Diff: arch/lpc17_emac.c

Revision:

0:f4db29eb9e47

Child:

1:0c9d93e2f51c

diff -r 000000000000 -r f4db29eb9e47 arch/lpc17_emac.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/arch/lpc17_emac.c	Fri Jun 22 09:32:29 2012 +0000
@@ -0,0 +1,1040 @@
+/**********************************************************************
+* $Id$        lpc17_emac.c            2011-11-20
+*//**
+* @file        lpc17_emac.c
+* @brief    LPC17 ethernet driver for LWIP
+* @version    1.0
+* @date        20. Nov. 2011
+* @author    NXP MCU SW Application Team
+* 
+* Copyright(C) 2011, NXP Semiconductor
+* All rights reserved.
+*
+***********************************************************************
+* Software that is described herein is for illustrative purposes only
+* which provides customers with programming information regarding the
+* products. This software is supplied "AS IS" without any warranties.
+* NXP Semiconductors assumes no responsibility or liability for the
+* use of the software, conveys no license or title under any patent,
+* copyright, or mask work right to the product. NXP Semiconductors
+* reserves the right to make changes in the software without
+* notification. NXP Semiconductors also make no representation or
+* warranty that such application will be suitable for the specified
+* use without further testing or modification.
+**********************************************************************/
+
+#include "lwip/opt.h"
+#include "lwip/sys.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/stats.h"
+#include "lwip/snmp.h"
+#include "netif/etharp.h"
+#include "netif/ppp_oe.h"
+
+#include "lpc177x_8x_emac.h"
+#include "lpc177x_8x_clkpwr.h"
+#include "lpc17_emac.h"
+#include "lpc_emac_config.h"
+#include "lpc_phy.h"
+
+#ifndef LPC_EMAC_RMII
+#error LPC_EMAC_RMII is not defined!
+#endif
+
+#if LPC_NUM_BUFF_TXDESCS < 2
+#error LPC_NUM_BUFF_TXDESCS must be at least 2
+#endif
+
+#if LPC_NUM_BUFF_RXDESCS < 3
+#error LPC_NUM_BUFF_RXDESCS must be at least 3
+#endif
+
+/** @defgroup lwip17xx_emac_DRIVER    lpc17 EMAC driver for LWIP
+ * @ingroup lwip_emac
+ *
+ * @{
+ */
+
+#if NO_SYS == 0
+/** \brief  Driver transmit and receive thread priorities
+ * 
+ * Thread priorities for receive thread and TX cleanup thread. Alter
+ * to prioritize receive or transmit bandwidth. In a heavily loaded
+ * system or with LEIP_DEBUG enabled, the priorities might be better
+ * the same. */
+#define tskRECPKT_PRIORITY   (DEFAULT_THREAD_PRIO + 4)
+#define tskTXCLEAN_PRIORITY  (DEFAULT_THREAD_PRIO + 5)
+
+/** \brief  Debug output formatter lock define
+ * 
+ * When using FreeRTOS and with LWIP_DEBUG enabled, enabling this
+ * define will allow RX debug messages to not interleave with the
+ * TX messages (so they are actually readable). Not enabling this
+ * define when the system is under load will cause the output to
+ * be unreadable. There is a small tradeoff in performance for this
+ * so use it only for debug. */
+//#define LOCK_RX_THREAD
+
+/** \brief  Receive group interrupts
+ */
+#define RXINTGROUP (EMAC_INT_RX_OVERRUN | EMAC_INT_RX_ERR | EMAC_INT_RX_DONE)
+
+/** \brief  Transmit group interrupts
+ */
+#define TXINTGROUP (EMAC_INT_TX_UNDERRUN | EMAC_INT_TX_ERR | EMAC_INT_TX_DONE)
+#else
+#define RXINTGROUP 0
+#define TXINTGROUP 0
+#endif
+
+ /** \brief  Structure of a TX/RX descriptor
+ */
+typedef struct
+{
+    volatile u32_t packet;        /**< Pointer to buffer */
+    volatile u32_t control;       /**< Control word */
+} LPC_TXRX_DESC_T;
+
+/** \brief  Structure of a RX status entry
+ */
+typedef struct
+{
+    volatile u32_t statusinfo;   /**< RX status word */
+    volatile u32_t statushashcrc; /**< RX hash CRC */
+} LPC_TXRX_STATUS_T;
+
+/* LPC EMAC driver data structure */
+struct lpc_enetdata {
+    /* prxs must be 8 byte aligned! */
+    LPC_TXRX_STATUS_T prxs[LPC_NUM_BUFF_RXDESCS]; /**< Pointer to RX statuses */
+    struct netif *netif;        /**< Reference back to LWIP parent netif */
+    LPC_TXRX_DESC_T ptxd[LPC_NUM_BUFF_TXDESCS];   /**< Pointer to TX descriptor list */
+    LPC_TXRX_STATUS_T ptxs[LPC_NUM_BUFF_TXDESCS]; /**< Pointer to TX statuses */
+    LPC_TXRX_DESC_T prxd[LPC_NUM_BUFF_RXDESCS];   /**< Pointer to RX descriptor list */
+    struct pbuf *rxb[LPC_NUM_BUFF_RXDESCS]; /**< RX pbuf pointer list, zero-copy mode */
+    u32_t rx_fill_desc_index; /**< RX descriptor next available index */
+    volatile u32_t rx_free_descs; /**< Count of free RX descriptors */
+    struct pbuf *txb[LPC_NUM_BUFF_TXDESCS]; /**< TX pbuf pointer list, zero-copy mode */
+    u32_t lpc_last_tx_idx; /**< TX last descriptor index, zero-copy mode */
+#if NO_SYS == 0
+    sys_sem_t RxSem; /**< RX receive thread wakeup semaphore */
+    sys_sem_t TxCleanSem; /**< TX cleanup thread wakeup semaphore */
+    sys_mutex_t TXLockMutex; /**< TX critical section mutex */
+    xSemaphoreHandle xTXDCountSem; /**< TX free buffer counting semaphore */
+#endif
+};
+
+/** \brief  LPC EMAC driver work data
+ */
+ALIGNED(8) struct lpc_enetdata lpc_enetdata;
+
+/* Write a value via the MII link (non-blocking) */
+void lpc_mii_write_noblock(u32_t PhyReg, u32_t Value)
+{
+    /* Write value at PHY address and register */
+    LPC_EMAC->MADR = (LPC_PHYDEF_PHYADDR << 8) | PhyReg;
+    LPC_EMAC->MWTD = Value;
+}
+
+/* Write a value via the MII link (blocking) */
+err_t lpc_mii_write(u32_t PhyReg, u32_t Value)
+{
+    u32_t mst = 250;
+    err_t sts = ERR_OK;
+
+    /* Write value at PHY address and register */
+    lpc_mii_write_noblock(PhyReg, Value);
+
+    /* Wait for unbusy status */
+    while (mst > 0) {
+        sts = LPC_EMAC->MIND;
+        if ((sts & EMAC_MIND_BUSY) == 0)
+            mst = 0;
+        else {
+            mst--;
+            msDelay(1);
+        }
+    }
+
+    if (sts != 0)
+        sts = ERR_TIMEOUT;
+
+    return sts;
+}
+
+/* Reads current MII link busy status */
+u32_t lpc_mii_is_busy(void)
+{
+    return (u32_t) (LPC_EMAC->MIND & EMAC_MIND_BUSY);
+}
+
+/* Starts a read operation via the MII link (non-blocking) */
+u32_t lpc_mii_read_data(void)
+{
+    u32_t data = LPC_EMAC->MRDD;
+    LPC_EMAC->MCMD = 0;
+
+    return data;
+}
+
+/* Starts a read operation via the MII link (non-blocking) */
+void lpc_mii_read_noblock(u32_t PhyReg) 
+{
+    /* Read value at PHY address and register */
+    LPC_EMAC->MADR = (LPC_PHYDEF_PHYADDR << 8) | PhyReg;
+    LPC_EMAC->MCMD = EMAC_MCMD_READ;
+}
+
+/* Read a value via the MII link (blocking) */
+err_t lpc_mii_read(u32_t PhyReg, u32_t *data) 
+{
+    u32_t mst = 250;
+    err_t sts = ERR_OK;
+
+    /* Read value at PHY address and register */
+    lpc_mii_read_noblock(PhyReg);
+
+    /* Wait for unbusy status */
+    while (mst > 0) {
+        sts = LPC_EMAC->MIND & ~EMAC_MIND_MII_LINK_FAIL;
+        if ((sts & EMAC_MIND_BUSY) == 0) {
+            mst = 0;
+            *data = LPC_EMAC->MRDD;
+        } else {
+            mst--;
+            msDelay(1);
+        }
+    }
+
+    LPC_EMAC->MCMD = 0;
+
+    if (sts != 0)
+        sts = ERR_TIMEOUT;
+
+    return sts;
+}
+
+/** \brief  Queues a pbuf into the RX descriptor list
+ *
+ *  \param[in] lpc_enetif Pointer to the drvier data structure
+ *  \param[in] p            Pointer to pbuf to queue
+ */
+static void lpc_rxqueue_pbuf(struct lpc_enetdata *lpc_enetif, struct pbuf *p)
+{
+    u32_t idx;
+
+    /* Get next free descriptor index */
+    idx = lpc_enetif->rx_fill_desc_index;
+
+    /* Setup descriptor and clear statuses */
+    lpc_enetif->prxd[idx].control = EMAC_RCTRL_INT | ((u32_t) (p->len - 1));
+    lpc_enetif->prxd[idx].packet = (u32_t) p->payload;
+    lpc_enetif->prxs[idx].statusinfo = 0xFFFFFFFF;
+    lpc_enetif->prxs[idx].statushashcrc = 0xFFFFFFFF;
+
+    /* Save pbuf pointer for push to network layer later */
+    lpc_enetif->rxb[idx] = p;
+
+    /* Wrap at end of descriptor list */
+    idx++;
+    if (idx >= LPC_NUM_BUFF_RXDESCS)
+        idx = 0;
+
+    /* Queue descriptor(s) */
+    lpc_enetif->rx_free_descs -= 1;
+    lpc_enetif->rx_fill_desc_index = idx;
+    LPC_EMAC->RxConsumeIndex = idx;
+
+    LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+        ("lpc_rxqueue_pbuf: pbuf packet queued: %p (free desc=%d)\n", p,
+            lpc_enetif->rx_free_descs));
+}
+
+/** \brief  Attempt to allocate and requeue a new pbuf for RX
+ *
+ *  \param[in]     netif Pointer to the netif structure
+ *  \returns         1 if a packet was allocated and requeued, otherwise 0
+ */
+s32_t lpc_rx_queue(struct netif *netif)
+{
+    struct lpc_enetdata *lpc_enetif = netif->state;
+    struct pbuf *p;
+    s32_t queued = 0;
+
+    /* Attempt to requeue as many packets as possible */
+    while (lpc_enetif->rx_free_descs > 0) {
+        /* Allocate a pbuf from the pool. We need to allocate at the
+           maximum size as we don't know the size of the yet to be
+           received packet. */
+        p = pbuf_alloc(PBUF_RAW, (u16_t) EMAC_ETH_MAX_FLEN, PBUF_RAM);
+        if (p == NULL) {
+            LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+                ("lpc_rx_queue: could not allocate RX pbuf (free desc=%d)\n",
+                lpc_enetif->rx_free_descs));
+            return queued;
+        }
+
+        /* pbufs allocated from the RAM pool should be non-chained. */
+        LWIP_ASSERT("lpc_rx_queue: pbuf is not contiguous (chained)",
+            pbuf_clen(p) <= 1);
+
+        /* Queue packet */
+        lpc_rxqueue_pbuf(lpc_enetif, p);
+
+        /* Update queued count */
+        queued++;
+    }
+
+    return queued;
+}
+
+/** \brief  Sets up the RX descriptor ring buffers.
+ * 
+ *  This function sets up the descriptor list used for receive packets.
+ *
+ *  \param[in]  lpc_enetif  Pointer to driver data structure
+ *  \returns                   Always returns ERR_OK
+ */
+static err_t lpc_rx_setup(struct lpc_enetdata *lpc_enetif)
+{
+    s32_t idx;
+
+    /* Setup pointers to RX structures */
+    LPC_EMAC->RxDescriptor = (u32_t) &lpc_enetif->prxd[0];
+    LPC_EMAC->RxStatus = (u32_t) &lpc_enetif->prxs[0];
+    LPC_EMAC->RxDescriptorNumber = LPC_NUM_BUFF_RXDESCS - 1;
+
+    lpc_enetif->rx_free_descs = LPC_NUM_BUFF_RXDESCS;
+    lpc_enetif->rx_fill_desc_index = 0;
+
+    /* Build RX buffer and descriptors */
+    lpc_rx_queue(lpc_enetif->netif);
+
+    return ERR_OK;
+}
+
+/** \brief  Allocates a pbuf and returns the data from the incoming packet.
+ *
+ *  \param[in] netif the lwip network interface structure for this lpc_enetif
+ *  \return a pbuf filled with the received packet (including MAC header)
+ *         NULL on memory error
+ */
+static struct pbuf *lpc_low_level_input(struct netif *netif)
+{
+    struct lpc_enetdata *lpc_enetif = netif->state;
+    struct pbuf *p = NULL, *q;
+    u32_t idx, length;
+    u8_t *src;
+
+#ifdef LOCK_RX_THREAD
+#if NO_SYS == 0
+    /* Get exclusive access */
+    sys_mutex_lock(&lpc_enetif->TXLockMutex);
+#endif
+#endif
+
+    /* Monitor RX overrun status. This should never happen unless
+       (possibly) the internal bus is behing held up by something.
+       Unless your system is running at a very low clock speed or
+       there are possibilities that the internal buses may be held
+       up for a long time, this can probably safely be removed. */
+    if (LPC_EMAC->IntStatus & EMAC_INT_RX_OVERRUN) {
+        LINK_STATS_INC(link.err);
+        LINK_STATS_INC(link.drop);
+
+        /* Temporarily disable RX */
+        LPC_EMAC->MAC1 &= ~EMAC_MAC1_REC_EN;
+
+        /* Reset the RX side */
+        LPC_EMAC->MAC1 |= EMAC_MAC1_RES_RX;
+        LPC_EMAC->IntClear = EMAC_INT_RX_OVERRUN;
+
+        /* De-allocate all queued RX pbufs */
+        for (idx = 0; idx < LPC_NUM_BUFF_RXDESCS; idx++) {
+            if (lpc_enetif->rxb[idx] != NULL) {
+                pbuf_free(lpc_enetif->rxb[idx]);
+                lpc_enetif->rxb[idx] = NULL;
+            }
+        }
+
+        /* Start RX side again */
+        lpc_rx_setup(lpc_enetif);
+
+        /* Re-enable RX */
+        LPC_EMAC->MAC1 |= EMAC_MAC1_REC_EN;
+
+#ifdef LOCK_RX_THREAD
+#if NO_SYS == 0
+        sys_mutex_unlock(&lpc_enetif->TXLockMutex);
+#endif
+#endif
+
+        return NULL;
+    }
+
+    /* Determine if a frame has been received */
+    length = 0;
+    idx = LPC_EMAC->RxConsumeIndex;
+    if (LPC_EMAC->RxProduceIndex != idx) {
+        /* Handle errors */
+        if (lpc_enetif->prxs[idx].statusinfo & (EMAC_RINFO_CRC_ERR |
+            EMAC_RINFO_SYM_ERR | EMAC_RINFO_ALIGN_ERR | EMAC_RINFO_LEN_ERR)) {
+#if LINK_STATS
+            if (lpc_enetif->prxs[idx].statusinfo & (EMAC_RINFO_CRC_ERR |
+                EMAC_RINFO_SYM_ERR | EMAC_RINFO_ALIGN_ERR))
+                LINK_STATS_INC(link.chkerr);
+            if (lpc_enetif->prxs[idx].statusinfo & EMAC_RINFO_LEN_ERR)
+                LINK_STATS_INC(link.lenerr);
+#endif
+
+            /* Drop the frame */
+            LINK_STATS_INC(link.drop);
+
+            /* Re-queue the pbuf for receive */
+            lpc_enetif->rx_free_descs++;
+            p = lpc_enetif->rxb[idx];
+            lpc_enetif->rxb[idx] = NULL;
+            lpc_rxqueue_pbuf(lpc_enetif, p);
+
+            LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+                ("lpc_low_level_input: Packet dropped with errors (0x%x)\n",
+                lpc_enetif->prxs[idx].statusinfo));
+        } else {
+            /* A packet is waiting, get length */
+            length = (lpc_enetif->prxs[idx].statusinfo & 0x7FF) + 1;
+
+            /* Zero-copy */
+            p = lpc_enetif->rxb[idx];
+            p->len = (u16_t) length;
+
+            /* Free pbuf from desriptor */
+            lpc_enetif->rxb[idx] = NULL;
+            lpc_enetif->rx_free_descs++;
+
+            LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+                ("lpc_low_level_input: Packet received: %p, size %d (index=%d)\n",
+                p, length, idx));
+
+            /* Save size */
+            p->tot_len = (u16_t) length;
+            LINK_STATS_INC(link.recv);
+
+            /* Queue new buffer(s) */
+            lpc_rx_queue(lpc_enetif->netif);
+        }
+    }
+
+#ifdef LOCK_RX_THREAD
+#if NO_SYS == 0
+    sys_mutex_unlock(&lpc_enetif->TXLockMutex);
+#endif
+#endif
+
+    return p;  
+}
+
+/** \brief  Attempt to read a packet from the EMAC interface.
+ *
+ *  \param[in] netif the lwip network interface structure for this lpc_enetif
+ */
+void lpc_enetif_input(struct netif *netif)
+{
+    struct eth_hdr *ethhdr;
+    struct pbuf *p;
+
+    /* move received packet into a new pbuf */
+    p = lpc_low_level_input(netif);
+    if (p == NULL)
+        return;
+
+    /* points to packet payload, which starts with an Ethernet header */
+    ethhdr = p->payload;
+
+    switch (htons(ethhdr->type)) {
+        case ETHTYPE_IP:
+        case ETHTYPE_ARP:
+#if PPPOE_SUPPORT
+        case ETHTYPE_PPPOEDISC:
+        case ETHTYPE_PPPOE:
+#endif /* PPPOE_SUPPORT */
+            /* full packet send to tcpip_thread to process */
+            if (netif->input(p, netif) != ERR_OK) {
+                LWIP_DEBUGF(NETIF_DEBUG, ("lpc_enetif_input: IP input error\n"));
+                /* Free buffer */
+                pbuf_free(p);
+            }
+            break;
+
+        default:
+            /* Return buffer */
+            pbuf_free(p);
+            break;
+    }
+}
+
+/** \brief  Determine if the passed address is usable for the ethernet
+ *          DMA controller.
+ *
+ *  \param[in] addr Address of packet to check for DMA safe operation
+ *  \return          1 if the packet address is not safe, otherwise 0
+ */
+static s32_t lpc_packet_addr_notsafe(void *addr) {
+    /* Check for legal address ranges */
+    if ((((u32_t) addr >= 0x20000000) && ((u32_t) addr < 0x20008000)) ||
+        (((u32_t) addr >= 0x80000000) && ((u32_t) addr < 0xF0000000)))
+        return 0;
+
+    return 1;
+}
+
+/** \brief  Sets up the TX descriptor ring buffers.
+ *
+ *  This function sets up the descriptor list used for transmit packets.
+ *
+ *  \param[in]      lpc_enetif  Pointer to driver data structure
+ */
+static err_t lpc_tx_setup(struct lpc_enetdata *lpc_enetif)
+{
+    s32_t idx;
+
+    /* Build TX descriptors for local buffers */
+    for (idx = 0; idx < LPC_NUM_BUFF_TXDESCS; idx++) {
+        lpc_enetif->ptxd[idx].control = 0;
+        lpc_enetif->ptxs[idx].statusinfo = 0xFFFFFFFF;
+    }
+
+    /* Setup pointers to TX structures */
+    LPC_EMAC->TxDescriptor = (u32_t) &lpc_enetif->ptxd[0];
+    LPC_EMAC->TxStatus = (u32_t) &lpc_enetif->ptxs[0];
+    LPC_EMAC->TxDescriptorNumber = LPC_NUM_BUFF_TXDESCS - 1;
+
+    lpc_enetif->lpc_last_tx_idx = 0;
+
+    return ERR_OK;
+}
+
+/** \brief  Free TX buffers that are complete
+ *
+ *  \param[in] lpc_enetif  Pointer to driver data structure
+ *  \param[in] cidx  EMAC current descriptor comsumer index
+ */
+static void lpc_tx_reclaim_st(struct lpc_enetdata *lpc_enetif, u32_t cidx)
+{
+#if NO_SYS == 0
+    /* Get exclusive access */
+    sys_mutex_lock(&lpc_enetif->TXLockMutex);
+#endif
+
+    while (cidx != lpc_enetif->lpc_last_tx_idx) {
+        if (lpc_enetif->txb[lpc_enetif->lpc_last_tx_idx] != NULL) {
+            LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+                ("lpc_tx_reclaim_st: Freeing packet %p (index %d)\n",
+                lpc_enetif->txb[lpc_enetif->lpc_last_tx_idx],
+                lpc_enetif->lpc_last_tx_idx));
+            pbuf_free(lpc_enetif->txb[lpc_enetif->lpc_last_tx_idx]);
+             lpc_enetif->txb[lpc_enetif->lpc_last_tx_idx] = NULL;
+        }
+
+#if NO_SYS == 0
+        xSemaphoreGive(lpc_enetif->xTXDCountSem);
+#endif
+        lpc_enetif->lpc_last_tx_idx++;
+        if (lpc_enetif->lpc_last_tx_idx >= LPC_NUM_BUFF_TXDESCS)
+            lpc_enetif->lpc_last_tx_idx = 0;
+    }
+
+#if NO_SYS == 0
+    /* Restore access */
+    sys_mutex_unlock(&lpc_enetif->TXLockMutex);
+#endif
+}
+
+/** \brief  User call for freeingTX buffers that are complete
+ *
+ *  \param[in] netif the lwip network interface structure for this lpc_enetif
+ */
+void lpc_tx_reclaim(struct netif *netif)
+{
+    lpc_tx_reclaim_st((struct lpc_enetdata *) netif->state,
+        LPC_EMAC->TxConsumeIndex);
+}
+
+ /** \brief  Polls if an available TX descriptor is ready. Can be used to
+ *           determine if the low level transmit function will block.
+ *
+ *  \param[in] netif the lwip network interface structure for this lpc_enetif
+ *  \return 0 if no descriptors are read, or >0
+ */
+s32_t lpc_tx_ready(struct netif *netif)
+{
+    s32_t fb;
+    u32_t idx, cidx;
+
+    cidx = LPC_EMAC->TxConsumeIndex;
+    idx = LPC_EMAC->TxProduceIndex;
+
+    /* Determine number of free buffers */
+    if (idx == cidx)
+        fb = LPC_NUM_BUFF_TXDESCS;
+    else if (cidx > idx)
+        fb = (LPC_NUM_BUFF_TXDESCS - 1) -
+            ((idx + LPC_NUM_BUFF_TXDESCS) - cidx);
+    else
+        fb = (LPC_NUM_BUFF_TXDESCS - 1) - (cidx - idx);
+
+    return fb;
+}
+
+/** \brief  Low level output of a packet. Never call this from an
+ *          interrupt context, as it may block until TX descriptors
+ *          become available.
+ *
+ *  \param[in] netif the lwip network interface structure for this lpc_enetif
+ *  \param[in] p the MAC packet to send (e.g. IP packet including MAC addresses and type)
+ *  \return ERR_OK if the packet could be sent or an err_t value if the packet couldn't be sent
+ */
+static err_t lpc_low_level_output(struct netif *netif, struct pbuf *p)
+{
+    struct lpc_enetdata *lpc_enetif = netif->state;
+    struct pbuf *q;
+    u8_t *dst;
+    u32_t idx, sz = 0;
+    err_t err = ERR_OK;
+    struct pbuf *np;
+    u32_t dn, notdmasafe = 0;
+
+    /* Zero-copy TX buffers may be fragmented across mutliple payload
+       chains. Determine the number of descriptors needed for the
+       transfer. The pbuf chaining can be a mess! */
+    dn = (u32_t) pbuf_clen(p);
+
+    /* Test to make sure packet addresses are DMA safe. A DMA safe
+       address is once that uses external memory or periphheral RAM.
+       IRAM and FLASH are not safe! */
+    for (q = p; q != NULL; q = q->next)
+        notdmasafe += lpc_packet_addr_notsafe(q->payload);
+
+#if LPC_TX_PBUF_BOUNCE_EN==1
+    /* If the pbuf is not DMA safe, a new bounce buffer (pbuf) will be
+       created that will be used instead. This requires an copy from the
+       non-safe DMA region to the new pbuf */
+    if (notdmasafe) {
+        /* Allocate a pbuf in DMA memory */
+        np = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
+        if (np == NULL)
+            return ERR_MEM;    
+
+        /* This buffer better be contiguous! */
+        LWIP_ASSERT("lpc_low_level_output: New transmit pbuf is chained",
+            (pbuf_clen(np) == 1));
+
+        /* Copy to DMA safe pbuf */
+        dst = (u8_t *) np->payload;
+         for(q = p; q != NULL; q = q->next) {
+            /* Copy the buffer to the descriptor's buffer */
+              MEMCPY(dst, (u8_t *) q->payload, q->len);
+          dst += q->len;
+        }
+        np->len = p->tot_len; 
+
+        LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+            ("lpc_low_level_output: Switched to DMA safe buffer, old=%p, new=%p\n",
+            q, np));
+
+        /* use the new buffer for descrptor queueing. The original pbuf will
+           be de-allocated outsuide this driver. */
+        p = np;
+        dn = 1;
+    }
+#else
+    if (notdmasafe)
+        LWIP_ASSERT("lpc_low_level_output: Not a DMA safe pbuf",
+            (notdmasafe == 0));
+#endif
+
+    /* Wait until enough descriptors are available for the transfer. */
+    /* THIS WILL BLOCK UNTIL THERE ARE ENOUGH DESCRIPTORS AVAILABLE */
+    while (dn > lpc_tx_ready(netif))
+#if NO_SYS == 0
+        xSemaphoreTake(lpc_enetif->xTXDCountSem, 0);
+#else
+        msDelay(1);
+#endif
+
+    /* Get free TX buffer index */
+    idx = LPC_EMAC->TxProduceIndex;
+
+#if NO_SYS == 0
+    /* Get exclusive access */
+    sys_mutex_lock(&lpc_enetif->TXLockMutex);
+#endif
+
+    /* Prevent LWIP from de-allocating this pbuf. The driver will
+       free it once it's been transmitted. */
+    if (!notdmasafe)
+        pbuf_ref(p);
+
+    /* Setup transfers */
+    q = p;
+    while (dn > 0) {
+        dn--;
+
+        /* Only save pointer to free on last descriptor */
+        if (dn == 0) {
+            /* Save size of packet and signal it's ready */
+            lpc_enetif->ptxd[idx].control = (q->len - 1) | EMAC_TCTRL_INT |
+                EMAC_TCTRL_LAST;
+            lpc_enetif->txb[idx] = p;
+        }
+        else {
+            /* Save size of packet, descriptor is not last */
+            lpc_enetif->ptxd[idx].control = (q->len - 1) | EMAC_TCTRL_INT;
+            lpc_enetif->txb[idx] = NULL;
+        }
+
+        LWIP_DEBUGF(UDP_LPC_EMAC | LWIP_DBG_TRACE,
+            ("lpc_low_level_output: pbuf packet(%p) sent, chain#=%d,"
+            " size = %d (index=%d)\n", q->payload, dn, q->len, idx));
+
+        lpc_enetif->ptxd[idx].packet = (u32_t) q->payload;
+
+        q = q->next;
+
+        idx++;
+        if (idx >= LPC_NUM_BUFF_TXDESCS)
+            idx = 0;
+    }
+
+    LPC_EMAC->TxProduceIndex = idx;
+
+    LINK_STATS_INC(link.xmit);
+
+#if NO_SYS == 0
+    /* Restore access */
+    sys_mutex_unlock(&lpc_enetif->TXLockMutex);
+#endif
+
+    return ERR_OK;
+}
+
+/** \brief  LPC EMAC interrupt handler.
+ *
+ *  This function handles the transmit, receive, and error interrupt of
+ *  the LPC177x_8x. This is meant to be used when NO_SYS=0.
+ */
+void ENET_IRQHandler(void)
+{
+#if NO_SYS == 1
+    /* Interrupts are not used without an RTOS */
+    NVIC_DisableIRQ(ENET_IRQn);
+#else
+    signed portBASE_TYPE xRecTaskWoken = pdFALSE, XTXTaskWoken = pdFALSE;
+    uint32_t ints;
+
+    /* Interrupts are of 2 groups - transmit or receive. Based on the
+       interrupt, kick off the receive or transmit (cleanup) task */
+
+    /* Get pending interrupts */
+    ints = LPC_EMAC->IntStatus;
+
+    if (ints & RXINTGROUP) {
+        /* RX group interrupt(s) */
+        /* Give semaphore to wakeup RX receive task. Note the FreeRTOS
+           method is used instead of the LWIP arch method. */
+        xSemaphoreGiveFromISR(lpc_enetdata.RxSem, &xRecTaskWoken);
+    }
+
+    if (ints & TXINTGROUP) {
+        /* TX group interrupt(s) */
+        /* Give semaphore to wakeup TX cleanup task. Note the FreeRTOS
+           method is used instead of the LWIP arch method. */
+        xSemaphoreGiveFromISR(lpc_enetdata.TxCleanSem, &XTXTaskWoken);
+    }
+
+    /* Clear pending interrupts */
+    LPC_EMAC->IntClear = ints;
+
+    /* Context switch needed? */
+    portEND_SWITCHING_ISR( xRecTaskWoken || XTXTaskWoken );
+#endif
+}
+
+#if NO_SYS == 0
+/** \brief  Packet reception task
+ *
+ * This task is called when a packet is received. It will
+ * pass the packet to the LWIP core.
+ *
+ *  \param[in] pvParameters Not used yet
+ */
+static portTASK_FUNCTION( vPacketReceiveTask, pvParameters )
+{
+    struct lpc_enetdata *lpc_enetif = pvParameters;
+
+    while (1) {
+        /* Wait for receive task to wakeup */
+        sys_arch_sem_wait(&lpc_enetif->RxSem, 0);
+
+        /* Process packets until all empty */
+        while (LPC_EMAC->RxConsumeIndex != LPC_EMAC->RxProduceIndex)
+            lpc_enetif_input(lpc_enetif->netif);
+    }
+}
+
+/** \brief  Transmit cleanup task
+ *
+ * This task is called when a transmit interrupt occurs and
+ * reclaims the pbuf and descriptor used for the packet once
+ * the packet has been transferred.
+ *
+ *  \param[in] pvParameters Not used yet
+ */
+static portTASK_FUNCTION( vTransmitCleanupTask, pvParameters )
+{
+    struct lpc_enetdata *lpc_enetif = pvParameters;
+    s32_t idx;
+
+    while (1) {
+        /* Wait for transmit cleanup task to wakeup */
+        sys_arch_sem_wait(&lpc_enetif->TxCleanSem, 0);
+
+        /* Error handling for TX underruns. This should never happen unless
+           something is holding the bus or the clocks are going too slow. It
+           can probably be safely removed. */
+         if (LPC_EMAC->IntStatus & EMAC_INT_TX_UNDERRUN) {
+            LINK_STATS_INC(link.err);
+            LINK_STATS_INC(link.drop);
+
+#if NO_SYS == 0
+            /* Get exclusive access */
+            sys_mutex_lock(&lpc_enetif->TXLockMutex);
+#endif
+            /* Reset the TX side */
+            LPC_EMAC->MAC1 |= EMAC_MAC1_RES_TX;
+            LPC_EMAC->IntClear = EMAC_INT_TX_UNDERRUN;
+
+            /* De-allocate all queued TX pbufs */
+            for (idx = 0; idx < LPC_NUM_BUFF_RXDESCS; idx++) {
+                if (lpc_enetif->txb[idx] != NULL) {
+                    pbuf_free(lpc_enetif->txb[idx]);
+                    lpc_enetif->txb[idx] = NULL;
+                }
+            }
+
+#if NO_SYS == 0
+            /* Restore access */
+            sys_mutex_unlock(&lpc_enetif->TXLockMutex);
+#endif
+            /* Start TX side again */
+            lpc_tx_setup(lpc_enetif);
+        } else {
+            /* Free TX buffers that are done sending */
+            lpc_tx_reclaim(lpc_enetdata.netif);
+        }
+    }
+}
+#endif
+
+/** \brief  Low level init of the MAC and PHY.
+ *
+ *  \param[in]      netif  Pointer to LWIP netif structure
+ */
+static err_t low_level_init(struct netif *netif)
+{
+    struct lpc_enetdata *lpc_enetif = netif->state;
+    err_t err = ERR_OK;
+
+    /* Enable MII clocking */
+    CLKPWR_ConfigPPWR(CLKPWR_PCONP_PCENET, ENABLE);
+
+    /* Reset all MAC logic */
+    LPC_EMAC->MAC1 = EMAC_MAC1_RES_TX | EMAC_MAC1_RES_MCS_TX |
+        EMAC_MAC1_RES_RX | EMAC_MAC1_RES_MCS_RX | EMAC_MAC1_SIM_RES |
+        EMAC_MAC1_SOFT_RES;
+    LPC_EMAC->Command = EMAC_CR_REG_RES | EMAC_CR_TX_RES | EMAC_CR_RX_RES |
+        EMAC_CR_PASS_RUNT_FRM;
+    msDelay(10);
+
+    /* Initial MAC initialization */
+    LPC_EMAC->MAC1 = EMAC_MAC1_PASS_ALL;
+    LPC_EMAC->MAC2 = EMAC_MAC2_CRC_EN | EMAC_MAC2_PAD_EN |
+        EMAC_MAC2_VLAN_PAD_EN;
+    LPC_EMAC->MAXF = EMAC_ETH_MAX_FLEN;
+
+    /* Set RMII management clock rate to lowest speed */
+    LPC_EMAC->MCFG = EMAC_MCFG_CLK_SEL(11) | EMAC_MCFG_RES_MII;
+    LPC_EMAC->MCFG &= ~EMAC_MCFG_RES_MII;
+
+    /* Maximum number of retries, 0x37 collision window, gap */
+    LPC_EMAC->CLRT = EMAC_CLRT_DEF;
+    LPC_EMAC->IPGR = EMAC_IPGR_P1_DEF | EMAC_IPGR_P2_DEF;
+
+#if LPC_EMAC_RMII
+    /* RMII setup */
+    LPC_EMAC->Command = EMAC_CR_PASS_RUNT_FRM | EMAC_CR_RMII;
+#else
+    /* MII setup */
+    LPC_EMAC->CR = EMAC_CR_PASS_RUNT_FRM;
+#endif
+
+    /* Initialize the PHY and reset */
+    err = lpc_phy_init(netif, LPC_EMAC_RMII);
+    if (err != ERR_OK)
+         return err;
+
+    /* Save station address */
+    LPC_EMAC->SA2 = (u32_t) netif->hwaddr[0] |
+        (((u32_t) netif->hwaddr[1]) << 8);
+    LPC_EMAC->SA1 = (u32_t) netif->hwaddr[2] |
+        (((u32_t) netif->hwaddr[3]) << 8);
+    LPC_EMAC->SA0 = (u32_t) netif->hwaddr[4] |
+        (((u32_t) netif->hwaddr[5]) << 8);
+
+    /* Setup transmit and receive descriptors */
+    if (lpc_tx_setup(lpc_enetif) != ERR_OK)
+        return ERR_BUF;
+    if (lpc_rx_setup(lpc_enetif) != ERR_OK)
+        return ERR_BUF;
+
+    /* Enable packet reception */
+#if IP_SOF_BROADCAST_RECV
+    LPC_EMAC->RxFilterCtrl = EMAC_RFC_PERFECT_EN | EMAC_RFC_BCAST_EN;
+#else
+    LPC_EMAC->RxFilterCtrl = EMAC_RFC_PERFECT_EN;
+#endif
+
+    /* Clear and enable rx/tx interrupts */
+    LPC_EMAC->IntClear = 0xFFFF;
+    LPC_EMAC->IntEnable = RXINTGROUP | TXINTGROUP;
+
+    /* Enable RX and TX */
+    LPC_EMAC->Command |= EMAC_CR_RX_EN | EMAC_CR_TX_EN;
+    LPC_EMAC->MAC1 |= EMAC_MAC1_REC_EN;
+
+    return err;
+}
+
+/* This function provides a method for the PHY to setup the EMAC
+   for the PHY negotiated duplex mode */
+void lpc_emac_set_duplex(int full_duplex)
+{
+    if (full_duplex) {
+        LPC_EMAC->MAC2    |= EMAC_MAC2_FULL_DUP;
+        LPC_EMAC->Command |= EMAC_CR_FULL_DUP;
+        LPC_EMAC->IPGT     = EMAC_IPGT_FULL_DUP;
+    } else {
+        LPC_EMAC->MAC2    &= ~EMAC_MAC2_FULL_DUP;
+        LPC_EMAC->Command &= ~EMAC_CR_FULL_DUP;
+        LPC_EMAC->IPGT = EMAC_IPGT_HALF_DUP;
+    }
+}
+
+/* This function provides a method for the PHY to setup the EMAC
+   for the PHY negotiated bit rate */
+void lpc_emac_set_speed(int mbs_100)
+{
+    if (mbs_100)
+        LPC_EMAC->SUPP = EMAC_SUPP_SPEED;
+    else
+        LPC_EMAC->SUPP = 0;
+}
+
+/**
+ * This function is the ethernet packet send function. It calls
+ * etharp_output after checking link status.
+ *
+ * \param[in] netif the lwip network interface structure for this lpc_enetif
+ * \param[in] q Pointer to pbug to send
+ * \param[in] ipaddr IP address 
+ * \return ERR_OK or error code
+ */
+err_t lpc_etharp_output(struct netif *netif, struct pbuf *q,
+    ip_addr_t *ipaddr)
+{
+    /* Only send packet is link is up */
+    if (netif->flags & NETIF_FLAG_LINK_UP)
+        return etharp_output(netif, q, ipaddr);
+
+    return ERR_CONN;
+}
+
+/**
+ * Should be called at the beginning of the program to set up the
+ * network interface.
+ *
+ * This function should be passed as a parameter to netif_add().
+ *
+ * @param[in] netif the lwip network interface structure for this lpc_enetif
+ * @return ERR_OK if the loopif is initialized
+ *         ERR_MEM if private data couldn't be allocated
+ *         any other err_t on error
+ */
+err_t lpc_enetif_init(struct netif *netif)
+{
+    err_t err;
+
+    LWIP_ASSERT("netif != NULL", (netif != NULL));
+    
+    lpc_enetdata.netif = netif;
+
+    /* set MAC hardware address */
+    board_get_macaddr(netif->hwaddr);
+    netif->hwaddr_len = ETHARP_HWADDR_LEN;
+
+     /* maximum transfer unit */
+    netif->mtu = 1500;
+
+    /* device capabilities */
+    netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_UP |
+        NETIF_FLAG_ETHERNET;
+
+    /* Initialize the hardware */
+    netif->state = &lpc_enetdata;
+    err = low_level_init(netif);
+    if (err != ERR_OK)
+        return err;
+
+#if LWIP_NETIF_HOSTNAME
+    /* Initialize interface hostname */
+    netif->hostname = "lwiplpc";
+#endif /* LWIP_NETIF_HOSTNAME */
+
+    netif->name[0] = 'e';
+    netif->name[1] = 'n';
+
+    netif->output = lpc_etharp_output;
+    netif->linkoutput = lpc_low_level_output;
+
+    /* For FreeRTOS, start tasks */
+#if NO_SYS == 0
+    lpc_enetdata.xTXDCountSem = xSemaphoreCreateCounting(LPC_NUM_BUFF_TXDESCS,
+        LPC_NUM_BUFF_TXDESCS);
+    LWIP_ASSERT("xTXDCountSem creation error",
+        (lpc_enetdata.xTXDCountSem != NULL));
+
+    err = sys_mutex_new(&lpc_enetdata.TXLockMutex);
+    LWIP_ASSERT("TXLockMutex creation error", (err == ERR_OK));
+
+    /* Packet receive task */
+    err = sys_sem_new(&lpc_enetdata.RxSem, 0);
+    LWIP_ASSERT("RxSem creation error", (err == ERR_OK));
+    sys_thread_new("receive_thread", vPacketReceiveTask, netif->state,
+        DEFAULT_THREAD_STACKSIZE, tskRECPKT_PRIORITY);
+
+    /* Transmit cleanup task */
+    err = sys_sem_new(&lpc_enetdata.TxCleanSem, 0);
+    LWIP_ASSERT("TxCleanSem creation error", (err == ERR_OK));
+    sys_thread_new("txclean_thread", vTransmitCleanupTask, netif->state,
+        DEFAULT_THREAD_STACKSIZE, tskTXCLEAN_PRIORITY);
+#endif
+
+    return ERR_OK;
+}
+
+/**
+ * @}
+ */
+
+/* --------------------------------- End Of File ------------------------------ */