[rtems-libbsd commit] ffec: Defragment transmit mbuf only if necessary
Sebastian Huber
sebh at rtems.org
Wed Oct 25 12:31:12 UTC 2017
Module: rtems-libbsd
Branch: master
Commit: 0cb40755cc3e20ebfccf427d6061920963d48b8e
Changeset: http://git.rtems.org/rtems-libbsd/commit/?id=0cb40755cc3e20ebfccf427d6061920963d48b8e
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Tue Oct 24 12:17:00 2017 +0200
ffec: Defragment transmit mbuf only if necessary
Use structure similar to TSEC (if_tsec) driver.
The use of bus_dmamap_sync() differs these network interface drivers.
This should not be the case.
Update #3090.
---
freebsd/sys/dev/ffec/if_ffec.c | 243 +++++++++++++++++++++++------------------
1 file changed, 139 insertions(+), 104 deletions(-)
diff --git a/freebsd/sys/dev/ffec/if_ffec.c b/freebsd/sys/dev/ffec/if_ffec.c
index 07b8c34..51c2e79 100644
--- a/freebsd/sys/dev/ffec/if_ffec.c
+++ b/freebsd/sys/dev/ffec/if_ffec.c
@@ -125,12 +125,13 @@ static struct ofw_compat_data compat_data[] = {
};
/*
- * Driver data and defines.
+ * Driver data and defines. The descriptor counts must be a power of two.
*/
#define RX_DESC_COUNT 64
#define RX_DESC_SIZE (sizeof(struct ffec_hwdesc) * RX_DESC_COUNT)
#define TX_DESC_COUNT 64
#define TX_DESC_SIZE (sizeof(struct ffec_hwdesc) * TX_DESC_COUNT)
+#define TX_MAX_DMA_SEGS 8
#define WATCHDOG_TIMEOUT_SECS 5
#define STATS_HARVEST_INTERVAL 3
@@ -187,7 +188,6 @@ struct ffec_softc {
struct ffec_bufmap txbuf_map[TX_DESC_COUNT];
uint32_t tx_idx_head;
uint32_t tx_idx_tail;
- int txcount;
};
#define FFEC_LOCK(sc) mtx_lock(&(sc)->mtx)
@@ -200,6 +200,8 @@ struct ffec_softc {
static void ffec_init_locked(struct ffec_softc *sc);
static void ffec_stop_locked(struct ffec_softc *sc);
+static void ffec_encap(struct ifnet *ifp, struct ffec_softc *sc,
+ struct mbuf *m0, int *start_tx);
static void ffec_txstart_locked(struct ffec_softc *sc);
static void ffec_txfinish_locked(struct ffec_softc *sc);
@@ -232,17 +234,39 @@ WR4(struct ffec_softc *sc, bus_size_t off, uint32_t val)
}
static inline uint32_t
-next_rxidx(struct ffec_softc *sc, uint32_t curidx)
+next_rxidx(uint32_t curidx)
{
- return ((curidx == RX_DESC_COUNT - 1) ? 0 : curidx + 1);
+ return ((curidx + 1) & (RX_DESC_COUNT - 1));
}
static inline uint32_t
-next_txidx(struct ffec_softc *sc, uint32_t curidx)
+next_txidx(uint32_t curidx)
{
- return ((curidx == TX_DESC_COUNT - 1) ? 0 : curidx + 1);
+ return ((curidx + 1) & (TX_DESC_COUNT - 1));
+}
+
+static inline uint32_t
+prev_txidx(uint32_t curidx)
+{
+
+ return ((curidx - 1) & (TX_DESC_COUNT - 1));
+}
+
+static inline uint32_t
+inc_txidx(uint32_t curidx, uint32_t inc)
+{
+
+ return ((curidx + inc) & (TX_DESC_COUNT - 1));
+}
+
+static inline uint32_t
+free_txdesc(struct ffec_softc *sc)
+{
+
+ return (((sc)->tx_idx_tail - (sc)->tx_idx_head - 1) &
+ (TX_DESC_COUNT - 1));
}
static void
@@ -569,105 +593,110 @@ ffec_tick(void *arg)
callout_reset(&sc->ffec_callout, hz, ffec_tick, sc);
}
-inline static uint32_t
-ffec_setup_txdesc(struct ffec_softc *sc, int idx, bus_addr_t paddr,
- uint32_t len)
+static void
+ffec_encap(struct ifnet *ifp, struct ffec_softc *sc, struct mbuf *m0,
+ int *start_tx)
{
- uint32_t nidx;
+ bus_dma_segment_t segs[TX_MAX_DMA_SEGS];
+ int error, i, nsegs;
+ struct ffec_bufmap *bmap;
+ uint32_t tx_idx;
uint32_t flags;
- nidx = next_txidx(sc, idx);
-
- /* Addr/len 0 means we're clearing the descriptor after xmit done. */
- if (paddr == 0 || len == 0) {
- flags = 0;
- --sc->txcount;
- } else {
- flags = FEC_TXDESC_READY | FEC_TXDESC_L | FEC_TXDESC_TC;
- ++sc->txcount;
- }
- if (nidx == 0)
- flags |= FEC_TXDESC_WRAP;
+ FFEC_ASSERT_LOCKED(sc);
- /*
- * The hardware requires 32-bit physical addresses. We set up the dma
- * tag to indicate that, so the cast to uint32_t should never lose
- * significant bits.
- */
- sc->txdesc_ring[idx].buf_paddr = (uint32_t)paddr;
- wmb();
- sc->txdesc_ring[idx].flags_len = flags | len; /* Must be set last! */
+ tx_idx = sc->tx_idx_head;
+ bmap = &sc->txbuf_map[tx_idx];
- return (nidx);
-}
+ /* Create mapping in DMA memory */
+ error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, bmap->map, m0,
+ segs, &nsegs, BUS_DMA_NOWAIT);
+ if (error == EFBIG) {
+ /* Too many segments! Defrag and try again. */
+ struct mbuf *m = m_defrag(m0, M_NOWAIT);
-static int
-ffec_setup_txbuf(struct ffec_softc *sc, int idx, struct mbuf **mp)
-{
- struct mbuf * m;
- int error, nsegs;
- struct bus_dma_segment seg;
-
- if ((m = m_defrag(*mp, M_NOWAIT)) == NULL)
- return (ENOMEM);
- *mp = m;
-
- error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag, sc->txbuf_map[idx].map,
- m, &seg, &nsegs, 0);
+ if (m == NULL) {
+ m_freem(m0);
+ return;
+ }
+ m0 = m;
+ error = bus_dmamap_load_mbuf_sg(sc->txbuf_tag,
+ bmap->map, m0, segs, &nsegs, BUS_DMA_NOWAIT);
+ }
if (error != 0) {
- return (ENOMEM);
+ /* Give up. */
+ m_freem(m0);
+ return;
}
+
#ifndef __rtems__
- bus_dmamap_sync(sc->txbuf_tag, sc->txbuf_map[idx].map,
- BUS_DMASYNC_PREWRITE);
-#else /* __rtems__ */
- rtems_cache_flush_multiple_data_lines((void *)seg.ds_addr, seg.ds_len);
+ bus_dmamap_sync(sc->txbuf_tag, bmap->map, BUS_DMASYNC_PREWRITE);
#endif /* __rtems__ */
+ bmap->mbuf = m0;
- sc->txbuf_map[idx].mbuf = m;
- ffec_setup_txdesc(sc, idx, seg.ds_addr, seg.ds_len);
+ /*
+ * Fill in the TX descriptors back to front so that READY bit in first
+ * descriptor is set last.
+ */
+ tx_idx = inc_txidx(tx_idx, (uint32_t)nsegs);
+ sc->tx_idx_head = tx_idx;
+ flags = FEC_TXDESC_L | FEC_TXDESC_READY | FEC_TXDESC_TC;
+ for (i = nsegs - 1; i >= 0; i--) {
+ struct ffec_hwdesc *tx_desc;
+
+ tx_idx = prev_txidx(tx_idx);;
+ tx_desc = &sc->txdesc_ring[tx_idx];
+ tx_desc->buf_paddr = segs[i].ds_addr;
+#ifdef __rtems__
+ rtems_cache_flush_multiple_data_lines((void *)segs[i].ds_addr,
+ segs[i].ds_len);
+#endif /* __rtems__ */
- return (0);
+ if (i == 0) {
+ wmb();
+ }
+ tx_desc->flags_len = (tx_idx == (TX_DESC_COUNT - 1) ?
+ FEC_TXDESC_WRAP : 0) | flags | segs[i].ds_len;
+
+ flags &= ~FEC_TXDESC_L;
+ }
+
+ BPF_MTAP(ifp, m0);
+ *start_tx = 1;
}
static void
ffec_txstart_locked(struct ffec_softc *sc)
{
struct ifnet *ifp;
- struct mbuf *m;
- int enqueued;
+ struct mbuf *m0;
+ int start_tx;
FFEC_ASSERT_LOCKED(sc);
- if (!sc->link_is_up)
- return;
-
ifp = sc->ifp;
+ start_tx = 0;
- if (ifp->if_drv_flags & IFF_DRV_OACTIVE)
+ if (!sc->link_is_up)
return;
- enqueued = 0;
-
for (;;) {
- if (sc->txcount == (TX_DESC_COUNT-1)) {
+ if (free_txdesc(sc) < TX_MAX_DMA_SEGS) {
+ /* No free descriptors */
ifp->if_drv_flags |= IFF_DRV_OACTIVE;
break;
}
- IFQ_DRV_DEQUEUE(&ifp->if_snd, m);
- if (m == NULL)
- break;
- if (ffec_setup_txbuf(sc, sc->tx_idx_head, &m) != 0) {
- IFQ_DRV_PREPEND(&ifp->if_snd, m);
+
+ /* Get packet from the queue */
+ IFQ_DRV_DEQUEUE(&ifp->if_snd, m0);
+ if (m0 == NULL)
break;
- }
- BPF_MTAP(ifp, m);
- sc->tx_idx_head = next_txidx(sc, sc->tx_idx_head);
- ++enqueued;
+
+ ffec_encap(ifp, sc, m0, &start_tx);
}
- if (enqueued != 0) {
+ if (start_tx ) {
bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_PREWRITE);
WR4(sc, FEC_TDAR_REG, FEC_TDAR_TDAR);
bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_POSTWRITE);
@@ -689,40 +718,43 @@ static void
ffec_txfinish_locked(struct ffec_softc *sc)
{
struct ifnet *ifp;
- struct ffec_hwdesc *desc;
- struct ffec_bufmap *bmap;
- boolean_t retired_buffer;
+ uint32_t tx_idx;
FFEC_ASSERT_LOCKED(sc);
+ ifp = sc->ifp;
+
/* XXX Can't set PRE|POST right now, but we need both. */
bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_PREREAD);
bus_dmamap_sync(sc->txdesc_tag, sc->txdesc_map, BUS_DMASYNC_POSTREAD);
- ifp = sc->ifp;
- retired_buffer = false;
- while (sc->tx_idx_tail != sc->tx_idx_head) {
- desc = &sc->txdesc_ring[sc->tx_idx_tail];
+
+ tx_idx = sc->tx_idx_tail;
+ while (tx_idx != sc->tx_idx_head) {
+ struct ffec_hwdesc *desc;
+ struct ffec_bufmap *bmap;
+
+ desc = &sc->txdesc_ring[tx_idx];
if (desc->flags_len & FEC_TXDESC_READY)
break;
- retired_buffer = true;
- bmap = &sc->txbuf_map[sc->tx_idx_tail];
- bus_dmamap_sync(sc->txbuf_tag, bmap->map,
+
+ bmap = &sc->txbuf_map[tx_idx];
+ tx_idx = next_txidx(tx_idx);
+ if (bmap->mbuf == NULL)
+ continue;
+
+ /*
+ * This is the last buf in this packet, so unmap and free it.
+ */
+ bus_dmamap_sync(sc->txbuf_tag, bmap->map,
BUS_DMASYNC_POSTWRITE);
bus_dmamap_unload(sc->txbuf_tag, bmap->map);
m_freem(bmap->mbuf);
bmap->mbuf = NULL;
- ffec_setup_txdesc(sc, sc->tx_idx_tail, 0, 0);
- sc->tx_idx_tail = next_txidx(sc, sc->tx_idx_tail);
}
+ sc->tx_idx_tail = tx_idx;
- /*
- * If we retired any buffers, there will be open tx slots available in
- * the descriptor ring, go try to start some new output.
- */
- if (retired_buffer) {
- ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
- ffec_txstart_locked(sc);
- }
+ ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
+ ffec_txstart_locked(sc);
/* If there are no buffers outstanding, muzzle the watchdog. */
if (sc->tx_idx_tail == sc->tx_idx_head) {
@@ -740,7 +772,7 @@ ffec_setup_rxdesc(struct ffec_softc *sc, int idx, bus_addr_t paddr)
* tag to indicate that, so the cast to uint32_t should never lose
* significant bits.
*/
- nidx = next_rxidx(sc, idx);
+ nidx = next_rxidx(idx);
sc->rxdesc_ring[idx].buf_paddr = (uint32_t)paddr;
wmb();
sc->rxdesc_ring[idx].flags_len = FEC_RXDESC_EMPTY |
@@ -924,7 +956,7 @@ ffec_rxfinish_locked(struct ffec_softc *sc)
*/
ffec_rxfinish_onebuf(sc, len);
}
- sc->rx_idx = next_rxidx(sc, sc->rx_idx);
+ sc->rx_idx = next_rxidx(sc->rx_idx);
}
if (produced_empty_buffer) {
@@ -1076,13 +1108,15 @@ ffec_stop_locked(struct ffec_softc *sc)
while (idx != sc->tx_idx_head) {
desc = &sc->txdesc_ring[idx];
bmap = &sc->txbuf_map[idx];
- if (desc->buf_paddr != 0) {
- bus_dmamap_unload(sc->txbuf_tag, bmap->map);
- m_freem(bmap->mbuf);
- bmap->mbuf = NULL;
- ffec_setup_txdesc(sc, idx, 0, 0);
- }
- idx = next_txidx(sc, idx);
+ idx = next_txidx(idx);
+ if (bmap->mbuf == NULL)
+ continue;
+
+ bus_dmamap_sync(sc->txbuf_tag, bmap->map,
+ BUS_DMASYNC_POSTWRITE);
+ bus_dmamap_unload(sc->txbuf_tag, bmap->map);
+ m_freem(bmap->mbuf);
+ bmap->mbuf = NULL;
}
/*
@@ -1210,7 +1244,6 @@ ffec_init_locked(struct ffec_softc *sc)
*/
sc->rx_idx = 0;
sc->tx_idx_head = sc->tx_idx_tail = 0;
- sc->txcount = 0;
WR4(sc, FEC_RDSR_REG, sc->rxdesc_ring_paddr);
WR4(sc, FEC_TDSR_REG, sc->txdesc_ring_paddr);
@@ -1593,7 +1626,7 @@ ffec_attach(device_t dev)
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 */
@@ -1612,7 +1645,9 @@ ffec_attach(device_t dev)
"could not create TX buffer DMA map.\n");
goto out;
}
- ffec_setup_txdesc(sc, idx, 0, 0);
+ sc->txdesc_ring[idx].buf_paddr = 0;
+ sc->txdesc_ring[idx].flags_len =
+ ((idx == TX_DESC_COUNT - 1) ? FEC_TXDESC_WRAP : 0);
}
/*
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