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linux-next/drivers/rtc/rtc-vr41xx.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

464 lines
11 KiB
C
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/*
* Driver for NEC VR4100 series Real Time Clock unit.
*
* Copyright (C) 2003-2006 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <asm/div64.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/vr41xx/irq.h>
MODULE_AUTHOR("Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>");
MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
MODULE_LICENSE("GPL");
#define RTC1_TYPE1_START 0x0b0000c0UL
#define RTC1_TYPE1_END 0x0b0000dfUL
#define RTC2_TYPE1_START 0x0b0001c0UL
#define RTC2_TYPE1_END 0x0b0001dfUL
#define RTC1_TYPE2_START 0x0f000100UL
#define RTC1_TYPE2_END 0x0f00011fUL
#define RTC2_TYPE2_START 0x0f000120UL
#define RTC2_TYPE2_END 0x0f00013fUL
#define RTC1_SIZE 0x20
#define RTC2_SIZE 0x20
/* RTC 1 registers */
#define ETIMELREG 0x00
#define ETIMEMREG 0x02
#define ETIMEHREG 0x04
/* RFU */
#define ECMPLREG 0x08
#define ECMPMREG 0x0a
#define ECMPHREG 0x0c
/* RFU */
#define RTCL1LREG 0x10
#define RTCL1HREG 0x12
#define RTCL1CNTLREG 0x14
#define RTCL1CNTHREG 0x16
#define RTCL2LREG 0x18
#define RTCL2HREG 0x1a
#define RTCL2CNTLREG 0x1c
#define RTCL2CNTHREG 0x1e
/* RTC 2 registers */
#define TCLKLREG 0x00
#define TCLKHREG 0x02
#define TCLKCNTLREG 0x04
#define TCLKCNTHREG 0x06
/* RFU */
#define RTCINTREG 0x1e
#define TCLOCK_INT 0x08
#define RTCLONG2_INT 0x04
#define RTCLONG1_INT 0x02
#define ELAPSEDTIME_INT 0x01
#define RTC_FREQUENCY 32768
#define MAX_PERIODIC_RATE 6553
static void __iomem *rtc1_base;
static void __iomem *rtc2_base;
#define rtc1_read(offset) readw(rtc1_base + (offset))
#define rtc1_write(offset, value) writew((value), rtc1_base + (offset))
#define rtc2_read(offset) readw(rtc2_base + (offset))
#define rtc2_write(offset, value) writew((value), rtc2_base + (offset))
static unsigned long epoch = 1970; /* Jan 1 1970 00:00:00 */
static DEFINE_SPINLOCK(rtc_lock);
static char rtc_name[] = "RTC";
static unsigned long periodic_frequency;
static unsigned long periodic_count;
struct resource rtc_resource[2] = {
{ .name = rtc_name,
.flags = IORESOURCE_MEM, },
{ .name = rtc_name,
.flags = IORESOURCE_MEM, },
};
static inline unsigned long read_elapsed_second(void)
{
unsigned long first_low, first_mid, first_high;
unsigned long second_low, second_mid, second_high;
do {
first_low = rtc1_read(ETIMELREG);
first_mid = rtc1_read(ETIMEMREG);
first_high = rtc1_read(ETIMEHREG);
second_low = rtc1_read(ETIMELREG);
second_mid = rtc1_read(ETIMEMREG);
second_high = rtc1_read(ETIMEHREG);
} while (first_low != second_low || first_mid != second_mid ||
first_high != second_high);
return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
}
static inline void write_elapsed_second(unsigned long sec)
{
spin_lock_irq(&rtc_lock);
rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));
spin_unlock_irq(&rtc_lock);
}
static void vr41xx_rtc_release(struct device *dev)
{
spin_lock_irq(&rtc_lock);
rtc1_write(ECMPLREG, 0);
rtc1_write(ECMPMREG, 0);
rtc1_write(ECMPHREG, 0);
rtc1_write(RTCL1LREG, 0);
rtc1_write(RTCL1HREG, 0);
spin_unlock_irq(&rtc_lock);
disable_irq(ELAPSEDTIME_IRQ);
disable_irq(RTCLONG1_IRQ);
}
static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time)
{
unsigned long epoch_sec, elapsed_sec;
epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
elapsed_sec = read_elapsed_second();
rtc_time_to_tm(epoch_sec + elapsed_sec, time);
return 0;
}
static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time)
{
unsigned long epoch_sec, current_sec;
epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
time->tm_hour, time->tm_min, time->tm_sec);
write_elapsed_second(current_sec - epoch_sec);
return 0;
}
static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
unsigned long low, mid, high;
struct rtc_time *time = &wkalrm->time;
spin_lock_irq(&rtc_lock);
low = rtc1_read(ECMPLREG);
mid = rtc1_read(ECMPMREG);
high = rtc1_read(ECMPHREG);
spin_unlock_irq(&rtc_lock);
rtc_time_to_tm((high << 17) | (mid << 1) | (low >> 15), time);
return 0;
}
static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
unsigned long alarm_sec;
struct rtc_time *time = &wkalrm->time;
alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
time->tm_hour, time->tm_min, time->tm_sec);
spin_lock_irq(&rtc_lock);
rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));
spin_unlock_irq(&rtc_lock);
return 0;
}
static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
unsigned long count;
switch (cmd) {
case RTC_AIE_ON:
enable_irq(ELAPSEDTIME_IRQ);
break;
case RTC_AIE_OFF:
disable_irq(ELAPSEDTIME_IRQ);
break;
case RTC_PIE_ON:
enable_irq(RTCLONG1_IRQ);
break;
case RTC_PIE_OFF:
disable_irq(RTCLONG1_IRQ);
break;
case RTC_IRQP_READ:
return put_user(periodic_frequency, (unsigned long __user *)arg);
break;
case RTC_IRQP_SET:
if (arg > MAX_PERIODIC_RATE)
return -EINVAL;
periodic_frequency = arg;
count = RTC_FREQUENCY;
do_div(count, arg);
periodic_count = count;
spin_lock_irq(&rtc_lock);
rtc1_write(RTCL1LREG, count);
rtc1_write(RTCL1HREG, count >> 16);
spin_unlock_irq(&rtc_lock);
break;
case RTC_EPOCH_READ:
return put_user(epoch, (unsigned long __user *)arg);
case RTC_EPOCH_SET:
/* Doesn't support before 1900 */
if (arg < 1900)
return -EINVAL;
epoch = arg;
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = (struct platform_device *)dev_id;
struct rtc_device *rtc = platform_get_drvdata(pdev);
rtc2_write(RTCINTREG, ELAPSEDTIME_INT);
rtc_update_irq(&rtc->class_dev, 1, RTC_AF);
return IRQ_HANDLED;
}
static irqreturn_t rtclong1_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = (struct platform_device *)dev_id;
struct rtc_device *rtc = platform_get_drvdata(pdev);
unsigned long count = periodic_count;
rtc2_write(RTCINTREG, RTCLONG1_INT);
rtc1_write(RTCL1LREG, count);
rtc1_write(RTCL1HREG, count >> 16);
rtc_update_irq(&rtc->class_dev, 1, RTC_PF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops vr41xx_rtc_ops = {
.release = vr41xx_rtc_release,
.ioctl = vr41xx_rtc_ioctl,
.read_time = vr41xx_rtc_read_time,
.set_time = vr41xx_rtc_set_time,
.read_alarm = vr41xx_rtc_read_alarm,
.set_alarm = vr41xx_rtc_set_alarm,
};
static int __devinit rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
unsigned int irq;
int retval;
if (pdev->num_resources != 2)
return -EBUSY;
rtc1_base = ioremap(pdev->resource[0].start, RTC1_SIZE);
if (rtc1_base == NULL)
return -EBUSY;
rtc2_base = ioremap(pdev->resource[1].start, RTC2_SIZE);
if (rtc2_base == NULL) {
iounmap(rtc1_base);
rtc1_base = NULL;
return -EBUSY;
}
rtc = rtc_device_register(rtc_name, &pdev->dev, &vr41xx_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
iounmap(rtc1_base);
iounmap(rtc2_base);
rtc1_base = NULL;
rtc2_base = NULL;
return PTR_ERR(rtc);
}
spin_lock_irq(&rtc_lock);
rtc1_write(ECMPLREG, 0);
rtc1_write(ECMPMREG, 0);
rtc1_write(ECMPHREG, 0);
rtc1_write(RTCL1LREG, 0);
rtc1_write(RTCL1HREG, 0);
spin_unlock_irq(&rtc_lock);
irq = ELAPSEDTIME_IRQ;
retval = request_irq(irq, elapsedtime_interrupt, IRQF_DISABLED,
"elapsed_time", pdev);
if (retval == 0) {
irq = RTCLONG1_IRQ;
retval = request_irq(irq, rtclong1_interrupt, IRQF_DISABLED,
"rtclong1", pdev);
}
if (retval < 0) {
printk(KERN_ERR "rtc: IRQ%d is busy\n", irq);
rtc_device_unregister(rtc);
if (irq == RTCLONG1_IRQ)
free_irq(ELAPSEDTIME_IRQ, NULL);
iounmap(rtc1_base);
iounmap(rtc2_base);
rtc1_base = NULL;
rtc2_base = NULL;
return retval;
}
platform_set_drvdata(pdev, rtc);
disable_irq(ELAPSEDTIME_IRQ);
disable_irq(RTCLONG1_IRQ);
printk(KERN_INFO "rtc: Real Time Clock of NEC VR4100 series\n");
return 0;
}
static int __devexit rtc_remove(struct platform_device *pdev)
{
struct rtc_device *rtc;
rtc = platform_get_drvdata(pdev);
if (rtc != NULL)
rtc_device_unregister(rtc);
platform_set_drvdata(pdev, NULL);
free_irq(ELAPSEDTIME_IRQ, NULL);
free_irq(RTCLONG1_IRQ, NULL);
if (rtc1_base != NULL)
iounmap(rtc1_base);
if (rtc2_base != NULL)
iounmap(rtc2_base);
return 0;
}
static struct platform_device *rtc_platform_device;
static struct platform_driver rtc_platform_driver = {
.probe = rtc_probe,
.remove = __devexit_p(rtc_remove),
.driver = {
.name = rtc_name,
.owner = THIS_MODULE,
},
};
static int __init vr41xx_rtc_init(void)
{
int retval;
switch (current_cpu_data.cputype) {
case CPU_VR4111:
case CPU_VR4121:
rtc_resource[0].start = RTC1_TYPE1_START;
rtc_resource[0].end = RTC1_TYPE1_END;
rtc_resource[1].start = RTC2_TYPE1_START;
rtc_resource[1].end = RTC2_TYPE1_END;
break;
case CPU_VR4122:
case CPU_VR4131:
case CPU_VR4133:
rtc_resource[0].start = RTC1_TYPE2_START;
rtc_resource[0].end = RTC1_TYPE2_END;
rtc_resource[1].start = RTC2_TYPE2_START;
rtc_resource[1].end = RTC2_TYPE2_END;
break;
default:
return -ENODEV;
break;
}
rtc_platform_device = platform_device_alloc("RTC", -1);
if (rtc_platform_device == NULL)
return -ENOMEM;
retval = platform_device_add_resources(rtc_platform_device,
rtc_resource, ARRAY_SIZE(rtc_resource));
if (retval == 0)
retval = platform_device_add(rtc_platform_device);
if (retval < 0) {
platform_device_put(rtc_platform_device);
return retval;
}
retval = platform_driver_register(&rtc_platform_driver);
if (retval < 0)
platform_device_unregister(rtc_platform_device);
return retval;
}
static void __exit vr41xx_rtc_exit(void)
{
platform_driver_unregister(&rtc_platform_driver);
platform_device_unregister(rtc_platform_device);
}
module_init(vr41xx_rtc_init);
module_exit(vr41xx_rtc_exit);
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