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Diffstat (limited to 'arch/x86/kernel/mfgpt_32.c')
-rw-r--r--arch/x86/kernel/mfgpt_32.c123
1 files changed, 65 insertions, 58 deletions
diff --git a/arch/x86/kernel/mfgpt_32.c b/arch/x86/kernel/mfgpt_32.c
index 219f86eb612..027fc067b39 100644
--- a/arch/x86/kernel/mfgpt_32.c
+++ b/arch/x86/kernel/mfgpt_32.c
@@ -12,48 +12,37 @@
*/
/*
- * We are using the 32Khz input clock - its the only one that has the
+ * We are using the 32.768kHz input clock - it's the only one that has the
* ranges we find desirable. The following table lists the suitable
- * divisors and the associated hz, minimum interval
- * and the maximum interval:
+ * divisors and the associated Hz, minimum interval and the maximum interval:
*
- * Divisor Hz Min Delta (S) Max Delta (S)
- * 1 32000 .0005 2.048
- * 2 16000 .001 4.096
- * 4 8000 .002 8.192
- * 8 4000 .004 16.384
- * 16 2000 .008 32.768
- * 32 1000 .016 65.536
- * 64 500 .032 131.072
- * 128 250 .064 262.144
- * 256 125 .128 524.288
+ * Divisor Hz Min Delta (s) Max Delta (s)
+ * 1 32768 .00048828125 2.000
+ * 2 16384 .0009765625 4.000
+ * 4 8192 .001953125 8.000
+ * 8 4096 .00390625 16.000
+ * 16 2048 .0078125 32.000
+ * 32 1024 .015625 64.000
+ * 64 512 .03125 128.000
+ * 128 256 .0625 256.000
+ * 256 128 .125 512.000
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
-#include <linux/module.h>
#include <asm/geode.h>
-#define F_AVAIL 0x01
-
static struct mfgpt_timer_t {
- int flags;
- struct module *owner;
+ unsigned int avail:1;
} mfgpt_timers[MFGPT_MAX_TIMERS];
/* Selected from the table above */
#define MFGPT_DIVISOR 16
#define MFGPT_SCALE 4 /* divisor = 2^(scale) */
-#define MFGPT_HZ (32000 / MFGPT_DIVISOR)
+#define MFGPT_HZ (32768 / MFGPT_DIVISOR)
#define MFGPT_PERIODIC (MFGPT_HZ / HZ)
-#ifdef CONFIG_GEODE_MFGPT_TIMER
-static int __init mfgpt_timer_setup(void);
-#else
-#define mfgpt_timer_setup() (0)
-#endif
-
/* Allow for disabling of MFGPTs */
static int disable;
static int __init mfgpt_disable(char *s)
@@ -85,28 +74,37 @@ __setup("mfgptfix", mfgpt_fix);
* In other cases (such as with VSAless OpenFirmware), the system firmware
* leaves timers available for us to use.
*/
-int __init geode_mfgpt_detect(void)
+
+
+static int timers = -1;
+
+static void geode_mfgpt_detect(void)
{
- int count = 0, i;
+ int i;
u16 val;
+ timers = 0;
+
if (disable) {
- printk(KERN_INFO "geode-mfgpt: Skipping MFGPT setup\n");
- return 0;
+ printk(KERN_INFO "geode-mfgpt: MFGPT support is disabled\n");
+ goto done;
+ }
+
+ if (!geode_get_dev_base(GEODE_DEV_MFGPT)) {
+ printk(KERN_INFO "geode-mfgpt: MFGPT LBAR is not set up\n");
+ goto done;
}
for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
val = geode_mfgpt_read(i, MFGPT_REG_SETUP);
if (!(val & MFGPT_SETUP_SETUP)) {
- mfgpt_timers[i].flags = F_AVAIL;
- count++;
+ mfgpt_timers[i].avail = 1;
+ timers++;
}
}
- /* set up clock event device, if desired */
- i = mfgpt_timer_setup();
-
- return count;
+done:
+ printk(KERN_INFO "geode-mfgpt: %d MFGPT timers available.\n", timers);
}
int geode_mfgpt_toggle_event(int timer, int cmp, int event, int enable)
@@ -183,36 +181,41 @@ int geode_mfgpt_set_irq(int timer, int cmp, int irq, int enable)
return 0;
}
-static int mfgpt_get(int timer, struct module *owner)
+static int mfgpt_get(int timer)
{
- mfgpt_timers[timer].flags &= ~F_AVAIL;
- mfgpt_timers[timer].owner = owner;
+ mfgpt_timers[timer].avail = 0;
printk(KERN_INFO "geode-mfgpt: Registered timer %d\n", timer);
return timer;
}
-int geode_mfgpt_alloc_timer(int timer, int domain, struct module *owner)
+int geode_mfgpt_alloc_timer(int timer, int domain)
{
int i;
- if (!geode_get_dev_base(GEODE_DEV_MFGPT))
- return -ENODEV;
+ if (timers == -1) {
+ /* timers haven't been detected yet */
+ geode_mfgpt_detect();
+ }
+
+ if (!timers)
+ return -1;
+
if (timer >= MFGPT_MAX_TIMERS)
- return -EIO;
+ return -1;
if (timer < 0) {
/* Try to find an available timer */
for (i = 0; i < MFGPT_MAX_TIMERS; i++) {
- if (mfgpt_timers[i].flags & F_AVAIL)
- return mfgpt_get(i, owner);
+ if (mfgpt_timers[i].avail)
+ return mfgpt_get(i);
if (i == 5 && domain == MFGPT_DOMAIN_WORKING)
break;
}
} else {
/* If they requested a specific timer, try to honor that */
- if (mfgpt_timers[timer].flags & F_AVAIL)
- return mfgpt_get(timer, owner);
+ if (mfgpt_timers[timer].avail)
+ return mfgpt_get(timer);
}
/* No timers available - too bad */
@@ -244,10 +247,11 @@ static int __init mfgpt_setup(char *str)
}
__setup("mfgpt_irq=", mfgpt_setup);
-static inline void mfgpt_disable_timer(u16 clock)
+static void mfgpt_disable_timer(u16 clock)
{
- u16 val = geode_mfgpt_read(clock, MFGPT_REG_SETUP);
- geode_mfgpt_write(clock, MFGPT_REG_SETUP, val & ~MFGPT_SETUP_CNTEN);
+ /* avoid races by clearing CMP1 and CMP2 unconditionally */
+ geode_mfgpt_write(clock, MFGPT_REG_SETUP, (u16) ~MFGPT_SETUP_CNTEN |
+ MFGPT_SETUP_CMP1 | MFGPT_SETUP_CMP2);
}
static int mfgpt_next_event(unsigned long, struct clock_event_device *);
@@ -263,7 +267,7 @@ static struct clock_event_device mfgpt_clockevent = {
.shift = 32
};
-static inline void mfgpt_start_timer(u16 clock, u16 delta)
+static void mfgpt_start_timer(u16 delta)
{
geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_CMP2, (u16) delta);
geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_COUNTER, 0);
@@ -278,21 +282,25 @@ static void mfgpt_set_mode(enum clock_event_mode mode,
mfgpt_disable_timer(mfgpt_event_clock);
if (mode == CLOCK_EVT_MODE_PERIODIC)
- mfgpt_start_timer(mfgpt_event_clock, MFGPT_PERIODIC);
+ mfgpt_start_timer(MFGPT_PERIODIC);
mfgpt_tick_mode = mode;
}
static int mfgpt_next_event(unsigned long delta, struct clock_event_device *evt)
{
- mfgpt_start_timer(mfgpt_event_clock, delta);
+ mfgpt_start_timer(delta);
return 0;
}
-/* Assume (foolishly?), that this interrupt was due to our tick */
-
static irqreturn_t mfgpt_tick(int irq, void *dev_id)
{
+ u16 val = geode_mfgpt_read(mfgpt_event_clock, MFGPT_REG_SETUP);
+
+ /* See if the interrupt was for us */
+ if (!(val & (MFGPT_SETUP_SETUP | MFGPT_SETUP_CMP2 | MFGPT_SETUP_CMP1)))
+ return IRQ_NONE;
+
/* Turn off the clock (and clear the event) */
mfgpt_disable_timer(mfgpt_event_clock);
@@ -320,13 +328,12 @@ static struct irqaction mfgptirq = {
.name = "mfgpt-timer"
};
-static int __init mfgpt_timer_setup(void)
+int __init mfgpt_timer_setup(void)
{
int timer, ret;
u16 val;
- timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING,
- THIS_MODULE);
+ timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
if (timer < 0) {
printk(KERN_ERR
"mfgpt-timer: Could not allocate a MFPGT timer\n");
@@ -363,7 +370,7 @@ static int __init mfgpt_timer_setup(void)
&mfgpt_clockevent);
printk(KERN_INFO
- "mfgpt-timer: registering the MFGT timer as a clock event.\n");
+ "mfgpt-timer: registering the MFGPT timer as a clock event.\n");
clockevents_register_device(&mfgpt_clockevent);
return 0;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-23 13:50:54 +0000