2 * Copyright (C) 2004-2006 Atmel Corporation
4 * See file CREDITS for list of people who contributed to this
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
25 #include <asm/errno.h>
27 #include <asm/processor.h>
28 #include <asm/sysreg.h>
30 #include <asm/arch/hardware.h>
32 #define HANDLER_MASK 0x00ffffff
33 #define INTLEV_SHIFT 30
34 #define INTLEV_MASK 0x00000003
36 DECLARE_GLOBAL_DATA_PTR;
38 /* Incremented whenever COUNT reaches 0xffffffff by timer_interrupt_handler */
39 volatile unsigned long timer_overflow;
42 * Instead of dividing by get_tbclk(), multiply by this constant and
43 * right-shift the result by 32 bits.
45 static unsigned long tb_factor;
47 unsigned long get_tbclk(void)
52 unsigned long long get_ticks(void)
54 unsigned long lo, hi_now, hi_prev;
57 hi_prev = timer_overflow;
58 lo = sysreg_read(COUNT);
59 hi_now = timer_overflow;
60 } while (hi_prev != hi_now);
62 return ((unsigned long long)hi_now << 32) | lo;
65 unsigned long get_timer(unsigned long base)
67 u64 now = get_ticks();
70 return (unsigned long)(now >> 32) - base;
74 * For short delays only. It will overflow after a few seconds.
76 void __udelay(unsigned long usec)
82 base = sysreg_read(COUNT);
83 cycles = ((usec * (get_tbclk() / 10000)) + 50) / 100;
86 now = sysreg_read(COUNT);
87 } while ((now - base) < cycles);
90 static int set_interrupt_handler(unsigned int nr, void (*handler)(void),
91 unsigned int priority)
93 extern void _evba(void);
95 unsigned long handler_addr = (unsigned long)handler;
97 handler_addr -= (unsigned long)&_evba;
99 if ((handler_addr & HANDLER_MASK) != handler_addr
100 || (priority & INTLEV_MASK) != priority)
103 intpr = (handler_addr & HANDLER_MASK);
104 intpr |= (priority & INTLEV_MASK) << INTLEV_SHIFT;
105 writel(intpr, (void *)ATMEL_BASE_INTC + 4 * nr);
110 void timer_init(void)
112 extern void timer_interrupt_handler(void);
115 sysreg_write(COUNT, 0);
117 tmp = (u64)CONFIG_SYS_HZ << 32;
118 tmp += gd->cpu_hz / 2;
119 do_div(tmp, gd->cpu_hz);
120 tb_factor = (u32)tmp;
122 if (set_interrupt_handler(0, &timer_interrupt_handler, 3))
125 /* For all practical purposes, this gives us an overflow interrupt */
126 sysreg_write(COMPARE, 0xffffffff);