from ARM/PowerPC code (read timebase as long long). * On Xtensa it just returns the timer value. */ unsigned long long get_ticks(void) { return get_timer(0); } /* * This function is derived from ARM/PowerPC code (timebase clock frequency). * On Xtensa it returns the number of timer ticks per second. */ ulong get_tbclk(void) { return CONFIG_SYS_HZ; } #if XCHAL_HAVE_CCOUNT unsigned long timer_get_us(void) { unsigned long ccount; __asm__ volatile ("rsr %0, CCOUNT" : "=a"(ccount)); return ccount / (get_board_sys_clk() / 1000000); } #endif