caif-u5500: CAIF shared memory transport protocol

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 744 insertions, 0 deletions

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 <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.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 = (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);
+}