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List: linux-mips
Subject: [PATCH v2 4/8] Alchemy: RTC counter clocksource / clockevent
From: Manuel Lauss <mano () roarinelk ! homelinux ! net>
Date: 2008-06-26 19:39:18
Message-ID: 20080626193918.GE21604 () roarinelk ! homelinux ! net
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From: Manuel Lauss <mano@roarinelk.homelinux.net>
Add support for the 32 kHz counter1 (RTC) as clocksource / clockevent
device to enable use of the 'wait' instruction.
If the 32kHz clock supply is unstable/stopped during init, the CP0 counter
clocksource/event will be used instead.
Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
---
arch/mips/au1000/Kconfig | 4 +-
arch/mips/au1000/common/power.c | 15 ++-
arch/mips/au1000/common/setup.c | 6 -
arch/mips/au1000/common/time.c | 313 ++++++++++++++++++---------------------
4 files changed, 156 insertions(+), 182 deletions(-)
diff --git a/arch/mips/au1000/Kconfig b/arch/mips/au1000/Kconfig
index 1fe97cc..c689cd6 100644
--- a/arch/mips/au1000/Kconfig
+++ b/arch/mips/au1000/Kconfig
@@ -128,8 +128,8 @@ config SOC_AU1200
config SOC_AU1X00
bool
select 64BIT_PHYS_ADDR
- select CEVT_R4K
- select CSRC_R4K
+ select CEVT_R4K_LIB
+ select CSRC_R4K_LIB
select IRQ_CPU
select SYS_HAS_CPU_MIPS32_R1
select SYS_SUPPORTS_32BIT_KERNEL
diff --git a/arch/mips/au1000/common/power.c b/arch/mips/au1000/common/power.c
index 2166b9e..0aa9522 100644
--- a/arch/mips/au1000/common/power.c
+++ b/arch/mips/au1000/common/power.c
@@ -87,7 +87,11 @@ static unsigned int sleep_static_memctlr[4][3];
#define SLEEP_TEST_TIMEOUT 1
#ifdef SLEEP_TEST_TIMEOUT
static int sleep_ticks;
-void wakeup_counter0_set(int ticks);
+static void wakeup_counter0_set(int ticks)
+{
+ au_writel(au_readl(SYS_TOYREAD) + ticks, SYS_TOYMATCH2);
+ au_sync();
+}
#endif
static void save_core_regs(void)
@@ -185,7 +189,6 @@ static void restore_core_regs(void)
}
restore_au1xxx_intctl();
- wakeup_counter0_adjust();
}
unsigned long suspend_mode;
@@ -410,6 +413,14 @@ static struct ctl_table pm_dir_table[] = {
*/
static int __init pm_init(void)
{
+ /* init TOY to tick at 1Hz. No need to wait for access bits
+ * since there's plenty of time between here and the first
+ * suspend cycle.
+ */
+ au_writel(32767, SYS_TOYTRIM);
+ au_writel(0, SYS_TOYWRITE);
+ au_sync();
+
register_sysctl_table(pm_dir_table);
return 0;
}
diff --git a/arch/mips/au1000/common/setup.c b/arch/mips/au1000/common/setup.c
index aa74846..398d665 100644
--- a/arch/mips/au1000/common/setup.c
+++ b/arch/mips/au1000/common/setup.c
@@ -90,12 +90,6 @@ void __init plat_mem_setup(void)
ioport_resource.end = IOPORT_RESOURCE_END;
iomem_resource.start = IOMEM_RESOURCE_START;
iomem_resource.end = IOMEM_RESOURCE_END;
-
- while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_E0S);
- au_writel(SYS_CNTRL_E0 | SYS_CNTRL_EN0, SYS_COUNTER_CNTRL);
- au_sync();
- while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T0S);
- au_writel(0, SYS_TOYTRIM);
}
#if defined(CONFIG_64BIT_PHYS_ADDR)
diff --git a/arch/mips/au1000/common/time.c b/arch/mips/au1000/common/time.c
index 1518570..e37aca7 100644
--- a/arch/mips/au1000/common/time.c
+++ b/arch/mips/au1000/common/time.c
@@ -23,131 +23,29 @@
*
* ########################################################################
*
- * Setting up the clock on the MIPS boards.
+ * Clocksource/event using the Au1000 counter1.
+ * Compared to the C0 timer, the Au1000 counters make for a very lousy
+ * clocksource and hrtimers are definitely unusable with them; but they
+ * enable the use of the 'wait' instructions for some power-savings
+ * during idle times. Counter1 is used because unlike counter 0 (TOY)
+ * it doesn't continue counting during sleep/hibernate, which is perfectly
+ * acceptable.
*
- * 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
+ * CP0 counter clocksource will be used if no 32kHz source is available.
*/
-#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
-
static DEFINE_SPINLOCK(time_lock);
-unsigned long wtimer;
-
-#ifdef CONFIG_PM
-static irqreturn_t counter0_irq(int irq, void *dev_id)
-{
- 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;
-}
-
-struct irqaction counter0_action = {
- .handler = counter0_irq,
- .flags = IRQF_DISABLED,
- .name = "alchemy-toy",
- .dev_id = NULL,
-};
-
-/* 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.....
@@ -162,37 +60,15 @@ void wakeup_counter0_set(int ticks)
* 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
+ * write-only PLL register. -- Dan
*/
unsigned long calc_clock(void)
{
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);
-
- 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;
-
/*
* On early Au1000, sys_cpupll was write-only. Since these
* silicon versions of Au1000 are not sold by AMD, we don't bend
@@ -215,6 +91,130 @@ unsigned long calc_clock(void)
return cpu_speed;
}
+static cycle_t au1x_counter1_read(void)
+{
+ return au_readl(SYS_RTCREAD);
+}
+
+static struct clocksource au1x_counter1_clocksource = {
+ .name = "au1000-counter1",
+ .read = au1x_counter1_read,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int au1x_rtcmatch2_set_next_event(unsigned long delta,
+ struct clock_event_device *cd)
+{
+ au_writel(au_readl(SYS_RTCREAD) + delta, SYS_RTCMATCH2);
+ au_sync();
+ return 0;
+}
+
+static void au1x_rtcmatch2_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *cd)
+{
+}
+
+static irqreturn_t au1x_rtcmatch2_irq(int irq, void *dev_id)
+{
+ struct clock_event_device *cd = dev_id;
+ cd->event_handler(cd);
+ return IRQ_HANDLED;
+}
+
+static struct clock_event_device au1x_ced_rtcmatch2 = {
+ .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,
+};
+
+struct irqaction au1x_rtcmatch2_action = {
+ .handler = au1x_rtcmatch2_irq,
+ .flags = IRQF_DISABLED,
+ .name = "rtcmatch2",
+ .dev_id = &au1x_ced_rtcmatch2,
+};
+
+static void au1x_rtcmatch2_clockevent_init(void)
+{
+ struct clock_event_device *cd = &au1x_ced_rtcmatch2;
+
+ cd->mult = div_sc(32768, NSEC_PER_SEC, 32);
+ cd->shift = 32;
+ cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
+
+ /* 0x140 -- boots AND BogoMIPS detection is pretty accurate too */
+ cd->min_delta_ns = clockevent_delta2ns(0x140, cd);
+ clockevents_register_device(cd);
+ setup_irq(AU1000_RTC_MATCH2_INT, &au1x_rtcmatch2_action);
+}
+
+/* Initialize Au1xxx counter1 (aka RTC) as clocksource/event device.
+ * NOTE: don't touch the counter0 (TOY) since we don't need it.
+ * Board code can do whatever it wants with it.
+ */
+static int au1x_counter1_init(void)
+{
+ unsigned long i;
+
+ /* enable 32kHz input */
+ i = au_readl(SYS_COUNTER_CNTRL);
+ au_writel(i | SYS_CNTRL_E0, SYS_COUNTER_CNTRL);
+ au_sync();
+
+ /* wait a bit for 32S flag (clock detected) to appear */
+ for (i = 0x00ffffff; i; i--) {
+ if ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_32S))
+ break;
+ }
+ if (!i)
+ goto out_err;
+
+ /*
+ * setup counter 1 (RTC) to tick at full speed
+ */
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S)
+ asm volatile ("nop");
+ au_writel(0, SYS_RTCTRIM); /* 32.768 kHz */
+ au_sync();
+ /* don't wait for RTCTRIM write confirmation, this may take a loooong
+ * time, up to 5 seconds(!!). It doesn't hurt though because it is
+ * zero anyway after power-up and after reset because we set it here.
+ */
+
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S)
+ asm volatile ("nop");
+ au_writel(0, SYS_RTCWRITE);
+ au_sync();
+ while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_C1S)
+ asm volatile ("nop");
+
+ /*
+ * register RTC clockevent device and clocksource.
+ */
+ au1x_rtcmatch2_clockevent_init();
+
+ au1x_counter1_clocksource.rating = 100;
+ clocksource_set_clock(&au1x_counter1_clocksource, 32768);
+ clocksource_register(&au1x_counter1_clocksource);
+ printk(KERN_INFO "Au1000 COUNTER1 (RTC) clocksource installed\n");
+
+ /* can now use 'wait' */
+ allow_au1k_wait = 1;
+
+ return 0;
+
+out_err:
+ au_writel(0, SYS_COUNTER_CNTRL);
+ au_sync();
+ return -ENXIO;
+}
+
void __init plat_time_init(void)
{
unsigned int est_freq = calc_clock();
@@ -225,41 +225,10 @@ void __init plat_time_init(void)
est_freq / 1000000, ((est_freq % 1000000) * 100) / 1000000);
set_au1x00_speed(est_freq);
-#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.
- */
- 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);
-
- /* 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);
-
- /* We can use the real 'wait' instruction. */
- allow_au1k_wait = 1;
+ if (au1x_counter1_init()) {
+ /* 32kHz is unusable -- install CP0 counter instead */
+ r4k_clockevent_init();
+ init_r4k_clocksource();
+ allow_au1k_wait = 0;
}
-
-#endif
}
--
1.5.5.4
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