linux/drivers/net/caif/caif_shmcore.c
Arnd Bergmann 6e4a76291e caif: include linux/io.h
The caif_shmcore requires io.h in order to use ioremap, so include that
explicitly to compile in all configurations.

Also add a note about the use of ioremap(), which is not a proper way
to map a DMA buffer into kernel space. It's not completely clear what
the intention is for using ioremap, but it is clear that the result
of ioremap must not simply be accessed using kernel pointers but
should use readl/writel or memcopy_{to,from}io. Assigning the result
of ioremap to a regular pointer that can also be set to something
else is not ok.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-21 15:28:47 -04:00

753 lines
18 KiB
C

/*
* Copyright (C) ST-Ericsson AB 2010
* Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
* Authors: Amarnath Revanna / amarnath.bangalore.revanna@stericsson.com,
* Daniel Martensson / daniel.martensson@stericsson.com
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":" fmt
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/io.h>
#include <net/caif/caif_device.h>
#include <net/caif/caif_shm.h>
#define NR_TX_BUF 6
#define NR_RX_BUF 6
#define TX_BUF_SZ 0x2000
#define RX_BUF_SZ 0x2000
#define CAIF_NEEDED_HEADROOM 32
#define CAIF_FLOW_ON 1
#define CAIF_FLOW_OFF 0
#define LOW_WATERMARK 3
#define HIGH_WATERMARK 4
/* Maximum number of CAIF buffers per shared memory buffer. */
#define SHM_MAX_FRMS_PER_BUF 10
/*
* Size in bytes of the descriptor area
* (With end of descriptor signalling)
*/
#define SHM_CAIF_DESC_SIZE ((SHM_MAX_FRMS_PER_BUF + 1) * \
sizeof(struct shm_pck_desc))
/*
* Offset to the first CAIF frame within a shared memory buffer.
* Aligned on 32 bytes.
*/
#define SHM_CAIF_FRM_OFS (SHM_CAIF_DESC_SIZE + (SHM_CAIF_DESC_SIZE % 32))
/* Number of bytes for CAIF shared memory header. */
#define SHM_HDR_LEN 1
/* Number of padding bytes for the complete CAIF frame. */
#define SHM_FRM_PAD_LEN 4
#define CAIF_MAX_MTU 4096
#define SHM_SET_FULL(x) (((x+1) & 0x0F) << 0)
#define SHM_GET_FULL(x) (((x >> 0) & 0x0F) - 1)
#define SHM_SET_EMPTY(x) (((x+1) & 0x0F) << 4)
#define SHM_GET_EMPTY(x) (((x >> 4) & 0x0F) - 1)
#define SHM_FULL_MASK (0x0F << 0)
#define SHM_EMPTY_MASK (0x0F << 4)
struct shm_pck_desc {
/*
* Offset from start of shared memory area to start of
* shared memory CAIF frame.
*/
u32 frm_ofs;
u32 frm_len;
};
struct buf_list {
unsigned char *desc_vptr;
u32 phy_addr;
u32 index;
u32 len;
u32 frames;
u32 frm_ofs;
struct list_head list;
};
struct shm_caif_frm {
/* Number of bytes of padding before the CAIF frame. */
u8 hdr_ofs;
};
struct shmdrv_layer {
/* caif_dev_common must always be first in the structure*/
struct caif_dev_common cfdev;
u32 shm_tx_addr;
u32 shm_rx_addr;
u32 shm_base_addr;
u32 tx_empty_available;
spinlock_t lock;
struct list_head tx_empty_list;
struct list_head tx_pend_list;
struct list_head tx_full_list;
struct list_head rx_empty_list;
struct list_head rx_pend_list;
struct list_head rx_full_list;
struct workqueue_struct *pshm_tx_workqueue;
struct workqueue_struct *pshm_rx_workqueue;
struct work_struct shm_tx_work;
struct work_struct shm_rx_work;
struct sk_buff_head sk_qhead;
struct shmdev_layer *pshm_dev;
};
static int shm_netdev_open(struct net_device *shm_netdev)
{
netif_wake_queue(shm_netdev);
return 0;
}
static int shm_netdev_close(struct net_device *shm_netdev)
{
netif_stop_queue(shm_netdev);
return 0;
}
int caif_shmdrv_rx_cb(u32 mbx_msg, void *priv)
{
struct buf_list *pbuf;
struct shmdrv_layer *pshm_drv;
struct list_head *pos;
u32 avail_emptybuff = 0;
unsigned long flags = 0;
pshm_drv = priv;
/* Check for received buffers. */
if (mbx_msg & SHM_FULL_MASK) {
int idx;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check whether we have any outstanding buffers. */
if (list_empty(&pshm_drv->rx_empty_list)) {
/* Release spin lock. */
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* We print even in IRQ context... */
pr_warn("No empty Rx buffers to fill: "
"mbx_msg:%x\n", mbx_msg);
/* Bail out. */
goto err_sync;
}
pbuf =
list_entry(pshm_drv->rx_empty_list.next,
struct buf_list, list);
idx = pbuf->index;
/* Check buffer synchronization. */
if (idx != SHM_GET_FULL(mbx_msg)) {
/* We print even in IRQ context... */
pr_warn(
"phyif_shm_mbx_msg_cb: RX full out of sync:"
" idx:%d, msg:%x SHM_GET_FULL(mbx_msg):%x\n",
idx, mbx_msg, SHM_GET_FULL(mbx_msg));
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Bail out. */
goto err_sync;
}
list_del_init(&pbuf->list);
list_add_tail(&pbuf->list, &pshm_drv->rx_full_list);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Schedule RX work queue. */
if (!work_pending(&pshm_drv->shm_rx_work))
queue_work(pshm_drv->pshm_rx_workqueue,
&pshm_drv->shm_rx_work);
}
/* Check for emptied buffers. */
if (mbx_msg & SHM_EMPTY_MASK) {
int idx;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check whether we have any outstanding buffers. */
if (list_empty(&pshm_drv->tx_full_list)) {
/* We print even in IRQ context... */
pr_warn("No TX to empty: msg:%x\n", mbx_msg);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Bail out. */
goto err_sync;
}
pbuf =
list_entry(pshm_drv->tx_full_list.next,
struct buf_list, list);
idx = pbuf->index;
/* Check buffer synchronization. */
if (idx != SHM_GET_EMPTY(mbx_msg)) {
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* We print even in IRQ context... */
pr_warn("TX empty "
"out of sync:idx:%d, msg:%x\n", idx, mbx_msg);
/* Bail out. */
goto err_sync;
}
list_del_init(&pbuf->list);
/* Reset buffer parameters. */
pbuf->frames = 0;
pbuf->frm_ofs = SHM_CAIF_FRM_OFS;
list_add_tail(&pbuf->list, &pshm_drv->tx_empty_list);
/* Check the available no. of buffers in the empty list */
list_for_each(pos, &pshm_drv->tx_empty_list)
avail_emptybuff++;
/* Check whether we have to wake up the transmitter. */
if ((avail_emptybuff > HIGH_WATERMARK) &&
(!pshm_drv->tx_empty_available)) {
pshm_drv->tx_empty_available = 1;
spin_unlock_irqrestore(&pshm_drv->lock, flags);
pshm_drv->cfdev.flowctrl
(pshm_drv->pshm_dev->pshm_netdev,
CAIF_FLOW_ON);
/* Schedule the work queue. if required */
if (!work_pending(&pshm_drv->shm_tx_work))
queue_work(pshm_drv->pshm_tx_workqueue,
&pshm_drv->shm_tx_work);
} else
spin_unlock_irqrestore(&pshm_drv->lock, flags);
}
return 0;
err_sync:
return -EIO;
}
static void shm_rx_work_func(struct work_struct *rx_work)
{
struct shmdrv_layer *pshm_drv;
struct buf_list *pbuf;
unsigned long flags = 0;
struct sk_buff *skb;
char *p;
int ret;
pshm_drv = container_of(rx_work, struct shmdrv_layer, shm_rx_work);
while (1) {
struct shm_pck_desc *pck_desc;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check for received buffers. */
if (list_empty(&pshm_drv->rx_full_list)) {
spin_unlock_irqrestore(&pshm_drv->lock, flags);
break;
}
pbuf =
list_entry(pshm_drv->rx_full_list.next, struct buf_list,
list);
list_del_init(&pbuf->list);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
/* Retrieve pointer to start of the packet descriptor area. */
pck_desc = (struct shm_pck_desc *) pbuf->desc_vptr;
/*
* Check whether descriptor contains a CAIF shared memory
* frame.
*/
while (pck_desc->frm_ofs) {
unsigned int frm_buf_ofs;
unsigned int frm_pck_ofs;
unsigned int frm_pck_len;
/*
* Check whether offset is within buffer limits
* (lower).
*/
if (pck_desc->frm_ofs <
(pbuf->phy_addr - pshm_drv->shm_base_addr))
break;
/*
* Check whether offset is within buffer limits
* (higher).
*/
if (pck_desc->frm_ofs >
((pbuf->phy_addr - pshm_drv->shm_base_addr) +
pbuf->len))
break;
/* Calculate offset from start of buffer. */
frm_buf_ofs =
pck_desc->frm_ofs - (pbuf->phy_addr -
pshm_drv->shm_base_addr);
/*
* Calculate offset and length of CAIF packet while
* taking care of the shared memory header.
*/
frm_pck_ofs =
frm_buf_ofs + SHM_HDR_LEN +
(*(pbuf->desc_vptr + frm_buf_ofs));
frm_pck_len =
(pck_desc->frm_len - SHM_HDR_LEN -
(*(pbuf->desc_vptr + frm_buf_ofs)));
/* Check whether CAIF packet is within buffer limits */
if ((frm_pck_ofs + pck_desc->frm_len) > pbuf->len)
break;
/* Get a suitable CAIF packet and copy in data. */
skb = netdev_alloc_skb(pshm_drv->pshm_dev->pshm_netdev,
frm_pck_len + 1);
if (skb == NULL) {
pr_info("OOM: Try next frame in descriptor\n");
break;
}
p = skb_put(skb, frm_pck_len);
memcpy(p, pbuf->desc_vptr + frm_pck_ofs, frm_pck_len);
skb->protocol = htons(ETH_P_CAIF);
skb_reset_mac_header(skb);
skb->dev = pshm_drv->pshm_dev->pshm_netdev;
/* Push received packet up the stack. */
ret = netif_rx_ni(skb);
if (!ret) {
pshm_drv->pshm_dev->pshm_netdev->stats.
rx_packets++;
pshm_drv->pshm_dev->pshm_netdev->stats.
rx_bytes += pck_desc->frm_len;
} else
++pshm_drv->pshm_dev->pshm_netdev->stats.
rx_dropped;
/* Move to next packet descriptor. */
pck_desc++;
}
spin_lock_irqsave(&pshm_drv->lock, flags);
list_add_tail(&pbuf->list, &pshm_drv->rx_pend_list);
spin_unlock_irqrestore(&pshm_drv->lock, flags);
}
/* Schedule the work queue. if required */
if (!work_pending(&pshm_drv->shm_tx_work))
queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);
}
static void shm_tx_work_func(struct work_struct *tx_work)
{
u32 mbox_msg;
unsigned int frmlen, avail_emptybuff, append = 0;
unsigned long flags = 0;
struct buf_list *pbuf = NULL;
struct shmdrv_layer *pshm_drv;
struct shm_caif_frm *frm;
struct sk_buff *skb;
struct shm_pck_desc *pck_desc;
struct list_head *pos;
pshm_drv = container_of(tx_work, struct shmdrv_layer, shm_tx_work);
do {
/* Initialize mailbox message. */
mbox_msg = 0x00;
avail_emptybuff = 0;
spin_lock_irqsave(&pshm_drv->lock, flags);
/* Check for pending receive buffers. */
if (!list_empty(&pshm_drv->rx_pend_list)) {
pbuf = list_entry(pshm_drv->rx_pend_list.next,
struct buf_list, list);
list_del_init(&pbuf->list);
list_add_tail(&pbuf->list, &pshm_drv->rx_empty_list);
/*
* Value index is never changed,
* so read access should be safe.
*/
mbox_msg |= SHM_SET_EMPTY(pbuf->index);
}
skb = skb_peek(&pshm_drv->sk_qhead);
if (skb == NULL)
goto send_msg;
/* Check the available no. of buffers in the empty list */
list_for_each(pos, &pshm_drv->tx_empty_list)
avail_emptybuff++;
if ((avail_emptybuff < LOW_WATERMARK) &&
pshm_drv->tx_empty_available) {
/* Update blocking condition. */
pshm_drv->tx_empty_available = 0;
spin_unlock_irqrestore(&pshm_drv->lock, flags);
pshm_drv->cfdev.flowctrl
(pshm_drv->pshm_dev->pshm_netdev,
CAIF_FLOW_OFF);
spin_lock_irqsave(&pshm_drv->lock, flags);
}
/*
* We simply return back to the caller if we do not have space
* either in Tx pending list or Tx empty list. In this case,
* we hold the received skb in the skb list, waiting to
* be transmitted once Tx buffers become available
*/
if (list_empty(&pshm_drv->tx_empty_list))
goto send_msg;
/* Get the first free Tx buffer. */
pbuf = list_entry(pshm_drv->tx_empty_list.next,
struct buf_list, list);
do {
if (append) {
skb = skb_peek(&pshm_drv->sk_qhead);
if (skb == NULL)
break;
}
frm = (struct shm_caif_frm *)
(pbuf->desc_vptr + pbuf->frm_ofs);
frm->hdr_ofs = 0;
frmlen = 0;
frmlen += SHM_HDR_LEN + frm->hdr_ofs + skb->len;
/* Add tail padding if needed. */
if (frmlen % SHM_FRM_PAD_LEN)
frmlen += SHM_FRM_PAD_LEN -
(frmlen % SHM_FRM_PAD_LEN);
/*
* Verify that packet, header and additional padding
* can fit within the buffer frame area.
*/
if (frmlen >= (pbuf->len - pbuf->frm_ofs))
break;
if (!append) {
list_del_init(&pbuf->list);
append = 1;
}
skb = skb_dequeue(&pshm_drv->sk_qhead);
if (skb == NULL)
break;
/* Copy in CAIF frame. */
skb_copy_bits(skb, 0, pbuf->desc_vptr +
pbuf->frm_ofs + SHM_HDR_LEN +
frm->hdr_ofs, skb->len);
pshm_drv->pshm_dev->pshm_netdev->stats.tx_packets++;
pshm_drv->pshm_dev->pshm_netdev->stats.tx_bytes +=
frmlen;
dev_kfree_skb_irq(skb);
/* Fill in the shared memory packet descriptor area. */
pck_desc = (struct shm_pck_desc *) (pbuf->desc_vptr);
/* Forward to current frame. */
pck_desc += pbuf->frames;
pck_desc->frm_ofs = (pbuf->phy_addr -
pshm_drv->shm_base_addr) +
pbuf->frm_ofs;
pck_desc->frm_len = frmlen;
/* Terminate packet descriptor area. */
pck_desc++;
pck_desc->frm_ofs = 0;
/* Update buffer parameters. */
pbuf->frames++;
pbuf->frm_ofs += frmlen + (frmlen % 32);
} while (pbuf->frames < SHM_MAX_FRMS_PER_BUF);
/* Assign buffer as full. */
list_add_tail(&pbuf->list, &pshm_drv->tx_full_list);
append = 0;
mbox_msg |= SHM_SET_FULL(pbuf->index);
send_msg:
spin_unlock_irqrestore(&pshm_drv->lock, flags);
if (mbox_msg)
pshm_drv->pshm_dev->pshmdev_mbxsend
(pshm_drv->pshm_dev->shm_id, mbox_msg);
} while (mbox_msg);
}
static int shm_netdev_tx(struct sk_buff *skb, struct net_device *shm_netdev)
{
struct shmdrv_layer *pshm_drv;
pshm_drv = netdev_priv(shm_netdev);
skb_queue_tail(&pshm_drv->sk_qhead, skb);
/* Schedule Tx work queue. for deferred processing of skbs*/
if (!work_pending(&pshm_drv->shm_tx_work))
queue_work(pshm_drv->pshm_tx_workqueue, &pshm_drv->shm_tx_work);
return 0;
}
static const struct net_device_ops netdev_ops = {
.ndo_open = shm_netdev_open,
.ndo_stop = shm_netdev_close,
.ndo_start_xmit = shm_netdev_tx,
};
static void shm_netdev_setup(struct net_device *pshm_netdev)
{
struct shmdrv_layer *pshm_drv;
pshm_netdev->netdev_ops = &netdev_ops;
pshm_netdev->mtu = CAIF_MAX_MTU;
pshm_netdev->type = ARPHRD_CAIF;
pshm_netdev->hard_header_len = CAIF_NEEDED_HEADROOM;
pshm_netdev->tx_queue_len = 0;
pshm_netdev->destructor = free_netdev;
pshm_drv = netdev_priv(pshm_netdev);
/* Initialize structures in a clean state. */
memset(pshm_drv, 0, sizeof(struct shmdrv_layer));
pshm_drv->cfdev.link_select = CAIF_LINK_LOW_LATENCY;
}
int caif_shmcore_probe(struct shmdev_layer *pshm_dev)
{
int result, j;
struct shmdrv_layer *pshm_drv = NULL;
pshm_dev->pshm_netdev = alloc_netdev(sizeof(struct shmdrv_layer),
"cfshm%d", shm_netdev_setup);
if (!pshm_dev->pshm_netdev)
return -ENOMEM;
pshm_drv = netdev_priv(pshm_dev->pshm_netdev);
pshm_drv->pshm_dev = pshm_dev;
/*
* Initialization starts with the verification of the
* availability of MBX driver by calling its setup function.
* MBX driver must be available by this time for proper
* functioning of SHM driver.
*/
if ((pshm_dev->pshmdev_mbxsetup
(caif_shmdrv_rx_cb, pshm_dev, pshm_drv)) != 0) {
pr_warn("Could not config. SHM Mailbox,"
" Bailing out.....\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENODEV;
}
skb_queue_head_init(&pshm_drv->sk_qhead);
pr_info("SHM DEVICE[%d] PROBED BY DRIVER, NEW SHM DRIVER"
" INSTANCE AT pshm_drv =0x%p\n",
pshm_drv->pshm_dev->shm_id, pshm_drv);
if (pshm_dev->shm_total_sz <
(NR_TX_BUF * TX_BUF_SZ + NR_RX_BUF * RX_BUF_SZ)) {
pr_warn("ERROR, Amount of available"
" Phys. SHM cannot accommodate current SHM "
"driver configuration, Bailing out ...\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENOMEM;
}
pshm_drv->shm_base_addr = pshm_dev->shm_base_addr;
pshm_drv->shm_tx_addr = pshm_drv->shm_base_addr;
if (pshm_dev->shm_loopback)
pshm_drv->shm_rx_addr = pshm_drv->shm_tx_addr;
else
pshm_drv->shm_rx_addr = pshm_dev->shm_base_addr +
(NR_TX_BUF * TX_BUF_SZ);
spin_lock_init(&pshm_drv->lock);
INIT_LIST_HEAD(&pshm_drv->tx_empty_list);
INIT_LIST_HEAD(&pshm_drv->tx_pend_list);
INIT_LIST_HEAD(&pshm_drv->tx_full_list);
INIT_LIST_HEAD(&pshm_drv->rx_empty_list);
INIT_LIST_HEAD(&pshm_drv->rx_pend_list);
INIT_LIST_HEAD(&pshm_drv->rx_full_list);
INIT_WORK(&pshm_drv->shm_tx_work, shm_tx_work_func);
INIT_WORK(&pshm_drv->shm_rx_work, shm_rx_work_func);
pshm_drv->pshm_tx_workqueue =
create_singlethread_workqueue("shm_tx_work");
pshm_drv->pshm_rx_workqueue =
create_singlethread_workqueue("shm_rx_work");
for (j = 0; j < NR_TX_BUF; j++) {
struct buf_list *tx_buf =
kmalloc(sizeof(struct buf_list), GFP_KERNEL);
if (tx_buf == NULL) {
pr_warn("ERROR, Could not"
" allocate dynamic mem. for tx_buf,"
" Bailing out ...\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENOMEM;
}
tx_buf->index = j;
tx_buf->phy_addr = pshm_drv->shm_tx_addr + (TX_BUF_SZ * j);
tx_buf->len = TX_BUF_SZ;
tx_buf->frames = 0;
tx_buf->frm_ofs = SHM_CAIF_FRM_OFS;
if (pshm_dev->shm_loopback)
tx_buf->desc_vptr = (unsigned char *)tx_buf->phy_addr;
else
/*
* FIXME: the result of ioremap is not a pointer - arnd
*/
tx_buf->desc_vptr =
ioremap(tx_buf->phy_addr, TX_BUF_SZ);
list_add_tail(&tx_buf->list, &pshm_drv->tx_empty_list);
}
for (j = 0; j < NR_RX_BUF; j++) {
struct buf_list *rx_buf =
kmalloc(sizeof(struct buf_list), GFP_KERNEL);
if (rx_buf == NULL) {
pr_warn("ERROR, Could not"
" allocate dynamic mem.for rx_buf,"
" Bailing out ...\n");
free_netdev(pshm_dev->pshm_netdev);
return -ENOMEM;
}
rx_buf->index = j;
rx_buf->phy_addr = pshm_drv->shm_rx_addr + (RX_BUF_SZ * j);
rx_buf->len = RX_BUF_SZ;
if (pshm_dev->shm_loopback)
rx_buf->desc_vptr = (unsigned char *)rx_buf->phy_addr;
else
rx_buf->desc_vptr =
ioremap(rx_buf->phy_addr, RX_BUF_SZ);
list_add_tail(&rx_buf->list, &pshm_drv->rx_empty_list);
}
pshm_drv->tx_empty_available = 1;
result = register_netdev(pshm_dev->pshm_netdev);
if (result)
pr_warn("ERROR[%d], SHM could not, "
"register with NW FRMWK Bailing out ...\n", result);
return result;
}
void caif_shmcore_remove(struct net_device *pshm_netdev)
{
struct buf_list *pbuf;
struct shmdrv_layer *pshm_drv = NULL;
pshm_drv = netdev_priv(pshm_netdev);
while (!(list_empty(&pshm_drv->tx_pend_list))) {
pbuf =
list_entry(pshm_drv->tx_pend_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->tx_full_list))) {
pbuf =
list_entry(pshm_drv->tx_full_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->tx_empty_list))) {
pbuf =
list_entry(pshm_drv->tx_empty_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->rx_full_list))) {
pbuf =
list_entry(pshm_drv->tx_full_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->rx_pend_list))) {
pbuf =
list_entry(pshm_drv->tx_pend_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
while (!(list_empty(&pshm_drv->rx_empty_list))) {
pbuf =
list_entry(pshm_drv->rx_empty_list.next,
struct buf_list, list);
list_del(&pbuf->list);
kfree(pbuf);
}
/* Destroy work queues. */
destroy_workqueue(pshm_drv->pshm_tx_workqueue);
destroy_workqueue(pshm_drv->pshm_rx_workqueue);
unregister_netdev(pshm_netdev);
}