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handle case when buffers are full and we need to transmit.

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this is a problem because there won't be a buffer available for the
acknowledgment. In this case use the dummy_ack packet which is always
free for this purpose.
This commit is contained in:
Mariano Alvira 2010-03-08 17:37:35 -05:00
parent d097647edd
commit 761d2c4cbf
1 changed files with 13 additions and 4 deletions
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17
lib/maca.c
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@ -31,6 +31,10 @@
static volatile packet_t packet_pool[NUM_PACKETS];
static volatile packet_t *free_head, *rx_head, *rx_end, *tx_head, *tx_end, *dma_tx, *dma_rx = 0;
/* used for ack recpetion if the packet_pool goes empty */
/* doesn't go back into the pool when freed */
static volatile packet_t dummy_ack;
enum posts {
NO_POST = 0,
TX_POST,
@ -100,6 +104,8 @@ void free_packet(volatile packet_t *p) {
safe_irq_disable(MACA);
if(!p) { PRINTF("free_packet passed packet 0\n\r"); return; }
if(p == &dummy_ack) { return; }
p->length = 0;
p->left = free_head; p->right = 0;
free_head = p;
@ -136,7 +142,7 @@ void post_receive(void) {
if(dma_rx == 0) {
dma_rx = get_free_packet();
if (dma_rx == 0) {
printf("trying to fill MACA_DMARX but out of packet buffers\n\r");
printf("trying to fill MACA_DMARX in post_receieve but out of packet buffers\n\r");
/* set the sftclock so that we return to the maca_isr */
*MACA_SFTCLK = *MACA_CLK + RECV_SOFTIMEOUT; /* soft timeout */
*MACA_TMREN = (1 << maca_tmren_sft);
@ -192,9 +198,12 @@ void post_tx(void) {
*MACA_DMATX = (uint32_t)&(dma_tx->data[ 0 + dma_tx->offset]);
if(dma_rx == 0) {
dma_rx = get_free_packet();
if (dma_rx == 0)
printf("trying to fill MACA_DMARX but out of packet buffers\n");
}
if (dma_rx == 0) {
dma_rx = &dummy_ack;
printf("trying to fill MACA_DMARX on post_tx but out of packet buffers\n\r");
}
}
*MACA_DMARX = (uint32_t)&(dma_rx->data[0]);
/* disable soft timeout clock */
/* disable start clock */