1 /* 2 * (C) Copyright 2009 3 * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com. 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 #include <asm/io.h> 26 #include <asm/arch/hardware.h> 27 #include <asm/arch/spr_gpt.h> 28 #include <asm/arch/spr_misc.h> 29 30 #define GPT_RESOLUTION (CONFIG_SPEAR_HZ_CLOCK / CONFIG_SPEAR_HZ) 31 #define READ_TIMER() (readl(&gpt_regs_p->count) & GPT_FREE_RUNNING) 32 33 static struct gpt_regs *const gpt_regs_p = 34 (struct gpt_regs *)CONFIG_SPEAR_TIMERBASE; 35 36 static struct misc_regs *const misc_regs_p = 37 (struct misc_regs *)CONFIG_SPEAR_MISCBASE; 38 39 DECLARE_GLOBAL_DATA_PTR; 40 41 #define timestamp gd->arch.tbl 42 #define lastdec gd->arch.lastinc 43 44 int timer_init(void) 45 { 46 u32 synth; 47 48 /* Prescaler setting */ 49 #if defined(CONFIG_SPEAR3XX) 50 writel(MISC_PRSC_CFG, &misc_regs_p->prsc2_clk_cfg); 51 synth = MISC_GPT4SYNTH; 52 #elif defined(CONFIG_SPEAR600) 53 writel(MISC_PRSC_CFG, &misc_regs_p->prsc1_clk_cfg); 54 synth = MISC_GPT3SYNTH; 55 #else 56 # error Incorrect config. Can only be spear{600|300|310|320} 57 #endif 58 59 writel(readl(&misc_regs_p->periph_clk_cfg) | synth, 60 &misc_regs_p->periph_clk_cfg); 61 62 /* disable timers */ 63 writel(GPT_PRESCALER_1 | GPT_MODE_AUTO_RELOAD, &gpt_regs_p->control); 64 65 /* load value for free running */ 66 writel(GPT_FREE_RUNNING, &gpt_regs_p->compare); 67 68 /* auto reload, start timer */ 69 writel(readl(&gpt_regs_p->control) | GPT_ENABLE, &gpt_regs_p->control); 70 71 /* Reset the timer */ 72 lastdec = READ_TIMER(); 73 timestamp = 0; 74 75 return 0; 76 } 77 78 /* 79 * timer without interrupts 80 */ 81 ulong get_timer(ulong base) 82 { 83 return (get_timer_masked() / GPT_RESOLUTION) - base; 84 } 85 86 void __udelay(unsigned long usec) 87 { 88 ulong tmo; 89 ulong start = get_timer_masked(); 90 ulong tenudelcnt = CONFIG_SPEAR_HZ_CLOCK / (1000 * 100); 91 ulong rndoff; 92 93 rndoff = (usec % 10) ? 1 : 0; 94 95 /* tenudelcnt timer tick gives 10 microsecconds delay */ 96 tmo = ((usec / 10) + rndoff) * tenudelcnt; 97 98 while ((ulong) (get_timer_masked() - start) < tmo) 99 ; 100 } 101 102 ulong get_timer_masked(void) 103 { 104 ulong now = READ_TIMER(); 105 106 if (now >= lastdec) { 107 /* normal mode */ 108 timestamp += now - lastdec; 109 } else { 110 /* we have an overflow ... */ 111 timestamp += now + GPT_FREE_RUNNING - lastdec; 112 } 113 lastdec = now; 114 115 return timestamp; 116 } 117 118 void udelay_masked(unsigned long usec) 119 { 120 return udelay(usec); 121 } 122 123 /* 124 * This function is derived from PowerPC code (read timebase as long long). 125 * On ARM it just returns the timer value. 126 */ 127 unsigned long long get_ticks(void) 128 { 129 return get_timer(0); 130 } 131 132 /* 133 * This function is derived from PowerPC code (timebase clock frequency). 134 * On ARM it returns the number of timer ticks per second. 135 */ 136 ulong get_tbclk(void) 137 { 138 return CONFIG_SPEAR_HZ; 139 } 140