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-rw-r--r--drivers/char/hpet.c1047
1 files changed, 1047 insertions, 0 deletions
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
new file mode 100644
index 000000000..ee71376f1
--- /dev/null
+++ b/drivers/char/hpet.c
@@ -0,0 +1,1047 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel & MS High Precision Event Timer Implementation.
+ *
+ * Copyright (C) 2003 Intel Corporation
+ * Venki Pallipadi
+ * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
+ * Bob Picco <robert.picco@hp.com>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/major.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/poll.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/spinlock.h>
+#include <linux/sysctl.h>
+#include <linux/wait.h>
+#include <linux/sched/signal.h>
+#include <linux/bcd.h>
+#include <linux/seq_file.h>
+#include <linux/bitops.h>
+#include <linux/compat.h>
+#include <linux/clocksource.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/acpi.h>
+#include <linux/hpet.h>
+#include <asm/current.h>
+#include <asm/irq.h>
+#include <asm/div64.h>
+
+/*
+ * The High Precision Event Timer driver.
+ * This driver is closely modelled after the rtc.c driver.
+ * See HPET spec revision 1.
+ */
+#define HPET_USER_FREQ (64)
+#define HPET_DRIFT (500)
+
+#define HPET_RANGE_SIZE 1024 /* from HPET spec */
+
+
+/* WARNING -- don't get confused. These macros are never used
+ * to write the (single) counter, and rarely to read it.
+ * They're badly named; to fix, someday.
+ */
+#if BITS_PER_LONG == 64
+#define write_counter(V, MC) writeq(V, MC)
+#define read_counter(MC) readq(MC)
+#else
+#define write_counter(V, MC) writel(V, MC)
+#define read_counter(MC) readl(MC)
+#endif
+
+static DEFINE_MUTEX(hpet_mutex); /* replaces BKL */
+static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
+
+/* This clocksource driver currently only works on ia64 */
+#ifdef CONFIG_IA64
+static void __iomem *hpet_mctr;
+
+static u64 read_hpet(struct clocksource *cs)
+{
+ return (u64)read_counter((void __iomem *)hpet_mctr);
+}
+
+static struct clocksource clocksource_hpet = {
+ .name = "hpet",
+ .rating = 250,
+ .read = read_hpet,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+static struct clocksource *hpet_clocksource;
+#endif
+
+/* A lock for concurrent access by app and isr hpet activity. */
+static DEFINE_SPINLOCK(hpet_lock);
+
+#define HPET_DEV_NAME (7)
+
+struct hpet_dev {
+ struct hpets *hd_hpets;
+ struct hpet __iomem *hd_hpet;
+ struct hpet_timer __iomem *hd_timer;
+ unsigned long hd_ireqfreq;
+ unsigned long hd_irqdata;
+ wait_queue_head_t hd_waitqueue;
+ struct fasync_struct *hd_async_queue;
+ unsigned int hd_flags;
+ unsigned int hd_irq;
+ unsigned int hd_hdwirq;
+ char hd_name[HPET_DEV_NAME];
+};
+
+struct hpets {
+ struct hpets *hp_next;
+ struct hpet __iomem *hp_hpet;
+ unsigned long hp_hpet_phys;
+ struct clocksource *hp_clocksource;
+ unsigned long long hp_tick_freq;
+ unsigned long hp_delta;
+ unsigned int hp_ntimer;
+ unsigned int hp_which;
+ struct hpet_dev hp_dev[];
+};
+
+static struct hpets *hpets;
+
+#define HPET_OPEN 0x0001
+#define HPET_IE 0x0002 /* interrupt enabled */
+#define HPET_PERIODIC 0x0004
+#define HPET_SHARED_IRQ 0x0008
+
+static irqreturn_t hpet_interrupt(int irq, void *data)
+{
+ struct hpet_dev *devp;
+ unsigned long isr;
+
+ devp = data;
+ isr = 1 << (devp - devp->hd_hpets->hp_dev);
+
+ if ((devp->hd_flags & HPET_SHARED_IRQ) &&
+ !(isr & readl(&devp->hd_hpet->hpet_isr)))
+ return IRQ_NONE;
+
+ spin_lock(&hpet_lock);
+ devp->hd_irqdata++;
+
+ /*
+ * For non-periodic timers, increment the accumulator.
+ * This has the effect of treating non-periodic like periodic.
+ */
+ if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
+ unsigned long t, mc, base, k;
+ struct hpet __iomem *hpet = devp->hd_hpet;
+ struct hpets *hpetp = devp->hd_hpets;
+
+ t = devp->hd_ireqfreq;
+ read_counter(&devp->hd_timer->hpet_compare);
+ mc = read_counter(&hpet->hpet_mc);
+ /* The time for the next interrupt would logically be t + m,
+ * however, if we are very unlucky and the interrupt is delayed
+ * for longer than t then we will completely miss the next
+ * interrupt if we set t + m and an application will hang.
+ * Therefore we need to make a more complex computation assuming
+ * that there exists a k for which the following is true:
+ * k * t + base < mc + delta
+ * (k + 1) * t + base > mc + delta
+ * where t is the interval in hpet ticks for the given freq,
+ * base is the theoretical start value 0 < base < t,
+ * mc is the main counter value at the time of the interrupt,
+ * delta is the time it takes to write the a value to the
+ * comparator.
+ * k may then be computed as (mc - base + delta) / t .
+ */
+ base = mc % t;
+ k = (mc - base + hpetp->hp_delta) / t;
+ write_counter(t * (k + 1) + base,
+ &devp->hd_timer->hpet_compare);
+ }
+
+ if (devp->hd_flags & HPET_SHARED_IRQ)
+ writel(isr, &devp->hd_hpet->hpet_isr);
+ spin_unlock(&hpet_lock);
+
+ wake_up_interruptible(&devp->hd_waitqueue);
+
+ kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
+
+ return IRQ_HANDLED;
+}
+
+static void hpet_timer_set_irq(struct hpet_dev *devp)
+{
+ unsigned long v;
+ int irq, gsi;
+ struct hpet_timer __iomem *timer;
+
+ spin_lock_irq(&hpet_lock);
+ if (devp->hd_hdwirq) {
+ spin_unlock_irq(&hpet_lock);
+ return;
+ }
+
+ timer = devp->hd_timer;
+
+ /* we prefer level triggered mode */
+ v = readl(&timer->hpet_config);
+ if (!(v & Tn_INT_TYPE_CNF_MASK)) {
+ v |= Tn_INT_TYPE_CNF_MASK;
+ writel(v, &timer->hpet_config);
+ }
+ spin_unlock_irq(&hpet_lock);
+
+ v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
+ Tn_INT_ROUTE_CAP_SHIFT;
+
+ /*
+ * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
+ * legacy device. In IO APIC mode, we skip all the legacy IRQS.
+ */
+ if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
+ v &= ~0xf3df;
+ else
+ v &= ~0xffff;
+
+ for_each_set_bit(irq, &v, HPET_MAX_IRQ) {
+ if (irq >= nr_irqs) {
+ irq = HPET_MAX_IRQ;
+ break;
+ }
+
+ gsi = acpi_register_gsi(NULL, irq, ACPI_LEVEL_SENSITIVE,
+ ACPI_ACTIVE_LOW);
+ if (gsi > 0)
+ break;
+
+ /* FIXME: Setup interrupt source table */
+ }
+
+ if (irq < HPET_MAX_IRQ) {
+ spin_lock_irq(&hpet_lock);
+ v = readl(&timer->hpet_config);
+ v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
+ writel(v, &timer->hpet_config);
+ devp->hd_hdwirq = gsi;
+ spin_unlock_irq(&hpet_lock);
+ }
+ return;
+}
+
+static int hpet_open(struct inode *inode, struct file *file)
+{
+ struct hpet_dev *devp;
+ struct hpets *hpetp;
+ int i;
+
+ if (file->f_mode & FMODE_WRITE)
+ return -EINVAL;
+
+ mutex_lock(&hpet_mutex);
+ spin_lock_irq(&hpet_lock);
+
+ for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
+ for (i = 0; i < hpetp->hp_ntimer; i++)
+ if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
+ continue;
+ } else {
+ devp = &hpetp->hp_dev[i];
+ break;
+ }
+
+ if (!devp) {
+ spin_unlock_irq(&hpet_lock);
+ mutex_unlock(&hpet_mutex);
+ return -EBUSY;
+ }
+
+ file->private_data = devp;
+ devp->hd_irqdata = 0;
+ devp->hd_flags |= HPET_OPEN;
+ spin_unlock_irq(&hpet_lock);
+ mutex_unlock(&hpet_mutex);
+
+ hpet_timer_set_irq(devp);
+
+ return 0;
+}
+
+static ssize_t
+hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
+{
+ DECLARE_WAITQUEUE(wait, current);
+ unsigned long data;
+ ssize_t retval;
+ struct hpet_dev *devp;
+
+ devp = file->private_data;
+ if (!devp->hd_ireqfreq)
+ return -EIO;
+
+ if (count < sizeof(unsigned long))
+ return -EINVAL;
+
+ add_wait_queue(&devp->hd_waitqueue, &wait);
+
+ for ( ; ; ) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ spin_lock_irq(&hpet_lock);
+ data = devp->hd_irqdata;
+ devp->hd_irqdata = 0;
+ spin_unlock_irq(&hpet_lock);
+
+ if (data) {
+ break;
+ } else if (file->f_flags & O_NONBLOCK) {
+ retval = -EAGAIN;
+ goto out;
+ } else if (signal_pending(current)) {
+ retval = -ERESTARTSYS;
+ goto out;
+ }
+ schedule();
+ }
+
+ retval = put_user(data, (unsigned long __user *)buf);
+ if (!retval)
+ retval = sizeof(unsigned long);
+out:
+ __set_current_state(TASK_RUNNING);
+ remove_wait_queue(&devp->hd_waitqueue, &wait);
+
+ return retval;
+}
+
+static __poll_t hpet_poll(struct file *file, poll_table * wait)
+{
+ unsigned long v;
+ struct hpet_dev *devp;
+
+ devp = file->private_data;
+
+ if (!devp->hd_ireqfreq)
+ return 0;
+
+ poll_wait(file, &devp->hd_waitqueue, wait);
+
+ spin_lock_irq(&hpet_lock);
+ v = devp->hd_irqdata;
+ spin_unlock_irq(&hpet_lock);
+
+ if (v != 0)
+ return EPOLLIN | EPOLLRDNORM;
+
+ return 0;
+}
+
+#ifdef CONFIG_HPET_MMAP
+#ifdef CONFIG_HPET_MMAP_DEFAULT
+static int hpet_mmap_enabled = 1;
+#else
+static int hpet_mmap_enabled = 0;
+#endif
+
+static __init int hpet_mmap_enable(char *str)
+{
+ get_option(&str, &hpet_mmap_enabled);
+ pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled");
+ return 1;
+}
+__setup("hpet_mmap=", hpet_mmap_enable);
+
+static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct hpet_dev *devp;
+ unsigned long addr;
+
+ if (!hpet_mmap_enabled)
+ return -EACCES;
+
+ devp = file->private_data;
+ addr = devp->hd_hpets->hp_hpet_phys;
+
+ if (addr & (PAGE_SIZE - 1))
+ return -ENOSYS;
+
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ return vm_iomap_memory(vma, addr, PAGE_SIZE);
+}
+#else
+static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ return -ENOSYS;
+}
+#endif
+
+static int hpet_fasync(int fd, struct file *file, int on)
+{
+ struct hpet_dev *devp;
+
+ devp = file->private_data;
+
+ if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
+ return 0;
+ else
+ return -EIO;
+}
+
+static int hpet_release(struct inode *inode, struct file *file)
+{
+ struct hpet_dev *devp;
+ struct hpet_timer __iomem *timer;
+ int irq = 0;
+
+ devp = file->private_data;
+ timer = devp->hd_timer;
+
+ spin_lock_irq(&hpet_lock);
+
+ writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
+ &timer->hpet_config);
+
+ irq = devp->hd_irq;
+ devp->hd_irq = 0;
+
+ devp->hd_ireqfreq = 0;
+
+ if (devp->hd_flags & HPET_PERIODIC
+ && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
+ unsigned long v;
+
+ v = readq(&timer->hpet_config);
+ v ^= Tn_TYPE_CNF_MASK;
+ writeq(v, &timer->hpet_config);
+ }
+
+ devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
+ spin_unlock_irq(&hpet_lock);
+
+ if (irq)
+ free_irq(irq, devp);
+
+ file->private_data = NULL;
+ return 0;
+}
+
+static int hpet_ioctl_ieon(struct hpet_dev *devp)
+{
+ struct hpet_timer __iomem *timer;
+ struct hpet __iomem *hpet;
+ struct hpets *hpetp;
+ int irq;
+ unsigned long g, v, t, m;
+ unsigned long flags, isr;
+
+ timer = devp->hd_timer;
+ hpet = devp->hd_hpet;
+ hpetp = devp->hd_hpets;
+
+ if (!devp->hd_ireqfreq)
+ return -EIO;
+
+ spin_lock_irq(&hpet_lock);
+
+ if (devp->hd_flags & HPET_IE) {
+ spin_unlock_irq(&hpet_lock);
+ return -EBUSY;
+ }
+
+ devp->hd_flags |= HPET_IE;
+
+ if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
+ devp->hd_flags |= HPET_SHARED_IRQ;
+ spin_unlock_irq(&hpet_lock);
+
+ irq = devp->hd_hdwirq;
+
+ if (irq) {
+ unsigned long irq_flags;
+
+ if (devp->hd_flags & HPET_SHARED_IRQ) {
+ /*
+ * To prevent the interrupt handler from seeing an
+ * unwanted interrupt status bit, program the timer
+ * so that it will not fire in the near future ...
+ */
+ writel(readl(&timer->hpet_config) & ~Tn_TYPE_CNF_MASK,
+ &timer->hpet_config);
+ write_counter(read_counter(&hpet->hpet_mc),
+ &timer->hpet_compare);
+ /* ... and clear any left-over status. */
+ isr = 1 << (devp - devp->hd_hpets->hp_dev);
+ writel(isr, &hpet->hpet_isr);
+ }
+
+ sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
+ irq_flags = devp->hd_flags & HPET_SHARED_IRQ ? IRQF_SHARED : 0;
+ if (request_irq(irq, hpet_interrupt, irq_flags,
+ devp->hd_name, (void *)devp)) {
+ printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
+ irq = 0;
+ }
+ }
+
+ if (irq == 0) {
+ spin_lock_irq(&hpet_lock);
+ devp->hd_flags ^= HPET_IE;
+ spin_unlock_irq(&hpet_lock);
+ return -EIO;
+ }
+
+ devp->hd_irq = irq;
+ t = devp->hd_ireqfreq;
+ v = readq(&timer->hpet_config);
+
+ /* 64-bit comparators are not yet supported through the ioctls,
+ * so force this into 32-bit mode if it supports both modes
+ */
+ g = v | Tn_32MODE_CNF_MASK | Tn_INT_ENB_CNF_MASK;
+
+ if (devp->hd_flags & HPET_PERIODIC) {
+ g |= Tn_TYPE_CNF_MASK;
+ v |= Tn_TYPE_CNF_MASK | Tn_VAL_SET_CNF_MASK;
+ writeq(v, &timer->hpet_config);
+ local_irq_save(flags);
+
+ /*
+ * NOTE: First we modify the hidden accumulator
+ * register supported by periodic-capable comparators.
+ * We never want to modify the (single) counter; that
+ * would affect all the comparators. The value written
+ * is the counter value when the first interrupt is due.
+ */
+ m = read_counter(&hpet->hpet_mc);
+ write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
+ /*
+ * Then we modify the comparator, indicating the period
+ * for subsequent interrupt.
+ */
+ write_counter(t, &timer->hpet_compare);
+ } else {
+ local_irq_save(flags);
+ m = read_counter(&hpet->hpet_mc);
+ write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
+ }
+
+ if (devp->hd_flags & HPET_SHARED_IRQ) {
+ isr = 1 << (devp - devp->hd_hpets->hp_dev);
+ writel(isr, &hpet->hpet_isr);
+ }
+ writeq(g, &timer->hpet_config);
+ local_irq_restore(flags);
+
+ return 0;
+}
+
+/* converts Hz to number of timer ticks */
+static inline unsigned long hpet_time_div(struct hpets *hpets,
+ unsigned long dis)
+{
+ unsigned long long m;
+
+ m = hpets->hp_tick_freq + (dis >> 1);
+ return div64_ul(m, dis);
+}
+
+static int
+hpet_ioctl_common(struct hpet_dev *devp, unsigned int cmd, unsigned long arg,
+ struct hpet_info *info)
+{
+ struct hpet_timer __iomem *timer;
+ struct hpets *hpetp;
+ int err;
+ unsigned long v;
+
+ switch (cmd) {
+ case HPET_IE_OFF:
+ case HPET_INFO:
+ case HPET_EPI:
+ case HPET_DPI:
+ case HPET_IRQFREQ:
+ timer = devp->hd_timer;
+ hpetp = devp->hd_hpets;
+ break;
+ case HPET_IE_ON:
+ return hpet_ioctl_ieon(devp);
+ default:
+ return -EINVAL;
+ }
+
+ err = 0;
+
+ switch (cmd) {
+ case HPET_IE_OFF:
+ if ((devp->hd_flags & HPET_IE) == 0)
+ break;
+ v = readq(&timer->hpet_config);
+ v &= ~Tn_INT_ENB_CNF_MASK;
+ writeq(v, &timer->hpet_config);
+ if (devp->hd_irq) {
+ free_irq(devp->hd_irq, devp);
+ devp->hd_irq = 0;
+ }
+ devp->hd_flags ^= HPET_IE;
+ break;
+ case HPET_INFO:
+ {
+ memset(info, 0, sizeof(*info));
+ if (devp->hd_ireqfreq)
+ info->hi_ireqfreq =
+ hpet_time_div(hpetp, devp->hd_ireqfreq);
+ info->hi_flags =
+ readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
+ info->hi_hpet = hpetp->hp_which;
+ info->hi_timer = devp - hpetp->hp_dev;
+ break;
+ }
+ case HPET_EPI:
+ v = readq(&timer->hpet_config);
+ if ((v & Tn_PER_INT_CAP_MASK) == 0) {
+ err = -ENXIO;
+ break;
+ }
+ devp->hd_flags |= HPET_PERIODIC;
+ break;
+ case HPET_DPI:
+ v = readq(&timer->hpet_config);
+ if ((v & Tn_PER_INT_CAP_MASK) == 0) {
+ err = -ENXIO;
+ break;
+ }
+ if (devp->hd_flags & HPET_PERIODIC &&
+ readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
+ v = readq(&timer->hpet_config);
+ v ^= Tn_TYPE_CNF_MASK;
+ writeq(v, &timer->hpet_config);
+ }
+ devp->hd_flags &= ~HPET_PERIODIC;
+ break;
+ case HPET_IRQFREQ:
+ if ((arg > hpet_max_freq) &&
+ !capable(CAP_SYS_RESOURCE)) {
+ err = -EACCES;
+ break;
+ }
+
+ if (!arg) {
+ err = -EINVAL;
+ break;
+ }
+
+ devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
+ }
+
+ return err;
+}
+
+static long
+hpet_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct hpet_info info;
+ int err;
+
+ mutex_lock(&hpet_mutex);
+ err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
+ mutex_unlock(&hpet_mutex);
+
+ if ((cmd == HPET_INFO) && !err &&
+ (copy_to_user((void __user *)arg, &info, sizeof(info))))
+ err = -EFAULT;
+
+ return err;
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_hpet_info {
+ compat_ulong_t hi_ireqfreq; /* Hz */
+ compat_ulong_t hi_flags; /* information */
+ unsigned short hi_hpet;
+ unsigned short hi_timer;
+};
+
+static long
+hpet_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct hpet_info info;
+ int err;
+
+ mutex_lock(&hpet_mutex);
+ err = hpet_ioctl_common(file->private_data, cmd, arg, &info);
+ mutex_unlock(&hpet_mutex);
+
+ if ((cmd == HPET_INFO) && !err) {
+ struct compat_hpet_info __user *u = compat_ptr(arg);
+ if (put_user(info.hi_ireqfreq, &u->hi_ireqfreq) ||
+ put_user(info.hi_flags, &u->hi_flags) ||
+ put_user(info.hi_hpet, &u->hi_hpet) ||
+ put_user(info.hi_timer, &u->hi_timer))
+ err = -EFAULT;
+ }
+
+ return err;
+}
+#endif
+
+static const struct file_operations hpet_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = hpet_read,
+ .poll = hpet_poll,
+ .unlocked_ioctl = hpet_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = hpet_compat_ioctl,
+#endif
+ .open = hpet_open,
+ .release = hpet_release,
+ .fasync = hpet_fasync,
+ .mmap = hpet_mmap,
+};
+
+static int hpet_is_known(struct hpet_data *hdp)
+{
+ struct hpets *hpetp;
+
+ for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
+ if (hpetp->hp_hpet_phys == hdp->hd_phys_address)
+ return 1;
+
+ return 0;
+}
+
+static struct ctl_table hpet_table[] = {
+ {
+ .procname = "max-user-freq",
+ .data = &hpet_max_freq,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {}
+};
+
+static struct ctl_table_header *sysctl_header;
+
+/*
+ * Adjustment for when arming the timer with
+ * initial conditions. That is, main counter
+ * ticks expired before interrupts are enabled.
+ */
+#define TICK_CALIBRATE (1000UL)
+
+static unsigned long __hpet_calibrate(struct hpets *hpetp)
+{
+ struct hpet_timer __iomem *timer = NULL;
+ unsigned long t, m, count, i, flags, start;
+ struct hpet_dev *devp;
+ int j;
+ struct hpet __iomem *hpet;
+
+ for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
+ if ((devp->hd_flags & HPET_OPEN) == 0) {
+ timer = devp->hd_timer;
+ break;
+ }
+
+ if (!timer)
+ return 0;
+
+ hpet = hpetp->hp_hpet;
+ t = read_counter(&timer->hpet_compare);
+
+ i = 0;
+ count = hpet_time_div(hpetp, TICK_CALIBRATE);
+
+ local_irq_save(flags);
+
+ start = read_counter(&hpet->hpet_mc);
+
+ do {
+ m = read_counter(&hpet->hpet_mc);
+ write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
+ } while (i++, (m - start) < count);
+
+ local_irq_restore(flags);
+
+ return (m - start) / i;
+}
+
+static unsigned long hpet_calibrate(struct hpets *hpetp)
+{
+ unsigned long ret = ~0UL;
+ unsigned long tmp;
+
+ /*
+ * Try to calibrate until return value becomes stable small value.
+ * If SMI interruption occurs in calibration loop, the return value
+ * will be big. This avoids its impact.
+ */
+ for ( ; ; ) {
+ tmp = __hpet_calibrate(hpetp);
+ if (ret <= tmp)
+ break;
+ ret = tmp;
+ }
+
+ return ret;
+}
+
+int hpet_alloc(struct hpet_data *hdp)
+{
+ u64 cap, mcfg;
+ struct hpet_dev *devp;
+ u32 i, ntimer;
+ struct hpets *hpetp;
+ struct hpet __iomem *hpet;
+ static struct hpets *last;
+ unsigned long period;
+ unsigned long long temp;
+ u32 remainder;
+
+ /*
+ * hpet_alloc can be called by platform dependent code.
+ * If platform dependent code has allocated the hpet that
+ * ACPI has also reported, then we catch it here.
+ */
+ if (hpet_is_known(hdp)) {
+ printk(KERN_DEBUG "%s: duplicate HPET ignored\n",
+ __func__);
+ return 0;
+ }
+
+ hpetp = kzalloc(struct_size(hpetp, hp_dev, hdp->hd_nirqs),
+ GFP_KERNEL);
+
+ if (!hpetp)
+ return -ENOMEM;
+
+ hpetp->hp_which = hpet_nhpet++;
+ hpetp->hp_hpet = hdp->hd_address;
+ hpetp->hp_hpet_phys = hdp->hd_phys_address;
+
+ hpetp->hp_ntimer = hdp->hd_nirqs;
+
+ for (i = 0; i < hdp->hd_nirqs; i++)
+ hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
+
+ hpet = hpetp->hp_hpet;
+
+ cap = readq(&hpet->hpet_cap);
+
+ ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
+
+ if (hpetp->hp_ntimer != ntimer) {
+ printk(KERN_WARNING "hpet: number irqs doesn't agree"
+ " with number of timers\n");
+ kfree(hpetp);
+ return -ENODEV;
+ }
+
+ if (last)
+ last->hp_next = hpetp;
+ else
+ hpets = hpetp;
+
+ last = hpetp;
+
+ period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
+ HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
+ temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
+ temp += period >> 1; /* round */
+ do_div(temp, period);
+ hpetp->hp_tick_freq = temp; /* ticks per second */
+
+ printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
+ hpetp->hp_which, hdp->hd_phys_address,
+ hpetp->hp_ntimer > 1 ? "s" : "");
+ for (i = 0; i < hpetp->hp_ntimer; i++)
+ printk(KERN_CONT "%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
+ printk(KERN_CONT "\n");
+
+ temp = hpetp->hp_tick_freq;
+ remainder = do_div(temp, 1000000);
+ printk(KERN_INFO
+ "hpet%u: %u comparators, %d-bit %u.%06u MHz counter\n",
+ hpetp->hp_which, hpetp->hp_ntimer,
+ cap & HPET_COUNTER_SIZE_MASK ? 64 : 32,
+ (unsigned) temp, remainder);
+
+ mcfg = readq(&hpet->hpet_config);
+ if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
+ write_counter(0L, &hpet->hpet_mc);
+ mcfg |= HPET_ENABLE_CNF_MASK;
+ writeq(mcfg, &hpet->hpet_config);
+ }
+
+ for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
+ struct hpet_timer __iomem *timer;
+
+ timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
+
+ devp->hd_hpets = hpetp;
+ devp->hd_hpet = hpet;
+ devp->hd_timer = timer;
+
+ /*
+ * If the timer was reserved by platform code,
+ * then make timer unavailable for opens.
+ */
+ if (hdp->hd_state & (1 << i)) {
+ devp->hd_flags = HPET_OPEN;
+ continue;
+ }
+
+ init_waitqueue_head(&devp->hd_waitqueue);
+ }
+
+ hpetp->hp_delta = hpet_calibrate(hpetp);
+
+/* This clocksource driver currently only works on ia64 */
+#ifdef CONFIG_IA64
+ if (!hpet_clocksource) {
+ hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
+ clocksource_hpet.archdata.fsys_mmio = hpet_mctr;
+ clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq);
+ hpetp->hp_clocksource = &clocksource_hpet;
+ hpet_clocksource = &clocksource_hpet;
+ }
+#endif
+
+ return 0;
+}
+
+static acpi_status hpet_resources(struct acpi_resource *res, void *data)
+{
+ struct hpet_data *hdp;
+ acpi_status status;
+ struct acpi_resource_address64 addr;
+
+ hdp = data;
+
+ status = acpi_resource_to_address64(res, &addr);
+
+ if (ACPI_SUCCESS(status)) {
+ hdp->hd_phys_address = addr.address.minimum;
+ hdp->hd_address = ioremap(addr.address.minimum, addr.address.address_length);
+ if (!hdp->hd_address)
+ return AE_ERROR;
+
+ if (hpet_is_known(hdp)) {
+ iounmap(hdp->hd_address);
+ return AE_ALREADY_EXISTS;
+ }
+ } else if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
+ struct acpi_resource_fixed_memory32 *fixmem32;
+
+ fixmem32 = &res->data.fixed_memory32;
+
+ hdp->hd_phys_address = fixmem32->address;
+ hdp->hd_address = ioremap(fixmem32->address,
+ HPET_RANGE_SIZE);
+ if (!hdp->hd_address)
+ return AE_ERROR;
+
+ if (hpet_is_known(hdp)) {
+ iounmap(hdp->hd_address);
+ return AE_ALREADY_EXISTS;
+ }
+ } else if (res->type == ACPI_RESOURCE_TYPE_EXTENDED_IRQ) {
+ struct acpi_resource_extended_irq *irqp;
+ int i, irq;
+
+ irqp = &res->data.extended_irq;
+
+ for (i = 0; i < irqp->interrupt_count; i++) {
+ if (hdp->hd_nirqs >= HPET_MAX_TIMERS)
+ break;
+
+ irq = acpi_register_gsi(NULL, irqp->interrupts[i],
+ irqp->triggering,
+ irqp->polarity);
+ if (irq < 0)
+ return AE_ERROR;
+
+ hdp->hd_irq[hdp->hd_nirqs] = irq;
+ hdp->hd_nirqs++;
+ }
+ }
+
+ return AE_OK;
+}
+
+static int hpet_acpi_add(struct acpi_device *device)
+{
+ acpi_status result;
+ struct hpet_data data;
+
+ memset(&data, 0, sizeof(data));
+
+ result =
+ acpi_walk_resources(device->handle, METHOD_NAME__CRS,
+ hpet_resources, &data);
+
+ if (ACPI_FAILURE(result))
+ return -ENODEV;
+
+ if (!data.hd_address || !data.hd_nirqs) {
+ if (data.hd_address)
+ iounmap(data.hd_address);
+ printk("%s: no address or irqs in _CRS\n", __func__);
+ return -ENODEV;
+ }
+
+ return hpet_alloc(&data);
+}
+
+static const struct acpi_device_id hpet_device_ids[] = {
+ {"PNP0103", 0},
+ {"", 0},
+};
+
+static struct acpi_driver hpet_acpi_driver = {
+ .name = "hpet",
+ .ids = hpet_device_ids,
+ .ops = {
+ .add = hpet_acpi_add,
+ },
+};
+
+static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
+
+static int __init hpet_init(void)
+{
+ int result;
+
+ result = misc_register(&hpet_misc);
+ if (result < 0)
+ return -ENODEV;
+
+ sysctl_header = register_sysctl("dev/hpet", hpet_table);
+
+ result = acpi_bus_register_driver(&hpet_acpi_driver);
+ if (result < 0) {
+ if (sysctl_header)
+ unregister_sysctl_table(sysctl_header);
+ misc_deregister(&hpet_misc);
+ return result;
+ }
+
+ return 0;
+}
+device_initcall(hpet_init);
+
+/*
+MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
+MODULE_LICENSE("GPL");
+*/
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 01:01:22 +0000