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linux/drivers/rtc/rtc-sh.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

467 lines
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/*
* SuperH On-Chip RTC Support
*
* Copyright (C) 2006 Paul Mundt
*
* Based on the old arch/sh/kernel/cpu/rtc.c by:
*
* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
* Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <asm/io.h>
#ifdef CONFIG_CPU_SH3
#define rtc_reg_size sizeof(u16)
#define RTC_BIT_INVERTED 0 /* No bug on SH7708, SH7709A */
#elif defined(CONFIG_CPU_SH4)
#define rtc_reg_size sizeof(u32)
#define RTC_BIT_INVERTED 0x40 /* bug on SH7750, SH7750S */
#endif
#define RTC_REG(r) ((r) * rtc_reg_size)
#define R64CNT RTC_REG(0)
#define RSECCNT RTC_REG(1)
#define RMINCNT RTC_REG(2)
#define RHRCNT RTC_REG(3)
#define RWKCNT RTC_REG(4)
#define RDAYCNT RTC_REG(5)
#define RMONCNT RTC_REG(6)
#define RYRCNT RTC_REG(7)
#define RSECAR RTC_REG(8)
#define RMINAR RTC_REG(9)
#define RHRAR RTC_REG(10)
#define RWKAR RTC_REG(11)
#define RDAYAR RTC_REG(12)
#define RMONAR RTC_REG(13)
#define RCR1 RTC_REG(14)
#define RCR2 RTC_REG(15)
/* RCR1 Bits */
#define RCR1_CF 0x80 /* Carry Flag */
#define RCR1_CIE 0x10 /* Carry Interrupt Enable */
#define RCR1_AIE 0x08 /* Alarm Interrupt Enable */
#define RCR1_AF 0x01 /* Alarm Flag */
/* RCR2 Bits */
#define RCR2_PEF 0x80 /* PEriodic interrupt Flag */
#define RCR2_PESMASK 0x70 /* Periodic interrupt Set */
#define RCR2_RTCEN 0x08 /* ENable RTC */
#define RCR2_ADJ 0x04 /* ADJustment (30-second) */
#define RCR2_RESET 0x02 /* Reset bit */
#define RCR2_START 0x01 /* Start bit */
struct sh_rtc {
void __iomem *regbase;
unsigned long regsize;
struct resource *res;
unsigned int alarm_irq, periodic_irq, carry_irq;
struct rtc_device *rtc_dev;
spinlock_t lock;
};
static irqreturn_t sh_rtc_interrupt(int irq, void *id)
{
struct platform_device *pdev = id;
struct sh_rtc *rtc = platform_get_drvdata(pdev);
unsigned int tmp, events = 0;
spin_lock(&rtc->lock);
tmp = readb(rtc->regbase + RCR1);
if (tmp & RCR1_AF)
events |= RTC_AF | RTC_IRQF;
tmp &= ~(RCR1_CF | RCR1_AF);
writeb(tmp, rtc->regbase + RCR1);
rtc_update_irq(&rtc->rtc_dev->class_dev, 1, events);
spin_unlock(&rtc->lock);
return IRQ_HANDLED;
}
static irqreturn_t sh_rtc_periodic(int irq, void *id)
{
struct sh_rtc *rtc = dev_get_drvdata(id);
spin_lock(&rtc->lock);
rtc_update_irq(&rtc->rtc_dev->class_dev, 1, RTC_PF | RTC_IRQF);
spin_unlock(&rtc->lock);
return IRQ_HANDLED;
}
static inline void sh_rtc_setpie(struct device *dev, unsigned int enable)
{
struct sh_rtc *rtc = dev_get_drvdata(dev);
unsigned int tmp;
spin_lock_irq(&rtc->lock);
tmp = readb(rtc->regbase + RCR2);
if (enable) {
tmp &= ~RCR2_PESMASK;
tmp |= RCR2_PEF | (2 << 4);
} else
tmp &= ~(RCR2_PESMASK | RCR2_PEF);
writeb(tmp, rtc->regbase + RCR2);
spin_unlock_irq(&rtc->lock);
}
static inline void sh_rtc_setaie(struct device *dev, unsigned int enable)
{
struct sh_rtc *rtc = dev_get_drvdata(dev);
unsigned int tmp;
spin_lock_irq(&rtc->lock);
tmp = readb(rtc->regbase + RCR1);
if (enable)
tmp |= RCR1_AIE;
else
tmp &= ~RCR1_AIE;
writeb(tmp, rtc->regbase + RCR1);
spin_unlock_irq(&rtc->lock);
}
static int sh_rtc_open(struct device *dev)
{
struct sh_rtc *rtc = dev_get_drvdata(dev);
unsigned int tmp;
int ret;
tmp = readb(rtc->regbase + RCR1);
tmp &= ~RCR1_CF;
tmp |= RCR1_CIE;
writeb(tmp, rtc->regbase + RCR1);
ret = request_irq(rtc->periodic_irq, sh_rtc_periodic, SA_INTERRUPT,
"sh-rtc period", dev);
if (unlikely(ret)) {
dev_err(dev, "request period IRQ failed with %d, IRQ %d\n",
ret, rtc->periodic_irq);
return ret;
}
ret = request_irq(rtc->carry_irq, sh_rtc_interrupt, SA_INTERRUPT,
"sh-rtc carry", dev);
if (unlikely(ret)) {
dev_err(dev, "request carry IRQ failed with %d, IRQ %d\n",
ret, rtc->carry_irq);
free_irq(rtc->periodic_irq, dev);
goto err_bad_carry;
}
ret = request_irq(rtc->alarm_irq, sh_rtc_interrupt, SA_INTERRUPT,
"sh-rtc alarm", dev);
if (unlikely(ret)) {
dev_err(dev, "request alarm IRQ failed with %d, IRQ %d\n",
ret, rtc->alarm_irq);
goto err_bad_alarm;
}
return 0;
err_bad_alarm:
free_irq(rtc->carry_irq, dev);
err_bad_carry:
free_irq(rtc->periodic_irq, dev);
return ret;
}
static void sh_rtc_release(struct device *dev)
{
struct sh_rtc *rtc = dev_get_drvdata(dev);
sh_rtc_setpie(dev, 0);
free_irq(rtc->periodic_irq, dev);
free_irq(rtc->carry_irq, dev);
free_irq(rtc->alarm_irq, dev);
}
static int sh_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct sh_rtc *rtc = dev_get_drvdata(dev);
unsigned int tmp;
tmp = readb(rtc->regbase + RCR1);
seq_printf(seq, "alarm_IRQ\t: %s\n",
(tmp & RCR1_AIE) ? "yes" : "no");
seq_printf(seq, "carry_IRQ\t: %s\n",
(tmp & RCR1_CIE) ? "yes" : "no");
tmp = readb(rtc->regbase + RCR2);
seq_printf(seq, "periodic_IRQ\t: %s\n",
(tmp & RCR2_PEF) ? "yes" : "no");
return 0;
}
static int sh_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
unsigned int ret = -ENOIOCTLCMD;
switch (cmd) {
case RTC_PIE_OFF:
case RTC_PIE_ON:
sh_rtc_setpie(dev, cmd == RTC_PIE_ON);
ret = 0;
break;
case RTC_AIE_OFF:
case RTC_AIE_ON:
sh_rtc_setaie(dev, cmd == RTC_AIE_ON);
ret = 0;
break;
}
return ret;
}
static int sh_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct sh_rtc *rtc = platform_get_drvdata(pdev);
unsigned int sec128, sec2, yr, yr100, cf_bit;
do {
unsigned int tmp;
spin_lock_irq(&rtc->lock);
tmp = readb(rtc->regbase + RCR1);
tmp &= ~RCR1_CF; /* Clear CF-bit */
tmp |= RCR1_CIE;
writeb(tmp, rtc->regbase + RCR1);
sec128 = readb(rtc->regbase + R64CNT);
tm->tm_sec = BCD2BIN(readb(rtc->regbase + RSECCNT));
tm->tm_min = BCD2BIN(readb(rtc->regbase + RMINCNT));
tm->tm_hour = BCD2BIN(readb(rtc->regbase + RHRCNT));
tm->tm_wday = BCD2BIN(readb(rtc->regbase + RWKCNT));
tm->tm_mday = BCD2BIN(readb(rtc->regbase + RDAYCNT));
tm->tm_mon = BCD2BIN(readb(rtc->regbase + RMONCNT));
#if defined(CONFIG_CPU_SH4)
yr = readw(rtc->regbase + RYRCNT);
yr100 = BCD2BIN(yr >> 8);
yr &= 0xff;
#else
yr = readb(rtc->regbase + RYRCNT);
yr100 = BCD2BIN((yr == 0x99) ? 0x19 : 0x20);
#endif
tm->tm_year = (yr100 * 100 + BCD2BIN(yr)) - 1900;
sec2 = readb(rtc->regbase + R64CNT);
cf_bit = readb(rtc->regbase + RCR1) & RCR1_CF;
spin_unlock_irq(&rtc->lock);
} while (cf_bit != 0 || ((sec128 ^ sec2) & RTC_BIT_INVERTED) != 0);
#if RTC_BIT_INVERTED != 0
if ((sec128 & RTC_BIT_INVERTED))
tm->tm_sec--;
#endif
dev_dbg(&dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__FUNCTION__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
if (rtc_valid_tm(tm) < 0)
dev_err(dev, "invalid date\n");
return 0;
}
static int sh_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct sh_rtc *rtc = platform_get_drvdata(pdev);
unsigned int tmp;
int year;
spin_lock_irq(&rtc->lock);
/* Reset pre-scaler & stop RTC */
tmp = readb(rtc->regbase + RCR2);
tmp |= RCR2_RESET;
writeb(tmp, rtc->regbase + RCR2);
writeb(BIN2BCD(tm->tm_sec), rtc->regbase + RSECCNT);
writeb(BIN2BCD(tm->tm_min), rtc->regbase + RMINCNT);
writeb(BIN2BCD(tm->tm_hour), rtc->regbase + RHRCNT);
writeb(BIN2BCD(tm->tm_wday), rtc->regbase + RWKCNT);
writeb(BIN2BCD(tm->tm_mday), rtc->regbase + RDAYCNT);
writeb(BIN2BCD(tm->tm_mon), rtc->regbase + RMONCNT);
#ifdef CONFIG_CPU_SH3
year = tm->tm_year % 100;
writeb(BIN2BCD(year), rtc->regbase + RYRCNT);
#else
year = (BIN2BCD((tm->tm_year + 1900) / 100) << 8) |
BIN2BCD(tm->tm_year % 100);
writew(year, rtc->regbase + RYRCNT);
#endif
/* Start RTC */
tmp = readb(rtc->regbase + RCR2);
tmp &= ~RCR2_RESET;
tmp |= RCR2_RTCEN | RCR2_START;
writeb(tmp, rtc->regbase + RCR2);
spin_unlock_irq(&rtc->lock);
return 0;
}
static struct rtc_class_ops sh_rtc_ops = {
.open = sh_rtc_open,
.release = sh_rtc_release,
.ioctl = sh_rtc_ioctl,
.read_time = sh_rtc_read_time,
.set_time = sh_rtc_set_time,
.proc = sh_rtc_proc,
};
static int __devinit sh_rtc_probe(struct platform_device *pdev)
{
struct sh_rtc *rtc;
struct resource *res;
int ret = -ENOENT;
rtc = kzalloc(sizeof(struct sh_rtc), GFP_KERNEL);
if (unlikely(!rtc))
return -ENOMEM;
spin_lock_init(&rtc->lock);
rtc->periodic_irq = platform_get_irq(pdev, 0);
if (unlikely(rtc->periodic_irq < 0)) {
dev_err(&pdev->dev, "No IRQ for period\n");
goto err_badres;
}
rtc->carry_irq = platform_get_irq(pdev, 1);
if (unlikely(rtc->carry_irq < 0)) {
dev_err(&pdev->dev, "No IRQ for carry\n");
goto err_badres;
}
rtc->alarm_irq = platform_get_irq(pdev, 2);
if (unlikely(rtc->alarm_irq < 0)) {
dev_err(&pdev->dev, "No IRQ for alarm\n");
goto err_badres;
}
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (unlikely(res == NULL)) {
dev_err(&pdev->dev, "No IO resource\n");
goto err_badres;
}
rtc->regsize = res->end - res->start + 1;
rtc->res = request_mem_region(res->start, rtc->regsize, pdev->name);
if (unlikely(!rtc->res)) {
ret = -EBUSY;
goto err_badres;
}
rtc->regbase = (void __iomem *)rtc->res->start;
if (unlikely(!rtc->regbase)) {
ret = -EINVAL;
goto err_badmap;
}
rtc->rtc_dev = rtc_device_register("sh", &pdev->dev,
&sh_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc->rtc_dev);
goto err_badmap;
}
platform_set_drvdata(pdev, rtc);
return 0;
err_badmap:
release_resource(rtc->res);
err_badres:
kfree(rtc);
return ret;
}
static int __devexit sh_rtc_remove(struct platform_device *pdev)
{
struct sh_rtc *rtc = platform_get_drvdata(pdev);
if (likely(rtc->rtc_dev))
rtc_device_unregister(rtc->rtc_dev);
sh_rtc_setpie(&pdev->dev, 0);
sh_rtc_setaie(&pdev->dev, 0);
release_resource(rtc->res);
platform_set_drvdata(pdev, NULL);
kfree(rtc);
return 0;
}
static struct platform_driver sh_rtc_platform_driver = {
.driver = {
.name = "sh-rtc",
.owner = THIS_MODULE,
},
.probe = sh_rtc_probe,
.remove = __devexit_p(sh_rtc_remove),
};
static int __init sh_rtc_init(void)
{
return platform_driver_register(&sh_rtc_platform_driver);
}
static void __exit sh_rtc_exit(void)
{
platform_driver_unregister(&sh_rtc_platform_driver);
}
module_init(sh_rtc_init);
module_exit(sh_rtc_exit);
MODULE_DESCRIPTION("SuperH on-chip RTC driver");
MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_LICENSE("GPL");
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