diff options
Diffstat (limited to 'arch/mips/au1000/common/time.c')
| -rw-r--r-- | arch/mips/au1000/common/time.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/arch/mips/au1000/common/time.c b/arch/mips/au1000/common/time.c new file mode 100644 index 00000000000..fe418f1620c --- /dev/null +++ b/arch/mips/au1000/common/time.c @@ -0,0 +1,469 @@ +/* + * + * Copyright (C) 2001 MontaVista Software, ppopov@mvista.com + * Copied and modified Carsten Langgaard's time.c + * + * Carsten Langgaard, carstenl@mips.com + * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. + * + * ######################################################################## + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * ######################################################################## + * + * Setting up the clock on the MIPS boards. + * + * Update. Always configure the kernel with CONFIG_NEW_TIME_C. This + * will use the user interface gettimeofday() functions from the + * arch/mips/kernel/time.c, and we provide the clock interrupt processing + * and the timer offset compute functions. If CONFIG_PM is selected, + * we also ensure the 32KHz timer is available. -- Dan + */ + +#include <linux/types.h> +#include <linux/config.h> +#include <linux/init.h> +#include <linux/kernel_stat.h> +#include <linux/sched.h> +#include <linux/spinlock.h> +#include <linux/hardirq.h> + +#include <asm/compiler.h> +#include <asm/mipsregs.h> +#include <asm/ptrace.h> +#include <asm/time.h> +#include <asm/div64.h> +#include <asm/mach-au1x00/au1000.h> + +#include <linux/mc146818rtc.h> +#include <linux/timex.h> + +extern void startup_match20_interrupt(void); +extern void do_softirq(void); +extern volatile unsigned long wall_jiffies; +unsigned long missed_heart_beats = 0; + +static unsigned long r4k_offset; /* Amount to increment compare reg each time */ +static unsigned long r4k_cur; /* What counter should be at next timer irq */ +int no_au1xxx_32khz; +void (*au1k_wait_ptr)(void); + +/* Cycle counter value at the previous timer interrupt.. */ +static unsigned int timerhi = 0, timerlo = 0; + +#ifdef CONFIG_PM +#define MATCH20_INC 328 +extern void startup_match20_interrupt(void); +static unsigned long last_pc0, last_match20; +#endif + +static DEFINE_SPINLOCK(time_lock); + +static inline void ack_r4ktimer(unsigned long newval) +{ + write_c0_compare(newval); +} + +/* + * There are a lot of conceptually broken versions of the MIPS timer interrupt + * handler floating around. This one is rather different, but the algorithm + * is provably more robust. + */ +unsigned long wtimer; +void mips_timer_interrupt(struct pt_regs *regs) +{ + int irq = 63; + unsigned long count; + + irq_enter(); + kstat_this_cpu.irqs[irq]++; + + if (r4k_offset == 0) + goto null; + + do { + count = read_c0_count(); + timerhi += (count < timerlo); /* Wrap around */ + timerlo = count; + + kstat_this_cpu.irqs[irq]++; + do_timer(regs); +#ifndef CONFIG_SMP + update_process_times(user_mode(regs)); +#endif + r4k_cur += r4k_offset; + ack_r4ktimer(r4k_cur); + + } while (((unsigned long)read_c0_count() + - r4k_cur) < 0x7fffffff); + + irq_exit(); + return; + +null: + ack_r4ktimer(0); +} + +#ifdef CONFIG_PM +void counter0_irq(int irq, void *dev_id, struct pt_regs *regs) +{ + unsigned long pc0; + int time_elapsed; + static int jiffie_drift = 0; + + kstat.irqs[0][irq]++; + if (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20) { + /* should never happen! */ + printk(KERN_WARNING "counter 0 w status eror\n"); + return; + } + + pc0 = au_readl(SYS_TOYREAD); + if (pc0 < last_match20) { + /* counter overflowed */ + time_elapsed = (0xffffffff - last_match20) + pc0; + } + else { + time_elapsed = pc0 - last_match20; + } + + while (time_elapsed > 0) { + do_timer(regs); +#ifndef CONFIG_SMP + update_process_times(user_mode(regs)); +#endif + time_elapsed -= MATCH20_INC; + last_match20 += MATCH20_INC; + jiffie_drift++; + } + + last_pc0 = pc0; + au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2); + au_sync(); + + /* our counter ticks at 10.009765625 ms/tick, we we're running + * almost 10uS too slow per tick. + */ + + if (jiffie_drift >= 999) { + jiffie_drift -= 999; + do_timer(regs); /* increment jiffies by one */ +#ifndef CONFIG_SMP + update_process_times(user_mode(regs)); +#endif + } +} + +/* When we wakeup from sleep, we have to "catch up" on all of the + * timer ticks we have missed. + */ +void +wakeup_counter0_adjust(void) +{ + unsigned long pc0; + int time_elapsed; + + pc0 = au_readl(SYS_TOYREAD); + if (pc0 < last_match20) { + /* counter overflowed */ + time_elapsed = (0xffffffff - last_match20) + pc0; + } + else { + time_elapsed = pc0 - last_match20; + } + + while (time_elapsed > 0) { + time_elapsed -= MATCH20_INC; + last_match20 += MATCH20_INC; + } + + last_pc0 = pc0; + au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2); + au_sync(); + +} + +/* This is just for debugging to set the timer for a sleep delay. +*/ +void +wakeup_counter0_set(int ticks) +{ + unsigned long pc0; + + pc0 = au_readl(SYS_TOYREAD); + last_pc0 = pc0; + au_writel(last_match20 + (MATCH20_INC * ticks), SYS_TOYMATCH2); + au_sync(); +} +#endif + +/* I haven't found anyone that doesn't use a 12 MHz source clock, + * but just in case..... + */ +#ifdef CONFIG_AU1000_SRC_CLK +#define AU1000_SRC_CLK CONFIG_AU1000_SRC_CLK +#else +#define AU1000_SRC_CLK 12000000 +#endif + +/* + * We read the real processor speed from the PLL. This is important + * because it is more accurate than computing it from the 32KHz + * counter, if it exists. If we don't have an accurate processor + * speed, all of the peripherals that derive their clocks based on + * this advertised speed will introduce error and sometimes not work + * properly. This function is futher convoluted to still allow configurations + * to do that in case they have really, really old silicon with a + * write-only PLL register, that we need the 32KHz when power management + * "wait" is enabled, and we need to detect if the 32KHz isn't present + * but requested......got it? :-) -- Dan + */ +unsigned long cal_r4koff(void) +{ + unsigned long count; + unsigned long cpu_speed; + unsigned long flags; + unsigned long counter; + + spin_lock_irqsave(&time_lock, flags); + + /* Power management cares if we don't have a 32KHz counter. + */ + no_au1xxx_32khz = 0; + counter = au_readl(SYS_COUNTER_CNTRL); + if (counter & SYS_CNTRL_E0) { + int trim_divide = 16; + + au_writel(counter | SYS_CNTRL_EN1, SYS_COUNTER_CNTRL); + + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S); + /* RTC now ticks at 32.768/16 kHz */ + au_writel(trim_divide-1, SYS_RTCTRIM); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S); + + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S); + au_writel (0, SYS_TOYWRITE); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S); + +#if defined(CONFIG_AU1000_USE32K) + { + unsigned long start, end; + + start = au_readl(SYS_RTCREAD); + start += 2; + /* wait for the beginning of a new tick + */ + while (au_readl(SYS_RTCREAD) < start); + + /* Start r4k counter. + */ + write_c0_count(0); + + /* Wait 0.5 seconds. + */ + end = start + (32768 / trim_divide)/2; + + while (end > au_readl(SYS_RTCREAD)); + + count = read_c0_count(); + cpu_speed = count * 2; + } +#else + cpu_speed = (au_readl(SYS_CPUPLL) & 0x0000003f) * + AU1000_SRC_CLK; + count = cpu_speed / 2; +#endif + } + else { + /* The 32KHz oscillator isn't running, so assume there + * isn't one and grab the processor speed from the PLL. + * NOTE: some old silicon doesn't allow reading the PLL. + */ + cpu_speed = (au_readl(SYS_CPUPLL) & 0x0000003f) * AU1000_SRC_CLK; + count = cpu_speed / 2; + no_au1xxx_32khz = 1; + } + mips_hpt_frequency = count; + // Equation: Baudrate = CPU / (SD * 2 * CLKDIV * 16) + set_au1x00_uart_baud_base(cpu_speed / (2 * ((int)(au_readl(SYS_POWERCTRL)&0x03) + 2) * 16)); + spin_unlock_irqrestore(&time_lock, flags); + return (cpu_speed / HZ); +} + +/* This is for machines which generate the exact clock. */ +#define USECS_PER_JIFFY (1000000/HZ) +#define USECS_PER_JIFFY_FRAC (0x100000000LL*1000000/HZ&0xffffffff) + +static unsigned long +div64_32(unsigned long v1, unsigned long v2, unsigned long v3) +{ + unsigned long r0; + do_div64_32(r0, v1, v2, v3); + return r0; +} + +static unsigned long do_fast_cp0_gettimeoffset(void) +{ + u32 count; + unsigned long res, tmp; + unsigned long r0; + + /* Last jiffy when do_fast_gettimeoffset() was called. */ + static unsigned long last_jiffies=0; + unsigned long quotient; + + /* + * Cached "1/(clocks per usec)*2^32" value. + * It has to be recalculated once each jiffy. + */ + static unsigned long cached_quotient=0; + + tmp = jiffies; + + quotient = cached_quotient; + + if (tmp && last_jiffies != tmp) { + last_jiffies = tmp; + if (last_jiffies != 0) { + r0 = div64_32(timerhi, timerlo, tmp); + quotient = div64_32(USECS_PER_JIFFY, USECS_PER_JIFFY_FRAC, r0); + cached_quotient = quotient; + } + } + + /* Get last timer tick in absolute kernel time */ + count = read_c0_count(); + + /* .. relative to previous jiffy (32 bits is enough) */ + count -= timerlo; + + __asm__("multu\t%1,%2\n\t" + "mfhi\t%0" + : "=r" (res) + : "r" (count), "r" (quotient) + : "hi", "lo", GCC_REG_ACCUM); + + /* + * Due to possible jiffies inconsistencies, we need to check + * the result so that we'll get a timer that is monotonic. + */ + if (res >= USECS_PER_JIFFY) + res = USECS_PER_JIFFY-1; + + return res; +} + +#ifdef CONFIG_PM +static unsigned long do_fast_pm_gettimeoffset(void) +{ + unsigned long pc0; + unsigned long offset; + + pc0 = au_readl(SYS_TOYREAD); + au_sync(); + offset = pc0 - last_pc0; + if (offset > 2*MATCH20_INC) { + printk("huge offset %x, last_pc0 %x last_match20 %x pc0 %x\n", + (unsigned)offset, (unsigned)last_pc0, + (unsigned)last_match20, (unsigned)pc0); + } + offset = (unsigned long)((offset * 305) / 10); + return offset; +} +#endif + +void au1xxx_timer_setup(struct irqaction *irq) +{ + unsigned int est_freq; + extern unsigned long (*do_gettimeoffset)(void); + extern void au1k_wait(void); + + printk("calculating r4koff... "); + r4k_offset = cal_r4koff(); + printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset); + + //est_freq = 2*r4k_offset*HZ; + est_freq = r4k_offset*HZ; + est_freq += 5000; /* round */ + est_freq -= est_freq%10000; + printk("CPU frequency %d.%02d MHz\n", est_freq/1000000, + (est_freq%1000000)*100/1000000); + set_au1x00_speed(est_freq); + set_au1x00_lcd_clock(); // program the LCD clock + + r4k_cur = (read_c0_count() + r4k_offset); + write_c0_compare(r4k_cur); + +#ifdef CONFIG_PM + /* + * setup counter 0, since it keeps ticking after a + * 'wait' instruction has been executed. The CP0 timer and + * counter 1 do NOT continue running after 'wait' + * + * It's too early to call request_irq() here, so we handle + * counter 0 interrupt as a special irq and it doesn't show + * up under /proc/interrupts. + * + * Check to ensure we really have a 32KHz oscillator before + * we do this. + */ + if (no_au1xxx_32khz) { + unsigned int c0_status; + + printk("WARNING: no 32KHz clock found.\n"); + do_gettimeoffset = do_fast_cp0_gettimeoffset; + + /* Ensure we get CPO_COUNTER interrupts. + */ + c0_status = read_c0_status(); + c0_status |= IE_IRQ5; + write_c0_status(c0_status); + } + else { + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S); + au_writel(0, SYS_TOYWRITE); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C0S); + + au_writel(au_readl(SYS_WAKEMSK) | (1<<8), SYS_WAKEMSK); + au_writel(~0, SYS_WAKESRC); + au_sync(); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20); + + /* setup match20 to interrupt once every 10ms */ + last_pc0 = last_match20 = au_readl(SYS_TOYREAD); + au_writel(last_match20 + MATCH20_INC, SYS_TOYMATCH2); + au_sync(); + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20); + startup_match20_interrupt(); + + do_gettimeoffset = do_fast_pm_gettimeoffset; + + /* We can use the real 'wait' instruction. + */ + au1k_wait_ptr = au1k_wait; + } + +#else + /* We have to do this here instead of in timer_init because + * the generic code in arch/mips/kernel/time.c will write + * over our function pointer. + */ + do_gettimeoffset = do_fast_cp0_gettimeoffset; +#endif +} + +void __init au1xxx_time_init(void) +{ +} |