From: sjur.brandeland@stericsson.com Date: Wed, 27 Oct 2010 08:34:40 +0000 (+0000) Subject: caif-u5500: CAIF shared memory transport protocol X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=dfae55d6a5873718fe0d996fc929519073a85ff7;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git caif-u5500: CAIF shared memory transport protocol Signed-off-by: Sjur Braendeland Signed-off-by: David S. Miller --- diff --git a/drivers/net/caif/caif_shmcore.c b/drivers/net/caif/caif_shmcore.c new file mode 100644 index 000000000000..19f9c0656667 --- /dev/null +++ b/drivers/net/caif/caif_shmcore.c @@ -0,0 +1,744 @@ +/* + * 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 ":" __func__ "():" fmt + +#include +#include +#include +#include +#include + +#include +#include + +#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 = (struct shmdrv_layer *)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; + pshm_drv->cfdev.flowctrl + (pshm_drv->pshm_dev->pshm_netdev, + CAIF_FLOW_ON); + + 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); + } 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); + + /* 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); + BUG_ON(skb == NULL); + + 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++; + } + + 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; + pshm_drv->cfdev.flowctrl + (pshm_drv->pshm_dev->pshm_netdev, + CAIF_FLOW_OFF); + } + /* + * 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); + /* 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(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; + unsigned long flags = 0; + + pshm_drv = netdev_priv(shm_netdev); + + spin_lock_irqsave(&pshm_drv->lock, flags); + + skb_queue_tail(&pshm_drv->sk_qhead, skb); + + spin_unlock_irqrestore(&pshm_drv->lock, flags); + + /* 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 accomodate 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); + + 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 = (char *)tx_buf->phy_addr; + else + 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 = (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); +}