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if_dwc: Avoid tx defrag if possible

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Drop packets in case of resource shortage.
This commit is contained in:
Sebastian Huber
2015-03-30 11:40:24 +02:00
parent 822aa5dee2
commit a681853878
1 changed files with 109 additions and 50 deletions
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159
freebsd/sys/dev/dwc/if_dwc.c
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@@ -149,6 +149,7 @@ struct dwc_hwdesc
#define TX_DESC_COUNT 64
#endif /* __rtems__ */
#define TX_DESC_SIZE (sizeof(struct dwc_hwdesc) * TX_DESC_COUNT)
#define TX_MAX_DMA_SEGS 8 /* maximum segs in a tx mbuf dma */
/*
* The hardware imposes alignment restrictions on various objects involved in
@@ -221,10 +222,10 @@ next_rxidx(struct dwc_softc *sc, uint32_t curidx)
}
static inline uint32_t
next_txidx(struct dwc_softc *sc, uint32_t curidx)
next_txidx(struct dwc_softc *sc, uint32_t curidx, int inc)
{
return ((curidx + 1) % TX_DESC_COUNT);
return ((curidx + (uint32_t)inc) % TX_DESC_COUNT);
}
#ifndef __rtems__
@@ -238,58 +239,121 @@ dwc_get1paddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
}
#endif /* __rtems__ */
inline static uint32_t
dwc_setup_txdesc(struct dwc_softc *sc, int idx, bus_addr_t paddr,
uint32_t len)
static void
dwc_setup_txdesc(struct dwc_softc *sc, int idx, bus_dma_segment_t segs[TX_MAX_DMA_SEGS],
int nsegs)
{
++sc->txcount;
int i;
sc->txdesc_ring[idx].addr = (uint32_t)(paddr);
sc->txdesc_ring[idx].tdes1 = len;
wmb();
sc->txcount += nsegs;
sc->txdesc_ring[idx].tdes0 = DDESC_TDES0_TXCHAIN | DDESC_TDES0_TXFIRST
| DDESC_TDES0_TXLAST | DDESC_TDES0_TXINT | DDESC_TDES0_OWN;
wmb();
idx = next_txidx(sc, idx, nsegs);
sc->tx_idx_head = idx;
return (next_txidx(sc, idx));
/*
* Fill in the TX descriptors back to front so that OWN bit in first
* descriptor is set last.
*/
for (i = nsegs - 1; i >= 0; i--) {
uint32_t tdes0;
idx = next_txidx(sc, idx, -1);
sc->txdesc_ring[idx].addr = segs[i].ds_addr;
sc->txdesc_ring[idx].tdes1 = segs[i].ds_len;
wmb();
tdes0 = DDESC_TDES0_TXCHAIN | DDESC_TDES0_TXINT |
DDESC_TDES0_OWN;
if (i == 0)
tdes0 |= DDESC_TDES0_TXFIRST;
if (i == nsegs - 1)
tdes0 |= DDESC_TDES0_TXLAST;
sc->txdesc_ring[idx].tdes0 = tdes0;
wmb();
if (i != 0)
sc->txbuf_map[idx].mbuf = NULL;
}
}
#ifdef __rtems__
static int
dwc_setup_txbuf(struct dwc_softc *sc, int idx, struct mbuf **mp)
dwc_get_segs_for_tx(struct mbuf *m, bus_dma_segment_t segs[TX_MAX_DMA_SEGS],
int *nsegs)
{
struct bus_dma_segment seg;
#ifndef __rtems__
int error, nsegs;
int i = 0;
do {
if (m->m_len > 0) {
segs[i].ds_addr = mtod(m, bus_addr_t);
segs[i].ds_len = m->m_len;
rtems_cache_flush_multiple_data_lines(m->m_data, m->m_len);
++i;
}
m = m->m_next;
if (m == NULL) {
*nsegs = i;
return (0);
}
} while (i < TX_MAX_DMA_SEGS);
return (EFBIG);
}
#endif /* __rtems__ */
struct mbuf * m;
if ((m = m_defrag(*mp, M_NOWAIT)) == NULL)
return (ENOMEM);
*mp = m;
static void
dwc_setup_txbuf(struct dwc_softc *sc, struct mbuf *m, int *start_tx)
{
bus_dma_segment_t segs[TX_MAX_DMA_SEGS];
int error, nsegs, idx;
idx = sc->tx_idx_head;
#ifndef __rtems__
error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, sc->txbuf_map[idx].map,
m, &seg, &nsegs, 0);
if (error != 0) {
return (ENOMEM);
}
m, &seg, &nsegs, BUS_DMA_NOWAIT);
KASSERT(nsegs == 1, ("%s: %d segments returned!", __func__, nsegs));
bus_dmamap_sync(sc->txbuf_tag, sc->txbuf_map[idx].map,
BUS_DMASYNC_PREWRITE);
#else /* __rtems__ */
rtems_cache_flush_multiple_data_lines(m->m_data, m->m_len);
seg.ds_addr = mtod(m, bus_addr_t);
seg.ds_len = m->m_len;
error = dwc_get_segs_for_tx(m, segs, &nsegs);
#endif /* __rtems__ */
if (error == EFBIG) {
/* Too many segments! Defrag and try again. */
struct mbuf *m2 = m_defrag(m, M_NOWAIT);
if (m2 == NULL) {
m_freem(m);
return;
}
m = m2;
#ifndef __rtems__
error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag,
sc->txbuf_map[idx].map, m, &seg, &nsegs, BUS_DMA_NOWAIT);
#else /* __rtems__ */
error = dwc_get_segs_for_tx(m, segs, &nsegs);
#endif /* __rtems__ */
}
if (error != 0) {
/* Give up. */
m_freem(m);
return;
}
sc->txbuf_map[idx].mbuf = m;
dwc_setup_txdesc(sc, idx, seg.ds_addr, seg.ds_len);
#ifndef __rtems__
bus_dmamap_sync(sc->txbuf_tag, sc->txbuf_map[idx].map,
BUS_DMASYNC_PREWRITE);
#endif /* __rtems__ */
return (0);
dwc_setup_txdesc(sc, idx, segs, nsegs);
ETHER_BPF_MTAP(sc->ifp, m);
*start_tx = 1;
}
static void
@@ -297,7 +361,7 @@ dwc_txstart_locked(struct dwc_softc *sc)
{
struct ifnet *ifp;
struct mbuf *m;
int enqueued;
int start_tx;
DWC_ASSERT_LOCKED(sc);
@@ -306,10 +370,10 @@ dwc_txstart_locked(struct dwc_softc *sc)
ifp = sc->ifp;
enqueued = 0;
start_tx = 0;
for (;;) {
if (sc->txcount == (TX_DESC_COUNT-1)) {
if (sc->txcount >= (TX_DESC_COUNT - 1 - TX_MAX_DMA_SEGS)) {
ifp->if_drv_flags |= IFF_DRV_OACTIVE;
break;
}
@@ -317,16 +381,11 @@ dwc_txstart_locked(struct dwc_softc *sc)
IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
if (m == NULL)
break;
if (dwc_setup_txbuf(sc, sc->tx_idx_head, &m) != 0) {
IFQ_DRV_PREPEND(&ifp->if_snd, m);
break;
}
BPF_MTAP(ifp, m);
sc->tx_idx_head = next_txidx(sc, sc->tx_idx_head);
++enqueued;
dwc_setup_txbuf(sc, m, &start_tx);
}
if (enqueued != 0) {
if (start_tx != 0) {
WRITE4(sc, TRANSMIT_POLL_DEMAND, 0x1);
sc->tx_watchdog_count = WATCHDOG_TIMEOUT_SECS;
}
@@ -557,7 +616,7 @@ dwc_setup_rxdesc(struct dwc_softc *sc, int idx, bus_addr_t paddr)
static int
dwc_setup_rxbuf(struct dwc_softc *sc, int idx, struct mbuf *m)
{
struct bus_dma_segment seg;
bus_dma_segment_t seg;
#ifndef __rtems__
int error, nsegs;
#endif /* __rtems__ */
@@ -803,7 +862,7 @@ dwc_txfinish_locked(struct dwc_softc *sc)
m_freem(bmap->mbuf);
bmap->mbuf = NULL;
--sc->txcount;
sc->tx_idx_tail = next_txidx(sc, sc->tx_idx_tail);
sc->tx_idx_tail = next_txidx(sc, sc->tx_idx_tail, 1);
}
sc->ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
@@ -969,7 +1028,7 @@ setup_dma(struct dwc_softc *sc)
sc->txdesc_ring[idx].addr = 0;
sc->txdesc_ring[idx].tdes0 = DDESC_TDES0_TXCHAIN;
sc->txdesc_ring[idx].tdes1 = 0;
nidx = next_txidx(sc, idx);
nidx = next_txidx(sc, idx, 1);
#ifndef __rtems__
sc->txdesc_ring[idx].addr_next = sc->txdesc_ring_paddr + \
(nidx * sizeof(struct dwc_hwdesc));
@@ -986,7 +1045,7 @@ setup_dma(struct dwc_softc *sc)
BUS_SPACE_MAXADDR_32BIT, /* lowaddr */
BUS_SPACE_MAXADDR, /* highaddr */
NULL, NULL, /* filter, filterarg */
MCLBYTES, 1, /* maxsize, nsegments */
MCLBYTES, TX_MAX_DMA_SEGS, /* maxsize, nsegments */
MCLBYTES, /* maxsegsize */
0, /* flags */
NULL, NULL, /* lockfunc, lockarg */