2 * Intel MIC Platform Software Stack (MPSS)
4 * Copyright(c) 2013 Intel Corporation.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License, version 2, as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * The full GNU General Public License is included in this distribution in
16 * the file called "COPYING".
18 * Intel MIC Host driver.
21 #include <linux/pci.h>
22 #include <linux/sched.h>
23 #include <linux/uaccess.h>
24 #include <linux/dmaengine.h>
25 #include <linux/mic_common.h>
27 #include "../common/mic_dev.h"
28 #include "mic_device.h"
30 #include "mic_virtio.h"
33 * Size of the internal buffer used during DMA's as an intermediate buffer
34 * for copy to/from user.
36 #define MIC_INT_DMA_BUF_SIZE PAGE_ALIGN(64 * 1024ULL)
38 static int mic_sync_dma(struct mic_device *mdev, dma_addr_t dst,
39 dma_addr_t src, size_t len)
42 struct dma_async_tx_descriptor *tx;
43 struct dma_chan *mic_ch = mdev->dma_ch[0];
50 tx = mic_ch->device->device_prep_dma_memcpy(mic_ch, dst, src, len,
56 dma_cookie_t cookie = tx->tx_submit(tx);
58 err = dma_submit_error(cookie);
61 err = dma_sync_wait(mic_ch, cookie);
65 dev_err(mdev->sdev->parent, "%s %d err %d\n",
66 __func__, __LINE__, err);
71 * Initiates the copies across the PCIe bus from card memory to a user
72 * space buffer. When transfers are done using DMA, source/destination
73 * addresses and transfer length must follow the alignment requirements of
76 static int mic_virtio_copy_to_user(struct mic_vdev *mvdev, void __user *ubuf,
77 size_t len, u64 daddr, size_t dlen,
80 struct mic_device *mdev = mvdev->mdev;
81 void __iomem *dbuf = mdev->aper.va + daddr;
82 struct mic_vringh *mvr = &mvdev->mvr[vr_idx];
83 size_t dma_alignment = 1 << mdev->dma_ch[0]->device->copy_align;
88 dma_offset = daddr - round_down(daddr, dma_alignment);
93 partlen = min_t(size_t, len, MIC_INT_DMA_BUF_SIZE);
95 err = mic_sync_dma(mdev, mvr->buf_da, daddr,
96 ALIGN(partlen, dma_alignment));
100 if (copy_to_user(ubuf, mvr->buf + dma_offset,
101 partlen - dma_offset)) {
108 mvdev->in_bytes_dma += partlen;
109 mvdev->in_bytes += partlen;
115 dev_err(mic_dev(mvdev), "%s %d err %d\n", __func__, __LINE__, err);
120 * Initiates copies across the PCIe bus from a user space buffer to card
121 * memory. When transfers are done using DMA, source/destination addresses
122 * and transfer length must follow the alignment requirements of the MIC
125 static int mic_virtio_copy_from_user(struct mic_vdev *mvdev, void __user *ubuf,
126 size_t len, u64 daddr, size_t dlen,
129 struct mic_device *mdev = mvdev->mdev;
130 void __iomem *dbuf = mdev->aper.va + daddr;
131 struct mic_vringh *mvr = &mvdev->mvr[vr_idx];
132 size_t dma_alignment = 1 << mdev->dma_ch[0]->device->copy_align;
136 if (daddr & (dma_alignment - 1)) {
137 mvdev->tx_dst_unaligned += len;
139 } else if (ALIGN(len, dma_alignment) > dlen) {
140 mvdev->tx_len_unaligned += len;
145 partlen = min_t(size_t, len, MIC_INT_DMA_BUF_SIZE);
147 if (copy_from_user(mvr->buf, ubuf, partlen)) {
151 err = mic_sync_dma(mdev, daddr, mvr->buf_da,
152 ALIGN(partlen, dma_alignment));
158 mvdev->out_bytes_dma += partlen;
159 mvdev->out_bytes += partlen;
164 * We are copying to IO below and should ideally use something
165 * like copy_from_user_toio(..) if it existed.
167 if (copy_from_user((void __force *)dbuf, ubuf, len)) {
171 mvdev->out_bytes += len;
174 dev_err(mic_dev(mvdev), "%s %d err %d\n", __func__, __LINE__, err);
178 #define MIC_VRINGH_READ true
180 /* The function to call to notify the card about added buffers */
181 static void mic_notify(struct vringh *vrh)
183 struct mic_vringh *mvrh = container_of(vrh, struct mic_vringh, vrh);
184 struct mic_vdev *mvdev = mvrh->mvdev;
185 s8 db = mvdev->dc->h2c_vdev_db;
188 mvdev->mdev->ops->send_intr(mvdev->mdev, db);
191 /* Determine the total number of bytes consumed in a VRINGH KIOV */
192 static inline u32 mic_vringh_iov_consumed(struct vringh_kiov *iov)
195 u32 total = iov->consumed;
197 for (i = 0; i < iov->i; i++)
198 total += iov->iov[i].iov_len;
203 * Traverse the VRINGH KIOV and issue the APIs to trigger the copies.
204 * This API is heavily based on the vringh_iov_xfer(..) implementation
205 * in vringh.c. The reason we cannot reuse vringh_iov_pull_kern(..)
206 * and vringh_iov_push_kern(..) directly is because there is no
207 * way to override the VRINGH xfer(..) routines as of v3.10.
209 static int mic_vringh_copy(struct mic_vdev *mvdev, struct vringh_kiov *iov,
210 void __user *ubuf, size_t len, bool read, int vr_idx,
214 size_t partlen, tot_len = 0;
216 while (len && iov->i < iov->used) {
217 partlen = min(iov->iov[iov->i].iov_len, len);
219 ret = mic_virtio_copy_to_user(mvdev, ubuf, partlen,
220 (u64)iov->iov[iov->i].iov_base,
221 iov->iov[iov->i].iov_len,
224 ret = mic_virtio_copy_from_user(mvdev, ubuf, partlen,
225 (u64)iov->iov[iov->i].iov_base,
226 iov->iov[iov->i].iov_len,
229 dev_err(mic_dev(mvdev), "%s %d err %d\n",
230 __func__, __LINE__, ret);
236 iov->consumed += partlen;
237 iov->iov[iov->i].iov_len -= partlen;
238 iov->iov[iov->i].iov_base += partlen;
239 if (!iov->iov[iov->i].iov_len) {
240 /* Fix up old iov element then increment. */
241 iov->iov[iov->i].iov_len = iov->consumed;
242 iov->iov[iov->i].iov_base -= iov->consumed;
253 * Use the standard VRINGH infrastructure in the kernel to fetch new
254 * descriptors, initiate the copies and update the used ring.
256 static int _mic_virtio_copy(struct mic_vdev *mvdev,
257 struct mic_copy_desc *copy)
260 u32 iovcnt = copy->iovcnt;
262 struct iovec __user *u_iov = copy->iov;
263 void __user *ubuf = NULL;
264 struct mic_vringh *mvr = &mvdev->mvr[copy->vr_idx];
265 struct vringh_kiov *riov = &mvr->riov;
266 struct vringh_kiov *wiov = &mvr->wiov;
267 struct vringh *vrh = &mvr->vrh;
268 u16 *head = &mvr->head;
269 struct mic_vring *vr = &mvr->vring;
270 size_t len = 0, out_len;
273 /* Fetch a new IOVEC if all previous elements have been processed */
274 if (riov->i == riov->used && wiov->i == wiov->used) {
275 ret = vringh_getdesc_kern(vrh, riov, wiov,
277 /* Check if there are available descriptors */
283 /* Copy over a new iovec from user space. */
284 ret = copy_from_user(&iov, u_iov, sizeof(*u_iov));
287 dev_err(mic_dev(mvdev), "%s %d err %d\n",
288 __func__, __LINE__, ret);
294 /* Issue all the read descriptors first */
295 ret = mic_vringh_copy(mvdev, riov, ubuf, len, MIC_VRINGH_READ,
296 copy->vr_idx, &out_len);
298 dev_err(mic_dev(mvdev), "%s %d err %d\n",
299 __func__, __LINE__, ret);
304 copy->out_len += out_len;
305 /* Issue the write descriptors next */
306 ret = mic_vringh_copy(mvdev, wiov, ubuf, len, !MIC_VRINGH_READ,
307 copy->vr_idx, &out_len);
309 dev_err(mic_dev(mvdev), "%s %d err %d\n",
310 __func__, __LINE__, ret);
315 copy->out_len += out_len;
317 /* One user space iovec is now completed */
321 /* Exit loop if all elements in KIOVs have been processed. */
322 if (riov->i == riov->used && wiov->i == wiov->used)
326 * Update the used ring if a descriptor was available and some data was
327 * copied in/out and the user asked for a used ring update.
329 if (*head != USHRT_MAX && copy->out_len && copy->update_used) {
332 /* Determine the total data consumed */
333 total += mic_vringh_iov_consumed(riov);
334 total += mic_vringh_iov_consumed(wiov);
335 vringh_complete_kern(vrh, *head, total);
337 if (vringh_need_notify_kern(vrh) > 0)
339 vringh_kiov_cleanup(riov);
340 vringh_kiov_cleanup(wiov);
341 /* Update avail idx for user space */
342 vr->info->avail_idx = vrh->last_avail_idx;
347 static inline int mic_verify_copy_args(struct mic_vdev *mvdev,
348 struct mic_copy_desc *copy)
350 if (copy->vr_idx >= mvdev->dd->num_vq) {
351 dev_err(mic_dev(mvdev), "%s %d err %d\n",
352 __func__, __LINE__, -EINVAL);
358 /* Copy a specified number of virtio descriptors in a chain */
359 int mic_virtio_copy_desc(struct mic_vdev *mvdev,
360 struct mic_copy_desc *copy)
363 struct mic_vringh *mvr = &mvdev->mvr[copy->vr_idx];
365 err = mic_verify_copy_args(mvdev, copy);
369 mutex_lock(&mvr->vr_mutex);
370 if (!mic_vdevup(mvdev)) {
372 dev_err(mic_dev(mvdev), "%s %d err %d\n",
373 __func__, __LINE__, err);
376 err = _mic_virtio_copy(mvdev, copy);
378 dev_err(mic_dev(mvdev), "%s %d err %d\n",
379 __func__, __LINE__, err);
382 mutex_unlock(&mvr->vr_mutex);
386 static void mic_virtio_init_post(struct mic_vdev *mvdev)
388 struct mic_vqconfig *vqconfig = mic_vq_config(mvdev->dd);
391 for (i = 0; i < mvdev->dd->num_vq; i++) {
392 if (!le64_to_cpu(vqconfig[i].used_address)) {
393 dev_warn(mic_dev(mvdev), "used_address zero??\n");
396 mvdev->mvr[i].vrh.vring.used =
397 (void __force *)mvdev->mdev->aper.va +
398 le64_to_cpu(vqconfig[i].used_address);
401 mvdev->dc->used_address_updated = 0;
403 dev_dbg(mic_dev(mvdev), "%s: device type %d LINKUP\n",
404 __func__, mvdev->virtio_id);
407 static inline void mic_virtio_device_reset(struct mic_vdev *mvdev)
411 dev_dbg(mic_dev(mvdev), "%s: status %d device type %d RESET\n",
412 __func__, mvdev->dd->status, mvdev->virtio_id);
414 for (i = 0; i < mvdev->dd->num_vq; i++)
416 * Avoid lockdep false positive. The + 1 is for the mic
417 * mutex which is held in the reset devices code path.
419 mutex_lock_nested(&mvdev->mvr[i].vr_mutex, i + 1);
421 /* 0 status means "reset" */
422 mvdev->dd->status = 0;
423 mvdev->dc->vdev_reset = 0;
424 mvdev->dc->host_ack = 1;
426 for (i = 0; i < mvdev->dd->num_vq; i++) {
427 struct vringh *vrh = &mvdev->mvr[i].vrh;
428 mvdev->mvr[i].vring.info->avail_idx = 0;
430 vrh->last_avail_idx = 0;
431 vrh->last_used_idx = 0;
434 for (i = 0; i < mvdev->dd->num_vq; i++)
435 mutex_unlock(&mvdev->mvr[i].vr_mutex);
438 void mic_virtio_reset_devices(struct mic_device *mdev)
440 struct list_head *pos, *tmp;
441 struct mic_vdev *mvdev;
443 dev_dbg(mdev->sdev->parent, "%s\n", __func__);
445 list_for_each_safe(pos, tmp, &mdev->vdev_list) {
446 mvdev = list_entry(pos, struct mic_vdev, list);
447 mic_virtio_device_reset(mvdev);
448 mvdev->poll_wake = 1;
449 wake_up(&mvdev->waitq);
453 void mic_bh_handler(struct work_struct *work)
455 struct mic_vdev *mvdev = container_of(work, struct mic_vdev,
458 if (mvdev->dc->used_address_updated)
459 mic_virtio_init_post(mvdev);
461 if (mvdev->dc->vdev_reset)
462 mic_virtio_device_reset(mvdev);
464 mvdev->poll_wake = 1;
465 wake_up(&mvdev->waitq);
468 static irqreturn_t mic_virtio_intr_handler(int irq, void *data)
470 struct mic_vdev *mvdev = data;
471 struct mic_device *mdev = mvdev->mdev;
473 mdev->ops->intr_workarounds(mdev);
474 schedule_work(&mvdev->virtio_bh_work);
478 int mic_virtio_config_change(struct mic_vdev *mvdev,
481 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
482 int ret = 0, retry, i;
483 struct mic_bootparam *bootparam = mvdev->mdev->dp;
484 s8 db = bootparam->h2c_config_db;
486 mutex_lock(&mvdev->mdev->mic_mutex);
487 for (i = 0; i < mvdev->dd->num_vq; i++)
488 mutex_lock_nested(&mvdev->mvr[i].vr_mutex, i + 1);
490 if (db == -1 || mvdev->dd->type == -1) {
495 if (copy_from_user(mic_vq_configspace(mvdev->dd),
496 argp, mvdev->dd->config_len)) {
497 dev_err(mic_dev(mvdev), "%s %d err %d\n",
498 __func__, __LINE__, -EFAULT);
502 mvdev->dc->config_change = MIC_VIRTIO_PARAM_CONFIG_CHANGED;
503 mvdev->mdev->ops->send_intr(mvdev->mdev, db);
505 for (retry = 100; retry--;) {
506 ret = wait_event_timeout(wake,
507 mvdev->dc->guest_ack, msecs_to_jiffies(100));
512 dev_dbg(mic_dev(mvdev),
513 "%s %d retry: %d\n", __func__, __LINE__, retry);
514 mvdev->dc->config_change = 0;
515 mvdev->dc->guest_ack = 0;
517 for (i = 0; i < mvdev->dd->num_vq; i++)
518 mutex_unlock(&mvdev->mvr[i].vr_mutex);
519 mutex_unlock(&mvdev->mdev->mic_mutex);
523 static int mic_copy_dp_entry(struct mic_vdev *mvdev,
526 struct mic_device_desc **devpage)
528 struct mic_device *mdev = mvdev->mdev;
529 struct mic_device_desc dd, *dd_config, *devp;
530 struct mic_vqconfig *vqconfig;
532 bool slot_found = false;
534 if (copy_from_user(&dd, argp, sizeof(dd))) {
535 dev_err(mic_dev(mvdev), "%s %d err %d\n",
536 __func__, __LINE__, -EFAULT);
540 if (mic_aligned_desc_size(&dd) > MIC_MAX_DESC_BLK_SIZE ||
541 dd.num_vq > MIC_MAX_VRINGS) {
542 dev_err(mic_dev(mvdev), "%s %d err %d\n",
543 __func__, __LINE__, -EINVAL);
547 dd_config = kmalloc(mic_desc_size(&dd), GFP_KERNEL);
548 if (dd_config == NULL) {
549 dev_err(mic_dev(mvdev), "%s %d err %d\n",
550 __func__, __LINE__, -ENOMEM);
553 if (copy_from_user(dd_config, argp, mic_desc_size(&dd))) {
555 dev_err(mic_dev(mvdev), "%s %d err %d\n",
556 __func__, __LINE__, ret);
560 vqconfig = mic_vq_config(dd_config);
561 for (i = 0; i < dd.num_vq; i++) {
562 if (le16_to_cpu(vqconfig[i].num) > MIC_MAX_VRING_ENTRIES) {
564 dev_err(mic_dev(mvdev), "%s %d err %d\n",
565 __func__, __LINE__, ret);
570 /* Find the first free device page entry */
571 for (i = sizeof(struct mic_bootparam);
572 i < MIC_DP_SIZE - mic_total_desc_size(dd_config);
573 i += mic_total_desc_size(devp)) {
575 if (devp->type == 0 || devp->type == -1) {
582 dev_err(mic_dev(mvdev), "%s %d err %d\n",
583 __func__, __LINE__, ret);
587 * Save off the type before doing the memcpy. Type will be set in the
588 * end after completing all initialization for the new device.
590 *type = dd_config->type;
592 memcpy(devp, dd_config, mic_desc_size(dd_config));
600 static void mic_init_device_ctrl(struct mic_vdev *mvdev,
601 struct mic_device_desc *devpage)
603 struct mic_device_ctrl *dc;
605 dc = (void *)devpage + mic_aligned_desc_size(devpage);
607 dc->config_change = 0;
611 dc->used_address_updated = 0;
612 dc->c2h_vdev_db = -1;
613 dc->h2c_vdev_db = -1;
617 int mic_virtio_add_device(struct mic_vdev *mvdev,
620 struct mic_device *mdev = mvdev->mdev;
621 struct mic_device_desc *dd = NULL;
622 struct mic_vqconfig *vqconfig;
623 int vr_size, i, j, ret;
627 struct mic_bootparam *bootparam = mdev->dp;
631 mutex_lock(&mdev->mic_mutex);
633 ret = mic_copy_dp_entry(mvdev, argp, &type, &dd);
635 mutex_unlock(&mdev->mic_mutex);
639 mic_init_device_ctrl(mvdev, dd);
642 mvdev->virtio_id = type;
643 vqconfig = mic_vq_config(dd);
644 INIT_WORK(&mvdev->virtio_bh_work, mic_bh_handler);
646 for (i = 0; i < dd->num_vq; i++) {
647 struct mic_vringh *mvr = &mvdev->mvr[i];
648 struct mic_vring *vr = &mvdev->mvr[i].vring;
649 num = le16_to_cpu(vqconfig[i].num);
650 mutex_init(&mvr->vr_mutex);
651 vr_size = PAGE_ALIGN(vring_size(num, MIC_VIRTIO_RING_ALIGN) +
652 sizeof(struct _mic_vring_info));
654 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
658 dev_err(mic_dev(mvdev), "%s %d err %d\n",
659 __func__, __LINE__, ret);
663 vr->info = vr->va + vring_size(num, MIC_VIRTIO_RING_ALIGN);
664 vr->info->magic = cpu_to_le32(MIC_MAGIC + mvdev->virtio_id + i);
665 vr_addr = mic_map_single(mdev, vr->va, vr_size);
666 if (mic_map_error(vr_addr)) {
667 free_pages((unsigned long)vr->va, get_order(vr_size));
669 dev_err(mic_dev(mvdev), "%s %d err %d\n",
670 __func__, __LINE__, ret);
673 vqconfig[i].address = cpu_to_le64(vr_addr);
675 vring_init(&vr->vr, num, vr->va, MIC_VIRTIO_RING_ALIGN);
676 ret = vringh_init_kern(&mvr->vrh,
677 *(u32 *)mic_vq_features(mvdev->dd), num, false,
678 vr->vr.desc, vr->vr.avail, vr->vr.used);
680 dev_err(mic_dev(mvdev), "%s %d err %d\n",
681 __func__, __LINE__, ret);
684 vringh_kiov_init(&mvr->riov, NULL, 0);
685 vringh_kiov_init(&mvr->wiov, NULL, 0);
686 mvr->head = USHRT_MAX;
688 mvr->vrh.notify = mic_notify;
689 dev_dbg(mdev->sdev->parent,
690 "%s %d index %d va %p info %p vr_size 0x%x\n",
691 __func__, __LINE__, i, vr->va, vr->info, vr_size);
692 mvr->buf = (void *)__get_free_pages(GFP_KERNEL,
693 get_order(MIC_INT_DMA_BUF_SIZE));
694 mvr->buf_da = mic_map_single(mvdev->mdev, mvr->buf,
695 MIC_INT_DMA_BUF_SIZE);
698 snprintf(irqname, sizeof(irqname), "mic%dvirtio%d", mdev->id,
700 mvdev->virtio_db = mic_next_db(mdev);
701 mvdev->virtio_cookie = mic_request_threaded_irq(mdev,
702 mic_virtio_intr_handler,
703 NULL, irqname, mvdev,
704 mvdev->virtio_db, MIC_INTR_DB);
705 if (IS_ERR(mvdev->virtio_cookie)) {
706 ret = PTR_ERR(mvdev->virtio_cookie);
707 dev_dbg(mdev->sdev->parent, "request irq failed\n");
711 mvdev->dc->c2h_vdev_db = mvdev->virtio_db;
713 list_add_tail(&mvdev->list, &mdev->vdev_list);
715 * Order the type update with previous stores. This write barrier
716 * is paired with the corresponding read barrier before the uncached
717 * system memory read of the type, on the card while scanning the
723 dev_dbg(mdev->sdev->parent, "Added virtio device id %d\n", dd->type);
725 db = bootparam->h2c_config_db;
727 mdev->ops->send_intr(mdev, db);
728 mutex_unlock(&mdev->mic_mutex);
731 vqconfig = mic_vq_config(dd);
732 for (j = 0; j < i; j++) {
733 struct mic_vringh *mvr = &mvdev->mvr[j];
734 mic_unmap_single(mdev, le64_to_cpu(vqconfig[j].address),
736 free_pages((unsigned long)mvr->vring.va,
737 get_order(mvr->vring.len));
739 mutex_unlock(&mdev->mic_mutex);
743 void mic_virtio_del_device(struct mic_vdev *mvdev)
745 struct list_head *pos, *tmp;
746 struct mic_vdev *tmp_mvdev;
747 struct mic_device *mdev = mvdev->mdev;
748 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
750 struct mic_vqconfig *vqconfig;
751 struct mic_bootparam *bootparam = mdev->dp;
754 mutex_lock(&mdev->mic_mutex);
755 db = bootparam->h2c_config_db;
757 goto skip_hot_remove;
758 dev_dbg(mdev->sdev->parent,
759 "Requesting hot remove id %d\n", mvdev->virtio_id);
760 mvdev->dc->config_change = MIC_VIRTIO_PARAM_DEV_REMOVE;
761 mdev->ops->send_intr(mdev, db);
762 for (retry = 100; retry--;) {
763 ret = wait_event_timeout(wake,
764 mvdev->dc->guest_ack, msecs_to_jiffies(100));
768 dev_dbg(mdev->sdev->parent,
769 "Device id %d config_change %d guest_ack %d retry %d\n",
770 mvdev->virtio_id, mvdev->dc->config_change,
771 mvdev->dc->guest_ack, retry);
772 mvdev->dc->config_change = 0;
773 mvdev->dc->guest_ack = 0;
775 mic_free_irq(mdev, mvdev->virtio_cookie, mvdev);
776 flush_work(&mvdev->virtio_bh_work);
777 vqconfig = mic_vq_config(mvdev->dd);
778 for (i = 0; i < mvdev->dd->num_vq; i++) {
779 struct mic_vringh *mvr = &mvdev->mvr[i];
781 mic_unmap_single(mvdev->mdev, mvr->buf_da,
782 MIC_INT_DMA_BUF_SIZE);
783 free_pages((unsigned long)mvr->buf,
784 get_order(MIC_INT_DMA_BUF_SIZE));
785 vringh_kiov_cleanup(&mvr->riov);
786 vringh_kiov_cleanup(&mvr->wiov);
787 mic_unmap_single(mdev, le64_to_cpu(vqconfig[i].address),
789 free_pages((unsigned long)mvr->vring.va,
790 get_order(mvr->vring.len));
793 list_for_each_safe(pos, tmp, &mdev->vdev_list) {
794 tmp_mvdev = list_entry(pos, struct mic_vdev, list);
795 if (tmp_mvdev == mvdev) {
797 dev_dbg(mdev->sdev->parent,
798 "Removing virtio device id %d\n",
804 * Order the type update with previous stores. This write barrier
805 * is paired with the corresponding read barrier before the uncached
806 * system memory read of the type, on the card while scanning the
810 mvdev->dd->type = -1;
811 mutex_unlock(&mdev->mic_mutex);