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kernel-ark/drivers/rtc/rtc-s3c.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

622 lines
14 KiB
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/* drivers/rtc/rtc-s3c.c
*
* Copyright (c) 2004,2006 Simtec Electronics
* Ben Dooks, <ben@simtec.co.uk>
* http://armlinux.simtec.co.uk/
*
* 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.
*
* S3C2410/S3C2440/S3C24XX Internal RTC Driver
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/clk.h>
#include <asm/hardware.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/rtc.h>
#include <asm/mach/time.h>
#include <asm/arch/regs-rtc.h>
/* I have yet to find an S3C implementation with more than one
* of these rtc blocks in */
static struct resource *s3c_rtc_mem;
static void __iomem *s3c_rtc_base;
static int s3c_rtc_alarmno = NO_IRQ;
static int s3c_rtc_tickno = NO_IRQ;
static int s3c_rtc_freq = 1;
static DEFINE_SPINLOCK(s3c_rtc_pie_lock);
static unsigned int tick_count;
/* IRQ Handlers */
static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
{
struct rtc_device *rdev = id;
rtc_update_irq(&rdev->class_dev, 1, RTC_AF | RTC_IRQF);
return IRQ_HANDLED;
}
static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
{
struct rtc_device *rdev = id;
rtc_update_irq(&rdev->class_dev, tick_count++, RTC_PF | RTC_IRQF);
return IRQ_HANDLED;
}
/* Update control registers */
static void s3c_rtc_setaie(int to)
{
unsigned int tmp;
pr_debug("%s: aie=%d\n", __FUNCTION__, to);
tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
if (to)
tmp |= S3C2410_RTCALM_ALMEN;
writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);
}
static void s3c_rtc_setpie(int to)
{
unsigned int tmp;
pr_debug("%s: pie=%d\n", __FUNCTION__, to);
spin_lock_irq(&s3c_rtc_pie_lock);
tmp = readb(s3c_rtc_base + S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;
if (to)
tmp |= S3C2410_TICNT_ENABLE;
writeb(tmp, s3c_rtc_base + S3C2410_TICNT);
spin_unlock_irq(&s3c_rtc_pie_lock);
}
static void s3c_rtc_setfreq(int freq)
{
unsigned int tmp;
spin_lock_irq(&s3c_rtc_pie_lock);
tmp = readb(s3c_rtc_base + S3C2410_TICNT) & S3C2410_TICNT_ENABLE;
s3c_rtc_freq = freq;
tmp |= (128 / freq)-1;
writeb(tmp, s3c_rtc_base + S3C2410_TICNT);
spin_unlock_irq(&s3c_rtc_pie_lock);
}
/* Time read/write */
static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
unsigned int have_retried = 0;
void __iomem *base = s3c_rtc_base;
retry_get_time:
rtc_tm->tm_min = readb(base + S3C2410_RTCMIN);
rtc_tm->tm_hour = readb(base + S3C2410_RTCHOUR);
rtc_tm->tm_mday = readb(base + S3C2410_RTCDATE);
rtc_tm->tm_mon = readb(base + S3C2410_RTCMON);
rtc_tm->tm_year = readb(base + S3C2410_RTCYEAR);
rtc_tm->tm_sec = readb(base + S3C2410_RTCSEC);
/* the only way to work out wether the system was mid-update
* when we read it is to check the second counter, and if it
* is zero, then we re-try the entire read
*/
if (rtc_tm->tm_sec == 0 && !have_retried) {
have_retried = 1;
goto retry_get_time;
}
pr_debug("read time %02x.%02x.%02x %02x/%02x/%02x\n",
rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);
BCD_TO_BIN(rtc_tm->tm_sec);
BCD_TO_BIN(rtc_tm->tm_min);
BCD_TO_BIN(rtc_tm->tm_hour);
BCD_TO_BIN(rtc_tm->tm_mday);
BCD_TO_BIN(rtc_tm->tm_mon);
BCD_TO_BIN(rtc_tm->tm_year);
rtc_tm->tm_year += 100;
rtc_tm->tm_mon -= 1;
return 0;
}
static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
{
void __iomem *base = s3c_rtc_base;
int year = tm->tm_year - 100;
pr_debug("set time %02d.%02d.%02d %02d/%02d/%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
/* we get around y2k by simply not supporting it */
if (year < 0 || year >= 100) {
dev_err(dev, "rtc only supports 100 years\n");
return -EINVAL;
}
writeb(BIN2BCD(tm->tm_sec), base + S3C2410_RTCSEC);
writeb(BIN2BCD(tm->tm_min), base + S3C2410_RTCMIN);
writeb(BIN2BCD(tm->tm_hour), base + S3C2410_RTCHOUR);
writeb(BIN2BCD(tm->tm_mday), base + S3C2410_RTCDATE);
writeb(BIN2BCD(tm->tm_mon + 1), base + S3C2410_RTCMON);
writeb(BIN2BCD(year), base + S3C2410_RTCYEAR);
return 0;
}
static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct rtc_time *alm_tm = &alrm->time;
void __iomem *base = s3c_rtc_base;
unsigned int alm_en;
alm_tm->tm_sec = readb(base + S3C2410_ALMSEC);
alm_tm->tm_min = readb(base + S3C2410_ALMMIN);
alm_tm->tm_hour = readb(base + S3C2410_ALMHOUR);
alm_tm->tm_mon = readb(base + S3C2410_ALMMON);
alm_tm->tm_mday = readb(base + S3C2410_ALMDATE);
alm_tm->tm_year = readb(base + S3C2410_ALMYEAR);
alm_en = readb(base + S3C2410_RTCALM);
pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n",
alm_en,
alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);
/* decode the alarm enable field */
if (alm_en & S3C2410_RTCALM_SECEN)
BCD_TO_BIN(alm_tm->tm_sec);
else
alm_tm->tm_sec = 0xff;
if (alm_en & S3C2410_RTCALM_MINEN)
BCD_TO_BIN(alm_tm->tm_min);
else
alm_tm->tm_min = 0xff;
if (alm_en & S3C2410_RTCALM_HOUREN)
BCD_TO_BIN(alm_tm->tm_hour);
else
alm_tm->tm_hour = 0xff;
if (alm_en & S3C2410_RTCALM_DAYEN)
BCD_TO_BIN(alm_tm->tm_mday);
else
alm_tm->tm_mday = 0xff;
if (alm_en & S3C2410_RTCALM_MONEN) {
BCD_TO_BIN(alm_tm->tm_mon);
alm_tm->tm_mon -= 1;
} else {
alm_tm->tm_mon = 0xff;
}
if (alm_en & S3C2410_RTCALM_YEAREN)
BCD_TO_BIN(alm_tm->tm_year);
else
alm_tm->tm_year = 0xffff;
return 0;
}
static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct rtc_time *tm = &alrm->time;
void __iomem *base = s3c_rtc_base;
unsigned int alrm_en;
pr_debug("s3c_rtc_setalarm: %d, %02x/%02x/%02x %02x.%02x.%02x\n",
alrm->enabled,
tm->tm_mday & 0xff, tm->tm_mon & 0xff, tm->tm_year & 0xff,
tm->tm_hour & 0xff, tm->tm_min & 0xff, tm->tm_sec);
alrm_en = readb(base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
writeb(0x00, base + S3C2410_RTCALM);
if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
alrm_en |= S3C2410_RTCALM_SECEN;
writeb(BIN2BCD(tm->tm_sec), base + S3C2410_ALMSEC);
}
if (tm->tm_min < 60 && tm->tm_min >= 0) {
alrm_en |= S3C2410_RTCALM_MINEN;
writeb(BIN2BCD(tm->tm_min), base + S3C2410_ALMMIN);
}
if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
alrm_en |= S3C2410_RTCALM_HOUREN;
writeb(BIN2BCD(tm->tm_hour), base + S3C2410_ALMHOUR);
}
pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);
writeb(alrm_en, base + S3C2410_RTCALM);
if (0) {
alrm_en = readb(base + S3C2410_RTCALM);
alrm_en &= ~S3C2410_RTCALM_ALMEN;
writeb(alrm_en, base + S3C2410_RTCALM);
disable_irq_wake(s3c_rtc_alarmno);
}
if (alrm->enabled)
enable_irq_wake(s3c_rtc_alarmno);
else
disable_irq_wake(s3c_rtc_alarmno);
return 0;
}
static int s3c_rtc_ioctl(struct device *dev,
unsigned int cmd, unsigned long arg)
{
unsigned int ret = -ENOIOCTLCMD;
switch (cmd) {
case RTC_AIE_OFF:
case RTC_AIE_ON:
s3c_rtc_setaie((cmd == RTC_AIE_ON) ? 1 : 0);
ret = 0;
break;
case RTC_PIE_OFF:
case RTC_PIE_ON:
tick_count = 0;
s3c_rtc_setpie((cmd == RTC_PIE_ON) ? 1 : 0);
ret = 0;
break;
case RTC_IRQP_READ:
ret = put_user(s3c_rtc_freq, (unsigned long __user *)arg);
break;
case RTC_IRQP_SET:
/* check for power of 2 */
if ((arg & (arg-1)) != 0 || arg < 1) {
ret = -EINVAL;
goto exit;
}
pr_debug("s3c2410_rtc: setting frequency %ld\n", arg);
s3c_rtc_setfreq(arg);
ret = 0;
break;
case RTC_UIE_ON:
case RTC_UIE_OFF:
ret = -EINVAL;
}
exit:
return ret;
}
static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned int rtcalm = readb(s3c_rtc_base + S3C2410_RTCALM);
unsigned int ticnt = readb(s3c_rtc_base + S3C2410_TICNT);
seq_printf(seq, "alarm_IRQ\t: %s\n",
(rtcalm & S3C2410_RTCALM_ALMEN) ? "yes" : "no" );
seq_printf(seq, "periodic_IRQ\t: %s\n",
(ticnt & S3C2410_TICNT_ENABLE) ? "yes" : "no" );
seq_printf(seq, "periodic_freq\t: %d\n", s3c_rtc_freq);
return 0;
}
static int s3c_rtc_open(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
int ret;
ret = request_irq(s3c_rtc_alarmno, s3c_rtc_alarmirq,
SA_INTERRUPT, "s3c2410-rtc alarm", rtc_dev);
if (ret) {
dev_err(dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);
return ret;
}
ret = request_irq(s3c_rtc_tickno, s3c_rtc_tickirq,
SA_INTERRUPT, "s3c2410-rtc tick", rtc_dev);
if (ret) {
dev_err(dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);
goto tick_err;
}
return ret;
tick_err:
free_irq(s3c_rtc_alarmno, rtc_dev);
return ret;
}
static void s3c_rtc_release(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
/* do not clear AIE here, it may be needed for wake */
s3c_rtc_setpie(0);
free_irq(s3c_rtc_alarmno, rtc_dev);
free_irq(s3c_rtc_tickno, rtc_dev);
}
static const struct rtc_class_ops s3c_rtcops = {
.open = s3c_rtc_open,
.release = s3c_rtc_release,
.ioctl = s3c_rtc_ioctl,
.read_time = s3c_rtc_gettime,
.set_time = s3c_rtc_settime,
.read_alarm = s3c_rtc_getalarm,
.set_alarm = s3c_rtc_setalarm,
.proc = s3c_rtc_proc,
};
static void s3c_rtc_enable(struct platform_device *pdev, int en)
{
void __iomem *base = s3c_rtc_base;
unsigned int tmp;
if (s3c_rtc_base == NULL)
return;
if (!en) {
tmp = readb(base + S3C2410_RTCCON);
writeb(tmp & ~S3C2410_RTCCON_RTCEN, base + S3C2410_RTCCON);
tmp = readb(base + S3C2410_TICNT);
writeb(tmp & ~S3C2410_TICNT_ENABLE, base + S3C2410_TICNT);
} else {
/* re-enable the device, and check it is ok */
if ((readb(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0){
dev_info(&pdev->dev, "rtc disabled, re-enabling\n");
tmp = readb(base + S3C2410_RTCCON);
writeb(tmp|S3C2410_RTCCON_RTCEN, base+S3C2410_RTCCON);
}
if ((readb(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)){
dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");
tmp = readb(base + S3C2410_RTCCON);
writeb(tmp& ~S3C2410_RTCCON_CNTSEL, base+S3C2410_RTCCON);
}
if ((readb(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)){
dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");
tmp = readb(base + S3C2410_RTCCON);
writeb(tmp & ~S3C2410_RTCCON_CLKRST, base+S3C2410_RTCCON);
}
}
}
static int s3c_rtc_remove(struct platform_device *dev)
{
struct rtc_device *rtc = platform_get_drvdata(dev);
platform_set_drvdata(dev, NULL);
rtc_device_unregister(rtc);
s3c_rtc_setpie(0);
s3c_rtc_setaie(0);
iounmap(s3c_rtc_base);
release_resource(s3c_rtc_mem);
kfree(s3c_rtc_mem);
return 0;
}
static int s3c_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
struct resource *res;
int ret;
pr_debug("%s: probe=%p\n", __FUNCTION__, pdev);
/* find the IRQs */
s3c_rtc_tickno = platform_get_irq(pdev, 1);
if (s3c_rtc_tickno < 0) {
dev_err(&pdev->dev, "no irq for rtc tick\n");
return -ENOENT;
}
s3c_rtc_alarmno = platform_get_irq(pdev, 0);
if (s3c_rtc_alarmno < 0) {
dev_err(&pdev->dev, "no irq for alarm\n");
return -ENOENT;
}
pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",
s3c_rtc_tickno, s3c_rtc_alarmno);
/* get the memory region */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&pdev->dev, "failed to get memory region resource\n");
return -ENOENT;
}
s3c_rtc_mem = request_mem_region(res->start,
res->end-res->start+1,
pdev->name);
if (s3c_rtc_mem == NULL) {
dev_err(&pdev->dev, "failed to reserve memory region\n");
ret = -ENOENT;
goto err_nores;
}
s3c_rtc_base = ioremap(res->start, res->end - res->start + 1);
if (s3c_rtc_base == NULL) {
dev_err(&pdev->dev, "failed ioremap()\n");
ret = -EINVAL;
goto err_nomap;
}
/* check to see if everything is setup correctly */
s3c_rtc_enable(pdev, 1);
pr_debug("s3c2410_rtc: RTCCON=%02x\n",
readb(s3c_rtc_base + S3C2410_RTCCON));
s3c_rtc_setfreq(s3c_rtc_freq);
/* register RTC and exit */
rtc = rtc_device_register("s3c", &pdev->dev, &s3c_rtcops,
THIS_MODULE);
if (IS_ERR(rtc)) {
dev_err(&pdev->dev, "cannot attach rtc\n");
ret = PTR_ERR(rtc);
goto err_nortc;
}
rtc->max_user_freq = 128;
platform_set_drvdata(pdev, rtc);
return 0;
err_nortc:
s3c_rtc_enable(pdev, 0);
iounmap(s3c_rtc_base);
err_nomap:
release_resource(s3c_rtc_mem);
err_nores:
return ret;
}
#ifdef CONFIG_PM
/* RTC Power management control */
static struct timespec s3c_rtc_delta;
static int ticnt_save;
static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
struct rtc_time tm;
struct timespec time;
time.tv_nsec = 0;
/* save TICNT for anyone using periodic interrupts */
ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);
/* calculate time delta for suspend */
s3c_rtc_gettime(&pdev->dev, &tm);
rtc_tm_to_time(&tm, &time.tv_sec);
save_time_delta(&s3c_rtc_delta, &time);
s3c_rtc_enable(pdev, 0);
return 0;
}
static int s3c_rtc_resume(struct platform_device *pdev)
{
struct rtc_time tm;
struct timespec time;
time.tv_nsec = 0;
s3c_rtc_enable(pdev, 1);
s3c_rtc_gettime(&pdev->dev, &tm);
rtc_tm_to_time(&tm, &time.tv_sec);
restore_time_delta(&s3c_rtc_delta, &time);
writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);
return 0;
}
#else
#define s3c_rtc_suspend NULL
#define s3c_rtc_resume NULL
#endif
static struct platform_driver s3c2410_rtcdrv = {
.probe = s3c_rtc_probe,
.remove = s3c_rtc_remove,
.suspend = s3c_rtc_suspend,
.resume = s3c_rtc_resume,
.driver = {
.name = "s3c2410-rtc",
.owner = THIS_MODULE,
},
};
static char __initdata banner[] = "S3C24XX RTC, (c) 2004,2006 Simtec Electronics\n";
static int __init s3c_rtc_init(void)
{
printk(banner);
return platform_driver_register(&s3c2410_rtcdrv);
}
static void __exit s3c_rtc_exit(void)
{
platform_driver_unregister(&s3c2410_rtcdrv);
}
module_init(s3c_rtc_init);
module_exit(s3c_rtc_exit);
MODULE_DESCRIPTION("Samsung S3C RTC Driver");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
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