2 * System Trace Module (STM) infrastructure
3 * Copyright (c) 2014, Intel Corporation.
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * STM class implements generic infrastructure for System Trace Module devices
15 * as defined in MIPI STPv2 specification.
18 #include <linux/uaccess.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/device.h>
22 #include <linux/compat.h>
23 #include <linux/kdev_t.h>
24 #include <linux/srcu.h>
25 #include <linux/slab.h>
26 #include <linux/stm.h>
31 #include <uapi/linux/stm.h>
33 static unsigned int stm_core_up;
36 * The SRCU here makes sure that STM device doesn't disappear from under a
37 * stm_source_write() caller, which may want to have as little overhead as
40 static struct srcu_struct stm_source_srcu;
42 static ssize_t masters_show(struct device *dev,
43 struct device_attribute *attr,
46 struct stm_device *stm = to_stm_device(dev);
49 ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
54 static DEVICE_ATTR_RO(masters);
56 static ssize_t channels_show(struct device *dev,
57 struct device_attribute *attr,
60 struct stm_device *stm = to_stm_device(dev);
63 ret = sprintf(buf, "%u\n", stm->data->sw_nchannels);
68 static DEVICE_ATTR_RO(channels);
70 static struct attribute *stm_attrs[] = {
71 &dev_attr_masters.attr,
72 &dev_attr_channels.attr,
76 ATTRIBUTE_GROUPS(stm);
78 static struct class stm_class = {
80 .dev_groups = stm_groups,
83 static int stm_dev_match(struct device *dev, const void *data)
85 const char *name = data;
87 return sysfs_streq(name, dev_name(dev));
91 * stm_find_device() - find stm device by name
92 * @buf: character buffer containing the name
94 * This is called when either policy gets assigned to an stm device or an
95 * stm_source device gets linked to an stm device.
97 * This grabs device's reference (get_device()) and module reference, both
98 * of which the calling path needs to make sure to drop with stm_put_device().
100 * Return: stm device pointer or null if lookup failed.
102 struct stm_device *stm_find_device(const char *buf)
104 struct stm_device *stm;
110 dev = class_find_device(&stm_class, NULL, buf, stm_dev_match);
114 stm = to_stm_device(dev);
115 if (!try_module_get(stm->owner)) {
116 /* matches class_find_device() above */
125 * stm_put_device() - drop references on the stm device
126 * @stm: stm device, previously acquired by stm_find_device()
128 * This drops the module reference and device reference taken by
129 * stm_find_device() or stm_char_open().
131 void stm_put_device(struct stm_device *stm)
133 module_put(stm->owner);
134 put_device(&stm->dev);
138 * Internally we only care about software-writable masters here, that is the
139 * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need
140 * original master numbers to be visible externally, since they are the ones
141 * that will appear in the STP stream. Thus, the internal bookkeeping uses
142 * $master - stm_data->sw_start to reference master descriptors and such.
145 #define __stm_master(_s, _m) \
146 ((_s)->masters[(_m) - (_s)->data->sw_start])
148 static inline struct stp_master *
149 stm_master(struct stm_device *stm, unsigned int idx)
151 if (idx < stm->data->sw_start || idx > stm->data->sw_end)
154 return __stm_master(stm, idx);
157 static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
159 struct stp_master *master;
162 size = ALIGN(stm->data->sw_nchannels, 8) / 8;
163 size += sizeof(struct stp_master);
164 master = kzalloc(size, GFP_ATOMIC);
168 master->nr_free = stm->data->sw_nchannels;
169 __stm_master(stm, idx) = master;
174 static void stp_master_free(struct stm_device *stm, unsigned int idx)
176 struct stp_master *master = stm_master(stm, idx);
181 __stm_master(stm, idx) = NULL;
185 static void stm_output_claim(struct stm_device *stm, struct stm_output *output)
187 struct stp_master *master = stm_master(stm, output->master);
189 lockdep_assert_held(&stm->mc_lock);
190 lockdep_assert_held(&output->lock);
192 if (WARN_ON_ONCE(master->nr_free < output->nr_chans))
195 bitmap_allocate_region(&master->chan_map[0], output->channel,
196 ilog2(output->nr_chans));
198 master->nr_free -= output->nr_chans;
202 stm_output_disclaim(struct stm_device *stm, struct stm_output *output)
204 struct stp_master *master = stm_master(stm, output->master);
206 lockdep_assert_held(&stm->mc_lock);
207 lockdep_assert_held(&output->lock);
209 bitmap_release_region(&master->chan_map[0], output->channel,
210 ilog2(output->nr_chans));
212 output->nr_chans = 0;
213 master->nr_free += output->nr_chans;
217 * This is like bitmap_find_free_region(), except it can ignore @start bits
220 static int find_free_channels(unsigned long *bitmap, unsigned int start,
221 unsigned int end, unsigned int width)
226 for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) {
227 pos = find_next_zero_bit(bitmap, end + 1, pos);
228 if (pos + width > end + 1)
231 if (pos & (width - 1))
234 for (i = 1; i < width && !test_bit(pos + i, bitmap); i++)
244 stm_find_master_chan(struct stm_device *stm, unsigned int width,
245 unsigned int *mstart, unsigned int mend,
246 unsigned int *cstart, unsigned int cend)
248 struct stp_master *master;
252 for (midx = *mstart; midx <= mend; midx++) {
253 if (!stm_master(stm, midx)) {
254 err = stp_master_alloc(stm, midx);
259 master = stm_master(stm, midx);
261 if (!master->nr_free)
264 pos = find_free_channels(master->chan_map, *cstart, cend,
277 static int stm_output_assign(struct stm_device *stm, unsigned int width,
278 struct stp_policy_node *policy_node,
279 struct stm_output *output)
281 unsigned int midx, cidx, mend, cend;
284 if (width > stm->data->sw_nchannels)
288 stp_policy_node_get_ranges(policy_node,
289 &midx, &mend, &cidx, &cend);
291 midx = stm->data->sw_start;
293 mend = stm->data->sw_end;
294 cend = stm->data->sw_nchannels - 1;
297 spin_lock(&stm->mc_lock);
298 spin_lock(&output->lock);
299 /* output is already assigned -- shouldn't happen */
300 if (WARN_ON_ONCE(output->nr_chans))
303 ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend);
307 output->master = midx;
308 output->channel = cidx;
309 output->nr_chans = width;
310 stm_output_claim(stm, output);
311 dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width);
315 spin_unlock(&output->lock);
316 spin_unlock(&stm->mc_lock);
321 static void stm_output_free(struct stm_device *stm, struct stm_output *output)
323 spin_lock(&stm->mc_lock);
324 spin_lock(&output->lock);
325 if (output->nr_chans)
326 stm_output_disclaim(stm, output);
327 spin_unlock(&output->lock);
328 spin_unlock(&stm->mc_lock);
331 static void stm_output_init(struct stm_output *output)
333 spin_lock_init(&output->lock);
336 static int major_match(struct device *dev, const void *data)
338 unsigned int major = *(unsigned int *)data;
340 return MAJOR(dev->devt) == major;
343 static int stm_char_open(struct inode *inode, struct file *file)
345 struct stm_file *stmf;
347 unsigned int major = imajor(inode);
350 dev = class_find_device(&stm_class, NULL, &major, major_match);
354 stmf = kzalloc(sizeof(*stmf), GFP_KERNEL);
358 stm_output_init(&stmf->output);
359 stmf->stm = to_stm_device(dev);
361 if (!try_module_get(stmf->stm->owner))
364 file->private_data = stmf;
366 return nonseekable_open(inode, file);
369 /* matches class_find_device() above */
376 static int stm_char_release(struct inode *inode, struct file *file)
378 struct stm_file *stmf = file->private_data;
379 struct stm_device *stm = stmf->stm;
381 if (stm->data->unlink)
382 stm->data->unlink(stm->data, stmf->output.master,
383 stmf->output.channel);
385 stm_output_free(stm, &stmf->output);
388 * matches the stm_char_open()'s
389 * class_find_device() + try_module_get()
397 static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width)
399 struct stm_device *stm = stmf->stm;
402 stmf->policy_node = stp_policy_node_lookup(stm, id);
404 ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output);
406 if (stmf->policy_node)
407 stp_policy_node_put(stmf->policy_node);
412 static ssize_t stm_write(struct stm_data *data, unsigned int master,
413 unsigned int channel, const char *buf, size_t count)
415 unsigned int flags = STP_PACKET_TIMESTAMPED;
416 const unsigned char *p = buf, nil = 0;
420 for (pos = 0, p = buf; count > pos; pos += sz, p += sz) {
421 sz = min_t(unsigned int, count - pos, 8);
422 sz = data->packet(data, master, channel, STP_PACKET_DATA, flags,
430 data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil);
435 static ssize_t stm_char_write(struct file *file, const char __user *buf,
436 size_t count, loff_t *ppos)
438 struct stm_file *stmf = file->private_data;
439 struct stm_device *stm = stmf->stm;
443 if (count + 1 > PAGE_SIZE)
444 count = PAGE_SIZE - 1;
447 * if no m/c have been assigned to this writer up to this
448 * point, use "default" policy entry
450 if (!stmf->output.nr_chans) {
451 err = stm_file_assign(stmf, "default", 1);
453 * EBUSY means that somebody else just assigned this
454 * output, which is just fine for write()
456 if (err && err != -EBUSY)
460 kbuf = kmalloc(count + 1, GFP_KERNEL);
464 err = copy_from_user(kbuf, buf, count);
470 count = stm_write(stm->data, stmf->output.master, stmf->output.channel,
478 static int stm_char_mmap(struct file *file, struct vm_area_struct *vma)
480 struct stm_file *stmf = file->private_data;
481 struct stm_device *stm = stmf->stm;
482 unsigned long size, phys;
484 if (!stm->data->mmio_addr)
490 size = vma->vm_end - vma->vm_start;
492 if (stmf->output.nr_chans * stm->data->sw_mmiosz != size)
495 phys = stm->data->mmio_addr(stm->data, stmf->output.master,
496 stmf->output.channel,
497 stmf->output.nr_chans);
502 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
503 vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
504 vm_iomap_memory(vma, phys, size);
509 static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
511 struct stm_device *stm = stmf->stm;
512 struct stp_policy_id *id;
516 if (stmf->output.nr_chans)
519 if (copy_from_user(&size, arg, sizeof(size)))
522 if (size >= PATH_MAX + sizeof(*id))
526 * size + 1 to make sure the .id string at the bottom is terminated,
527 * which is also why memdup_user() is not useful here
529 id = kzalloc(size + 1, GFP_KERNEL);
533 if (copy_from_user(id, arg, size)) {
538 if (id->__reserved_0 || id->__reserved_1)
542 id->width > PAGE_SIZE / stm->data->sw_mmiosz)
545 ret = stm_file_assign(stmf, id->id, id->width);
550 ret = stm->data->link(stm->data, stmf->output.master,
551 stmf->output.channel);
554 stm_output_free(stmf->stm, &stmf->output);
562 static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg)
564 struct stp_policy_id id = {
566 .master = stmf->output.master,
567 .channel = stmf->output.channel,
568 .width = stmf->output.nr_chans,
573 return copy_to_user(arg, &id, id.size) ? -EFAULT : 0;
577 stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
579 struct stm_file *stmf = file->private_data;
580 struct stm_data *stm_data = stmf->stm->data;
585 case STP_POLICY_ID_SET:
586 err = stm_char_policy_set_ioctl(stmf, (void __user *)arg);
590 return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
592 case STP_POLICY_ID_GET:
593 return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
595 case STP_SET_OPTIONS:
596 if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64)))
599 if (stm_data->set_options)
600 err = stm_data->set_options(stm_data,
602 stmf->output.channel,
603 stmf->output.nr_chans,
616 stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
618 return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
621 #define stm_char_compat_ioctl NULL
624 static const struct file_operations stm_fops = {
625 .open = stm_char_open,
626 .release = stm_char_release,
627 .write = stm_char_write,
628 .mmap = stm_char_mmap,
629 .unlocked_ioctl = stm_char_ioctl,
630 .compat_ioctl = stm_char_compat_ioctl,
634 static void stm_device_release(struct device *dev)
636 struct stm_device *stm = to_stm_device(dev);
641 int stm_register_device(struct device *parent, struct stm_data *stm_data,
642 struct module *owner)
644 struct stm_device *stm;
645 unsigned int nmasters;
649 return -EPROBE_DEFER;
651 if (!stm_data->packet || !stm_data->sw_nchannels)
654 nmasters = stm_data->sw_end - stm_data->sw_start;
655 stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
659 stm->major = register_chrdev(0, stm_data->name, &stm_fops);
663 device_initialize(&stm->dev);
664 stm->dev.devt = MKDEV(stm->major, 0);
665 stm->dev.class = &stm_class;
666 stm->dev.parent = parent;
667 stm->dev.release = stm_device_release;
669 mutex_init(&stm->link_mutex);
670 spin_lock_init(&stm->link_lock);
671 INIT_LIST_HEAD(&stm->link_list);
673 /* initialize the object before it is accessible via sysfs */
674 spin_lock_init(&stm->mc_lock);
675 mutex_init(&stm->policy_mutex);
676 stm->sw_nmasters = nmasters;
678 stm->data = stm_data;
681 err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name);
685 err = device_add(&stm->dev);
692 unregister_chrdev(stm->major, stm_data->name);
694 /* matches device_initialize() above */
695 put_device(&stm->dev);
701 EXPORT_SYMBOL_GPL(stm_register_device);
703 static int __stm_source_link_drop(struct stm_source_device *src,
704 struct stm_device *stm);
706 void stm_unregister_device(struct stm_data *stm_data)
708 struct stm_device *stm = stm_data->stm;
709 struct stm_source_device *src, *iter;
712 mutex_lock(&stm->link_mutex);
713 list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
714 ret = __stm_source_link_drop(src, stm);
716 * src <-> stm link must not change under the same
717 * stm::link_mutex, so complain loudly if it has;
718 * also in this situation ret!=0 means this src is
719 * not connected to this stm and it should be otherwise
720 * safe to proceed with the tear-down of stm.
724 mutex_unlock(&stm->link_mutex);
726 synchronize_srcu(&stm_source_srcu);
728 unregister_chrdev(stm->major, stm_data->name);
730 mutex_lock(&stm->policy_mutex);
732 stp_policy_unbind(stm->policy);
733 mutex_unlock(&stm->policy_mutex);
735 for (i = 0; i < stm->sw_nmasters; i++)
736 stp_master_free(stm, i);
738 device_unregister(&stm->dev);
739 stm_data->stm = NULL;
741 EXPORT_SYMBOL_GPL(stm_unregister_device);
744 * stm::link_list access serialization uses a spinlock and a mutex; holding
745 * either of them guarantees that the list is stable; modification requires
746 * holding both of them.
748 * Lock ordering is as follows:
755 * stm_source_link_add() - connect an stm_source device to an stm device
756 * @src: stm_source device
759 * This function establishes a link from stm_source to an stm device so that
760 * the former can send out trace data to the latter.
762 * Return: 0 on success, -errno otherwise.
764 static int stm_source_link_add(struct stm_source_device *src,
765 struct stm_device *stm)
770 mutex_lock(&stm->link_mutex);
771 spin_lock(&stm->link_lock);
772 spin_lock(&src->link_lock);
774 /* src->link is dereferenced under stm_source_srcu but not the list */
775 rcu_assign_pointer(src->link, stm);
776 list_add_tail(&src->link_entry, &stm->link_list);
778 spin_unlock(&src->link_lock);
779 spin_unlock(&stm->link_lock);
780 mutex_unlock(&stm->link_mutex);
782 id = kstrdup(src->data->name, GFP_KERNEL);
785 stp_policy_node_lookup(stm, id);
790 err = stm_output_assign(stm, src->data->nr_chans,
791 src->policy_node, &src->output);
793 if (src->policy_node)
794 stp_policy_node_put(src->policy_node);
799 /* this is to notify the STM device that a new link has been made */
801 err = stm->data->link(stm->data, src->output.master,
802 src->output.channel);
805 goto fail_free_output;
807 /* this is to let the source carry out all necessary preparations */
809 src->data->link(src->data);
814 stm_output_free(stm, &src->output);
817 mutex_lock(&stm->link_mutex);
818 spin_lock(&stm->link_lock);
819 spin_lock(&src->link_lock);
821 rcu_assign_pointer(src->link, NULL);
822 list_del_init(&src->link_entry);
824 spin_unlock(&src->link_lock);
825 spin_unlock(&stm->link_lock);
826 mutex_unlock(&stm->link_mutex);
832 * __stm_source_link_drop() - detach stm_source from an stm device
833 * @src: stm_source device
836 * If @stm is @src::link, disconnect them from one another and put the
837 * reference on the @stm device.
839 * Caller must hold stm::link_mutex.
841 static int __stm_source_link_drop(struct stm_source_device *src,
842 struct stm_device *stm)
844 struct stm_device *link;
847 lockdep_assert_held(&stm->link_mutex);
849 /* for stm::link_list modification, we hold both mutex and spinlock */
850 spin_lock(&stm->link_lock);
851 spin_lock(&src->link_lock);
852 link = srcu_dereference_check(src->link, &stm_source_srcu, 1);
855 * The linked device may have changed since we last looked, because
856 * we weren't holding the src::link_lock back then; if this is the
857 * case, tell the caller to retry.
864 stm_output_free(link, &src->output);
865 list_del_init(&src->link_entry);
866 /* matches stm_find_device() from stm_source_link_store() */
867 stm_put_device(link);
868 rcu_assign_pointer(src->link, NULL);
871 spin_unlock(&src->link_lock);
872 spin_unlock(&stm->link_lock);
875 * Call the unlink callbacks for both source and stm, when we know
876 * that we have actually performed the unlinking.
879 if (src->data->unlink)
880 src->data->unlink(src->data);
882 if (stm->data->unlink)
883 stm->data->unlink(stm->data, src->output.master,
884 src->output.channel);
891 * stm_source_link_drop() - detach stm_source from its stm device
892 * @src: stm_source device
894 * Unlinking means disconnecting from source's STM device; after this
895 * writes will be unsuccessful until it is linked to a new STM device.
897 * This will happen on "stm_source_link" sysfs attribute write to undo
898 * the existing link (if any), or on linked STM device's de-registration.
900 static void stm_source_link_drop(struct stm_source_device *src)
902 struct stm_device *stm;
906 idx = srcu_read_lock(&stm_source_srcu);
908 * The stm device will be valid for the duration of this
909 * read section, but the link may change before we grab
910 * the src::link_lock in __stm_source_link_drop().
912 stm = srcu_dereference(src->link, &stm_source_srcu);
916 mutex_lock(&stm->link_mutex);
917 ret = __stm_source_link_drop(src, stm);
918 mutex_unlock(&stm->link_mutex);
921 srcu_read_unlock(&stm_source_srcu, idx);
923 /* if it did change, retry */
928 static ssize_t stm_source_link_show(struct device *dev,
929 struct device_attribute *attr,
932 struct stm_source_device *src = to_stm_source_device(dev);
933 struct stm_device *stm;
936 idx = srcu_read_lock(&stm_source_srcu);
937 stm = srcu_dereference(src->link, &stm_source_srcu);
938 ret = sprintf(buf, "%s\n",
939 stm ? dev_name(&stm->dev) : "<none>");
940 srcu_read_unlock(&stm_source_srcu, idx);
945 static ssize_t stm_source_link_store(struct device *dev,
946 struct device_attribute *attr,
947 const char *buf, size_t count)
949 struct stm_source_device *src = to_stm_source_device(dev);
950 struct stm_device *link;
953 stm_source_link_drop(src);
955 link = stm_find_device(buf);
959 err = stm_source_link_add(src, link);
961 /* matches the stm_find_device() above */
962 stm_put_device(link);
965 return err ? : count;
968 static DEVICE_ATTR_RW(stm_source_link);
970 static struct attribute *stm_source_attrs[] = {
971 &dev_attr_stm_source_link.attr,
975 ATTRIBUTE_GROUPS(stm_source);
977 static struct class stm_source_class = {
978 .name = "stm_source",
979 .dev_groups = stm_source_groups,
982 static void stm_source_device_release(struct device *dev)
984 struct stm_source_device *src = to_stm_source_device(dev);
990 * stm_source_register_device() - register an stm_source device
991 * @parent: parent device
992 * @data: device description structure
994 * This will create a device of stm_source class that can write
995 * data to an stm device once linked.
997 * Return: 0 on success, -errno otherwise.
999 int stm_source_register_device(struct device *parent,
1000 struct stm_source_data *data)
1002 struct stm_source_device *src;
1006 return -EPROBE_DEFER;
1008 src = kzalloc(sizeof(*src), GFP_KERNEL);
1012 device_initialize(&src->dev);
1013 src->dev.class = &stm_source_class;
1014 src->dev.parent = parent;
1015 src->dev.release = stm_source_device_release;
1017 err = kobject_set_name(&src->dev.kobj, "%s", data->name);
1021 err = device_add(&src->dev);
1025 stm_output_init(&src->output);
1026 spin_lock_init(&src->link_lock);
1027 INIT_LIST_HEAD(&src->link_entry);
1034 put_device(&src->dev);
1039 EXPORT_SYMBOL_GPL(stm_source_register_device);
1042 * stm_source_unregister_device() - unregister an stm_source device
1043 * @data: device description that was used to register the device
1045 * This will remove a previously created stm_source device from the system.
1047 void stm_source_unregister_device(struct stm_source_data *data)
1049 struct stm_source_device *src = data->src;
1051 stm_source_link_drop(src);
1053 device_destroy(&stm_source_class, src->dev.devt);
1055 EXPORT_SYMBOL_GPL(stm_source_unregister_device);
1057 int stm_source_write(struct stm_source_data *data, unsigned int chan,
1058 const char *buf, size_t count)
1060 struct stm_source_device *src = data->src;
1061 struct stm_device *stm;
1064 if (!src->output.nr_chans)
1067 if (chan >= src->output.nr_chans)
1070 idx = srcu_read_lock(&stm_source_srcu);
1072 stm = srcu_dereference(src->link, &stm_source_srcu);
1074 count = stm_write(stm->data, src->output.master,
1075 src->output.channel + chan,
1080 srcu_read_unlock(&stm_source_srcu, idx);
1084 EXPORT_SYMBOL_GPL(stm_source_write);
1086 static int __init stm_core_init(void)
1090 err = class_register(&stm_class);
1094 err = class_register(&stm_source_class);
1098 err = stp_configfs_init();
1102 init_srcu_struct(&stm_source_srcu);
1109 class_unregister(&stm_source_class);
1111 class_unregister(&stm_class);
1116 module_init(stm_core_init);
1118 static void __exit stm_core_exit(void)
1120 cleanup_srcu_struct(&stm_source_srcu);
1121 class_unregister(&stm_source_class);
1122 class_unregister(&stm_class);
1123 stp_configfs_exit();
1126 module_exit(stm_core_exit);
1128 MODULE_LICENSE("GPL v2");
1129 MODULE_DESCRIPTION("System Trace Module device class");
1130 MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");