From 750fad37f0fb73634306a1a22731691c59199967 Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Fri, 27 Mar 2015 13:04:43 -0600 Subject: [PATCH] SAMV7 Ethernet: Fix some errors in circular queue handling --- arch/arm/src/samv7/sam_emac.c | 50 +++++++++++++++++++++++------------ 1 file changed, 33 insertions(+), 17 deletions(-) diff --git a/arch/arm/src/samv7/sam_emac.c b/arch/arm/src/samv7/sam_emac.c index 4a34bb6d82..b173fd8290 100644 --- a/arch/arm/src/samv7/sam_emac.c +++ b/arch/arm/src/samv7/sam_emac.c @@ -1010,7 +1010,7 @@ static uint16_t sam_txfree(struct sam_emac_s *priv, int qid) * the configured size minus 1. */ - return (priv->xfrq[qid].ntxbuffers-1) - sam_txinuse(priv, qid); + return (priv->xfrq[qid].ntxbuffers - 1) - sam_txinuse(priv, qid); } /**************************************************************************** @@ -1321,7 +1321,7 @@ static int sam_transmit(struct sam_emac_s *priv, int qid) /* Update TX descriptor status. */ status = dev->d_len | EMACTXD_STA_LAST; - if (txhead == priv->xfrq[qid].ntxbuffers-1) + if (txhead == priv->xfrq[qid].ntxbuffers - 1) { status |= EMACTXD_STA_WRAP; } @@ -1556,7 +1556,9 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) if ((rxdesc->status & EMACRXD_STA_SOF) != 0) { - /* Skip previous fragments */ + /* Skip previous fragments. Loop incrementing the index to the + * start fragment until it is equal to the index with the SOF mark + */ while (rxndx != priv->xfrq[qid].rxndx) { @@ -1571,7 +1573,7 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) (uintptr_t)rxdesc + sizeof(struct emac_rxdesc_s)); - /* Increment the RX index */ + /* Increment the RX index to the start fragment */ if (++priv->xfrq[qid].rxndx >= priv->xfrq[qid].nrxbuffers) { @@ -1589,7 +1591,10 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) isframe = true; } - /* Increment the working index */ + /* Increment the working index. rxndx points to the next fragment + * in this frame (or, if the LAST bit was set, to the first fragment + * of the next frame). + */ if (++rxndx >= priv->xfrq[qid].nrxbuffers) { @@ -1664,7 +1669,8 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) priv->xfrq[qid].rxndx, rxndx, dev->d_len); /* All data have been copied in the application frame buffer, - * release the RX descriptor + * release the RX descriptor(s). Loop until all descriptors + * have been released up to the start of the next frame. */ while (priv->xfrq[qid].rxndx != rxndx) @@ -1680,7 +1686,9 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) (uintptr_t)rxdesc + sizeof(struct emac_rxdesc_s)); - /* Increment the RX index */ + /* Increment the RX index of the descriptor that was just + * released. + */ if (++priv->xfrq[qid].rxndx >= priv->xfrq[qid].nrxbuffers) { @@ -1705,8 +1713,9 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) } } - /* We have not encountered the SOF yet... discard this fragment and - * keep looking + /* We found a descriptor that we own, but we have not encountered the + * SOF yet... discard this fragment and keep looking starting at the + * next fragment. */ else @@ -1720,10 +1729,17 @@ static int sam_recvframe(struct sam_emac_s *priv, int qid) arch_clean_dcache((uintptr_t)rxdesc, (uintptr_t)rxdesc + sizeof(struct emac_rxdesc_s)); + + /* rxndx already points to the next fragment to be examined. + * Use it to update the candidate Start-of-Frame. + */ + priv->xfrq[qid].rxndx = rxndx; } - /* Process the next buffer */ + /* Set-up rocess the next fragment. Get the RX descriptor + * associated with the next fragment. + */ rxdesc = &priv->xfrq[qid].rxdesc[rxndx]; @@ -1932,7 +1948,7 @@ static void sam_txdone(struct sam_emac_s *priv, int qid) txdesc = &priv->xfrq[qid].txdesc[tail]; - /* REVISIT: If the rxdesc is not aligned with the cacheline boundary + /* REVISIT: If the txdesc is not aligned with the cacheline boundary * then won't this also invalidate some surrounding memory? */ @@ -1959,7 +1975,7 @@ static void sam_txdone(struct sam_emac_s *priv, int qid) { /* Increment the tail index */ - if (++tail > priv->xfrq[qid].ntxbuffers) + if (++tail >= priv->xfrq[qid].ntxbuffers) { tail = 0; } @@ -1974,7 +1990,7 @@ static void sam_txdone(struct sam_emac_s *priv, int qid) /* Go to first buffer of the next frame */ if (tail != priv->xfrq[qid].txhead && - ++tail > priv->xfrq[qid].ntxbuffers) + ++tail >= priv->xfrq[qid].ntxbuffers) { tail = 0; } @@ -2070,7 +2086,7 @@ static void sam_txerr_interrupt(FAR struct sam_emac_s *priv, int qid) { /* Increment the tail index */ - if (++tail > priv->xfrq[qid].ntxbuffers) + if (++tail >= priv->xfrq[qid].ntxbuffers) { tail = 0; } @@ -2085,7 +2101,7 @@ static void sam_txerr_interrupt(FAR struct sam_emac_s *priv, int qid) /* Go to first buffer of the next frame */ if (tail != priv->xfrq[qid].txhead && - ++tail > priv->xfrq[qid].ntxbuffers) + ++tail >= priv->xfrq[qid].ntxbuffers) { tail = 0; } @@ -5073,8 +5089,8 @@ errout: * netdev ioctl. The application level code have gotten the MAC * address from some configuration parameter or by accessing some * non-volatile storage containing the address. This is the - * "cannonically correct" way to set the MAC address. - * 2) Alterntively, the board logic may support some other less obvious + * "canonically correct" way to set the MAC address. + * 2) Alternatively, the board logic may support some other less obvious * non-volatile storage and the board-level boot-up code may access * this and use this interface to set the Ethernet MAC address more * directly. This is mostly a kludge for the case where you just don't