drivers/char/uv_mmtimer.c: add memory mapped RTC driver for UV (fbd8ae10) · Commits · e / devices / android_kernel_teracube_2e

Documentation/ioctl/ioctl-number.txt

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		@@ -135,6 +135,7 @@ Code Seq# Include File Comments
		<http://mikonos.dia.unisa.it/tcfs>
		'l' 40-7F linux/udf_fs_i.h in development:
		<http://sourceforge.net/projects/linux-udf/>
		'm' 00-09 linux/mmtimer.h
		'm' all linux/mtio.h conflict!
		'm' all linux/soundcard.h conflict!
		'm' all linux/synclink.h conflict!

drivers/char/Kconfig

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		@@ -1087,6 +1087,14 @@ config MMTIMER
		The mmtimer device allows direct userspace access to the
		Altix system timer.

		config UV_MMTIMER
		tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
		depends on X86_UV
		default m
		help
		The uv_mmtimer device allows direct userspace access to the
		UV system timer.

		source "drivers/char/tpm/Kconfig"

		config TELCLOCK

drivers/char/Makefile

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		@@ -58,6 +58,7 @@ obj-$(CONFIG_RAW_DRIVER) += raw.o
		obj-$(CONFIG_SGI_SNSC) += snsc.o snsc_event.o
		obj-$(CONFIG_MSPEC) += mspec.o
		obj-$(CONFIG_MMTIMER) += mmtimer.o
		obj-$(CONFIG_UV_MMTIMER) += uv_mmtimer.o
		obj-$(CONFIG_VIOTAPE) += viotape.o
		obj-$(CONFIG_HVCS) += hvcs.o
		obj-$(CONFIG_IBM_BSR) += bsr.o

drivers/char/uv_mmtimer.c

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		/*
		* 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 <linux/smp_lock.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,
		};

		/**
		* 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 */
		/*
		* UV RTC register is on its own page
		*/
		if (PAGE_SIZE <= (1 << 16))
		ret = ((UV_LOCAL_MMR_BASE \| UVH_RTC) & (PAGE_SIZE-1))
		/ 8;
		else
		ret = -ENOSYS;
		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: /* can we mmap the clock into userspace? */
		ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0;
		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);