Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

	Real Time Clock Driver for Linux

	================================

	Real Time Clock (RTC) Drivers for Linux

	=======================================

When Linux developers talk about a "Real Time Clock", they usually mean

something that tracks wall clock time and is battery backed so that it

works even with system power off.  Such clocks will normally not track

the local time zone or daylight savings time -- unless they dual boot

with MS-Windows -- but will instead be set to Coordinated Universal Time

(UTC, formerly "Greenwich Mean Time").

The newest non-PC hardware tends to just count seconds, like the time(2)

system call reports, but RTCs also very commonly represent time using

the Gregorian calendar and 24 hour time, as reported by gmtime(3).

Linux has two largely-compatible userspace RTC API families you may

need to know about:

    *	/dev/rtc ... is the RTC provided by PC compatible systems,

	so it's not very portable to non-x86 systems.

    *	/dev/rtc0, /dev/rtc1 ... are part of a framework that's

	supported by a wide variety of RTC chips on all systems.

Programmers need to understand that the PC/AT functionality is not

always available, and some systems can do much more.  That is, the

RTCs use the same API to make requests in both RTC frameworks (using

different filenames of course), but the hardware may not offer the

same functionality.  For example, not every RTC is hooked up to an

IRQ, so they can't all issue alarms; and where standard PC RTCs can

only issue an alarm up to 24 hours in the future, other hardware may

be able to schedule one any time in the upcoming century.

	Old PC/AT-Compatible driver:  /dev/rtc

	--------------------------------------

All PCs (even Alpha machines) have a Real Time Clock built into them.

Usually they are built into the chipset of the computer, but some may

actually have a Motorola MC146818 (or clone) on the board. This is the

clock that keeps the date and time while your computer is turned off.

ACPI has standardized that MC146818 functionality, and extended it in

a few ways (enabling longer alarm periods, and wake-from-hibernate).

That functionality is NOT exposed in the old driver.

However it can also be used to generate signals from a slow 2Hz to a

relatively fast 8192Hz, in increments of powers of two. These signals

are reported by interrupt number 8. (Oh! So *that* is what IRQ 8 is

perhaps more useful to include a small test program that demonstrates

how to use them, and demonstrates the features of the driver. This is

probably a lot more useful to people interested in writing applications

that will be using this driver.

that will be using this driver.  See the code at the end of this document.

(The original /dev/rtc driver was written by Paul Gortmaker.)

	New portable "RTC Class" drivers:  /dev/rtcN

	--------------------------------------------

Because Linux supports many non-ACPI and non-PC platforms, some of which

have more than one RTC style clock, it needed a more portable solution

than expecting a single battery-backed MC146818 clone on every system.

Accordingly, a new "RTC Class" framework has been defined.  It offers

three different userspace interfaces:

    *	/dev/rtcN ... much the same as the older /dev/rtc interface

    *	/sys/class/rtc/rtcN ... sysfs attributes support readonly

	access to some RTC attributes.

    *	/proc/driver/rtc ... the first RTC (rtc0) may expose itself

	using a procfs interface.  More information is (currently) shown

	here than through sysfs.

The RTC Class framework supports a wide variety of RTCs, ranging from those

integrated into embeddable system-on-chip (SOC) processors to discrete chips

using I2C, SPI, or some other bus to communicate with the host CPU.  There's

even support for PC-style RTCs ... including the features exposed on newer PCs

through ACPI.

The new framework also removes the "one RTC per system" restriction.  For

example, maybe the low-power battery-backed RTC is a discrete I2C chip, but

a high functionality RTC is integrated into the SOC.  That system might read

the system clock from the discrete RTC, but use the integrated one for all

other tasks, because of its greater functionality.

The ioctl() calls supported by /dev/rtc are also supported by the RTC class

framework.  However, because the chips and systems are not standardized,

some PC/AT functionality might not be provided.  And in the same way, some

newer features -- including those enabled by ACPI -- are exposed by the

RTC class framework, but can't be supported by the older driver.

    *	RTC_RD_TIME, RTC_SET_TIME ... every RTC supports at least reading

	time, returning the result as a Gregorian calendar date and 24 hour

	wall clock time.  To be most useful, this time may also be updated.

    *	RTC_AIE_ON, RTC_AIE_OFF, RTC_ALM_SET, RTC_ALM_READ ... when the RTC

	is connected to an IRQ line, it can often issue an alarm IRQ up to

	24 hours in the future.

    *	RTC_WKALM_SET, RTC_WKALM_READ ... RTCs that can issue alarms beyond

	the next 24 hours use a slightly more powerful API, which supports

	setting the longer alarm time and enabling its IRQ using a single

	request (using the same model as EFI firmware).

    *	RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, it probably

	also offers update IRQs whenever the "seconds" counter changes.

	If needed, the RTC framework can emulate this mechanism.

    *	RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... another

	feature often accessible with an IRQ line is a periodic IRQ, issued

	at settable frequencies (usually 2^N Hz).

In many cases, the RTC alarm can be a system wake event, used to force

Linux out of a low power sleep state (or hibernation) back to a fully

operational state.  For example, a system could enter a deep power saving

state until it's time to execute some scheduled tasks.

						Paul Gortmaker

-------------------- 8< ---------------- 8< -----------------------------

 */

#include <stdio.h>

#include <stdlib.h>

#include <linux/rtc.h>

#include <sys/ioctl.h>

#include <sys/time.h>

#include <sys/types.h>

#include <fcntl.h>

#include <unistd.h>

#include <stdlib.h>

#include <errno.h>

int main(void) {

/*

 * This expects the new RTC class driver framework, working with

 * clocks that will often not be clones of what the PC-AT had.

 * Use the command line to specify another RTC if you need one.

 */

static const char default_rtc[] = "/dev/rtc0";

int main(int argc, char **argv)

{

	int i, fd, retval, irqcount = 0;

	unsigned long tmp, data;

	struct rtc_time rtc_tm;

	const char *rtc = default_rtc;

	switch (argc) {

	case 2:

		rtc = argv[1];

		/* FALLTHROUGH */

	case 1:

		break;

	default:

		fprintf(stderr, "usage:  rtctest [rtcdev]\n");

		return 1;

	}

fd = open ("/dev/rtc", O_RDONLY);

	fd = open(rtc, O_RDONLY);

	if (fd ==  -1) {

	perror("/dev/rtc");

		perror(rtc);

		exit(errno);

	}

	/* Turn on update interrupts (one per second) */

	retval = ioctl(fd, RTC_UIE_ON, 0);

	if (retval == -1) {

		if (errno == ENOTTY) {

			fprintf(stderr,

				"\n...Update IRQs not supported.\n");

			goto test_READ;

		}

		perror("ioctl");

		exit(errno);

	}

fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading /dev/rtc:");

	fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading %s:",

			rtc);

	fflush(stderr);

	for (i=1; i<6; i++) {

		/* This read will block */

		exit(errno);

	}

test_READ:

	/* Read the RTC time/date */

	retval = ioctl(fd, RTC_RD_TIME, &rtc_tm);

	if (retval == -1) {

	retval = ioctl(fd, RTC_ALM_SET, &rtc_tm);

	if (retval == -1) {

		if (errno == ENOTTY) {

			fprintf(stderr,

				"\n...Alarm IRQs not supported.\n");

			goto test_PIE;

		}

		perror("ioctl");

		exit(errno);

	}

		exit(errno);

	}

test_PIE:

	/* Read periodic IRQ rate */

	retval = ioctl(fd, RTC_IRQP_READ, &tmp);

	if (retval == -1) {

		/* not all RTCs support periodic IRQs */

		if (errno == ENOTTY) {

			fprintf(stderr, "\nNo periodic IRQ support\n");

			return 0;

		}

		perror("ioctl");

		exit(errno);

	}

fprintf(stderr, "\nPeriodic IRQ rate was %ldHz.\n", tmp);

	fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", tmp);

	fprintf(stderr, "Counting 20 interrupts at:");

	fflush(stderr);

		retval = ioctl(fd, RTC_IRQP_SET, tmp);

		if (retval == -1) {

			/* not all RTCs can change their periodic IRQ rate */

			if (errno == ENOTTY) {

				fprintf(stderr,

					"\n...Periodic IRQ rate is fixed\n");

				goto done;

			}

		        perror("ioctl");

		        exit(errno);

		}

		}

	}

done:

	fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");

fprintf(stderr, "\nTyping \"cat /proc/interrupts\" will show %d more events on IRQ 8.\n\n",

								 irqcount);

	close(fd);

return 0;

} /* end main */

	return 0;

}

M:	rpurdie@rpsys.net

S:	Maintained

ARM/HP JORNADA 7XX MACHINE SUPPORT

P:      Kristoffer Ericson

M:      kristoffer_e1@hotmail.com

W:      www.jlime.com

S:      Maintained

ARM/TOSA MACHINE SUPPORT

P:	Dirk Opfer

M:	dirk@opfer-online.de

source "drivers/scsi/Kconfig"

source "drivers/ata/Kconfig"

source "drivers/md/Kconfig"

source "drivers/message/fusion/Kconfig"

#include <asm/io.h>

#include <asm/page.h>

static void __iomem *__isamem_convert_addr(void __iomem *addr)

static void __iomem *__isamem_convert_addr(const volatile void __iomem *addr)

{

	u32 ret, a = (u32 __force) addr;

/*

 * read[bwl] and write[bwl]

 */

u8 __readb(void __iomem *addr)

u8 __readb(const volatile void __iomem *addr)

{

	void __iomem *a = __isamem_convert_addr(addr);

	u32 ret;

	return ret;

}

u16 __readw(void __iomem *addr)

u16 __readw(const volatile void __iomem *addr)

{

	void __iomem *a = __isamem_convert_addr(addr);

	return __raw_readw(a);

}

u32 __readl(void __iomem *addr)

u32 __readl(const volatile void __iomem *addr)

{

	void __iomem *a = __isamem_convert_addr(addr);

	u32 ret;

/*

 * Make an area consistent for devices.

 * Note: Drivers should NOT use this function directly, as it will break

 * platforms with CONFIG_DMABOUNCE.

 * Use the driver DMA support - see dma-mapping.h (dma_sync_*)

 */

void consistent_sync(void *vaddr, size_t size, int direction)

{