From 7d7355f58ba4f9d68d2fb79864bab4ccb618e4e1 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 3 Mar 2015 00:52:00 +0000 Subject: sh_eth: Ensure proper ordering of descriptor active bit write/read When submitting a DMA descriptor, the active bit must be written last. When reading a completed DMA descriptor, the active bit must be read first. Add memory barriers to ensure that this ordering is maintained. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 654b48d1e61a..5c212a833bcf 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1410,6 +1410,8 @@ static int sh_eth_txfree(struct net_device *ndev) txdesc = &mdp->tx_ring[entry]; if (txdesc->status & cpu_to_edmac(mdp, TD_TACT)) break; + /* TACT bit must be checked before all the following reads */ + rmb(); /* Free the original skb. */ if (mdp->tx_skbuff[entry]) { dma_unmap_single(&ndev->dev, txdesc->addr, @@ -1447,6 +1449,8 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) limit = boguscnt; rxdesc = &mdp->rx_ring[entry]; while (!(rxdesc->status & cpu_to_edmac(mdp, RD_RACT))) { + /* RACT bit must be checked before all the following reads */ + rmb(); desc_status = edmac_to_cpu(mdp, rxdesc->status); pkt_len = rxdesc->frame_length; @@ -1526,6 +1530,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) skb_checksum_none_assert(skb); rxdesc->addr = dma_addr; } + wmb(); /* RACT bit must be set after all the above writes */ if (entry >= mdp->num_rx_ring - 1) rxdesc->status |= cpu_to_edmac(mdp, RD_RACT | RD_RFP | RD_RDEL); @@ -2195,6 +2200,7 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev) } txdesc->buffer_length = skb->len; + wmb(); /* TACT bit must be set after all the above writes */ if (entry >= mdp->num_tx_ring - 1) txdesc->status |= cpu_to_edmac(mdp, TD_TACT | TD_TDLE); else -- cgit v1.2.3 From 6ded286555c2518be2f2d438f83dfaba3f0100fd Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 3 Mar 2015 00:52:08 +0000 Subject: sh_eth: Fix RX recovery on R-Car in case of RX ring underrun In case of RX ring underrun (RDE), we attempt to reset the software descriptor pointers (dirty_rx and cur_rx) to match where the hardware will read the next descriptor from, as that might not be the first dirty descriptor. This relies on reading RDFAR, but that register doesn't exist on all supported chips - specifically, not on the R-Car chips. This will result in unpredictable behaviour on those chips after an RDE. Make this pointer reset conditional and assume that it isn't needed on the R-Car chips. This fix also assumes that RDFAR is never exposed at offset 0 in the memory map - this is currently true, and a subsequent commit will fix the ambiguity between offset 0 and no-offset in the register offset maps. Fixes: 79fba9f51755 ("net: sh_eth: fix the rxdesc pointer when rx ...") Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 5c212a833bcf..3309494d12ad 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1543,7 +1543,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) /* If we don't need to check status, don't. -KDU */ if (!(sh_eth_read(ndev, EDRRR) & EDRRR_R)) { /* fix the values for the next receiving if RDE is set */ - if (intr_status & EESR_RDE) { + if (intr_status & EESR_RDE && mdp->reg_offset[RDFAR] != 0) { u32 count = (sh_eth_read(ndev, RDFAR) - sh_eth_read(ndev, RDLAR)) >> 4; -- cgit v1.2.3 From 9b4a6364a6b3176511956ad186f8dffbe2e60c3e Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 3 Mar 2015 00:52:39 +0000 Subject: Revert "sh_eth: Enable Rx descriptor word 0 shift for r8a7790" This reverts commit fd9af07c3404ac9ecbd0d859563360f51ce1ffde. The hardware manual states that the frame error and multicast bits are copied to bits 9:0 of RD0, not bits 25:16. I've tested that this is true for RFS1 (CRC error), RFS3 (frame too short), RFS4 (frame too long) and RFS8 (multicast). Also adjust a comment to agree with this. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 3309494d12ad..3406cda57a45 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -508,7 +508,6 @@ static struct sh_eth_cpu_data r8a779x_data = { .tpauser = 1, .hw_swap = 1, .rmiimode = 1, - .shift_rd0 = 1, }; static void sh_eth_set_rate_sh7724(struct net_device *ndev) @@ -1462,8 +1461,8 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) /* In case of almost all GETHER/ETHERs, the Receive Frame State * (RFS) bits in the Receive Descriptor 0 are from bit 9 to - * bit 0. However, in case of the R8A7740, R8A779x, and - * R7S72100 the RFS bits are from bit 25 to bit 16. So, the + * bit 0. However, in case of the R8A7740 and R7S72100 + * the RFS bits are from bit 25 to bit 16. So, the * driver needs right shifting by 16. */ if (mdp->cd->shift_rd0) -- cgit v1.2.3 From dacc73e0cf930e87e2e6a94d29156f1d5776b18f Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 3 Mar 2015 00:53:08 +0000 Subject: sh_eth: Really fix padding of short frames on TX MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit My previous fix to clear padding of short frames used skb->len as the DMA length, assuming that skb_padto() extended skb->len to include the padding. That isn't the case; we need to use skb_put_padto() instead. (This wasn't immediately obvious because software padding isn't actually needed on the R-Car H2. We could make it conditional on which chip is being driven, but it's probably not worth the effort.) Reported-by: "Violeta Menéndez González" Fixes: 612a17a54b50 ("sh_eth: Fix padding of short frames on TX") Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/sh_eth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 3406cda57a45..736d5d1624a1 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -2181,7 +2181,7 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev) } spin_unlock_irqrestore(&mdp->lock, flags); - if (skb_padto(skb, ETH_ZLEN)) + if (skb_put_padto(skb, ETH_ZLEN)) return NETDEV_TX_OK; entry = mdp->cur_tx % mdp->num_tx_ring; -- cgit v1.2.3