1 /* 2 * (C) Copyright 2000, 2001 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <common.h> 9 10 /* ------------------------------------------------------------------------- */ 11 12 /* 13 * This function is intended for SHORT delays only. 14 * It will overflow at around 10 seconds @ 400MHz, 15 * or 20 seconds @ 200MHz. 16 */ 17 unsigned long usec2ticks(unsigned long usec) 18 { 19 ulong ticks; 20 21 if (usec < 1000) { 22 ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000; 23 } else { 24 ticks = ((usec / 10) * (get_tbclk() / 100000)); 25 } 26 27 return (ticks); 28 } 29 30 /* ------------------------------------------------------------------------- */ 31 32 /* 33 * We implement the delay by converting the delay (the number of 34 * microseconds to wait) into a number of time base ticks; then we 35 * watch the time base until it has incremented by that amount. 36 */ 37 void __udelay(unsigned long usec) 38 { 39 ulong ticks = usec2ticks (usec); 40 wait_ticks (ticks); 41 } 42 43 /* ------------------------------------------------------------------------- */ 44 #ifndef CONFIG_NAND_SPL 45 unsigned long ticks2usec(unsigned long ticks) 46 { 47 ulong tbclk = get_tbclk(); 48 49 /* usec = ticks * 1000000 / tbclk 50 * Multiplication would overflow at ~4.2e3 ticks, 51 * so we break it up into 52 * usec = ( ( ticks * 1000) / tbclk ) * 1000; 53 */ 54 ticks *= 1000L; 55 ticks /= tbclk; 56 ticks *= 1000L; 57 58 return ((ulong)ticks); 59 } 60 #endif 61 /* ------------------------------------------------------------------------- */ 62 63 int init_timebase (void) 64 { 65 unsigned long temp; 66 67 #if defined(CONFIG_5xx) || defined(CONFIG_8xx) 68 volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR; 69 70 /* unlock */ 71 immap->im_sitk.sitk_tbk = KAPWR_KEY; 72 #endif 73 74 /* reset */ 75 asm volatile("li %0,0 ; mttbu %0 ; mttbl %0;" 76 : "=&r"(temp) ); 77 78 #if defined(CONFIG_5xx) || defined(CONFIG_8xx) 79 /* enable */ 80 immap->im_sit.sit_tbscr |= TBSCR_TBE; 81 #endif 82 return (0); 83 } 84 /* ------------------------------------------------------------------------- */ 85