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Fix a lockup in tx path for cspw.

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Sometimes the software loses the race when appending more descriptors to
the tx ring and the tx queue stops.

This commit detects this condition and restart the tx queue whenever it stall.

Tested by:	sobomax@, Keith White <kwhite@site.uottawa.ca>,
	Paul Mather <paul@gromit.dlib.vt.edu>
Sponsored by:	Rubicon Communications (Netgate)
Approved by:	re (kib)
This commit is contained in:
Luiz Otavio O Souza 2016-07-07 20:01:03 +00:00
parent 34caa842a4
commit cde7231a7f
2 changed files with 18 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
sys/arm/ti/cpsw/if_cpsw.c
View File

@ -1874,6 +1874,7 @@ cpswp_tx_enqueue(struct cpswp_softc *sc)
return;
} else if (last_old_slot == NULL) {
/* Start a fresh queue. */
sc->swsc->last_hdp = cpsw_cpdma_bd_paddr(sc->swsc, first_new_slot);
cpsw_write_hdp_slot(sc->swsc, &sc->swsc->tx, first_new_slot);
} else {
/* Add buffers to end of current queue. */
@ -1882,6 +1883,7 @@ cpswp_tx_enqueue(struct cpswp_softc *sc)
/* If underrun, restart queue. */
if (cpsw_cpdma_read_bd_flags(sc->swsc, last_old_slot) &
CPDMA_BD_EOQ) {
sc->swsc->last_hdp = cpsw_cpdma_bd_paddr(sc->swsc, first_new_slot);
cpsw_write_hdp_slot(sc->swsc, &sc->swsc->tx,
first_new_slot);
}
@ -1897,6 +1899,7 @@ static int
cpsw_tx_dequeue(struct cpsw_softc *sc)
{
struct cpsw_slot *slot, *last_removed_slot = NULL;
struct cpsw_cpdma_bd bd;
uint32_t flags, removed = 0;
slot = STAILQ_FIRST(&sc->tx.active);
@ -1931,13 +1934,26 @@ cpsw_tx_dequeue(struct cpsw_softc *sc)
}
/* TearDown complete is only marked on the SOP for the packet. */
if (flags & CPDMA_BD_TDOWNCMPLT) {
if ((flags & (CPDMA_BD_SOP | CPDMA_BD_TDOWNCMPLT)) ==
(CPDMA_BD_EOP | CPDMA_BD_TDOWNCMPLT)) {
CPSW_DEBUGF(sc, ("TX teardown in progress"));
cpsw_write_cp(sc, &sc->tx, 0xfffffffc);
// TODO: Increment a count of dropped TX packets
sc->tx.running = 0;
break;
}
if ((flags & CPDMA_BD_EOP) == 0)
flags = cpsw_cpdma_read_bd_flags(sc, last_removed_slot);
if ((flags & (CPDMA_BD_EOP | CPDMA_BD_EOQ)) ==
(CPDMA_BD_EOP | CPDMA_BD_EOQ)) {
cpsw_cpdma_read_bd(sc, last_removed_slot, &bd);
if (bd.next != 0 && bd.next != sc->last_hdp) {
/* Restart the queue. */
sc->last_hdp = bd.next;
cpsw_write_4(sc, sc->tx.hdp_offset, bd.next);
}
}
}
if (removed != 0) {

1
sys/arm/ti/cpsw/if_cpswvar.h
View File

@ -83,6 +83,7 @@ struct cpsw_softc {
/* RX and TX buffer tracking */
struct cpsw_queue rx, tx;
uint32_t last_hdp;
/* We expect 1 memory resource and 4 interrupts from the device tree. */
int mem_rid;