/**
* This function will read a single packet from the Stellaris ethernet
* interface, if available, and return a pointer to a pbuf. The timestamp
* of the packet will be placed into the pbuf structure.
*
* @param netif the lwip network interface structure for this ethernetif
* @return pointer to pbuf packet if available, NULL otherswise.
*/
static struct pbuf * low_level_input(struct netif *netif)
{
struct pbuf *p, *q;
u16_t len;
u32_t temp;
int i;
unsigned long *ptr;
#if LWIP_PTPD
u32_t time_s, time_ns;
/* Get the current timestamp if PTPD is enabled */
lwIPHostGetTime(&time_s, &time_ns);
#endif
/* Check if a packet is available, if not, return NULL packet. */
if ((HWREG(ETH_BASE + MAC_O_NP) & MAC_NP_NPR_M) == 0)
{
int err = ETHServiceTaskLastError(0);
if ((ETH_ERROR & err) && (ETH_OVERFLOW & err))
{
LWIP_DEBUGF(CORTEX_DEBUG, ("low_level_input: Ethernet overflow\n"));LINK_STATS_INC(link.drop);
}
return (NULL);
}
/**
* Obtain the size of the packet and put it into the "len" variable.
* Note: The length returned in the FIFO length position includes the
* two bytes for the length + the 4 bytes for the FCS.
*
*/
temp = HWREG(ETH_BASE + MAC_O_DATA);
len = temp & 0xFFFF;
/* We allocate a pbuf chain of pbufs from the pool. */
p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
/* If a pbuf was allocated, read the packet into the pbuf. */
if (p != NULL)
{
/* Place the first word into the first pbuf location. */
*(unsigned long *) p->payload = temp;
p->payload = (char *) (p->payload) + 4;
p->len -= 4;
/* Process all but the last buffer in the pbuf chain. */
q = p;
while (q != NULL)
{
/* Setup a byte pointer into the payload section of the pbuf. */
ptr = q->payload;
/**
* Read data from FIFO into the current pbuf
* (assume pbuf length is modulo 4)
*
*/
for (i = 0; i < q->len; i += 4)
{
*ptr++ = HWREG(ETH_BASE + MAC_O_DATA);
}
/* Link in the next pbuf in the chain. */
q = q->next;
}
/* Restore the first pbuf parameters to their original values. */
p->payload = (char *) (p->payload) - 4;
p->len += 4;
/* Adjust the link statistics */
LINK_STATS_INC(link.recv);
#if LWIP_PTPD
// Place the timestamp in the PBUF
p->time_s = time_s;
p->time_ns = time_ns;
#endif
}
// If no pbuf available, just drain the RX fifo.
else
{
for (i = 4; i < len; i += 4)
{
temp = HWREG(ETH_BASE + MAC_O_DATA);
}
// Adjust the link statistics
LINK_STATS_INC(link.memerr);LINK_STATS_INC(link.drop);
}
return (p);
}
/**
* This function will read a single packet from the Stellaris ethernet
* interface, if available, and return a pointer to a pbuf. The timestamp
* of the packet will be placed into the pbuf structure.
*
* @param netif the lwip network interface structure for this ethernetif
* @return pointer to pbuf packet if available, NULL otherswise.
*/
static struct pbuf *low_level_receive(struct netif *netif)
{
MAC_Type* mac = (MAC_Type*)netif->state;
struct pbuf *p, *q;
u16_t len;
u32_t temp;
int i;
unsigned long *ptr;
#if LWIP_PTPD
u32_t time_s, time_ns;
/* Get the current timestamp if PTPD is enabled */
lwIPHostGetTime(&time_s, &time_ns);
#endif
/* Check if a packet is available, if not, return NULL packet. */
if ((mac->MACNP & MAC_NP_NPR_M) == 0)
{
return (NULL);
}
/**
* Obtain the size of the packet and put it into the "len" variable.
* Note: The length returned in the FIFO length position includes the
* two bytes for the length + the 4 bytes for the FCS.
*
*/
temp = mac->MACDATA;
len = temp & 0xFFFF;
/* We allocate a pbuf chain of pbufs from the pool. */
p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
/* If a pbuf was allocated, read the packet into the pbuf. */
if (p != NULL)
{
/* Place the first word into the first pbuf location. */
*(unsigned long *) p->payload = temp;
p->payload = (char *) (p->payload) + 4;
p->len -= 4;
/* Process all but the last buffer in the pbuf chain. */
q = p;
while (q != NULL)
{
/* Setup a byte pointer into the payload section of the pbuf. */
ptr = (unsigned long *)q->payload;
/**
* Read data from FIFO into the current pbuf
* (assume pbuf length is modulo 4)
*
*/
for (i = 0; i < q->len; i += 4)
{
*ptr++ = mac->MACDATA;
}
/* Link in the next pbuf in the chain. */
q = q->next;
}
/* Restore the first pbuf parameters to their original values. */
p->payload = (char *) (p->payload) - 4;
p->len += 4;
/* Adjust the link statistics */
LINK_STATS_INC(link.recv);
#if LWIP_PTPD
/* Place the timestamp in the PBUF */
p->time_s = time_s;
p->time_ns = time_ns;
#endif
}
/* If no pbuf available, just drain the RX fifo. */
else
{
for (i = 4; i < len; i += 4)
{
temp = mac->MACDATA;
}
/* Adjust the link statistics */
LINK_STATS_INC(link.memerr);
LINK_STATS_INC(link.drop);
}
return (p);
}
