2 * Intel & MS High Precision Event Timer Implementation.
4 * Copyright (C) 2003 Intel Corporation
6 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
7 * Bob Picco <robert.picco@hp.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/config.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/types.h>
19 #include <linux/miscdevice.h>
20 #include <linux/major.h>
21 #include <linux/ioport.h>
22 #include <linux/fcntl.h>
23 #include <linux/init.h>
24 #include <linux/poll.h>
25 #include <linux/proc_fs.h>
26 #include <linux/spinlock.h>
27 #include <linux/sysctl.h>
28 #include <linux/wait.h>
29 #include <linux/bcd.h>
30 #include <linux/seq_file.h>
31 #include <linux/bitops.h>
33 #include <asm/current.h>
34 #include <asm/uaccess.h>
35 #include <asm/system.h>
38 #include <asm/div64.h>
40 #include <linux/acpi.h>
41 #include <acpi/acpi_bus.h>
42 #include <linux/hpet.h>
45 * The High Precision Event Timer driver.
46 * This driver is closely modelled after the rtc.c driver.
47 * http://www.intel.com/labs/platcomp/hpet/hpetspec.htm
49 #define HPET_USER_FREQ (64)
50 #define HPET_DRIFT (500)
52 static u32 hpet_ntimer, hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
54 /* A lock for concurrent access by app and isr hpet activity. */
55 static DEFINE_SPINLOCK(hpet_lock);
56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
57 static DEFINE_SPINLOCK(hpet_task_lock);
59 #define HPET_DEV_NAME (7)
62 struct hpets *hd_hpets;
63 struct hpet __iomem *hd_hpet;
64 struct hpet_timer __iomem *hd_timer;
65 unsigned long hd_ireqfreq;
66 unsigned long hd_irqdata;
67 wait_queue_head_t hd_waitqueue;
68 struct fasync_struct *hd_async_queue;
69 struct hpet_task *hd_task;
70 unsigned int hd_flags;
72 unsigned int hd_hdwirq;
73 char hd_name[HPET_DEV_NAME];
77 struct hpets *hp_next;
78 struct hpet __iomem *hp_hpet;
79 struct time_interpolator *hp_interpolator;
80 unsigned long hp_period;
81 unsigned long hp_delta;
82 unsigned int hp_ntimer;
83 unsigned int hp_which;
84 struct hpet_dev hp_dev[1];
87 static struct hpets *hpets;
89 #define HPET_OPEN 0x0001
90 #define HPET_IE 0x0002 /* interrupt enabled */
91 #define HPET_PERIODIC 0x0004
93 #if BITS_PER_LONG == 64
94 #define write_counter(V, MC) writeq(V, MC)
95 #define read_counter(MC) readq(MC)
97 #define write_counter(V, MC) writel(V, MC)
98 #define read_counter(MC) readl(MC)
102 static unsigned long long __inline readq(void __iomem *addr)
104 return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
109 static void __inline writeq(unsigned long long v, void __iomem *addr)
111 writel(v & 0xffffffff, addr);
112 writel(v >> 32, addr + 4);
116 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
118 struct hpet_dev *devp;
123 spin_lock(&hpet_lock);
127 * For non-periodic timers, increment the accumulator.
128 * This has the effect of treating non-periodic like periodic.
130 if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
133 t = devp->hd_ireqfreq;
134 m = read_counter(&devp->hd_hpet->hpet_mc);
135 write_counter(t + m + devp->hd_hpets->hp_delta,
136 &devp->hd_timer->hpet_compare);
139 isr = (1 << (devp - devp->hd_hpets->hp_dev));
140 writeq(isr, &devp->hd_hpet->hpet_isr);
141 spin_unlock(&hpet_lock);
143 spin_lock(&hpet_task_lock);
145 devp->hd_task->ht_func(devp->hd_task->ht_data);
146 spin_unlock(&hpet_task_lock);
148 wake_up_interruptible(&devp->hd_waitqueue);
150 kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
155 static int hpet_open(struct inode *inode, struct file *file)
157 struct hpet_dev *devp;
161 if (file->f_mode & FMODE_WRITE)
164 spin_lock_irq(&hpet_lock);
166 for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
167 for (i = 0; i < hpetp->hp_ntimer; i++)
168 if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
169 || hpetp->hp_dev[i].hd_task)
172 devp = &hpetp->hp_dev[i];
177 spin_unlock_irq(&hpet_lock);
181 file->private_data = devp;
182 devp->hd_irqdata = 0;
183 devp->hd_flags |= HPET_OPEN;
184 spin_unlock_irq(&hpet_lock);
190 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
192 DECLARE_WAITQUEUE(wait, current);
195 struct hpet_dev *devp;
197 devp = file->private_data;
198 if (!devp->hd_ireqfreq)
201 if (count < sizeof(unsigned long))
204 add_wait_queue(&devp->hd_waitqueue, &wait);
207 set_current_state(TASK_INTERRUPTIBLE);
209 spin_lock_irq(&hpet_lock);
210 data = devp->hd_irqdata;
211 devp->hd_irqdata = 0;
212 spin_unlock_irq(&hpet_lock);
216 else if (file->f_flags & O_NONBLOCK) {
219 } else if (signal_pending(current)) {
220 retval = -ERESTARTSYS;
226 retval = put_user(data, (unsigned long __user *)buf);
228 retval = sizeof(unsigned long);
230 __set_current_state(TASK_RUNNING);
231 remove_wait_queue(&devp->hd_waitqueue, &wait);
236 static unsigned int hpet_poll(struct file *file, poll_table * wait)
239 struct hpet_dev *devp;
241 devp = file->private_data;
243 if (!devp->hd_ireqfreq)
246 poll_wait(file, &devp->hd_waitqueue, wait);
248 spin_lock_irq(&hpet_lock);
249 v = devp->hd_irqdata;
250 spin_unlock_irq(&hpet_lock);
253 return POLLIN | POLLRDNORM;
258 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
260 #ifdef CONFIG_HPET_MMAP
261 struct hpet_dev *devp;
264 if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
267 devp = file->private_data;
268 addr = (unsigned long)devp->hd_hpet;
270 if (addr & (PAGE_SIZE - 1))
273 vma->vm_flags |= VM_IO;
274 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
277 if (remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
278 PAGE_SIZE, vma->vm_page_prot)) {
279 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
289 static int hpet_fasync(int fd, struct file *file, int on)
291 struct hpet_dev *devp;
293 devp = file->private_data;
295 if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
301 static int hpet_release(struct inode *inode, struct file *file)
303 struct hpet_dev *devp;
304 struct hpet_timer __iomem *timer;
307 devp = file->private_data;
308 timer = devp->hd_timer;
310 spin_lock_irq(&hpet_lock);
312 writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
313 &timer->hpet_config);
318 devp->hd_ireqfreq = 0;
320 if (devp->hd_flags & HPET_PERIODIC
321 && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
324 v = readq(&timer->hpet_config);
325 v ^= Tn_TYPE_CNF_MASK;
326 writeq(v, &timer->hpet_config);
329 devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
330 spin_unlock_irq(&hpet_lock);
335 if (file->f_flags & FASYNC)
336 hpet_fasync(-1, file, 0);
338 file->private_data = NULL;
342 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
345 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
348 struct hpet_dev *devp;
350 devp = file->private_data;
351 return hpet_ioctl_common(devp, cmd, arg, 0);
354 static int hpet_ioctl_ieon(struct hpet_dev *devp)
356 struct hpet_timer __iomem *timer;
357 struct hpet __iomem *hpet;
360 unsigned long g, v, t, m;
361 unsigned long flags, isr;
363 timer = devp->hd_timer;
364 hpet = devp->hd_hpet;
365 hpetp = devp->hd_hpets;
367 v = readq(&timer->hpet_config);
368 spin_lock_irq(&hpet_lock);
370 if (devp->hd_flags & HPET_IE) {
371 spin_unlock_irq(&hpet_lock);
375 devp->hd_flags |= HPET_IE;
376 spin_unlock_irq(&hpet_lock);
378 t = readq(&timer->hpet_config);
379 irq = devp->hd_hdwirq;
382 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
385 (irq, hpet_interrupt, SA_INTERRUPT, devp->hd_name, (void *)devp)) {
386 printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
392 spin_lock_irq(&hpet_lock);
393 devp->hd_flags ^= HPET_IE;
394 spin_unlock_irq(&hpet_lock);
399 t = devp->hd_ireqfreq;
400 v = readq(&timer->hpet_config);
401 g = v | Tn_INT_ENB_CNF_MASK;
403 if (devp->hd_flags & HPET_PERIODIC) {
404 write_counter(t, &timer->hpet_compare);
405 g |= Tn_TYPE_CNF_MASK;
406 v |= Tn_TYPE_CNF_MASK;
407 writeq(v, &timer->hpet_config);
408 v |= Tn_VAL_SET_CNF_MASK;
409 writeq(v, &timer->hpet_config);
410 local_irq_save(flags);
411 m = read_counter(&hpet->hpet_mc);
412 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
414 local_irq_save(flags);
415 m = read_counter(&hpet->hpet_mc);
416 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
419 isr = (1 << (devp - hpets->hp_dev));
420 writeq(isr, &hpet->hpet_isr);
421 writeq(g, &timer->hpet_config);
422 local_irq_restore(flags);
427 static inline unsigned long hpet_time_div(unsigned long dis)
429 unsigned long long m = 1000000000000000ULL;
433 return (unsigned long)m;
437 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
439 struct hpet_timer __iomem *timer;
440 struct hpet __iomem *hpet;
451 timer = devp->hd_timer;
452 hpet = devp->hd_hpet;
453 hpetp = devp->hd_hpets;
456 return hpet_ioctl_ieon(devp);
465 if ((devp->hd_flags & HPET_IE) == 0)
467 v = readq(&timer->hpet_config);
468 v &= ~Tn_INT_ENB_CNF_MASK;
469 writeq(v, &timer->hpet_config);
471 free_irq(devp->hd_irq, devp);
474 devp->hd_flags ^= HPET_IE;
478 struct hpet_info info;
480 info.hi_ireqfreq = hpet_time_div(hpetp->hp_period *
483 readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
484 info.hi_hpet = devp->hd_hpets->hp_which;
485 info.hi_timer = devp - devp->hd_hpets->hp_dev;
486 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
491 v = readq(&timer->hpet_config);
492 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
496 devp->hd_flags |= HPET_PERIODIC;
499 v = readq(&timer->hpet_config);
500 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
504 if (devp->hd_flags & HPET_PERIODIC &&
505 readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
506 v = readq(&timer->hpet_config);
507 v ^= Tn_TYPE_CNF_MASK;
508 writeq(v, &timer->hpet_config);
510 devp->hd_flags &= ~HPET_PERIODIC;
513 if (!kernel && (arg > hpet_max_freq) &&
514 !capable(CAP_SYS_RESOURCE)) {
519 if (arg & (arg - 1)) {
524 devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg);
530 static struct file_operations hpet_fops = {
531 .owner = THIS_MODULE,
537 .release = hpet_release,
538 .fasync = hpet_fasync,
542 EXPORT_SYMBOL(hpet_alloc);
543 EXPORT_SYMBOL(hpet_register);
544 EXPORT_SYMBOL(hpet_unregister);
545 EXPORT_SYMBOL(hpet_control);
547 int hpet_register(struct hpet_task *tp, int periodic)
551 struct hpet_timer __iomem *timer;
552 struct hpet_dev *devp;
557 mask = Tn_PER_INT_CAP_MASK;
566 spin_lock_irq(&hpet_task_lock);
567 spin_lock(&hpet_lock);
569 for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
570 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
571 i < hpetp->hp_ntimer; i++, timer++) {
572 if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
576 devp = &hpetp->hp_dev[i];
578 if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
583 tp->ht_opaque = devp;
588 spin_unlock(&hpet_lock);
589 spin_unlock_irq(&hpet_task_lock);
597 static inline int hpet_tpcheck(struct hpet_task *tp)
599 struct hpet_dev *devp;
602 devp = tp->ht_opaque;
607 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
608 if (devp >= hpetp->hp_dev
609 && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
610 && devp->hd_hpet == hpetp->hp_hpet)
616 int hpet_unregister(struct hpet_task *tp)
618 struct hpet_dev *devp;
619 struct hpet_timer __iomem *timer;
622 if ((err = hpet_tpcheck(tp)))
625 spin_lock_irq(&hpet_task_lock);
626 spin_lock(&hpet_lock);
628 devp = tp->ht_opaque;
629 if (devp->hd_task != tp) {
630 spin_unlock(&hpet_lock);
631 spin_unlock_irq(&hpet_task_lock);
635 timer = devp->hd_timer;
636 writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
637 &timer->hpet_config);
638 devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
639 devp->hd_task = NULL;
640 spin_unlock(&hpet_lock);
641 spin_unlock_irq(&hpet_task_lock);
646 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
648 struct hpet_dev *devp;
651 if ((err = hpet_tpcheck(tp)))
654 spin_lock_irq(&hpet_lock);
655 devp = tp->ht_opaque;
656 if (devp->hd_task != tp) {
657 spin_unlock_irq(&hpet_lock);
660 spin_unlock_irq(&hpet_lock);
661 return hpet_ioctl_common(devp, cmd, arg, 1);
664 static ctl_table hpet_table[] = {
667 .procname = "max-user-freq",
668 .data = &hpet_max_freq,
669 .maxlen = sizeof(int),
671 .proc_handler = &proc_dointvec,
676 static ctl_table hpet_root[] = {
687 static ctl_table dev_root[] = {
698 static struct ctl_table_header *sysctl_header;
700 static void hpet_register_interpolator(struct hpets *hpetp)
702 #ifdef CONFIG_TIME_INTERPOLATION
703 struct time_interpolator *ti;
705 ti = kmalloc(sizeof(*ti), GFP_KERNEL);
709 memset(ti, 0, sizeof(*ti));
710 ti->source = TIME_SOURCE_MMIO64;
712 ti->addr = &hpetp->hp_hpet->hpet_mc;
713 ti->frequency = hpet_time_div(hpets->hp_period);
714 ti->drift = ti->frequency * HPET_DRIFT / 1000000;
717 hpetp->hp_interpolator = ti;
718 register_time_interpolator(ti);
723 * Adjustment for when arming the timer with
724 * initial conditions. That is, main counter
725 * ticks expired before interrupts are enabled.
727 #define TICK_CALIBRATE (1000UL)
729 static unsigned long hpet_calibrate(struct hpets *hpetp)
731 struct hpet_timer __iomem *timer = NULL;
732 unsigned long t, m, count, i, flags, start;
733 struct hpet_dev *devp;
735 struct hpet __iomem *hpet;
737 for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
738 if ((devp->hd_flags & HPET_OPEN) == 0) {
739 timer = devp->hd_timer;
746 hpet = hpets->hp_hpet;
747 t = read_counter(&timer->hpet_compare);
750 count = hpet_time_div(hpetp->hp_period * TICK_CALIBRATE);
752 local_irq_save(flags);
754 start = read_counter(&hpet->hpet_mc);
757 m = read_counter(&hpet->hpet_mc);
758 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
759 } while (i++, (m - start) < count);
761 local_irq_restore(flags);
763 return (m - start) / i;
766 int hpet_alloc(struct hpet_data *hdp)
769 struct hpet_dev *devp;
773 struct hpet __iomem *hpet;
774 static struct hpets *last = (struct hpets *)0;
778 * hpet_alloc can be called by platform dependent code.
779 * if platform dependent code has allocated the hpet
780 * ACPI also reports hpet, then we catch it here.
782 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
783 if (hpetp->hp_hpet == hdp->hd_address)
786 siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
787 sizeof(struct hpet_dev));
789 hpetp = kmalloc(siz, GFP_KERNEL);
794 memset(hpetp, 0, siz);
796 hpetp->hp_which = hpet_nhpet++;
797 hpetp->hp_hpet = hdp->hd_address;
799 hpetp->hp_ntimer = hdp->hd_nirqs;
801 for (i = 0; i < hdp->hd_nirqs; i++)
802 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
804 hpet = hpetp->hp_hpet;
806 cap = readq(&hpet->hpet_cap);
808 ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
810 if (hpetp->hp_ntimer != ntimer) {
811 printk(KERN_WARNING "hpet: number irqs doesn't agree"
812 " with number of timers\n");
818 last->hp_next = hpetp;
824 hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
825 HPET_COUNTER_CLK_PERIOD_SHIFT;
827 printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
828 hpetp->hp_which, hdp->hd_phys_address,
829 hpetp->hp_ntimer > 1 ? "s" : "");
830 for (i = 0; i < hpetp->hp_ntimer; i++)
831 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
834 ns = hpetp->hp_period; /* femptoseconds, 10^-15 */
835 do_div(ns, 1000000); /* convert to nanoseconds, 10^-9 */
836 printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n",
837 hpetp->hp_which, ns, hpetp->hp_ntimer,
838 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32);
840 mcfg = readq(&hpet->hpet_config);
841 if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
842 write_counter(0L, &hpet->hpet_mc);
843 mcfg |= HPET_ENABLE_CNF_MASK;
844 writeq(mcfg, &hpet->hpet_config);
847 for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer;
848 i++, hpet_ntimer++, devp++) {
850 struct hpet_timer __iomem *timer;
852 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
853 v = readq(&timer->hpet_config);
855 devp->hd_hpets = hpetp;
856 devp->hd_hpet = hpet;
857 devp->hd_timer = timer;
860 * If the timer was reserved by platform code,
861 * then make timer unavailable for opens.
863 if (hdp->hd_state & (1 << i)) {
864 devp->hd_flags = HPET_OPEN;
868 init_waitqueue_head(&devp->hd_waitqueue);
871 hpetp->hp_delta = hpet_calibrate(hpetp);
872 hpet_register_interpolator(hpetp);
877 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
879 struct hpet_data *hdp;
881 struct acpi_resource_address64 addr;
886 status = acpi_resource_to_address64(res, &addr);
888 if (ACPI_SUCCESS(status)) {
891 size = addr.max_address_range - addr.min_address_range + 1;
892 hdp->hd_phys_address = addr.min_address_range;
893 hdp->hd_address = ioremap(addr.min_address_range, size);
895 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
896 if (hpetp->hp_hpet == hdp->hd_address)
898 } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
899 struct acpi_resource_ext_irq *irqp;
902 irqp = &res->data.extended_irq;
904 if (irqp->number_of_interrupts > 0) {
905 hdp->hd_nirqs = irqp->number_of_interrupts;
907 for (i = 0; i < hdp->hd_nirqs; i++)
909 acpi_register_gsi(irqp->interrupts[i],
911 irqp->active_high_low);
918 static int hpet_acpi_add(struct acpi_device *device)
921 struct hpet_data data;
923 memset(&data, 0, sizeof(data));
926 acpi_walk_resources(device->handle, METHOD_NAME__CRS,
927 hpet_resources, &data);
929 if (ACPI_FAILURE(result))
932 if (!data.hd_address || !data.hd_nirqs) {
933 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
937 return hpet_alloc(&data);
940 static int hpet_acpi_remove(struct acpi_device *device, int type)
942 /* XXX need to unregister interpolator, dealloc mem, etc */
946 static struct acpi_driver hpet_acpi_driver = {
950 .add = hpet_acpi_add,
951 .remove = hpet_acpi_remove,
955 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
957 static int __init hpet_init(void)
961 result = misc_register(&hpet_misc);
965 sysctl_header = register_sysctl_table(dev_root, 0);
967 result = acpi_bus_register_driver(&hpet_acpi_driver);
970 unregister_sysctl_table(sysctl_header);
971 misc_deregister(&hpet_misc);
978 static void __exit hpet_exit(void)
980 acpi_bus_unregister_driver(&hpet_acpi_driver);
983 unregister_sysctl_table(sysctl_header);
984 misc_deregister(&hpet_misc);
989 module_init(hpet_init);
990 module_exit(hpet_exit);
991 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
992 MODULE_LICENSE("GPL");