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Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

Browse Source 
* 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clocksource: apb: Share APB timer code with other platforms
This commit is contained in:
Linus Torvalds 2011-07-23 10:34:47 -07:00
commit 9d0715630e
7 changed files with 533 additions and 360 deletions
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1
arch/x86/Kconfig
View File

@ -623,6 +623,7 @@ config HPET_EMULATE_RTC
config APB_TIMER
def_bool y if MRST
prompt "Langwell APB Timer Support" if X86_MRST
select DW_APB_TIMER
help
APB timer is the replacement for 8254, HPET on X86 MID platforms.
The APBT provides a stable time base on SMP

22
arch/x86/include/asm/apb_timer.h
View File

@ -18,24 +18,6 @@
#ifdef CONFIG_APB_TIMER
/* Langwell DW APB timer registers */
#define APBTMR_N_LOAD_COUNT 0x00
#define APBTMR_N_CURRENT_VALUE 0x04
#define APBTMR_N_CONTROL 0x08
#define APBTMR_N_EOI 0x0c
#define APBTMR_N_INT_STATUS 0x10
#define APBTMRS_INT_STATUS 0xa0
#define APBTMRS_EOI 0xa4
#define APBTMRS_RAW_INT_STATUS 0xa8
#define APBTMRS_COMP_VERSION 0xac
#define APBTMRS_REG_SIZE 0x14
/* register bits */
#define APBTMR_CONTROL_ENABLE (1<<0)
#define APBTMR_CONTROL_MODE_PERIODIC (1<<1) /*1: periodic 0:free running */
#define APBTMR_CONTROL_INT (1<<2)
/* default memory mapped register base */
#define LNW_SCU_ADDR 0xFF100000
#define LNW_EXT_TIMER_OFFSET 0x1B800
@ -43,8 +25,8 @@
#define LNW_EXT_TIMER_PGOFFSET 0x800
/* APBT clock speed range from PCLK to fabric base, 25-100MHz */
#define APBT_MAX_FREQ 50
#define APBT_MIN_FREQ 1
#define APBT_MAX_FREQ 50000000
#define APBT_MIN_FREQ 1000000
#define APBT_MMAP_SIZE 1024
#define APBT_DEV_USED 1

409
arch/x86/kernel/apb_timer.c
View File

@ -27,15 +27,12 @@
* timer, but by default APB timer has higher rating than local APIC timers.
*/
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/dw_apb_timer.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/sysdev.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/pci.h>
#include <linux/sfi.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
@ -46,75 +43,46 @@
#include <asm/mrst.h>
#include <asm/time.h>
#define APBT_MASK CLOCKSOURCE_MASK(32)
#define APBT_SHIFT 22
#define APBT_CLOCKEVENT_RATING 110
#define APBT_CLOCKSOURCE_RATING 250
#define APBT_MIN_DELTA_USEC 200
#define EVT_TO_APBT_DEV(evt) container_of(evt, struct apbt_dev, evt)
#define APBT_CLOCKEVENT0_NUM (0)
#define APBT_CLOCKEVENT1_NUM (1)
#define APBT_CLOCKSOURCE_NUM (2)
static unsigned long apbt_address;
static phys_addr_t apbt_address;
static int apb_timer_block_enabled;
static void __iomem *apbt_virt_address;
static int phy_cs_timer_id;
/*
* Common DW APB timer info
*/
static uint64_t apbt_freq;
static void apbt_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt);
static int apbt_next_event(unsigned long delta,
struct clock_event_device *evt);
static cycle_t apbt_read_clocksource(struct clocksource *cs);
static void apbt_restart_clocksource(struct clocksource *cs);
static unsigned long apbt_freq;
struct apbt_dev {
struct clock_event_device evt;
unsigned int num;
int cpu;
unsigned int irq;
unsigned int tick;
unsigned int count;
unsigned int flags;
char name[10];
struct dw_apb_clock_event_device *timer;
unsigned int num;
int cpu;
unsigned int irq;
char name[10];
};
static struct dw_apb_clocksource *clocksource_apbt;
static inline void __iomem *adev_virt_addr(struct apbt_dev *adev)
{
return apbt_virt_address + adev->num * APBTMRS_REG_SIZE;
}
static DEFINE_PER_CPU(struct apbt_dev, cpu_apbt_dev);
#ifdef CONFIG_SMP
static unsigned int apbt_num_timers_used;
static struct apbt_dev *apbt_devs;
#endif
static inline unsigned long apbt_readl_reg(unsigned long a)
{
return readl(apbt_virt_address + a);
}
static inline void apbt_writel_reg(unsigned long d, unsigned long a)
{
writel(d, apbt_virt_address + a);
}
static inline unsigned long apbt_readl(int n, unsigned long a)
{
return readl(apbt_virt_address + a + n * APBTMRS_REG_SIZE);
}
static inline void apbt_writel(int n, unsigned long d, unsigned long a)
{
writel(d, apbt_virt_address + a + n * APBTMRS_REG_SIZE);
}
static inline void apbt_set_mapping(void)
{
struct sfi_timer_table_entry *mtmr;
int phy_cs_timer_id = 0;
if (apbt_virt_address) {
pr_debug("APBT base already mapped\n");
@ -126,21 +94,18 @@ static inline void apbt_set_mapping(void)
APBT_CLOCKEVENT0_NUM);
return;
}
apbt_address = (unsigned long)mtmr->phys_addr;
apbt_address = (phys_addr_t)mtmr->phys_addr;
if (!apbt_address) {
printk(KERN_WARNING "No timer base from SFI, use default\n");
apbt_address = APBT_DEFAULT_BASE;
}
apbt_virt_address = ioremap_nocache(apbt_address, APBT_MMAP_SIZE);
if (apbt_virt_address) {
pr_debug("Mapped APBT physical addr %p at virtual addr %p\n",\
(void *)apbt_address, (void *)apbt_virt_address);
} else {
pr_debug("Failed mapping APBT phy address at %p\n",\
(void *)apbt_address);
if (!apbt_virt_address) {
pr_debug("Failed mapping APBT phy address at %lu\n",\
(unsigned long)apbt_address);
goto panic_noapbt;
}
apbt_freq = mtmr->freq_hz / USEC_PER_SEC;
apbt_freq = mtmr->freq_hz;
sfi_free_mtmr(mtmr);
/* Now figure out the physical timer id for clocksource device */
@ -149,9 +114,14 @@ static inline void apbt_set_mapping(void)
goto panic_noapbt;
/* Now figure out the physical timer id */
phy_cs_timer_id = (unsigned int)(mtmr->phys_addr & 0xff)
/ APBTMRS_REG_SIZE;
pr_debug("Use timer %d for clocksource\n", phy_cs_timer_id);
pr_debug("Use timer %d for clocksource\n",
(int)(mtmr->phys_addr & 0xff) / APBTMRS_REG_SIZE);
phy_cs_timer_id = (unsigned int)(mtmr->phys_addr & 0xff) /
APBTMRS_REG_SIZE;
clocksource_apbt = dw_apb_clocksource_init(APBT_CLOCKSOURCE_RATING,
"apbt0", apbt_virt_address + phy_cs_timer_id *
APBTMRS_REG_SIZE, apbt_freq);
return;
panic_noapbt:
@ -173,82 +143,6 @@ static inline int is_apbt_capable(void)
return apbt_virt_address ? 1 : 0;
}
static struct clocksource clocksource_apbt = {
.name = "apbt",
.rating = APBT_CLOCKSOURCE_RATING,
.read = apbt_read_clocksource,
.mask = APBT_MASK,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.resume = apbt_restart_clocksource,
};
/* boot APB clock event device */
static struct clock_event_device apbt_clockevent = {
.name = "apbt0",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = apbt_set_mode,
.set_next_event = apbt_next_event,
.shift = APBT_SHIFT,
.irq = 0,
.rating = APBT_CLOCKEVENT_RATING,
};
/*
* start count down from 0xffff_ffff. this is done by toggling the enable bit
* then load initial load count to ~0.
*/
static void apbt_start_counter(int n)
{
unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(n, ctrl, APBTMR_N_CONTROL);
apbt_writel(n, ~0, APBTMR_N_LOAD_COUNT);
/* enable, mask interrupt */
ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT);
apbt_writel(n, ctrl, APBTMR_N_CONTROL);
/* read it once to get cached counter value initialized */
apbt_read_clocksource(&clocksource_apbt);
}
static irqreturn_t apbt_interrupt_handler(int irq, void *data)
{
struct apbt_dev *dev = (struct apbt_dev *)data;
struct clock_event_device *aevt = &dev->evt;
if (!aevt->event_handler) {
printk(KERN_INFO "Spurious APBT timer interrupt on %d\n",
dev->num);
return IRQ_NONE;
}
aevt->event_handler(aevt);
return IRQ_HANDLED;
}
static void apbt_restart_clocksource(struct clocksource *cs)
{
apbt_start_counter(phy_cs_timer_id);
}
static void apbt_enable_int(int n)
{
unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
/* clear pending intr */
apbt_readl(n, APBTMR_N_EOI);
ctrl &= ~APBTMR_CONTROL_INT;
apbt_writel(n, ctrl, APBTMR_N_CONTROL);
}
static void apbt_disable_int(int n)
{
unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
ctrl |= APBTMR_CONTROL_INT;
apbt_writel(n, ctrl, APBTMR_N_CONTROL);
}
static int __init apbt_clockevent_register(void)
{
struct sfi_timer_table_entry *mtmr;
@ -261,45 +155,21 @@ static int __init apbt_clockevent_register(void)
return -ENODEV;
}
/*
* We need to calculate the scaled math multiplication factor for
* nanosecond to apbt tick conversion.
* mult = (nsec/cycle)*2^APBT_SHIFT
*/
apbt_clockevent.mult = div_sc((unsigned long) mtmr->freq_hz
, NSEC_PER_SEC, APBT_SHIFT);
/* Calculate the min / max delta */
apbt_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
&apbt_clockevent);
apbt_clockevent.min_delta_ns = clockevent_delta2ns(
APBT_MIN_DELTA_USEC*apbt_freq,
&apbt_clockevent);
/*
* Start apbt with the boot cpu mask and make it
* global if not used for per cpu timer.
*/
apbt_clockevent.cpumask = cpumask_of(smp_processor_id());
adev->num = smp_processor_id();
memcpy(&adev->evt, &apbt_clockevent, sizeof(struct clock_event_device));
adev->timer = dw_apb_clockevent_init(smp_processor_id(), "apbt0",
mrst_timer_options == MRST_TIMER_LAPIC_APBT ?
APBT_CLOCKEVENT_RATING - 100 : APBT_CLOCKEVENT_RATING,
adev_virt_addr(adev), 0, apbt_freq);
/* Firmware does EOI handling for us. */
adev->timer->eoi = NULL;
if (mrst_timer_options == MRST_TIMER_LAPIC_APBT) {
adev->evt.rating = APBT_CLOCKEVENT_RATING - 100;
global_clock_event = &adev->evt;
global_clock_event = &adev->timer->ced;
printk(KERN_DEBUG "%s clockevent registered as global\n",
global_clock_event->name);
}
if (request_irq(apbt_clockevent.irq, apbt_interrupt_handler,
IRQF_TIMER | IRQF_DISABLED | IRQF_NOBALANCING,
apbt_clockevent.name, adev)) {
printk(KERN_ERR "Failed request IRQ for APBT%d\n",
apbt_clockevent.irq);
}
clockevents_register_device(&adev->evt);
/* Start APBT 0 interrupts */
apbt_enable_int(APBT_CLOCKEVENT0_NUM);
dw_apb_clockevent_register(adev->timer);
sfi_free_mtmr(mtmr);
return 0;
@ -317,52 +187,34 @@ static void apbt_setup_irq(struct apbt_dev *adev)
irq_set_affinity(adev->irq, cpumask_of(adev->cpu));
/* APB timer irqs are set up as mp_irqs, timer is edge type */
__irq_set_handler(adev->irq, handle_edge_irq, 0, "edge");
if (system_state == SYSTEM_BOOTING) {
if (request_irq(adev->irq, apbt_interrupt_handler,
IRQF_TIMER | IRQF_DISABLED |
IRQF_NOBALANCING,
adev->name, adev)) {
printk(KERN_ERR "Failed request IRQ for APBT%d\n",
adev->num);
}
} else
enable_irq(adev->irq);
}
/* Should be called with per cpu */
void apbt_setup_secondary_clock(void)
{
struct apbt_dev *adev;
struct clock_event_device *aevt;
int cpu;
/* Don't register boot CPU clockevent */
cpu = smp_processor_id();
if (!cpu)
return;
/*
* We need to calculate the scaled math multiplication factor for
* nanosecond to apbt tick conversion.
* mult = (nsec/cycle)*2^APBT_SHIFT
*/
printk(KERN_INFO "Init per CPU clockevent %d\n", cpu);
adev = &per_cpu(cpu_apbt_dev, cpu);
aevt = &adev->evt;
memcpy(aevt, &apbt_clockevent, sizeof(*aevt));
aevt->cpumask = cpumask_of(cpu);
aevt->name = adev->name;
aevt->mode = CLOCK_EVT_MODE_UNUSED;
adev = &__get_cpu_var(cpu_apbt_dev);
if (!adev->timer) {
adev->timer = dw_apb_clockevent_init(cpu, adev->name,
APBT_CLOCKEVENT_RATING, adev_virt_addr(adev),
adev->irq, apbt_freq);
adev->timer->eoi = NULL;
} else {
dw_apb_clockevent_resume(adev->timer);
}
printk(KERN_INFO "Registering CPU %d clockevent device %s, mask %08x\n",
cpu, aevt->name, *(u32 *)aevt->cpumask);
printk(KERN_INFO "Registering CPU %d clockevent device %s, cpu %08x\n",
cpu, adev->name, adev->cpu);
apbt_setup_irq(adev);
clockevents_register_device(aevt);
apbt_enable_int(cpu);
dw_apb_clockevent_register(adev->timer);
return;
}
@ -385,13 +237,12 @@ static int apbt_cpuhp_notify(struct notifier_block *n,
switch (action & 0xf) {
case CPU_DEAD:
disable_irq(adev->irq);
apbt_disable_int(cpu);
dw_apb_clockevent_pause(adev->timer);
if (system_state == SYSTEM_RUNNING) {
pr_debug("skipping APBT CPU %lu offline\n", cpu);
} else if (adev) {
pr_debug("APBT clockevent for cpu %lu offline\n", cpu);
free_irq(adev->irq, adev);
dw_apb_clockevent_stop(adev->timer);
}
break;
default:
@ -416,116 +267,16 @@ void apbt_setup_secondary_clock(void) {}
#endif /* CONFIG_SMP */
static void apbt_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned long ctrl;
uint64_t delta;
int timer_num;
struct apbt_dev *adev = EVT_TO_APBT_DEV(evt);
BUG_ON(!apbt_virt_address);
timer_num = adev->num;
pr_debug("%s CPU %d timer %d mode=%d\n",
__func__, first_cpu(*evt->cpumask), timer_num, mode);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * apbt_clockevent.mult;
delta >>= apbt_clockevent.shift;
ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
ctrl |= APBTMR_CONTROL_MODE_PERIODIC;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
/*
* DW APB p. 46, have to disable timer before load counter,
* may cause sync problem.
*/
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
udelay(1);
pr_debug("Setting clock period %d for HZ %d\n", (int)delta, HZ);
apbt_writel(timer_num, delta, APBTMR_N_LOAD_COUNT);
ctrl |= APBTMR_CONTROL_ENABLE;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
break;
/* APB timer does not have one-shot mode, use free running mode */
case CLOCK_EVT_MODE_ONESHOT:
ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
/*
* set free running mode, this mode will let timer reload max
* timeout which will give time (3min on 25MHz clock) to rearm
* the next event, therefore emulate the one-shot mode.
*/
ctrl &= ~APBTMR_CONTROL_ENABLE;
ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
/* write again to set free running mode */
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
/*
* DW APB p. 46, load counter with all 1s before starting free
* running mode.
*/
apbt_writel(timer_num, ~0, APBTMR_N_LOAD_COUNT);
ctrl &= ~APBTMR_CONTROL_INT;
ctrl |= APBTMR_CONTROL_ENABLE;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
apbt_disable_int(timer_num);
ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
break;
case CLOCK_EVT_MODE_RESUME:
apbt_enable_int(timer_num);
break;
}
}
static int apbt_next_event(unsigned long delta,
struct clock_event_device *evt)
{
unsigned long ctrl;
int timer_num;
struct apbt_dev *adev = EVT_TO_APBT_DEV(evt);
timer_num = adev->num;
/* Disable timer */
ctrl = apbt_readl(timer_num, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
/* write new count */
apbt_writel(timer_num, delta, APBTMR_N_LOAD_COUNT);
ctrl |= APBTMR_CONTROL_ENABLE;
apbt_writel(timer_num, ctrl, APBTMR_N_CONTROL);
return 0;
}
static cycle_t apbt_read_clocksource(struct clocksource *cs)
{
unsigned long current_count;
current_count = apbt_readl(phy_cs_timer_id, APBTMR_N_CURRENT_VALUE);
return (cycle_t)~current_count;
}
static int apbt_clocksource_register(void)
{
u64 start, now;
cycle_t t1;
/* Start the counter, use timer 2 as source, timer 0/1 for event */
apbt_start_counter(phy_cs_timer_id);
dw_apb_clocksource_start(clocksource_apbt);
/* Verify whether apbt counter works */
t1 = apbt_read_clocksource(&clocksource_apbt);
t1 = dw_apb_clocksource_read(clocksource_apbt);
rdtscll(start);
/*
@ -540,10 +291,10 @@ static int apbt_clocksource_register(void)
} while ((now - start) < 200000UL);
/* APBT is the only always on clocksource, it has to work! */
if (t1 == apbt_read_clocksource(&clocksource_apbt))
if (t1 == dw_apb_clocksource_read(clocksource_apbt))
panic("APBT counter not counting. APBT disabled\n");
clocksource_register_khz(&clocksource_apbt, (u32)apbt_freq*1000);
dw_apb_clocksource_register(clocksource_apbt);
return 0;
}
@ -567,10 +318,7 @@ void __init apbt_time_init(void)
if (apb_timer_block_enabled)
return;
apbt_set_mapping();
if (apbt_virt_address) {
pr_debug("Found APBT version 0x%lx\n",\
apbt_readl_reg(APBTMRS_COMP_VERSION));
} else
if (!apbt_virt_address)
goto out_noapbt;
/*
* Read the frequency and check for a sane value, for ESL model
@ -578,7 +326,7 @@ void __init apbt_time_init(void)
*/
if (apbt_freq < APBT_MIN_FREQ || apbt_freq > APBT_MAX_FREQ) {
pr_debug("APBT has invalid freq 0x%llx\n", apbt_freq);
pr_debug("APBT has invalid freq 0x%lx\n", apbt_freq);
goto out_noapbt;
}
if (apbt_clocksource_register()) {
@ -604,30 +352,20 @@ void __init apbt_time_init(void)
} else {
percpu_timer = 0;
apbt_num_timers_used = 1;
adev = &per_cpu(cpu_apbt_dev, 0);
adev->flags &= ~APBT_DEV_USED;
}
pr_debug("%s: %d APB timers used\n", __func__, apbt_num_timers_used);
/* here we set up per CPU timer data structure */
apbt_devs = kzalloc(sizeof(struct apbt_dev) * apbt_num_timers_used,
GFP_KERNEL);
if (!apbt_devs) {
printk(KERN_ERR "Failed to allocate APB timer devices\n");
return;
}
for (i = 0; i < apbt_num_timers_used; i++) {
adev = &per_cpu(cpu_apbt_dev, i);
adev->num = i;
adev->cpu = i;
p_mtmr = sfi_get_mtmr(i);
if (p_mtmr) {
adev->tick = p_mtmr->freq_hz;
if (p_mtmr)
adev->irq = p_mtmr->irq;
} else
else
printk(KERN_ERR "Failed to get timer for cpu %d\n", i);
adev->count = 0;
sprintf(adev->name, "apbt%d", i);
snprintf(adev->name, sizeof(adev->name) - 1, "apbt%d", i);
}
#endif
@ -639,17 +377,8 @@ out_noapbt:
panic("failed to enable APB timer\n");
}
static inline void apbt_disable(int n)
{
if (is_apbt_capable()) {
unsigned long ctrl = apbt_readl(n, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(n, ctrl, APBTMR_N_CONTROL);
}
}
/* called before apb_timer_enable, use early map */
unsigned long apbt_quick_calibrate()
unsigned long apbt_quick_calibrate(void)
{
int i, scale;
u64 old, new;
@ -658,31 +387,31 @@ unsigned long apbt_quick_calibrate()
u32 loop, shift;
apbt_set_mapping();
apbt_start_counter(phy_cs_timer_id);
dw_apb_clocksource_start(clocksource_apbt);
/* check if the timer can count down, otherwise return */
old = apbt_read_clocksource(&clocksource_apbt);
old = dw_apb_clocksource_read(clocksource_apbt);
i = 10000;
while (--i) {
if (old != apbt_read_clocksource(&clocksource_apbt))
if (old != dw_apb_clocksource_read(clocksource_apbt))
break;
}
if (!i)
goto failed;
/* count 16 ms */
loop = (apbt_freq * 1000) << 4;
loop = (apbt_freq / 1000) << 4;
/* restart the timer to ensure it won't get to 0 in the calibration */
apbt_start_counter(phy_cs_timer_id);
dw_apb_clocksource_start(clocksource_apbt);
old = apbt_read_clocksource(&clocksource_apbt);
old = dw_apb_clocksource_read(clocksource_apbt);
old += loop;
t1 = __native_read_tsc();
do {
new = apbt_read_clocksource(&clocksource_apbt);
new = dw_apb_clocksource_read(clocksource_apbt);
} while (new < old);
t2 = __native_read_tsc();
@ -694,7 +423,7 @@ unsigned long apbt_quick_calibrate()
return 0;
}
scale = (int)div_u64((t2 - t1), loop >> shift);
khz = (scale * apbt_freq * 1000) >> shift;
khz = (scale * (apbt_freq / 1000)) >> shift;
printk(KERN_INFO "TSC freq calculated by APB timer is %lu khz\n", khz);
return khz;
failed:

3
drivers/clocksource/Kconfig
View File

@ -12,3 +12,6 @@ config CLKBLD_I8253
config CLKSRC_MMIO
bool
config DW_APB_TIMER
bool

1
drivers/clocksource/Makefile
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@ -8,3 +8,4 @@ obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o
obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o
obj-$(CONFIG_CLKBLD_I8253) += i8253.o
obj-$(CONFIG_CLKSRC_MMIO) += mmio.o
obj-$(CONFIG_DW_APB_TIMER) += dw_apb_timer.o

401
drivers/clocksource/dw_apb_timer.c Normal file
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@ -0,0 +1,401 @@
/*
* (C) Copyright 2009 Intel Corporation
* Author: Jacob Pan (jacob.jun.pan@intel.com)
*
* Shared with ARM platforms, Jamie Iles, Picochip 2011
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Support for the Synopsys DesignWare APB Timers.
*/
#include <linux/dw_apb_timer.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/slab.h>
#define APBT_MIN_PERIOD 4
#define APBT_MIN_DELTA_USEC 200
#define APBTMR_N_LOAD_COUNT 0x00
#define APBTMR_N_CURRENT_VALUE 0x04
#define APBTMR_N_CONTROL 0x08
#define APBTMR_N_EOI 0x0c
#define APBTMR_N_INT_STATUS 0x10
#define APBTMRS_INT_STATUS 0xa0
#define APBTMRS_EOI 0xa4
#define APBTMRS_RAW_INT_STATUS 0xa8
#define APBTMRS_COMP_VERSION 0xac
#define APBTMR_CONTROL_ENABLE (1 << 0)
/* 1: periodic, 0:free running. */
#define APBTMR_CONTROL_MODE_PERIODIC (1 << 1)
#define APBTMR_CONTROL_INT (1 << 2)
static inline struct dw_apb_clock_event_device *
ced_to_dw_apb_ced(struct clock_event_device *evt)
{
return container_of(evt, struct dw_apb_clock_event_device, ced);
}
static inline struct dw_apb_clocksource *
clocksource_to_dw_apb_clocksource(struct clocksource *cs)
{
return container_of(cs, struct dw_apb_clocksource, cs);
}
static unsigned long apbt_readl(struct dw_apb_timer *timer, unsigned long offs)
{
return readl(timer->base + offs);
}
static void apbt_writel(struct dw_apb_timer *timer, unsigned long val,
unsigned long offs)
{
writel(val, timer->base + offs);
}
static void apbt_disable_int(struct dw_apb_timer *timer)
{
unsigned long ctrl = apbt_readl(timer, APBTMR_N_CONTROL);
ctrl |= APBTMR_CONTROL_INT;
apbt_writel(timer, ctrl, APBTMR_N_CONTROL);
}
/**
* dw_apb_clockevent_pause() - stop the clock_event_device from running
*
* @dw_ced: The APB clock to stop generating events.
*/
void dw_apb_clockevent_pause(struct dw_apb_clock_event_device *dw_ced)
{
disable_irq(dw_ced->timer.irq);
apbt_disable_int(&dw_ced->timer);
}
static void apbt_eoi(struct dw_apb_timer *timer)
{
apbt_readl(timer, APBTMR_N_EOI);
}
static irqreturn_t dw_apb_clockevent_irq(int irq, void *data)
{
struct clock_event_device *evt = data;
struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt);
if (!evt->event_handler) {
pr_info("Spurious APBT timer interrupt %d", irq);
return IRQ_NONE;
}
if (dw_ced->eoi)
dw_ced->eoi(&dw_ced->timer);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static void apbt_enable_int(struct dw_apb_timer *timer)
{
unsigned long ctrl = apbt_readl(timer, APBTMR_N_CONTROL);
/* clear pending intr */
apbt_readl(timer, APBTMR_N_EOI);
ctrl &= ~APBTMR_CONTROL_INT;
apbt_writel(timer, ctrl, APBTMR_N_CONTROL);
}
static void apbt_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned long ctrl;
unsigned long period;
struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt);
pr_debug("%s CPU %d mode=%d\n", __func__, first_cpu(*evt->cpumask),
mode);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
period = DIV_ROUND_UP(dw_ced->timer.freq, HZ);
ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
ctrl |= APBTMR_CONTROL_MODE_PERIODIC;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
/*
* DW APB p. 46, have to disable timer before load counter,
* may cause sync problem.
*/
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
udelay(1);
pr_debug("Setting clock period %lu for HZ %d\n", period, HZ);
apbt_writel(&dw_ced->timer, period, APBTMR_N_LOAD_COUNT);
ctrl |= APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
break;
case CLOCK_EVT_MODE_ONESHOT:
ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
/*
* set free running mode, this mode will let timer reload max
* timeout which will give time (3min on 25MHz clock) to rearm
* the next event, therefore emulate the one-shot mode.
*/
ctrl &= ~APBTMR_CONTROL_ENABLE;
ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
/* write again to set free running mode */
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
/*
* DW APB p. 46, load counter with all 1s before starting free
* running mode.
*/
apbt_writel(&dw_ced->timer, ~0, APBTMR_N_LOAD_COUNT);
ctrl &= ~APBTMR_CONTROL_INT;
ctrl |= APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
break;
case CLOCK_EVT_MODE_RESUME:
apbt_enable_int(&dw_ced->timer);
break;
}
}
static int apbt_next_event(unsigned long delta,
struct clock_event_device *evt)
{
unsigned long ctrl;
struct dw_apb_clock_event_device *dw_ced = ced_to_dw_apb_ced(evt);
/* Disable timer */
ctrl = apbt_readl(&dw_ced->timer, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
/* write new count */
apbt_writel(&dw_ced->timer, delta, APBTMR_N_LOAD_COUNT);
ctrl |= APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_ced->timer, ctrl, APBTMR_N_CONTROL);
return 0;
}
/**
* dw_apb_clockevent_init() - use an APB timer as a clock_event_device
*
* @cpu: The CPU the events will be targeted at.
* @name: The name used for the timer and the IRQ for it.
* @rating: The rating to give the timer.
* @base: I/O base for the timer registers.
* @irq: The interrupt number to use for the timer.
* @freq: The frequency that the timer counts at.
*
* This creates a clock_event_device for using with the generic clock layer
* but does not start and register it. This should be done with
* dw_apb_clockevent_register() as the next step. If this is the first time
* it has been called for a timer then the IRQ will be requested, if not it
* just be enabled to allow CPU hotplug to avoid repeatedly requesting and
* releasing the IRQ.
*/
struct dw_apb_clock_event_device *
dw_apb_clockevent_init(int cpu, const char *name, unsigned rating,
void __iomem *base, int irq, unsigned long freq)
{
struct dw_apb_clock_event_device *dw_ced =
kzalloc(sizeof(*dw_ced), GFP_KERNEL);
int err;
if (!dw_ced)
return NULL;
dw_ced->timer.base = base;
dw_ced->timer.irq = irq;
dw_ced->timer.freq = freq;
clockevents_calc_mult_shift(&dw_ced->ced, freq, APBT_MIN_PERIOD);
dw_ced->ced.max_delta_ns = clockevent_delta2ns(0x7fffffff,
&dw_ced->ced);
dw_ced->ced.min_delta_ns = clockevent_delta2ns(5000, &dw_ced->ced);
dw_ced->ced.cpumask = cpumask_of(cpu);
dw_ced->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
dw_ced->ced.set_mode = apbt_set_mode;
dw_ced->ced.set_next_event = apbt_next_event;
dw_ced->ced.irq = dw_ced->timer.irq;
dw_ced->ced.rating = rating;
dw_ced->ced.name = name;
dw_ced->irqaction.name = dw_ced->ced.name;
dw_ced->irqaction.handler = dw_apb_clockevent_irq;
dw_ced->irqaction.dev_id = &dw_ced->ced;
dw_ced->irqaction.irq = irq;
dw_ced->irqaction.flags = IRQF_TIMER | IRQF_IRQPOLL |
IRQF_NOBALANCING |
IRQF_DISABLED;
dw_ced->eoi = apbt_eoi;
err = setup_irq(irq, &dw_ced->irqaction);
if (err) {
pr_err("failed to request timer irq\n");
kfree(dw_ced);
dw_ced = NULL;
}
return dw_ced;
}
/**
* dw_apb_clockevent_resume() - resume a clock that has been paused.
*
* @dw_ced: The APB clock to resume.
*/
void dw_apb_clockevent_resume(struct dw_apb_clock_event_device *dw_ced)
{
enable_irq(dw_ced->timer.irq);
}
/**
* dw_apb_clockevent_stop() - stop the clock_event_device and release the IRQ.
*
* @dw_ced: The APB clock to stop generating the events.
*/
void dw_apb_clockevent_stop(struct dw_apb_clock_event_device *dw_ced)
{
free_irq(dw_ced->timer.irq, &dw_ced->ced);
}
/**
* dw_apb_clockevent_register() - register the clock with the generic layer
*
* @dw_ced: The APB clock to register as a clock_event_device.
*/
void dw_apb_clockevent_register(struct dw_apb_clock_event_device *dw_ced)
{
apbt_writel(&dw_ced->timer, 0, APBTMR_N_CONTROL);
clockevents_register_device(&dw_ced->ced);
apbt_enable_int(&dw_ced->timer);
}
/**
* dw_apb_clocksource_start() - start the clocksource counting.
*
* @dw_cs: The clocksource to start.
*
* This is used to start the clocksource before registration and can be used
* to enable calibration of timers.
*/
void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs)
{
/*
* start count down from 0xffff_ffff. this is done by toggling the
* enable bit then load initial load count to ~0.
*/
unsigned long ctrl = apbt_readl(&dw_cs->timer, APBTMR_N_CONTROL);
ctrl &= ~APBTMR_CONTROL_ENABLE;
apbt_writel(&dw_cs->timer, ctrl, APBTMR_N_CONTROL);
apbt_writel(&dw_cs->timer, ~0, APBTMR_N_LOAD_COUNT);
/* enable, mask interrupt */
ctrl &= ~APBTMR_CONTROL_MODE_PERIODIC;
ctrl |= (APBTMR_CONTROL_ENABLE | APBTMR_CONTROL_INT);
apbt_writel(&dw_cs->timer, ctrl, APBTMR_N_CONTROL);
/* read it once to get cached counter value initialized */
dw_apb_clocksource_read(dw_cs);
}
static cycle_t __apbt_read_clocksource(struct clocksource *cs)
{
unsigned long current_count;
struct dw_apb_clocksource *dw_cs =
clocksource_to_dw_apb_clocksource(cs);
current_count = apbt_readl(&dw_cs->timer, APBTMR_N_CURRENT_VALUE);
return (cycle_t)~current_count;
}
static void apbt_restart_clocksource(struct clocksource *cs)
{
struct dw_apb_clocksource *dw_cs =
clocksource_to_dw_apb_clocksource(cs);
dw_apb_clocksource_start(dw_cs);
}
/**
* dw_apb_clocksource_init() - use an APB timer as a clocksource.
*
* @rating: The rating to give the clocksource.
* @name: The name for the clocksource.
* @base: The I/O base for the timer registers.
* @freq: The frequency that the timer counts at.
*
* This creates a clocksource using an APB timer but does not yet register it
* with the clocksource system. This should be done with
* dw_apb_clocksource_register() as the next step.
*/
struct dw_apb_clocksource *
dw_apb_clocksource_init(unsigned rating, char *name, void __iomem *base,
unsigned long freq)
{
struct dw_apb_clocksource *dw_cs = kzalloc(sizeof(*dw_cs), GFP_KERNEL);
if (!dw_cs)
return NULL;
dw_cs->timer.base = base;
dw_cs->timer.freq = freq;
dw_cs->cs.name = name;
dw_cs->cs.rating = rating;
dw_cs->cs.read = __apbt_read_clocksource;
dw_cs->cs.mask = CLOCKSOURCE_MASK(32);
dw_cs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
dw_cs->cs.resume = apbt_restart_clocksource;
return dw_cs;
}
/**
* dw_apb_clocksource_register() - register the APB clocksource.
*
* @dw_cs: The clocksource to register.
*/
void dw_apb_clocksource_register(struct dw_apb_clocksource *dw_cs)
{
clocksource_register_hz(&dw_cs->cs, dw_cs->timer.freq);
}
/**
* dw_apb_clocksource_read() - read the current value of a clocksource.
*
* @dw_cs: The clocksource to read.
*/
cycle_t dw_apb_clocksource_read(struct dw_apb_clocksource *dw_cs)
{
return (cycle_t)~apbt_readl(&dw_cs->timer, APBTMR_N_CURRENT_VALUE);
}
/**
* dw_apb_clocksource_unregister() - unregister and free a clocksource.
*
* @dw_cs: The clocksource to unregister/free.
*/
void dw_apb_clocksource_unregister(struct dw_apb_clocksource *dw_cs)
{
clocksource_unregister(&dw_cs->cs);
kfree(dw_cs);
}

56
include/linux/dw_apb_timer.h Normal file
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@ -0,0 +1,56 @@
/*
* (C) Copyright 2009 Intel Corporation
* Author: Jacob Pan (jacob.jun.pan@intel.com)
*
* Shared with ARM platforms, Jamie Iles, Picochip 2011
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Support for the Synopsys DesignWare APB Timers.
*/
#ifndef __DW_APB_TIMER_H__
#define __DW_APB_TIMER_H__
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#define APBTMRS_REG_SIZE 0x14
struct dw_apb_timer {
void __iomem *base;
unsigned long freq;
int irq;
};
struct dw_apb_clock_event_device {
struct clock_event_device ced;
struct dw_apb_timer timer;
struct irqaction irqaction;
void (*eoi)(struct dw_apb_timer *);
};
struct dw_apb_clocksource {
struct dw_apb_timer timer;
struct clocksource cs;
};
void dw_apb_clockevent_register(struct dw_apb_clock_event_device *dw_ced);
void dw_apb_clockevent_pause(struct dw_apb_clock_event_device *dw_ced);
void dw_apb_clockevent_resume(struct dw_apb_clock_event_device *dw_ced);
void dw_apb_clockevent_stop(struct dw_apb_clock_event_device *dw_ced);
struct dw_apb_clock_event_device *
dw_apb_clockevent_init(int cpu, const char *name, unsigned rating,
void __iomem *base, int irq, unsigned long freq);
struct dw_apb_clocksource *
dw_apb_clocksource_init(unsigned rating, char *name, void __iomem *base,
unsigned long freq);
void dw_apb_clocksource_register(struct dw_apb_clocksource *dw_cs);
void dw_apb_clocksource_start(struct dw_apb_clocksource *dw_cs);
cycle_t dw_apb_clocksource_read(struct dw_apb_clocksource *dw_cs);
void dw_apb_clocksource_unregister(struct dw_apb_clocksource *dw_cs);
#endif /* __DW_APB_TIMER_H__ */