1 /* 2 * (C) Copyright 2000, 2001 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 */ 23 24 #include <common.h> 25 26 /* ------------------------------------------------------------------------- */ 27 28 /* 29 * This function is intended for SHORT delays only. 30 * It will overflow at around 10 seconds @ 400MHz, 31 * or 20 seconds @ 200MHz. 32 */ 33 unsigned long usec2ticks(unsigned long usec) 34 { 35 ulong ticks; 36 37 if (usec < 1000) { 38 ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000; 39 } else { 40 ticks = ((usec / 10) * (get_tbclk() / 100000)); 41 } 42 43 return (ticks); 44 } 45 46 /* ------------------------------------------------------------------------- */ 47 48 /* 49 * We implement the delay by converting the delay (the number of 50 * microseconds to wait) into a number of time base ticks; then we 51 * watch the time base until it has incremented by that amount. 52 */ 53 void __udelay(unsigned long usec) 54 { 55 ulong ticks = usec2ticks (usec); 56 wait_ticks (ticks); 57 } 58 59 /* ------------------------------------------------------------------------- */ 60 #ifndef CONFIG_NAND_SPL 61 unsigned long ticks2usec(unsigned long ticks) 62 { 63 ulong tbclk = get_tbclk(); 64 65 /* usec = ticks * 1000000 / tbclk 66 * Multiplication would overflow at ~4.2e3 ticks, 67 * so we break it up into 68 * usec = ( ( ticks * 1000) / tbclk ) * 1000; 69 */ 70 ticks *= 1000L; 71 ticks /= tbclk; 72 ticks *= 1000L; 73 74 return ((ulong)ticks); 75 } 76 #endif 77 /* ------------------------------------------------------------------------- */ 78 79 int init_timebase (void) 80 { 81 #if defined(CONFIG_5xx) || defined(CONFIG_8xx) 82 volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR; 83 84 /* unlock */ 85 immap->im_sitk.sitk_tbk = KAPWR_KEY; 86 #endif 87 88 /* reset */ 89 asm ("li 3,0 ; mttbu 3 ; mttbl 3 ;"); 90 91 #if defined(CONFIG_5xx) || defined(CONFIG_8xx) 92 /* enable */ 93 immap->im_sit.sit_tbscr |= TBSCR_TBE; 94 #endif 95 return (0); 96 } 97 /* ------------------------------------------------------------------------- */ 98