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MIPS: Alchemy: RTC counter clocksource / clockevent support.

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Add support for the 32 kHz counter1 (RTC) as clocksource / clockevent
device.  As a nice side effect, this also enables use of the 'wait'
instruction for runtime idle power savings.

If the counters aren't enabled/working properly, fall back on the
cp0 counter clock code.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Manuel Lauss 2008-12-21 09:26:23 +01:00 committed by Ralf Baechle
parent 779e7d41ad
commit 0c694de12b
5 changed files with 143 additions and 181 deletions
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4
arch/mips/alchemy/Kconfig
View File

@ -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

16
arch/mips/alchemy/common/power.c
View File

@ -85,7 +85,11 @@ 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)
@ -183,7 +187,6 @@ static void restore_core_regs(void)
}
restore_au1xxx_intctl();
wakeup_counter0_adjust();
}
unsigned long suspend_mode;
@ -411,6 +414,15 @@ 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.
*/
if (au_readl(SYS_TOYTRIM) != 32767) {
au_writel(32767, SYS_TOYTRIM);
au_sync();
}
register_sysctl_table(pm_dir_table);
return 0;
}

6
arch/mips/alchemy/common/setup.c
View File

@ -63,12 +63,6 @@ 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)

286
arch/mips/alchemy/common/time.c
View File

@ -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
*
@ -23,131 +25,27 @@
*
* ########################################################################
*
* 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;
/* 32kHz clock enabled and detected */
#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)
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
@ -215,8 +91,65 @@ 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 = "alchemy-counter1",
.read = au1x_counter1_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.rating = 100,
};
static int au1x_rtcmatch2_set_next_event(unsigned long delta,
struct clock_event_device *cd)
{
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;
}
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_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,
};
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)
{
struct clock_event_device *cd = &au1x_rtcmatch2_clockdev;
unsigned long t;
unsigned int est_freq = calc_clock();
est_freq += 5000; /* round */
@ -225,41 +158,62 @@ 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.
/* 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 (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);
if (CNTR_OK != (au_readl(SYS_COUNTER_CNTRL) & CNTR_OK))
goto cntr_err;
au_writel(au_readl(SYS_WAKEMSK) | (1 << 8), SYS_WAKEMSK);
au_writel(~0, SYS_WAKESRC);
/*
* setup counter 1 (RTC) to tick at full speed
*/
t = 0xffffff;
while ((au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_T1S) && t--)
asm volatile ("nop");
if (!t)
goto cntr_err;
au_writel(0, SYS_RTCTRIM); /* 32.768 kHz */
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);
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();
while (au_readl(SYS_COUNTER_CNTRL) & SYS_CNTRL_M20);
setup_irq(AU1000_TOY_MATCH2_INT, &counter0_action);
/* We can use the real 'wait' instruction. */
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;
#endif
cntr_err:
/* counters unusable, use C0 counter */
r4k_clockevent_init();
init_r4k_clocksource();
allow_au1k_wait = 0;
}

4
arch/mips/kernel/cpu-probe.c
View File

@ -96,6 +96,9 @@ int allow_au1k_wait;
static void au1k_wait(void)
{
if (!allow_au1k_wait)
return;
/* using the wait instruction makes CP0 counter unusable */
__asm__(" .set mips3 \n"
" cache 0x14, 0(%0) \n"
@ -186,7 +189,6 @@ void __init check_wait(void)
case CPU_AU1200:
case CPU_AU1210:
case CPU_AU1250:
if (allow_au1k_wait)
cpu_wait = au1k_wait;
break;
case CPU_20KC: