diff options
Diffstat (limited to 'arch/mips/alchemy/common/time.c')
| -rw-r--r-- | arch/mips/alchemy/common/time.c | 311 |
1 files changed, 105 insertions, 206 deletions
diff --git a/arch/mips/alchemy/common/time.c b/arch/mips/alchemy/common/time.c index 563d939..3288014 100644 --- a/arch/mips/alchemy/common/time.c +++ b/arch/mips/alchemy/common/time.c @@ -1,5 +1,7 @@ /* + * Copyright (C) 2008 Manuel Lauss <mano@roarinelk.homelinux.net> * + * Previous incarnations were: * Copyright (C) 2001, 2006, 2008 MontaVista Software, <source@mvista.com> * Copied and modified Carsten Langgaard's time.c * @@ -23,244 +25,141 @@ * * ######################################################################## * - * Setting up the clock on the MIPS boards. - * - * 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 + * Clocksource/event using the 32.768kHz-clocked Counter1 ('RTC' in the + * databooks). Firmware/Board init code must enable the counters in the + * counter control register, otherwise the CP0 counter clocksource/event + * will be installed instead (and use of 'wait' instruction is prohibited). */ -#include <linux/types.h> -#include <linux/init.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/interrupt.h> #include <linux/spinlock.h> -#include <asm/mipsregs.h> #include <asm/time.h> #include <asm/mach-au1x00/au1000.h> -static int no_au1xxx_32khz; -extern int allow_au1k_wait; /* default off for CP0 Counter */ - -#ifdef CONFIG_PM -#if HZ < 100 || HZ > 1000 -#error "unsupported HZ value! Must be in [100,1000]" -#endif -#define MATCH20_INC (328 * 100 / HZ) /* magic number 328 is for HZ=100... */ -static unsigned long last_pc0, last_match20; -#endif +/* 32kHz clock enabled and detected */ +#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S) -static DEFINE_SPINLOCK(time_lock); - -unsigned long wtimer; +extern int allow_au1k_wait; /* default off for CP0 Counter */ -#ifdef CONFIG_PM -static irqreturn_t counter0_irq(int irq, void *dev_id) +static cycle_t au1x_counter1_read(void) { - unsigned long pc0; - int time_elapsed; - static int jiffie_drift; - - if (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20) { - /* should never happen! */ - printk(KERN_WARNING "counter 0 w status error\n"); - return IRQ_NONE; - } - - 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(1); -#ifndef CONFIG_SMP - update_process_times(user_mode(get_irq_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 10 uS too slow per tick. - */ - - if (jiffie_drift >= 999) { - jiffie_drift -= 999; - do_timer(1); /* increment jiffies by one */ -#ifndef CONFIG_SMP - update_process_times(user_mode(get_irq_regs())); -#endif - } - - return IRQ_HANDLED; + return au_readl(SYS_RTCREAD); } -struct irqaction counter0_action = { - .handler = counter0_irq, - .flags = IRQF_DISABLED, - .name = "alchemy-toy", - .dev_id = NULL, +static struct clocksource au1x_counter1_clocksource = { + .name = "alchemy-counter1", + .read = au1x_counter1_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .rating = 100, }; -/* When we wakeup from sleep, we have to "catch up" on all of the - * timer ticks we have missed. - */ -void wakeup_counter0_adjust(void) +static int au1x_rtcmatch2_set_next_event(unsigned long delta, + struct clock_event_device *cd) { - 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); + delta += au_readl(SYS_RTCREAD); + /* wait for register access */ + while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M21) + ; + au_writel(delta, SYS_RTCMATCH2); au_sync(); + return 0; } -/* This is just for debugging to set the timer for a sleep delay. */ -void wakeup_counter0_set(int ticks) +static void au1x_rtcmatch2_set_mode(enum clock_event_mode mode, + struct clock_event_device *cd) { - 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..... - */ -#define AU1000_SRC_CLK 12000000 - -/* - * We read the real processor speed from the PLL. This is important - * because it is more accurate than computing it from the 32 KHz - * 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 32 KHz when power management - * "wait" is enabled, and we need to detect if the 32 KHz isn't present - * but requested......got it? :-) -- Dan - */ -unsigned long calc_clock(void) +static irqreturn_t au1x_rtcmatch2_irq(int irq, void *dev_id) { - 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 32 KHz 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); + struct clock_event_device *cd = dev_id; + cd->event_handler(cd); + return IRQ_HANDLED; +} - while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S); - au_writel(0, SYS_TOYWRITE); - while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S); - } else - no_au1xxx_32khz = 1; +static struct clock_event_device au1x_rtcmatch2_clockdev = { + .name = "rtcmatch2", + .features = CLOCK_EVT_FEAT_ONESHOT, + .rating = 100, + .irq = AU1000_RTC_MATCH2_INT, + .set_next_event = au1x_rtcmatch2_set_next_event, + .set_mode = au1x_rtcmatch2_set_mode, + .cpumask = CPU_MASK_ALL, +}; - /* - * On early Au1000, sys_cpupll was write-only. Since these - * silicon versions of Au1000 are not sold by AMD, we don't bend - * over backwards trying to determine the frequency. - */ - if (cur_cpu_spec[0]->cpu_pll_wo) -#ifdef CONFIG_SOC_AU1000_FREQUENCY - cpu_speed = CONFIG_SOC_AU1000_FREQUENCY; -#else - cpu_speed = 396000000; -#endif - else - cpu_speed = (au_readl(SYS_CPUPLL) & 0x0000003f) * AU1000_SRC_CLK; - /* On Alchemy CPU:counter ratio is 1:1 */ - mips_hpt_frequency = cpu_speed; - /* 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; -} +static struct irqaction au1x_rtcmatch2_irqaction = { + .handler = au1x_rtcmatch2_irq, + .flags = IRQF_DISABLED | IRQF_TIMER, + .name = "timer", + .dev_id = &au1x_rtcmatch2_clockdev, +}; void __init plat_time_init(void) { - unsigned int est_freq = calc_clock(); - - est_freq += 5000; /* round */ - est_freq -= est_freq%10000; - printk(KERN_INFO "CPU frequency %u.%02u MHz\n", - est_freq / 1000000, ((est_freq % 1000000) * 100) / 1000000); - set_au1x00_speed(est_freq); - set_au1x00_lcd_clock(); /* program the LCD clock */ + struct clock_event_device *cd = &au1x_rtcmatch2_clockdev; + unsigned long t; + + /* Check if firmware (YAMON, ...) has enabled 32kHz and clock + * has been detected. If so install the rtcmatch2 clocksource, + * otherwise don't bother. Note that both bits being set is by + * no means a definite guarantee that the counters actually work + * (the 32S bit seems to be stuck set to 1 once a single clock- + * edge is detected, hence the timeouts). + */ + if (CNTR_OK != (au_readl(SYS_COUNTER_CNTRL) & CNTR_OK)) + goto cntr_err; -#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 32 KHz oscillator before - * we do this. + * setup counter 1 (RTC) to tick at full speed */ - if (no_au1xxx_32khz) - printk(KERN_WARNING "WARNING: no 32KHz clock found.\n"); - 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); + t = 0xffffff; + while ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S) && t--) + asm volatile ("nop"); + if (!t) + goto cntr_err; - /* Setup match20 to interrupt once every HZ */ - 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); - setup_irq(AU1000_TOY_MATCH2_INT, &counter0_action); + au_writel(0, SYS_RTCTRIM); /* 32.768 kHz */ + au_sync(); - /* We can use the real 'wait' instruction. */ - allow_au1k_wait = 1; - } + t = 0xffffff; + while ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S) && t--) + asm volatile ("nop"); + if (!t) + goto cntr_err; + au_writel(0, SYS_RTCWRITE); + au_sync(); -#endif + t = 0xffffff; + while ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S) && t--) + asm volatile ("nop"); + if (!t) + goto cntr_err; + + /* register counter1 clocksource and event device */ + clocksource_set_clock(&au1x_counter1_clocksource, 32768); + clocksource_register(&au1x_counter1_clocksource); + + cd->shift = 32; + cd->mult = div_sc(32768, NSEC_PER_SEC, cd->shift); + cd->max_delta_ns = clockevent_delta2ns(0xffffffff, cd); + cd->min_delta_ns = clockevent_delta2ns(8, cd); /* ~0.25ms */ + clockevents_register_device(cd); + setup_irq(AU1000_RTC_MATCH2_INT, &au1x_rtcmatch2_irqaction); + + printk(KERN_INFO "Alchemy clocksource installed\n"); + + /* can now use 'wait' */ + allow_au1k_wait = 1; + return; + +cntr_err: + /* counters unusable, use C0 counter */ + r4k_clockevent_init(); + init_r4k_clocksource(); + allow_au1k_wait = 0; } |
