[PATCH] HPET driver

The driver supports the High Precision Event Timer.  The driver has adopted
a similar API to the Real Time Clock driver.  It can support any number of
HPET devices and the maximum number of timers per HPET device.  For further
information look at the documentation in the patch.

Thanks to Venki at Intel for testing the driver on X86 hardware with HPET.

HPET documentation is available at http://www.intel.com/design/chipsets/datashts/252516.htmSigned-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/filesystems/proc.txt

@@ -201,7 +201,7 @@ Table 1-3: Kernel info in /proc
  devices     Available devices (block and character)           
  dma         Used DMS channels                                 
  filesystems Supported filesystems                             
- driver	     Various drivers grouped here, currently rtc	(2.4)
+ driver	     Various drivers grouped here, currently rtc (2.4) and hpet (2.6)
  execdomains Execdomains, related to security			(2.4)
  fb	     Frame Buffer devices				(2.4)
  fs	     File system parameters, currently nfs/exports	(2.4)

Documentation/hpet.txt

+		High Precision Event Timer Driver for Linux
+
+The High Precision Event Timer (HPET) hardware is the future replacement for the 8254 and Real
+Time Clock (RTC) periodic timer functionality.  Each HPET can have up two 32 timers.  It is possible
+to configure the first two timers as legacy replacements for 8254 and RTC periodic.  A specification
+done by INTEL and Microsoft can be found at http://www.intel.com/labs/platcomp/hpet/hpetspec.htm.
+
+The driver supports detection of HPET driver allocation and initialization of the HPET before the
+driver module_init routine is called.  This enables platform code which uses timer 0 or 1 as the
+main timer to intercept HPET initialization.  An example of this initialization can be found in
+arch/i386/kernel/time_hpet.c.
+
+The driver provides two APIs which are very similar to the API found in the rtc.c driver.
+There is a user space API and a kernel space API.  An example user space program is provided
+below.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <memory.h>
+#include <malloc.h>
+#include <time.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <linux/hpet.h>
+
+
+extern void hpet_open_close(int, const char **);
+extern void hpet_info(int, const char **);
+extern void hpet_poll(int, const char **);
+extern void hpet_fasync(int, const char **);
+extern void hpet_read(int, const char **);
+
+#include <sys/poll.h>
+#include <sys/ioctl.h>
+#include <signal.h>
+
+struct hpet_command {
+	char		*command;
+	void		(*func)(int argc, const char ** argv);
+} hpet_command[] = {
+	{
+		"open-close",
+		hpet_open_close
+	},
+	{
+		"info",
+		hpet_info
+	},
+	{
+		"poll",
+		hpet_poll
+	},
+	{
+		"fasync",
+		hpet_fasync
+	},
+};
+
+int
+main(int argc, const char ** argv)
+{
+	int	i;
+
+	argc--;
+	argv++;
+
+	if (!argc) {
+		fprintf(stderr, "-hpet: requires command\n");
+		return -1;
+	}
+
+
+	for (i = 0; i < (sizeof (hpet_command) / sizeof (hpet_command[0])); i++)
+		if (!strcmp(argv[0], hpet_command[i].command)) {
+			argc--;
+			argv++;
+			fprintf(stderr, "-hpet: executing %s\n",
+				hpet_command[i].command);
+			hpet_command[i].func(argc, argv);
+			return 0;
+		}
+
+	fprintf(stderr, "do_hpet: command %s not implemented\n", argv[0]);
+
+	return -1;
+}
+
+void
+hpet_open_close(int argc, const char **argv)
+{
+	int	fd;
+
+	if (argc != 1) {
+		fprintf(stderr, "hpet_open_close: device-name\n");
+		return;
+	}
+
+	fd = open(argv[0], O_RDWR);
+	if (fd < 0)
+		fprintf(stderr, "hpet_open_close: open failed\n");
+	else
+		close(fd);
+
+	return;
+}
+
+void
+hpet_info(int argc, const char **argv)
+{
+}
+
+void
+hpet_poll(int argc, const char **argv)
+{
+	unsigned long		freq;
+	int			iterations, i, fd;
+	struct pollfd		pfd;
+	struct hpet_info	info;
+	struct timeval		stv, etv;
+	struct timezone		tz;
+	long			usec;
+
+	if (argc != 3) {
+		fprintf(stderr, "hpet_poll: device-name freq iterations\n");
+		return;
+	}
+
+	freq = atoi(argv[1]);
+	iterations = atoi(argv[2]);
+
+	fd = open(argv[0], O_RDWR);
+
+	if (fd < 0) {
+		fprintf(stderr, "hpet_poll: open of %s failed\n", argv[0]);
+		return;
+	}
+
+	if (ioctl(fd, HPET_IRQFREQ, freq) < 0) {
+		fprintf(stderr, "hpet_poll: HPET_IRQFREQ failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_INFO, &info) < 0) {
+		fprintf(stderr, "hpet_poll: failed to get info\n");
+		goto out;
+	}
+
+	fprintf(stderr, "hpet_poll: info.hi_flags 0x%lx\n", info.hi_flags);
+
+	if (info.hi_flags && (ioctl(fd, HPET_EPI, 0) < 0)) {
+		fprintf(stderr, "hpet_poll: HPET_EPI failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_IE_ON, 0) < 0) {
+		fprintf(stderr, "hpet_poll, HPET_IE_ON failed\n");
+		goto out;
+	}
+
+	pfd.fd = fd;
+	pfd.events = POLLIN;
+
+	for (i = 0; i < iterations; i++) {
+		pfd.revents = 0;
+		gettimeofday(&stv, &tz);
+		if (poll(&pfd, 1, -1) < 0)
+			fprintf(stderr, "hpet_poll: poll failed\n");
+		else {
+			long 	data;
+
+			gettimeofday(&etv, &tz);
+			usec = stv.tv_sec * 1000000 + stv.tv_usec;
+			usec = (etv.tv_sec * 1000000 + etv.tv_usec) - usec;
+
+			fprintf(stderr,
+				"hpet_poll: expired time = 0x%lx\n", usec);
+
+			fprintf(stderr, "hpet_poll: revents = 0x%x\n",
+				pfd.revents);
+
+			if (read(fd, &data, sizeof(data)) != sizeof(data)) {
+				fprintf(stderr, "hpet_poll: read failed\n");
+			}
+			else
+				fprintf(stderr, "hpet_poll: data 0x%lx\n",
+					data);
+		}
+	}
+
+out:
+	close(fd);
+	return;
+}
+
+static int hpet_sigio_count;
+
+static void
+hpet_sigio(int val)
+{
+	fprintf(stderr, "hpet_sigio: called\n");
+	hpet_sigio_count++;
+}
+
+void
+hpet_fasync(int argc, const char **argv)
+{
+	unsigned long		freq;
+	int			iterations, i, fd, value;
+	sig_t			oldsig;
+	struct hpet_info	info;
+
+	hpet_sigio_count = 0;
+	fd = -1;
+
+	if ((oldsig = signal(SIGIO, hpet_sigio)) == SIG_ERR) {
+		fprintf(stderr, "hpet_fasync: failed to set signal handler\n");
+		return;
+	}
+
+	if (argc != 3) {
+		fprintf(stderr, "hpet_fasync: device-name freq iterations\n");
+		goto out;
+	}
+
+	fd = open(argv[0], O_RDWR);
+
+	if (fd < 0) {
+		fprintf(stderr, "hpet_fasync: failed to open %s\n", argv[0]);
+		return;
+	}
+
+
+	if ((fcntl(fd, F_SETOWN, getpid()) == 1) ||
+		((value = fcntl(fd, F_GETFL)) == 1) ||
+		(fcntl(fd, F_SETFL, value | O_ASYNC) == 1)) {
+		fprintf(stderr, "hpet_fasync: fcntl failed\n");
+		goto out;
+	}
+
+	freq = atoi(argv[1]);
+	iterations = atoi(argv[2]);
+
+	if (ioctl(fd, HPET_IRQFREQ, freq) < 0) {
+		fprintf(stderr, "hpet_fasync: HPET_IRQFREQ failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_INFO, &info) < 0) {
+		fprintf(stderr, "hpet_fasync: failed to get info\n");
+		goto out;
+	}
+
+	fprintf(stderr, "hpet_fasync: info.hi_flags 0x%lx\n", info.hi_flags);
+
+	if (info.hi_flags && (ioctl(fd, HPET_EPI, 0) < 0)) {
+		fprintf(stderr, "hpet_fasync: HPET_EPI failed\n");
+		goto out;
+	}
+
+	if (ioctl(fd, HPET_IE_ON, 0) < 0) {
+		fprintf(stderr, "hpet_fasync, HPET_IE_ON failed\n");
+		goto out;
+	}
+
+	for (i = 0; i < iterations; i++) {
+		(void) pause();
+		fprintf(stderr, "hpet_fasync: count = %d\n", hpet_sigio_count);
+	}
+
+out:
+	signal(SIGIO, oldsig);
+
+	if (fd >= 0)
+		close(fd);
+
+	return;
+}
+
+The kernel API has three interfaces exported from the driver:
+
+	hpet_register(struct hpet_task *tp, int periodic)
+	hpet_unregister(struct hpet_task *tp)
+	hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
+
+The kernel module using this interface fills in the ht_func and ht_data members of the
+hpet_task structure before calling hpet_register.  hpet_control simply vectors to the hpet_ioctl
+routine and has the same commands and respective arguments as the user API.  hpet_unregister
+is used to terminate usage of the HPET timer reserved by hpet_register.
+
+

arch/i386/Kconfig

@@ -436,7 +436,8 @@ config HPET_TIMER
 	  Choose N to continue using the legacy 8254 timer.
 
 config HPET_EMULATE_RTC
-	def_bool HPET_TIMER && RTC=y
+	bool "Provide RTC interrupt"
+	depends on HPET_TIMER && RTC=y
 
 config SMP
 	bool "Symmetric multi-processing support"

arch/i386/kernel/time_hpet.c

@@ -21,6 +21,7 @@
 #include <linux/config.h>
 
 #include <asm/hpet.h>
+#include <linux/hpet.h>
 
 unsigned long hpet_period;	/* fsecs / HPET clock */
 unsigned long hpet_tick;	/* hpet clks count per tick */
@@ -135,6 +136,51 @@ int __init hpet_enable(void)
 	hpet_writel(cfg, HPET_CFG);
 
 	use_hpet = 1;
+
+#ifdef	CONFIG_HPET
+	{
+		struct hpet_data	hd;
+		unsigned int 		ntimer;
+
+		memset(&hd, 0, sizeof (hd));
+
+		ntimer = hpet_readl(HPET_ID);
+		ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT;
+		ntimer++;
+
+		/*
+		 * Register with driver.
+		 * Timer0 and Timer1 is used by platform.
+		 */
+		hd.hd_address = hpet_virt_address;
+		hd.hd_nirqs = ntimer;
+		hd.hd_flags = HPET_DATA_PLATFORM;
+#ifndef	CONFIG_HPET_EMULATE_RTC
+		hd.hd_state = 0x1;
+#else
+		hd.hd_state = 0x3;
+#endif
+		hd.hd_irq[0] = HPET_LEGACY_8254;
+		hd.hd_irq[1] = HPET_LEGACY_RTC;
+		if (ntimer > 2) {
+			struct hpet		*hpet;
+			struct hpet_timer	*timer;
+			int			i;
+
+			hpet = (struct hpet *) hpet_virt_address;
+
+			for (i = 2, timer = &hpet->hpet_timers[2]; i < ntimer;
+				timer++, i++)
+				hd.hd_irq[i] = (timer->hpet_config &
+					Tn_INT_ROUTE_CNF_MASK) >>
+					Tn_INT_ROUTE_CNF_SHIFT;
+
+		}
+
+		hpet_alloc(&hd);
+	}
+#endif
+
 #ifdef CONFIG_X86_LOCAL_APIC
 	wait_timer_tick = wait_hpet_tick;
 #endif

drivers/char/Kconfig

@@ -957,6 +957,33 @@ config RAW_DRIVER
           kernels.  Applications should simply open the device (eg /dev/hda1)
           with the O_DIRECT flag.
 
+config HPET
+	bool "HPET - High Precision Event Timer" if (X86 || IA64)
+	default n
+	depends on ACPI
+	help
+	  If you say Y here, you will have a device named "/dev/hpet/XX" for
+	  each timer supported by the HPET.  The timers are
+	  non-periodioc and/or periodic.
+
+config HPET_RTC_IRQ
+	bool "HPET Control RTC IRQ" if !HPET_EMULATE_RTC
+	default n
+	depends on HPET
+	help
+	  If you say Y here, you will disable RTC_IRQ in drivers/char/rtc.c. It
+	  is assumed the platform called hpet_alloc with the RTC IRQ values for
+	  the HPET timers.
+
+config HPET_NOMMAP
+	bool "HPET - Control mmap capability."
+	default n
+	depends on HPET
+	help
+	  If you say Y here, then the mmap interface for the HPET driver returns ENOSYS.
+	  Some hardware implementations might not want all the memory in the page the
+	  HPET control registers reside to be exposed.
+
 config MAX_RAW_DEVS
 	int "Maximum number of RAW devices to support (1-8192)"
 	depends on RAW_DRIVER

drivers/char/Makefile

@@ -54,6 +54,7 @@ obj-$(CONFIG_R3964) += n_r3964.o
 obj-$(CONFIG_APPLICOM) += applicom.o
 obj-$(CONFIG_SONYPI) += sonypi.o
 obj-$(CONFIG_RTC) += rtc.o
+obj-$(CONFIG_HPET) += hpet.o
 obj-$(CONFIG_GEN_RTC) += genrtc.o
 obj-$(CONFIG_EFI_RTC) += efirtc.o
 ifeq ($(CONFIG_GENERIC_NVRAM),y)

drivers/char/rtc.c

@@ -97,6 +97,11 @@ static unsigned long rtc_port;
 static int rtc_irq = PCI_IRQ_NONE;
 #endif
 
+#ifdef	CONFIG_HPET_RTC_IRQ
+#undef	RTC_IRQ
+#define	RTC_IRQ	0
+#endif
+
 #ifdef RTC_IRQ
 static int rtc_has_irq = 1;
 #endif

include/asm-i386/hpet.h

@@ -57,9 +57,12 @@
 #define HPET_ID_LEGSUP	0x00008000
 #define HPET_ID_NUMBER	0x00001f00
 #define HPET_ID_REV	0x000000ff
+#define	HPET_ID_NUMBER_SHIFT	8
 
 #define HPET_CFG_ENABLE	0x001
 #define HPET_CFG_LEGACY	0x002
+#define	HPET_LEGACY_8254	2
+#define	HPET_LEGACY_RTC		8
 
 #define HPET_TN_ENABLE		0x004
 #define HPET_TN_PERIODIC	0x008

include/linux/hpet.h

+#ifndef	__HPET__
+#define	__HPET__ 1
+
+/*
+ * Offsets into HPET Registers
+ */
+
+struct hpet {
+	u64 hpet_cap;		/* capabilities */
+	u64 res0;		/* reserved */
+	u64 hpet_config;	/* configuration */
+	u64 res1;		/* reserved */
+	u64 hpet_isr;		/* interrupt status reg */
+	u64 res2[25];		/* reserved */
+	union {			/* main counter */
+		u64 _hpet_mc64;
+		u32 _hpet_mc32;
+		unsigned long _hpet_mc;
+	} _u0;
+	u64 res3;		/* reserved */
+	struct hpet_timer {
+		u64 hpet_config;	/* configuration/cap */
+		union {		/* timer compare register */
+			u64 _hpet_hc64;
+			u32 _hpet_hc32;
+			unsigned long _hpet_compare;
+		} _u1;
+		u64 hpet_fsb[2];	/* FSB route */
+	} hpet_timers[1];
+};
+
+#define	hpet_mc		_u0._hpet_mc
+#define	hpet_compare	_u1._hpet_compare
+
+#define	HPET_MAX_TIMERS	(32)
+
+/*
+ * HPET general capabilities register
+ */
+
+#define	HPET_COUNTER_CLK_PERIOD_MASK	(0xffffffff00000000ULL)
+#define	HPET_COUNTER_CLK_PERIOD_SHIFT	(32UL)
+#define	HPET_VENDOR_ID_MASK		(0x00000000ffff0000ULL)
+#define	HPET_VENDOR_ID_SHIFT		(16ULL)
+#define	HPET_LEG_RT_CAP_MASK		(0x8000)
+#define	HPET_COUNTER_SIZE_MASK		(0x2000)
+#define	HPET_NUM_TIM_CAP_MASK		(0x1f00)
+#define	HPET_NUM_TIM_CAP_SHIFT		(8ULL)
+
+/*
+ * HPET general configuration register
+ */
+
+#define	HPET_LEG_RT_CNF_MASK		(2UL)
+#define	HPET_ENABLE_CNF_MASK		(1UL)
+
+/*
+ * HPET interrupt status register
+ */
+
+#define	HPET_ISR_CLEAR(HPET, TIMER)				\
+		(HPET)->hpet_isr |= (1UL << TIMER)
+
+/*
+ * Timer configuration register
+ */
+
+#define	Tn_INT_ROUTE_CAP_MASK		(0xffffffff00000000ULL)
+#define	Tn_INI_ROUTE_CAP_SHIFT		(32UL)
+#define	Tn_FSB_INT_DELCAP_MASK		(0x8000UL)
+#define	Tn_FSB_INT_DELCAP_SHIFT		(15)
+#define	Tn_FSB_EN_CNF_MASK		(0x4000UL)
+#define	Tn_FSB_EN_CNF_SHIFT		(14)
+#define	Tn_INT_ROUTE_CNF_MASK		(0x3e00UL)
+#define	Tn_INT_ROUTE_CNF_SHIFT		(9)
+#define	Tn_32MODE_CNF_MASK		(0x0100UL)
+#define	Tn_VAL_SET_CNF_MASK		(0x0040UL)
+#define	Tn_SIZE_CAP_MASK		(0x0020UL)
+#define	Tn_PER_INT_CAP_MASK		(0x0010UL)
+#define	Tn_TYPE_CNF_MASK		(0x0008UL)
+#define	Tn_INT_ENB_CNF_MASK		(0x0004UL)
+#define	Tn_INT_TYPE_CNF_MASK		(0x0002UL)
+
+/*
+ * Timer FSB Interrupt Route Register
+ */
+
+#define	Tn_FSB_INT_ADDR_MASK		(0xffffffff00000000ULL)
+#define	Tn_FSB_INT_ADDR_SHIFT		(32UL)
+#define	Tn_FSB_INT_VAL_MASK		(0x00000000ffffffffULL)
+
+struct hpet_info {
+	unsigned long hi_ireqfreq;	/* Hz */
+	unsigned long hi_flags;	/* information */
+	unsigned short hi_hpet;
+	unsigned short hi_timer;
+};
+
+#define	HPET_INFO_PERIODIC	0x0001	/* timer is periodic */
+
+#define	HPET_IE_ON	_IO('h', 0x01)	/* interrupt on */
+#define	HPET_IE_OFF	_IO('h', 0x02)	/* interrupt off */
+#define	HPET_INFO	_IOR('h', 0x03, struct hpet_info)
+#define	HPET_EPI	_IO('h', 0x04)	/* enable periodic */
+#define	HPET_DPI	_IO('h', 0x05)	/* disable periodic */
+#define	HPET_IRQFREQ	_IOW('h', 0x6, unsigned long)	/* IRQFREQ usec */
+
+/*
+ * exported interfaces
+ */
+
+struct hpet_task {
+	void (*ht_func) (void *);
+	void *ht_data;
+	void *ht_opaque;
+};
+
+struct hpet_data {
+	unsigned long hd_address;
+	unsigned short hd_nirqs;
+	unsigned short hd_flags;
+	unsigned int hd_state;	/* timer allocated */
+	unsigned int hd_irq[HPET_MAX_TIMERS];
+};
+
+#define	HPET_DATA_PLATFORM	0x0001	/* platform call to hpet_alloc */
+
+int hpet_alloc(struct hpet_data *);
+int hpet_register(struct hpet_task *, int);
+int hpet_unregister(struct hpet_task *);
+int hpet_control(struct hpet_task *, unsigned int, unsigned long);
+
+#endif				/* !__HPET__ */

include/linux/miscdevice.h

@@ -33,6 +33,7 @@
 #define SGI_STREAMS_KEYBOARD 150
 /* drivers/sgi/char/usema.c */
 #define SGI_USEMACLONE	     151
+#define	HPET_MINOR	     152
 
 #define TUN_MINOR	     200