/*
+ * 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
*
*
* ########################################################################
*
- * 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_PTR,
+};
- /*
- * 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;
}
projects / cascardo / linux.git / blobdiff