ZeroCopyRx.c

00001 typedef struct my_custom_pbuf
00002 {
00003    struct pbuf_custom p;
00004    void* dma_descriptor;
00005 } my_custom_pbuf_t;
00006 
00007 LWIP_MEMPOOL_DECLARE(RX_POOL, 10, sizeof(my_custom_pbuf_t), "Zero-copy RX PBUF pool");
00008 
00009 void my_pbuf_free_custom(void* p)
00010 {
00011   SYS_ARCH_DECL_PROTECT(old_level);
00012 
00013   my_custom_pbuf_t* my_puf = (my_custom_pbuf_t*)p;
00014 
00015   // invalidate data cache here - lwIP and/or application may have written into buffer!
00016   // (invalidate is faster than flushing, and noone needs the correct data in the buffer)
00017   invalidate_cpu_cache(p->payload, p->tot_len);
00018 
00019   SYS_ARCH_PROTECT(old_level);
00020   free_rx_dma_descriptor(my_pbuf->dma_descriptor);
00021   LWIP_MEMPOOL_FREE(RX_POOL, my_pbuf);
00022   SYS_ARCH_UNPROTECT(old_level);
00023 }
00024 
00025 void eth_rx_irq()
00026 {
00027   dma_descriptor*   dma_desc = get_RX_DMA_descriptor_from_ethernet();
00028   my_custom_pbuf_t* my_pbuf  = (my_custom_pbuf_t*)LWIP_MEMPOOL_ALLOC(RX_POOL);
00029 
00030   my_pbuf->p.custom_free_function = my_pbuf_free_custom;
00031   my_pbuf->dma_descriptor         = dma_desc;
00032 
00033   invalidate_cpu_cache(dma_desc->rx_data, dma_desc->rx_length);
00034   
00035   struct pbuf* p = pbuf_alloced_custom(PBUF_RAW,
00036      dma_desc->rx_length,
00037      PBUF_REF,
00038      &my_pbuf->p,
00039      dma_desc->rx_data,
00040      dma_desc->max_buffer_size);
00041 
00042   if(netif->input(p, netif) != ERR_OK) {
00043     pbuf_free(p);
00044   }
00045 }