Message-Id: <20170526090311.3377-2-hch@lst.de>
Date:   Fri, 26 May 2017 12:03:10 +0300
From:   Christoph Hellwig <hch@....de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Dimitri Sivanich <sivanich@....com>,
        Mike Travis <mike.travis@....com>, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] remove the SGI SN2 mmtimer driver

This driver supports direct system clock access on the ancient SGI SN2
IA64 systems, and implement the only non-builtin k_clock instance.
Remove it as any remaining IA64 altix user will be running just as old
distros anyway.

Note that this does not affect the never uv_mmtimer driver for x86-based
Altix systems.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 drivers/char/Kconfig   |   9 -
 drivers/char/Makefile  |   1 -
 drivers/char/mmtimer.c | 858 -------------------------------------------------
 3 files changed, 868 deletions(-)
 delete mode 100644 drivers/char/mmtimer.c

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 31adbebf812e..2af70014ee5a 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -539,15 +539,6 @@ config HANGCHECK_TIMER
 	  out to lunch past a certain margin.  It can reboot the system
 	  or merely print a warning.
 
-config MMTIMER
-	tristate "MMTIMER Memory mapped RTC for SGI Altix"
-	depends on IA64_GENERIC || IA64_SGI_SN2
-	depends on POSIX_TIMERS
-	default y
-	help
-	  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
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 6e6c244a66a0..53e33720818c 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -10,7 +10,6 @@ obj-$(CONFIG_VIRTIO_CONSOLE)	+= virtio_console.o
 obj-$(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-$(CONFIG_IBM_BSR)		+= bsr.o
 obj-$(CONFIG_SGI_MBCS)		+= mbcs.o
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
deleted file mode 100644
index 0e7fcb04f01e..000000000000
--- a/drivers/char/mmtimer.c
+++ /dev/null
@@ -1,858 +0,0 @@
-/*
- * Timer device implementation for SGI SN platforms.
- *
- * 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) 2001-2006 Silicon Graphics, Inc.  All rights reserved.
- *
- * This driver exports an API that should be supportable by any HPET or IA-PC
- * multimedia timer.  The code below is currently specific to the SGI Altix
- * SHub RTC, however.
- *
- * 11/01/01 - jbarnes - initial revision
- * 9/10/04 - Christoph Lameter - remove interrupt support for kernel inclusion
- * 10/1/04 - Christoph Lameter - provide posix clock CLOCK_SGI_CYCLE
- * 10/13/04 - Christoph Lameter, Dimitri Sivanich - provide timer interrupt
- *		support via the posix timer interface
- */
-
-#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/mutex.h>
-#include <linux/slab.h>
-
-#include <linux/uaccess.h>
-#include <asm/sn/addrs.h>
-#include <asm/sn/intr.h>
-#include <asm/sn/shub_mmr.h>
-#include <asm/sn/nodepda.h>
-#include <asm/sn/shubio.h>
-
-MODULE_AUTHOR("Jesse Barnes <jbarnes@....com>");
-MODULE_DESCRIPTION("SGI Altix RTC Timer");
-MODULE_LICENSE("GPL");
-
-/* name of the device, usually in /dev */
-#define MMTIMER_NAME "mmtimer"
-#define MMTIMER_DESC "SGI Altix RTC Timer"
-#define MMTIMER_VERSION "2.1"
-
-#define RTC_BITS 55 /* 55 bits for this implementation */
-
-static struct k_clock sgi_clock;
-
-extern unsigned long sn_rtc_cycles_per_second;
-
-#define RTC_COUNTER_ADDR        ((long *)LOCAL_MMR_ADDR(SH_RTC))
-
-#define rtc_time()              (*RTC_COUNTER_ADDR)
-
-static DEFINE_MUTEX(mmtimer_mutex);
-static long mmtimer_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg);
-static int mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
-
-/*
- * Period in femtoseconds (10^-15 s)
- */
-static unsigned long mmtimer_femtoperiod = 0;
-
-static const struct file_operations mmtimer_fops = {
-	.owner = THIS_MODULE,
-	.mmap =	mmtimer_mmap,
-	.unlocked_ioctl = mmtimer_ioctl,
-	.llseek = noop_llseek,
-};
-
-/*
- * We only have comparison registers RTC1-4 currently available per
- * node.  RTC0 is used by SAL.
- */
-/* Check for an RTC interrupt pending */
-static int mmtimer_int_pending(int comparator)
-{
-	if (HUB_L((unsigned long *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED)) &
-			SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator)
-		return 1;
-	else
-		return 0;
-}
-
-/* Clear the RTC interrupt pending bit */
-static void mmtimer_clr_int_pending(int comparator)
-{
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_EVENT_OCCURRED_ALIAS),
-		SH_EVENT_OCCURRED_RTC1_INT_MASK << comparator);
-}
-
-/* Setup timer on comparator RTC1 */
-static void mmtimer_setup_int_0(int cpu, u64 expires)
-{
-	u64 val;
-
-	/* Disable interrupt */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 0UL);
-
-	/* Initialize comparator value */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), -1L);
-
-	/* Clear pending bit */
-	mmtimer_clr_int_pending(0);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC1_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC1_INT_CONFIG_PID_SHFT);
-
-	/* Set configuration */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_CONFIG), val);
-
-	/* Enable RTC interrupts */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE), 1UL);
-
-	/* Initialize comparator value */
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPB), expires);
-
-
-}
-
-/* Setup timer on comparator RTC2 */
-static void mmtimer_setup_int_1(int cpu, u64 expires)
-{
-	u64 val;
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 0UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), -1L);
-
-	mmtimer_clr_int_pending(1);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC2_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC2_INT_CONFIG_PID_SHFT);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_CONFIG), val);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE), 1UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPC), expires);
-}
-
-/* Setup timer on comparator RTC3 */
-static void mmtimer_setup_int_2(int cpu, u64 expires)
-{
-	u64 val;
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 0UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), -1L);
-
-	mmtimer_clr_int_pending(2);
-
-	val = ((u64)SGI_MMTIMER_VECTOR << SH_RTC3_INT_CONFIG_IDX_SHFT) |
-		((u64)cpu_physical_id(cpu) <<
-			SH_RTC3_INT_CONFIG_PID_SHFT);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_CONFIG), val);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE), 1UL);
-
-	HUB_S((u64 *)LOCAL_MMR_ADDR(SH_INT_CMPD), expires);
-}
-
-/*
- * This function must be called with interrupts disabled and preemption off
- * in order to insure that the setup succeeds in a deterministic time frame.
- * It will check if the interrupt setup succeeded.
- */
-static int mmtimer_setup(int cpu, int comparator, unsigned long expires,
-	u64 *set_completion_time)
-{
-	switch (comparator) {
-	case 0:
-		mmtimer_setup_int_0(cpu, expires);
-		break;
-	case 1:
-		mmtimer_setup_int_1(cpu, expires);
-		break;
-	case 2:
-		mmtimer_setup_int_2(cpu, expires);
-		break;
-	}
-	/* We might've missed our expiration time */
-	*set_completion_time = rtc_time();
-	if (*set_completion_time <= expires)
-		return 1;
-
-	/*
-	 * If an interrupt is already pending then its okay
-	 * if not then we failed
-	 */
-	return mmtimer_int_pending(comparator);
-}
-
-static int mmtimer_disable_int(long nasid, int comparator)
-{
-	switch (comparator) {
-	case 0:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC1_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC1_INT_ENABLE, 0UL);
-		break;
-	case 1:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC2_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC2_INT_ENABLE, 0UL);
-		break;
-	case 2:
-		nasid == -1 ? HUB_S((u64 *)LOCAL_MMR_ADDR(SH_RTC3_INT_ENABLE),
-			0UL) : REMOTE_HUB_S(nasid, SH_RTC3_INT_ENABLE, 0UL);
-		break;
-	default:
-		return -EFAULT;
-	}
-	return 0;
-}
-
-#define COMPARATOR	1		/* The comparator to use */
-
-#define TIMER_OFF	0xbadcabLL	/* Timer is not setup */
-#define TIMER_SET	0		/* Comparator is set for this timer */
-
-#define MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT 40
-
-/* There is one of these for each timer */
-struct mmtimer {
-	struct rb_node list;
-	struct k_itimer *timer;
-	int cpu;
-};
-
-struct mmtimer_node {
-	spinlock_t lock ____cacheline_aligned;
-	struct rb_root timer_head;
-	struct rb_node *next;
-	struct tasklet_struct tasklet;
-};
-static struct mmtimer_node *timers;
-
-static unsigned mmtimer_interval_retry_increment =
-	MMTIMER_INTERVAL_RETRY_INCREMENT_DEFAULT;
-module_param(mmtimer_interval_retry_increment, uint, 0644);
-MODULE_PARM_DESC(mmtimer_interval_retry_increment,
-	"RTC ticks to add to expiration on interval retry (default 40)");
-
-/*
- * Add a new mmtimer struct to the node's mmtimer list.
- * This function assumes the struct mmtimer_node is locked.
- */
-static void mmtimer_add_list(struct mmtimer *n)
-{
-	int nodeid = n->timer->it.mmtimer.node;
-	unsigned long expires = n->timer->it.mmtimer.expires;
-	struct rb_node **link = &timers[nodeid].timer_head.rb_node;
-	struct rb_node *parent = NULL;
-	struct mmtimer *x;
-
-	/*
-	 * Find the right place in the rbtree:
-	 */
-	while (*link) {
-		parent = *link;
-		x = rb_entry(parent, struct mmtimer, list);
-
-		if (expires < x->timer->it.mmtimer.expires)
-			link = &(*link)->rb_left;
-		else
-			link = &(*link)->rb_right;
-	}
-
-	/*
-	 * Insert the timer to the rbtree and check whether it
-	 * replaces the first pending timer
-	 */
-	rb_link_node(&n->list, parent, link);
-	rb_insert_color(&n->list, &timers[nodeid].timer_head);
-
-	if (!timers[nodeid].next || expires < rb_entry(timers[nodeid].next,
-			struct mmtimer, list)->timer->it.mmtimer.expires)
-		timers[nodeid].next = &n->list;
-}
-
-/*
- * Set the comparator for the next timer.
- * This function assumes the struct mmtimer_node is locked.
- */
-static void mmtimer_set_next_timer(int nodeid)
-{
-	struct mmtimer_node *n = &timers[nodeid];
-	struct mmtimer *x;
-	struct k_itimer *t;
-	u64 expires, exp, set_completion_time;
-	int i;
-
-restart:
-	if (n->next == NULL)
-		return;
-
-	x = rb_entry(n->next, struct mmtimer, list);
-	t = x->timer;
-	if (!t->it.mmtimer.incr) {
-		/* Not an interval timer */
-		if (!mmtimer_setup(x->cpu, COMPARATOR,
-					t->it.mmtimer.expires,
-					&set_completion_time)) {
-			/* Late setup, fire now */
-			tasklet_schedule(&n->tasklet);
-		}
-		return;
-	}
-
-	/* Interval timer */
-	i = 0;
-	expires = exp = t->it.mmtimer.expires;
-	while (!mmtimer_setup(x->cpu, COMPARATOR, expires,
-				&set_completion_time)) {
-		int to;
-
-		i++;
-		expires = set_completion_time +
-				mmtimer_interval_retry_increment + (1 << i);
-		/* Calculate overruns as we go. */
-		to = ((u64)(expires - exp) / t->it.mmtimer.incr);
-		if (to) {
-			t->it_overrun += to;
-			t->it.mmtimer.expires += t->it.mmtimer.incr * to;
-			exp = t->it.mmtimer.expires;
-		}
-		if (i > 20) {
-			printk(KERN_ALERT "mmtimer: cannot reschedule timer\n");
-			t->it.mmtimer.clock = TIMER_OFF;
-			n->next = rb_next(&x->list);
-			rb_erase(&x->list, &n->timer_head);
-			kfree(x);
-			goto restart;
-		}
-	}
-}
-
-/**
- * mmtimer_ioctl - ioctl interface for /dev/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 the 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 mmtimer_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg)
-{
-	int ret = 0;
-
-	mutex_lock(&mmtimer_mutex);
-
-	switch (cmd) {
-	case MMTIMER_GETOFFSET:	/* offset of the counter */
-		/*
-		 * SN RTC registers are on their own 64k page
-		 */
-		if(PAGE_SIZE <= (1 << 16))
-			ret = (((long)RTC_COUNTER_ADDR) & (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,
-				&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 = RTC_BITS;
-		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,
-				RTC_COUNTER_ADDR, sizeof(unsigned long)))
-			ret = -EFAULT;
-		break;
-	default:
-		ret = -ENOTTY;
-		break;
-	}
-	mutex_unlock(&mmtimer_mutex);
-	return ret;
-}
-
-/**
- * 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 mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	unsigned long 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);
-
-	mmtimer_addr = __pa(RTC_COUNTER_ADDR);
-	mmtimer_addr &= ~(PAGE_SIZE - 1);
-	mmtimer_addr &= 0xfffffffffffffffUL;
-
-	if (remap_pfn_range(vma, vma->vm_start, mmtimer_addr >> PAGE_SHIFT,
-					PAGE_SIZE, vma->vm_page_prot)) {
-		printk(KERN_ERR "remap_pfn_range failed in mmtimer.c\n");
-		return -EAGAIN;
-	}
-
-	return 0;
-}
-
-static struct miscdevice mmtimer_miscdev = {
-	.minor = SGI_MMTIMER,
-	.name = MMTIMER_NAME,
-	.fops = &mmtimer_fops
-};
-
-static struct timespec sgi_clock_offset;
-static int sgi_clock_period;
-
-/*
- * Posix Timer Interface
- */
-
-static struct timespec sgi_clock_offset;
-static int sgi_clock_period;
-
-static int sgi_clock_get(clockid_t clockid, struct timespec64 *tp)
-{
-	u64 nsec;
-
-	nsec = rtc_time() * sgi_clock_period
-			+ sgi_clock_offset.tv_nsec;
-	*tp = ns_to_timespec64(nsec);
-	tp->tv_sec += sgi_clock_offset.tv_sec;
-	return 0;
-};
-
-static int sgi_clock_set(const clockid_t clockid, const struct timespec64 *tp)
-{
-
-	u64 nsec;
-	u32 rem;
-
-	nsec = rtc_time() * sgi_clock_period;
-
-	sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
-
-	if (rem <= tp->tv_nsec)
-		sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
-	else {
-		sgi_clock_offset.tv_nsec = tp->tv_sec + NSEC_PER_SEC - rem;
-		sgi_clock_offset.tv_sec--;
-	}
-	return 0;
-}
-
-/**
- * mmtimer_interrupt - timer interrupt handler
- * @irq: irq received
- * @dev_id: device the irq came from
- *
- * Called when one of the comarators matches the counter, This
- * routine will send signals to processes that have requested
- * them.
- *
- * This interrupt is run in an interrupt context
- * by the SHUB. It is therefore safe to locally access SHub
- * registers.
- */
-static irqreturn_t
-mmtimer_interrupt(int irq, void *dev_id)
-{
-	unsigned long expires = 0;
-	int result = IRQ_NONE;
-	unsigned indx = cpu_to_node(smp_processor_id());
-	struct mmtimer *base;
-
-	spin_lock(&timers[indx].lock);
-	base = rb_entry(timers[indx].next, struct mmtimer, list);
-	if (base == NULL) {
-		spin_unlock(&timers[indx].lock);
-		return result;
-	}
-
-	if (base->cpu == smp_processor_id()) {
-		if (base->timer)
-			expires = base->timer->it.mmtimer.expires;
-		/* expires test won't work with shared irqs */
-		if ((mmtimer_int_pending(COMPARATOR) > 0) ||
-			(expires && (expires <= rtc_time()))) {
-			mmtimer_clr_int_pending(COMPARATOR);
-			tasklet_schedule(&timers[indx].tasklet);
-			result = IRQ_HANDLED;
-		}
-	}
-	spin_unlock(&timers[indx].lock);
-	return result;
-}
-
-static void mmtimer_tasklet(unsigned long data)
-{
-	int nodeid = data;
-	struct mmtimer_node *mn = &timers[nodeid];
-	struct mmtimer *x;
-	struct k_itimer *t;
-	unsigned long flags;
-
-	/* Send signal and deal with periodic signals */
-	spin_lock_irqsave(&mn->lock, flags);
-	if (!mn->next)
-		goto out;
-
-	x = rb_entry(mn->next, struct mmtimer, list);
-	t = x->timer;
-
-	if (t->it.mmtimer.clock == TIMER_OFF)
-		goto out;
-
-	t->it_overrun = 0;
-
-	mn->next = rb_next(&x->list);
-	rb_erase(&x->list, &mn->timer_head);
-
-	if (posix_timer_event(t, 0) != 0)
-		t->it_overrun++;
-
-	if(t->it.mmtimer.incr) {
-		t->it.mmtimer.expires += t->it.mmtimer.incr;
-		mmtimer_add_list(x);
-	} else {
-		/* Ensure we don't false trigger in mmtimer_interrupt */
-		t->it.mmtimer.clock = TIMER_OFF;
-		t->it.mmtimer.expires = 0;
-		kfree(x);
-	}
-	/* Set comparator for next timer, if there is one */
-	mmtimer_set_next_timer(nodeid);
-
-	t->it_overrun_last = t->it_overrun;
-out:
-	spin_unlock_irqrestore(&mn->lock, flags);
-}
-
-static int sgi_timer_create(struct k_itimer *timer)
-{
-	/* Insure that a newly created timer is off */
-	timer->it.mmtimer.clock = TIMER_OFF;
-	return 0;
-}
-
-/* This does not really delete a timer. It just insures
- * that the timer is not active
- *
- * Assumption: it_lock is already held with irq's disabled
- */
-static int sgi_timer_del(struct k_itimer *timr)
-{
-	cnodeid_t nodeid = timr->it.mmtimer.node;
-	unsigned long irqflags;
-
-	spin_lock_irqsave(&timers[nodeid].lock, irqflags);
-	if (timr->it.mmtimer.clock != TIMER_OFF) {
-		unsigned long expires = timr->it.mmtimer.expires;
-		struct rb_node *n = timers[nodeid].timer_head.rb_node;
-		struct mmtimer *uninitialized_var(t);
-		int r = 0;
-
-		timr->it.mmtimer.clock = TIMER_OFF;
-		timr->it.mmtimer.expires = 0;
-
-		while (n) {
-			t = rb_entry(n, struct mmtimer, list);
-			if (t->timer == timr)
-				break;
-
-			if (expires < t->timer->it.mmtimer.expires)
-				n = n->rb_left;
-			else
-				n = n->rb_right;
-		}
-
-		if (!n) {
-			spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-			return 0;
-		}
-
-		if (timers[nodeid].next == n) {
-			timers[nodeid].next = rb_next(n);
-			r = 1;
-		}
-
-		rb_erase(n, &timers[nodeid].timer_head);
-		kfree(t);
-
-		if (r) {
-			mmtimer_disable_int(cnodeid_to_nasid(nodeid),
-				COMPARATOR);
-			mmtimer_set_next_timer(nodeid);
-		}
-	}
-	spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-	return 0;
-}
-
-/* Assumption: it_lock is already held with irq's disabled */
-static void sgi_timer_get(struct k_itimer *timr, struct itimerspec64 *cur_setting)
-{
-
-	if (timr->it.mmtimer.clock == TIMER_OFF) {
-		cur_setting->it_interval.tv_nsec = 0;
-		cur_setting->it_interval.tv_sec = 0;
-		cur_setting->it_value.tv_nsec = 0;
-		cur_setting->it_value.tv_sec =0;
-		return;
-	}
-
-	cur_setting->it_interval = ns_to_timespec64(timr->it.mmtimer.incr * sgi_clock_period);
-	cur_setting->it_value = ns_to_timespec64((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
-}
-
-
-static int sgi_timer_set(struct k_itimer *timr, int flags,
-	struct itimerspec64 *new_setting,
-	struct itimerspec64 *old_setting)
-{
-	unsigned long when, period, irqflags;
-	int err = 0;
-	cnodeid_t nodeid;
-	struct mmtimer *base;
-	struct rb_node *n;
-
-	if (old_setting)
-		sgi_timer_get(timr, old_setting);
-
-	sgi_timer_del(timr);
-	when = timespec64_to_ns(&new_setting->it_value);
-	period = timespec64_to_ns(&new_setting->it_interval);
-
-	if (when == 0)
-		/* Clear timer */
-		return 0;
-
-	base = kmalloc(sizeof(struct mmtimer), GFP_KERNEL);
-	if (base == NULL)
-		return -ENOMEM;
-
-	if (flags & TIMER_ABSTIME) {
-		struct timespec64 n;
-		unsigned long now;
-
-		getnstimeofday64(&n);
-		now = timespec64_to_ns(&n);
-		if (when > now)
-			when -= now;
-		else
-			/* Fire the timer immediately */
-			when = 0;
-	}
-
-	/*
-	 * Convert to sgi clock period. Need to keep rtc_time() as near as possible
-	 * to getnstimeofday() in order to be as faithful as possible to the time
-	 * specified.
-	 */
-	when = (when + sgi_clock_period - 1) / sgi_clock_period + rtc_time();
-	period = (period + sgi_clock_period - 1)  / sgi_clock_period;
-
-	/*
-	 * We are allocating a local SHub comparator. If we would be moved to another
-	 * cpu then another SHub may be local to us. Prohibit that by switching off
-	 * preemption.
-	 */
-	preempt_disable();
-
-	nodeid =  cpu_to_node(smp_processor_id());
-
-	/* Lock the node timer structure */
-	spin_lock_irqsave(&timers[nodeid].lock, irqflags);
-
-	base->timer = timr;
-	base->cpu = smp_processor_id();
-
-	timr->it.mmtimer.clock = TIMER_SET;
-	timr->it.mmtimer.node = nodeid;
-	timr->it.mmtimer.incr = period;
-	timr->it.mmtimer.expires = when;
-
-	n = timers[nodeid].next;
-
-	/* Add the new struct mmtimer to node's timer list */
-	mmtimer_add_list(base);
-
-	if (timers[nodeid].next == n) {
-		/* No need to reprogram comparator for now */
-		spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-		preempt_enable();
-		return err;
-	}
-
-	/* We need to reprogram the comparator */
-	if (n)
-		mmtimer_disable_int(cnodeid_to_nasid(nodeid), COMPARATOR);
-
-	mmtimer_set_next_timer(nodeid);
-
-	/* Unlock the node timer structure */
-	spin_unlock_irqrestore(&timers[nodeid].lock, irqflags);
-
-	preempt_enable();
-
-	return err;
-}
-
-static int sgi_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
-{
-	tp->tv_sec = 0;
-	tp->tv_nsec = sgi_clock_period;
-	return 0;
-}
-
-static struct k_clock sgi_clock = {
-	.clock_set	= sgi_clock_set,
-	.clock_get	= sgi_clock_get,
-	.clock_getres	= sgi_clock_getres,
-	.timer_create	= sgi_timer_create,
-	.timer_set	= sgi_timer_set,
-	.timer_del	= sgi_timer_del,
-	.timer_get	= sgi_timer_get
-};
-
-/**
- * mmtimer_init - device initialization routine
- *
- * Does initial setup for the mmtimer device.
- */
-static int __init mmtimer_init(void)
-{
-	cnodeid_t node, maxn = -1;
-
-	if (!ia64_platform_is("sn2"))
-		return 0;
-
-	/*
-	 * Sanity check the cycles/sec variable
-	 */
-	if (sn_rtc_cycles_per_second < 100000) {
-		printk(KERN_ERR "%s: unable to determine clock frequency\n",
-		       MMTIMER_NAME);
-		goto out1;
-	}
-
-	mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
-			       2) / sn_rtc_cycles_per_second;
-
-	if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
-		printk(KERN_WARNING "%s: unable to allocate interrupt.",
-			MMTIMER_NAME);
-		goto out1;
-	}
-
-	if (misc_register(&mmtimer_miscdev)) {
-		printk(KERN_ERR "%s: failed to register device\n",
-		       MMTIMER_NAME);
-		goto out2;
-	}
-
-	/* Get max numbered node, calculate slots needed */
-	for_each_online_node(node) {
-		maxn = node;
-	}
-	maxn++;
-
-	/* Allocate list of node ptrs to mmtimer_t's */
-	timers = kzalloc(sizeof(struct mmtimer_node)*maxn, GFP_KERNEL);
-	if (!timers) {
-		printk(KERN_ERR "%s: failed to allocate memory for device\n",
-				MMTIMER_NAME);
-		goto out3;
-	}
-
-	/* Initialize struct mmtimer's for each online node */
-	for_each_online_node(node) {
-		spin_lock_init(&timers[node].lock);
-		tasklet_init(&timers[node].tasklet, mmtimer_tasklet,
-			(unsigned long) node);
-	}
-
-	sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
-	posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
-
-	printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
-	       sn_rtc_cycles_per_second/(unsigned long)1E6);
-
-	return 0;
-
-out3:
-	misc_deregister(&mmtimer_miscdev);
-out2:
-	free_irq(SGI_MMTIMER_VECTOR, NULL);
-out1:
-	return -1;
-}
-
-module_init(mmtimer_init);
-- 
2.11.0

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