From dc1d0e6d55006a48ebc0f40a74485ca430f05046 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 27 Jan 2015 00:41:16 +0000 Subject: [PATCH 1/4] sh_eth: Remove RX overflow log messages If RX traffic is overflowing the FIFO or DMA ring, logging every time this happens just makes things worse. These errors are visible in the statistics anyway. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 99a838db032e..bb15cd83134f 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1575,7 +1575,6 @@ ignore_link: if (intr_status & EESR_RFRMER) { /* Receive Frame Overflow int */ ndev->stats.rx_frame_errors++; - netif_err(mdp, rx_err, ndev, "Receive Abort\n"); } } @@ -1594,13 +1593,11 @@ ignore_link: if (intr_status & EESR_RDE) { /* Receive Descriptor Empty int */ ndev->stats.rx_over_errors++; - netif_err(mdp, rx_err, ndev, "Receive Descriptor Empty\n"); } if (intr_status & EESR_RFE) { /* Receive FIFO Overflow int */ ndev->stats.rx_fifo_errors++; - netif_err(mdp, rx_err, ndev, "Receive FIFO Overflow\n"); } if (!mdp->cd->no_ade && (intr_status & EESR_ADE)) { From 740c7f31c094703cfb3902412e66e243eb24b707 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 27 Jan 2015 00:49:32 +0000 Subject: [PATCH 2/4] sh_eth: Ensure DMA engines are stopped before freeing buffers Currently we try to clear EDRRR and EDTRR and immediately continue to free buffers. This is unsafe because: - In general, register writes are not serialised with DMA, so we still have to wait for DMA to complete somehow - The R8A7790 (R-Car H2) manual states that the TX running flag cannot be cleared by writing to EDTRR - The same manual states that clearing the RX running flag only stops RX DMA at the next packet boundary I applied this patch to the driver to detect DMA writes to freed buffers: > --- a/drivers/net/ethernet/renesas/sh_eth.c > +++ b/drivers/net/ethernet/renesas/sh_eth.c > @@ -1098,7 +1098,14 @@ static void sh_eth_ring_free(struct net_device *ndev) > /* Free Rx skb ringbuffer */ > if (mdp->rx_skbuff) { > for (i = 0; i < mdp->num_rx_ring; i++) > + memcpy(mdp->rx_skbuff[i]->data, > + "Hello, world", 12); > + msleep(100); > + for (i = 0; i < mdp->num_rx_ring; i++) { > + WARN_ON(memcmp(mdp->rx_skbuff[i]->data, > + "Hello, world", 12)); > dev_kfree_skb(mdp->rx_skbuff[i]); > + } > } > kfree(mdp->rx_skbuff); > mdp->rx_skbuff = NULL; then ran the loop: while ethtool -G eth0 rx 128 ; ethtool -G eth0 rx 64; do echo -n .; done and 'ping -f' toward the sh_eth port from another machine. The warning fired several times a minute. To fix these issues: - Deactivate all TX descriptors rather than writing to EDTRR - As there seems to be no way of telling when RX DMA is stopped, perform a soft reset to ensure that both DMA enginess are stopped - To reduce the possibility of the reset truncating a transmitted frame, disable egress and wait a reasonable time to reach a packet boundary before resetting - Update statistics before resetting (The 'reasonable time' does not allow for CS/CD in half-duplex mode, but half-duplex no longer seems reasonable!) Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 39 ++++++++++++++++++++++----- 1 file changed, 32 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index bb15cd83134f..245166bbccfd 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -396,6 +396,9 @@ static const u16 sh_eth_offset_fast_sh3_sh2[SH_ETH_MAX_REGISTER_OFFSET] = { [TSU_ADRL31] = 0x01fc, }; +static void sh_eth_rcv_snd_disable(struct net_device *ndev); +static struct net_device_stats *sh_eth_get_stats(struct net_device *ndev); + static bool sh_eth_is_gether(struct sh_eth_private *mdp) { return mdp->reg_offset == sh_eth_offset_gigabit; @@ -1358,6 +1361,33 @@ static int sh_eth_dev_init(struct net_device *ndev, bool start) return ret; } +static void sh_eth_dev_exit(struct net_device *ndev) +{ + struct sh_eth_private *mdp = netdev_priv(ndev); + int i; + + /* Deactivate all TX descriptors, so DMA should stop at next + * packet boundary if it's currently running + */ + for (i = 0; i < mdp->num_tx_ring; i++) + mdp->tx_ring[i].status &= ~cpu_to_edmac(mdp, TD_TACT); + + /* Disable TX FIFO egress to MAC */ + sh_eth_rcv_snd_disable(ndev); + + /* Stop RX DMA at next packet boundary */ + sh_eth_write(ndev, 0, EDRRR); + + /* Aside from TX DMA, we can't tell when the hardware is + * really stopped, so we need to reset to make sure. + * Before doing that, wait for long enough to *probably* + * finish transmitting the last packet and poll stats. + */ + msleep(2); /* max frame time at 10 Mbps < 1250 us */ + sh_eth_get_stats(ndev); + sh_eth_reset(ndev); +} + /* free Tx skb function */ static int sh_eth_txfree(struct net_device *ndev) { @@ -1986,9 +2016,7 @@ static int sh_eth_set_ringparam(struct net_device *ndev, napi_synchronize(&mdp->napi); sh_eth_write(ndev, 0x0000, EESIPR); - /* Stop the chip's Tx and Rx processes. */ - sh_eth_write(ndev, 0, EDTRR); - sh_eth_write(ndev, 0, EDRRR); + sh_eth_dev_exit(ndev); /* Free all the skbuffs in the Rx queue. */ sh_eth_ring_free(ndev); @@ -2207,11 +2235,8 @@ static int sh_eth_close(struct net_device *ndev) napi_disable(&mdp->napi); sh_eth_write(ndev, 0x0000, EESIPR); - /* Stop the chip's Tx and Rx processes. */ - sh_eth_write(ndev, 0, EDTRR); - sh_eth_write(ndev, 0, EDRRR); + sh_eth_dev_exit(ndev); - sh_eth_get_stats(ndev); /* PHY Disconnect */ if (mdp->phydev) { phy_stop(mdp->phydev); From aa3933b87309c61b4fa4bb93c1ad4c3f08afb1b8 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 27 Jan 2015 00:49:47 +0000 Subject: [PATCH 3/4] sh_eth: Check for DMA mapping errors on transmit dma_map_single() may fail if an IOMMU or swiotlb is in use, so we need to check for this. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 245166bbccfd..4a085da57188 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -2174,6 +2174,10 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev) skb->len + 2); txdesc->addr = dma_map_single(&ndev->dev, skb->data, skb->len, DMA_TO_DEVICE); + if (dma_mapping_error(&ndev->dev, txdesc->addr)) { + kfree_skb(skb); + return NETDEV_TX_OK; + } txdesc->buffer_length = skb->len; if (entry >= mdp->num_tx_ring - 1) From 52b9fa3696c44151a2f1d361a00be7c5513db026 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 27 Jan 2015 00:50:24 +0000 Subject: [PATCH 4/4] sh_eth: Fix DMA-API usage for RX buffers - Use the return value of dma_map_single(), rather than calling virt_to_page() separately - Check for mapping failue - Call dma_unmap_single() rather than dma_sync_single_for_cpu() Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 34 ++++++++++++++++++--------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 4a085da57188..04283fe0e6a7 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1123,6 +1123,7 @@ static void sh_eth_ring_format(struct net_device *ndev) int rx_ringsize = sizeof(*rxdesc) * mdp->num_rx_ring; int tx_ringsize = sizeof(*txdesc) * mdp->num_tx_ring; int skbuff_size = mdp->rx_buf_sz + SH_ETH_RX_ALIGN - 1; + dma_addr_t dma_addr; mdp->cur_rx = 0; mdp->cur_tx = 0; @@ -1136,7 +1137,6 @@ static void sh_eth_ring_format(struct net_device *ndev) /* skb */ mdp->rx_skbuff[i] = NULL; skb = netdev_alloc_skb(ndev, skbuff_size); - mdp->rx_skbuff[i] = skb; if (skb == NULL) break; sh_eth_set_receive_align(skb); @@ -1145,9 +1145,15 @@ static void sh_eth_ring_format(struct net_device *ndev) rxdesc = &mdp->rx_ring[i]; /* The size of the buffer is a multiple of 16 bytes. */ rxdesc->buffer_length = ALIGN(mdp->rx_buf_sz, 16); - dma_map_single(&ndev->dev, skb->data, rxdesc->buffer_length, - DMA_FROM_DEVICE); - rxdesc->addr = virt_to_phys(skb->data); + dma_addr = dma_map_single(&ndev->dev, skb->data, + rxdesc->buffer_length, + DMA_FROM_DEVICE); + if (dma_mapping_error(&ndev->dev, dma_addr)) { + kfree_skb(skb); + break; + } + mdp->rx_skbuff[i] = skb; + rxdesc->addr = dma_addr; rxdesc->status = cpu_to_edmac(mdp, RD_RACT | RD_RFP); /* Rx descriptor address set */ @@ -1432,6 +1438,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) u16 pkt_len = 0; u32 desc_status; int skbuff_size = mdp->rx_buf_sz + SH_ETH_RX_ALIGN - 1; + dma_addr_t dma_addr; boguscnt = min(boguscnt, *quota); limit = boguscnt; @@ -1479,9 +1486,9 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) mdp->rx_skbuff[entry] = NULL; if (mdp->cd->rpadir) skb_reserve(skb, NET_IP_ALIGN); - dma_sync_single_for_cpu(&ndev->dev, rxdesc->addr, - ALIGN(mdp->rx_buf_sz, 16), - DMA_FROM_DEVICE); + dma_unmap_single(&ndev->dev, rxdesc->addr, + ALIGN(mdp->rx_buf_sz, 16), + DMA_FROM_DEVICE); skb_put(skb, pkt_len); skb->protocol = eth_type_trans(skb, ndev); netif_receive_skb(skb); @@ -1501,15 +1508,20 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) if (mdp->rx_skbuff[entry] == NULL) { skb = netdev_alloc_skb(ndev, skbuff_size); - mdp->rx_skbuff[entry] = skb; if (skb == NULL) break; /* Better luck next round. */ sh_eth_set_receive_align(skb); - dma_map_single(&ndev->dev, skb->data, - rxdesc->buffer_length, DMA_FROM_DEVICE); + dma_addr = dma_map_single(&ndev->dev, skb->data, + rxdesc->buffer_length, + DMA_FROM_DEVICE); + if (dma_mapping_error(&ndev->dev, dma_addr)) { + kfree_skb(skb); + break; + } + mdp->rx_skbuff[entry] = skb; skb_checksum_none_assert(skb); - rxdesc->addr = virt_to_phys(skb->data); + rxdesc->addr = dma_addr; } if (entry >= mdp->num_rx_ring - 1) rxdesc->status |=