[linux-2.6-block.git] / drivers / char / uv_mmtimer.c

/*
 * Timer device implementation for SGI UV platform.
 *
 * 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.
 *
 * Copyright (c) 2009 Silicon Graphics, Inc.  All rights reserved.
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/ioctl.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/mmtimer.h>
#include <linux/miscdevice.h>
#include <linux/posix-timers.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/math64.h>

#include <asm/genapic.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/bios.h>
#include <asm/uv/uv.h>

MODULE_AUTHOR("Dimitri Sivanich <sivanich@sgi.com>");
MODULE_DESCRIPTION("SGI UV Memory Mapped RTC Timer");
MODULE_LICENSE("GPL");

/* name of the device, usually in /dev */
#define UV_MMTIMER_NAME "mmtimer"
#define UV_MMTIMER_DESC "SGI UV Memory Mapped RTC Timer"
#define UV_MMTIMER_VERSION "1.0"

static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
						unsigned long arg);
static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma);

/*
 * Period in femtoseconds (10^-15 s)
 */
static unsigned long uv_mmtimer_femtoperiod;

static const struct file_operations uv_mmtimer_fops = {
	.owner = THIS_MODULE,
	.mmap =	uv_mmtimer_mmap,
	.unlocked_ioctl = uv_mmtimer_ioctl,
	.llseek = noop_llseek,
};

/**
 * uv_mmtimer_ioctl - ioctl interface for /dev/uv_mmtimer
 * @file: file structure for the device
 * @cmd: command to execute
 * @arg: optional argument to command
 *
 * Executes the command specified by @cmd.  Returns 0 for success, < 0 for
 * failure.
 *
 * Valid commands:
 *
 * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
 * of the page where the registers are mapped) for the counter in question.
 *
 * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
 * seconds
 *
 * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
 * specified by @arg
 *
 * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
 *
 * %MMTIMER_MMAPAVAIL - Returns 1 if registers can be mmap'd into userspace
 *
 * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
 * in the address specified by @arg.
 */
static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
						unsigned long arg)
{
	int ret = 0;

	switch (cmd) {
	case MMTIMER_GETOFFSET:	/* offset of the counter */
		/*
		 * Starting with HUB rev 2.0, the UV RTC register is
		 * replicated across all cachelines of it's own page.
		 * This allows faster simultaneous reads from a given socket.
		 *
		 * The offset returned is in 64 bit units.
		 */
		if (uv_get_min_hub_revision_id() == 1)
			ret = 0;
		else
			ret = ((uv_blade_processor_id() * L1_CACHE_BYTES) %
					PAGE_SIZE) / 8;
		break;

	case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
		if (copy_to_user((unsigned long __user *)arg,
				&uv_mmtimer_femtoperiod, sizeof(unsigned long)))
			ret = -EFAULT;
		break;

	case MMTIMER_GETFREQ: /* frequency in Hz */
		if (copy_to_user((unsigned long __user *)arg,
				&sn_rtc_cycles_per_second,
				sizeof(unsigned long)))
			ret = -EFAULT;
		break;

	case MMTIMER_GETBITS: /* number of bits in the clock */
		ret = hweight64(UVH_RTC_REAL_TIME_CLOCK_MASK);
		break;

	case MMTIMER_MMAPAVAIL:
		ret = 1;
		break;

	case MMTIMER_GETCOUNTER:
		if (copy_to_user((unsigned long __user *)arg,
				(unsigned long *)uv_local_mmr_address(UVH_RTC),
				sizeof(unsigned long)))
			ret = -EFAULT;
		break;
	default:
		ret = -ENOTTY;
		break;
	}
	return ret;
}

/**
 * uv_mmtimer_mmap - maps the clock's registers into userspace
 * @file: file structure for the device
 * @vma: VMA to map the registers into
 *
 * Calls remap_pfn_range() to map the clock's registers into
 * the calling process' address space.
 */
static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
{
	unsigned long uv_mmtimer_addr;

	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
		return -EINVAL;

	if (vma->vm_flags & VM_WRITE)
		return -EPERM;

	if (PAGE_SIZE > (1 << 16))
		return -ENOSYS;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	uv_mmtimer_addr = UV_LOCAL_MMR_BASE | UVH_RTC;
	uv_mmtimer_addr &= ~(PAGE_SIZE - 1);
	uv_mmtimer_addr &= 0xfffffffffffffffUL;

	if (remap_pfn_range(vma, vma->vm_start, uv_mmtimer_addr >> PAGE_SHIFT,
					PAGE_SIZE, vma->vm_page_prot)) {
		printk(KERN_ERR "remap_pfn_range failed in uv_mmtimer_mmap\n");
		return -EAGAIN;
	}

	return 0;
}

static struct miscdevice uv_mmtimer_miscdev = {
	MISC_DYNAMIC_MINOR,
	UV_MMTIMER_NAME,
	&uv_mmtimer_fops
};


/**
 * uv_mmtimer_init - device initialization routine
 *
 * Does initial setup for the uv_mmtimer device.
 */
static int __init uv_mmtimer_init(void)
{
	if (!is_uv_system()) {
		printk(KERN_ERR "%s: Hardware unsupported\n", UV_MMTIMER_NAME);
		return -1;
	}

	/*
	 * Sanity check the cycles/sec variable
	 */
	if (sn_rtc_cycles_per_second < 100000) {
		printk(KERN_ERR "%s: unable to determine clock frequency\n",
		       UV_MMTIMER_NAME);
		return -1;
	}

	uv_mmtimer_femtoperiod = ((unsigned long)1E15 +
				sn_rtc_cycles_per_second / 2) /
				sn_rtc_cycles_per_second;

	if (misc_register(&uv_mmtimer_miscdev)) {
		printk(KERN_ERR "%s: failed to register device\n",
		       UV_MMTIMER_NAME);
		return -1;
	}

	printk(KERN_INFO "%s: v%s, %ld MHz\n", UV_MMTIMER_DESC,
		UV_MMTIMER_VERSION,
		sn_rtc_cycles_per_second/(unsigned long)1E6);

	return 0;
}

module_init(uv_mmtimer_init);
Commit	Line	Data
fbd8ae10 DS	1	/*
	2	* Timer device implementation for SGI UV platform.
	3	*
	4	* This file is subject to the terms and conditions of the GNU General Public
	5	* License. See the file "COPYING" in the main directory of this archive
	6	* for more details.
	7	*
	8	* Copyright (c) 2009 Silicon Graphics, Inc. All rights reserved.
	9	*
	10	*/
	11
	12	#include <linux/types.h>
	13	#include <linux/kernel.h>
	14	#include <linux/ioctl.h>
	15	#include <linux/module.h>
	16	#include <linux/init.h>
	17	#include <linux/errno.h>
	18	#include <linux/mm.h>
	19	#include <linux/fs.h>
	20	#include <linux/mmtimer.h>
	21	#include <linux/miscdevice.h>
	22	#include <linux/posix-timers.h>
	23	#include <linux/interrupt.h>
	24	#include <linux/time.h>
	25	#include <linux/math64.h>
fbd8ae10 DS	26
	27	#include <asm/genapic.h>
	28	#include <asm/uv/uv_hub.h>
	29	#include <asm/uv/bios.h>
	30	#include <asm/uv/uv.h>
	31
	32	MODULE_AUTHOR("Dimitri Sivanich <sivanich@sgi.com>");
	33	MODULE_DESCRIPTION("SGI UV Memory Mapped RTC Timer");
	34	MODULE_LICENSE("GPL");
	35
	36	/* name of the device, usually in /dev */
	37	#define UV_MMTIMER_NAME "mmtimer"
	38	#define UV_MMTIMER_DESC "SGI UV Memory Mapped RTC Timer"
	39	#define UV_MMTIMER_VERSION "1.0"
	40
	41	static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
	42	unsigned long arg);
	43	static int uv_mmtimer_mmap(struct file file, struct vm_area_struct vma);
	44
	45	/*
	46	* Period in femtoseconds (10^-15 s)
	47	*/
	48	static unsigned long uv_mmtimer_femtoperiod;
	49
	50	static const struct file_operations uv_mmtimer_fops = {
	51	.owner = THIS_MODULE,
	52	.mmap = uv_mmtimer_mmap,
	53	.unlocked_ioctl = uv_mmtimer_ioctl,
6038f373	54	.llseek = noop_llseek,
fbd8ae10 DS	55	};
	56
	57	/**
	58	* uv_mmtimer_ioctl - ioctl interface for /dev/uv_mmtimer
	59	* @file: file structure for the device
	60	* @cmd: command to execute
	61	* @arg: optional argument to command
	62	*
	63	* Executes the command specified by @cmd. Returns 0 for success, < 0 for
	64	* failure.
	65	*
	66	* Valid commands:
	67	*
	68	* %MMTIMER_GETOFFSET - Should return the offset (relative to the start
	69	* of the page where the registers are mapped) for the counter in question.
	70	*
	71	* %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
	72	* seconds
	73	*
	74	* %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
	75	* specified by @arg
	76	*
	77	* %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
	78	*
	79	* %MMTIMER_MMAPAVAIL - Returns 1 if registers can be mmap'd into userspace
	80	*
	81	* %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
	82	* in the address specified by @arg.
	83	*/
	84	static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
	85	unsigned long arg)
	86	{
	87	int ret = 0;
	88
	89	switch (cmd) {
	90	case MMTIMER_GETOFFSET: /* offset of the counter */
	91	/*
aca3bb59 DS	92	* Starting with HUB rev 2.0, the UV RTC register is
	93	* replicated across all cachelines of it's own page.
	94	* This allows faster simultaneous reads from a given socket.
	95	*
	96	* The offset returned is in 64 bit units.
fbd8ae10	97	*/
aca3bb59 DS	98	if (uv_get_min_hub_revision_id() == 1)
aca3bb59 DS	99	ret = 0;
fbd8ae10	100	else
aca3bb59 DS	101	ret = ((uv_blade_processor_id() * L1_CACHE_BYTES) %
aca3bb59 DS	102	PAGE_SIZE) / 8;
fbd8ae10 DS	103	break;
	104
	105	case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
	106	if (copy_to_user((unsigned long __user *)arg,
	107	&uv_mmtimer_femtoperiod, sizeof(unsigned long)))
	108	ret = -EFAULT;
	109	break;
	110
	111	case MMTIMER_GETFREQ: /* frequency in Hz */
	112	if (copy_to_user((unsigned long __user *)arg,
	113	&sn_rtc_cycles_per_second,
	114	sizeof(unsigned long)))
	115	ret = -EFAULT;
	116	break;
	117
	118	case MMTIMER_GETBITS: /* number of bits in the clock */
	119	ret = hweight64(UVH_RTC_REAL_TIME_CLOCK_MASK);
	120	break;
	121
aca3bb59 DS	122	case MMTIMER_MMAPAVAIL:
aca3bb59 DS	123	ret = 1;
fbd8ae10 DS	124	break;
	125
	126	case MMTIMER_GETCOUNTER:
	127	if (copy_to_user((unsigned long __user *)arg,
	128	(unsigned long *)uv_local_mmr_address(UVH_RTC),
	129	sizeof(unsigned long)))
	130	ret = -EFAULT;
	131	break;
	132	default:
	133	ret = -ENOTTY;
	134	break;
	135	}
	136	return ret;
	137	}
	138
	139	/**
	140	* uv_mmtimer_mmap - maps the clock's registers into userspace
	141	* @file: file structure for the device
	142	* @vma: VMA to map the registers into
	143	*
	144	* Calls remap_pfn_range() to map the clock's registers into
	145	* the calling process' address space.
	146	*/
	147	static int uv_mmtimer_mmap(struct file file, struct vm_area_struct vma)
	148	{
	149	unsigned long uv_mmtimer_addr;
	150
	151	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
	152	return -EINVAL;
	153
	154	if (vma->vm_flags & VM_WRITE)
	155	return -EPERM;
	156
	157	if (PAGE_SIZE > (1 << 16))
	158	return -ENOSYS;
	159
	160	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	161
	162	uv_mmtimer_addr = UV_LOCAL_MMR_BASE \| UVH_RTC;
	163	uv_mmtimer_addr &= ~(PAGE_SIZE - 1);
	164	uv_mmtimer_addr &= 0xfffffffffffffffUL;
	165
	166	if (remap_pfn_range(vma, vma->vm_start, uv_mmtimer_addr >> PAGE_SHIFT,
	167	PAGE_SIZE, vma->vm_page_prot)) {
	168	printk(KERN_ERR "remap_pfn_range failed in uv_mmtimer_mmap\n");
	169	return -EAGAIN;
	170	}
	171
	172	return 0;
	173	}
	174
	175	static struct miscdevice uv_mmtimer_miscdev = {
	176	MISC_DYNAMIC_MINOR,
	177	UV_MMTIMER_NAME,
	178	&uv_mmtimer_fops
	179	};
	180
	181
	182	/**
	183	* uv_mmtimer_init - device initialization routine
	184	*
	185	* Does initial setup for the uv_mmtimer device.
	186	*/
	187	static int __init uv_mmtimer_init(void)
188	{
189	if (!is_uv_system()) {
190	printk(KERN_ERR "%s: Hardware unsupported\n", UV_MMTIMER_NAME);
191	return -1;
192	}
193
194	/*
195	* Sanity check the cycles/sec variable
196	*/
197	if (sn_rtc_cycles_per_second < 100000) {
198	printk(KERN_ERR "%s: unable to determine clock frequency\n",
199	UV_MMTIMER_NAME);
200	return -1;
201	}
202
203	uv_mmtimer_femtoperiod = ((unsigned long)1E15 +
204	sn_rtc_cycles_per_second / 2) /
205	sn_rtc_cycles_per_second;
206
207	if (misc_register(&uv_mmtimer_miscdev)) {
208	printk(KERN_ERR "%s: failed to register device\n",
209	UV_MMTIMER_NAME);
210	return -1;
211	}
212
213	printk(KERN_INFO "%s: v%s, %ld MHz\n", UV_MMTIMER_DESC,
214	UV_MMTIMER_VERSION,
215	sn_rtc_cycles_per_second/(unsigned long)1E6);
216
217	return 0;
218	}
219
220	module_init(uv_mmtimer_init);