/*
* 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 <[email protected]>");
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);
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