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Message-Id: <20171204141744.18599-3-thomas.petazzoni@free-electrons.com>
Date: Mon, 4 Dec 2017 15:17:44 +0100
From: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
To: "David S. Miller" <davem@...emloft.net>,
Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
Niklas Söderlund
<niklas.soderlund+renesas@...natech.se>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Simon Horman <horms+renesas@...ge.net.au>
Cc: netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
Subject: [PATCH 2/2] net: sh_eth: make work on big endian systems
The sh_eth driver uses cpu_to_le32() and le32_to_cpu() to manipulate
the fields of the DMA descriptors, making the assumption that the DMA
descriptors are little-endian.
However, testing on the Renesas SH7786 running in big-endian mode
reveals that the DMA descriptors are also big-endian when running
big-endian. Therefore, all the endianness conversion needs to be
removed for the sh_eth driver to work.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
---
Note: I see that Sergei Shtylyov has done some work around endianness
on this driver back in 2015. I am not sure if it's used on other
non-SuperH platforms in platforms where the CPU might run big-endian
but the IP still be little-endian. If this is the case, then we would
need a different approach and more discussion.
Therefore, it would be useful to wait for an ACK from Sergei before
applying this patch.
---
drivers/net/ethernet/renesas/sh_eth.c | 64 ++++++++++++++++-------------------
1 file changed, 30 insertions(+), 34 deletions(-)
diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index a3c48b2a713c..0de8fae143ab 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1163,31 +1163,29 @@ static int sh_eth_tx_free(struct net_device *ndev, bool sent_only)
for (; mdp->cur_tx - mdp->dirty_tx > 0; mdp->dirty_tx++) {
entry = mdp->dirty_tx % mdp->num_tx_ring;
txdesc = &mdp->tx_ring[entry];
- sent = !(txdesc->status & cpu_to_le32(TD_TACT));
+ sent = !(txdesc->status & TD_TACT);
if (sent_only && !sent)
break;
/* TACT bit must be checked before all the following reads */
dma_rmb();
netif_info(mdp, tx_done, ndev,
"tx entry %d status 0x%08x\n",
- entry, le32_to_cpu(txdesc->status));
+ entry, txdesc->status);
/* Free the original skb. */
if (mdp->tx_skbuff[entry]) {
- dma_unmap_single(&mdp->pdev->dev,
- le32_to_cpu(txdesc->addr),
- le32_to_cpu(txdesc->len) >> 16,
- DMA_TO_DEVICE);
+ dma_unmap_single(&mdp->pdev->dev, txdesc->addr,
+ txdesc->len >> 16, DMA_TO_DEVICE);
dev_kfree_skb_irq(mdp->tx_skbuff[entry]);
mdp->tx_skbuff[entry] = NULL;
free_num++;
}
- txdesc->status = cpu_to_le32(TD_TFP);
+ txdesc->status = TD_TFP;
if (entry >= mdp->num_tx_ring - 1)
- txdesc->status |= cpu_to_le32(TD_TDLE);
+ txdesc->status |= TD_TDLE;
if (sent) {
ndev->stats.tx_packets++;
- ndev->stats.tx_bytes += le32_to_cpu(txdesc->len) >> 16;
+ ndev->stats.tx_bytes += txdesc->len >> 16;
}
}
return free_num;
@@ -1204,8 +1202,7 @@ static void sh_eth_ring_free(struct net_device *ndev)
if (mdp->rx_skbuff[i]) {
struct sh_eth_rxdesc *rxdesc = &mdp->rx_ring[i];
- dma_unmap_single(&mdp->pdev->dev,
- le32_to_cpu(rxdesc->addr),
+ dma_unmap_single(&mdp->pdev->dev, rxdesc->addr,
ALIGN(mdp->rx_buf_sz, 32),
DMA_FROM_DEVICE);
}
@@ -1280,9 +1277,9 @@ static void sh_eth_ring_format(struct net_device *ndev)
/* RX descriptor */
rxdesc = &mdp->rx_ring[i];
- rxdesc->len = cpu_to_le32(buf_len << 16);
- rxdesc->addr = cpu_to_le32(dma_addr);
- rxdesc->status = cpu_to_le32(RD_RACT | RD_RFP);
+ rxdesc->len = buf_len << 16;
+ rxdesc->addr = dma_addr;
+ rxdesc->status = RD_RACT | RD_RFP;
/* Rx descriptor address set */
if (i == 0) {
@@ -1297,7 +1294,7 @@ static void sh_eth_ring_format(struct net_device *ndev)
/* Mark the last entry as wrapping the ring. */
if (rxdesc)
- rxdesc->status |= cpu_to_le32(RD_RDLE);
+ rxdesc->status |= RD_RDLE;
memset(mdp->tx_ring, 0, tx_ringsize);
@@ -1305,8 +1302,8 @@ static void sh_eth_ring_format(struct net_device *ndev)
for (i = 0; i < mdp->num_tx_ring; i++) {
mdp->tx_skbuff[i] = NULL;
txdesc = &mdp->tx_ring[i];
- txdesc->status = cpu_to_le32(TD_TFP);
- txdesc->len = cpu_to_le32(0);
+ txdesc->status = TD_TFP;
+ txdesc->len = 0;
if (i == 0) {
/* Tx descriptor address set */
sh_eth_write(ndev, mdp->tx_desc_dma, TDLAR);
@@ -1316,7 +1313,7 @@ static void sh_eth_ring_format(struct net_device *ndev)
}
}
- txdesc->status |= cpu_to_le32(TD_TDLE);
+ txdesc->status |= TD_TDLE;
}
/* Get skb and descriptor buffer */
@@ -1462,7 +1459,7 @@ static void sh_eth_dev_exit(struct net_device *ndev)
* packet boundary if it's currently running
*/
for (i = 0; i < mdp->num_tx_ring; i++)
- mdp->tx_ring[i].status &= ~cpu_to_le32(TD_TACT);
+ mdp->tx_ring[i].status &= ~TD_TACT;
/* Disable TX FIFO egress to MAC */
sh_eth_rcv_snd_disable(ndev);
@@ -1502,11 +1499,11 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
boguscnt = min(boguscnt, *quota);
limit = boguscnt;
rxdesc = &mdp->rx_ring[entry];
- while (!(rxdesc->status & cpu_to_le32(RD_RACT))) {
+ while (!(rxdesc->status & RD_RACT)) {
/* RACT bit must be checked before all the following reads */
dma_rmb();
- desc_status = le32_to_cpu(rxdesc->status);
- pkt_len = le32_to_cpu(rxdesc->len) & RD_RFL;
+ desc_status = rxdesc->status;
+ pkt_len = rxdesc->len & RD_RFL;
if (--boguscnt < 0)
break;
@@ -1544,7 +1541,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
if (desc_status & RD_RFS10)
ndev->stats.rx_over_errors++;
} else if (skb) {
- dma_addr = le32_to_cpu(rxdesc->addr);
+ dma_addr = rxdesc->addr;
if (!mdp->cd->hw_swap)
sh_eth_soft_swap(
phys_to_virt(ALIGN(dma_addr, 4)),
@@ -1573,7 +1570,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
rxdesc = &mdp->rx_ring[entry];
/* The size of the buffer is 32 byte boundary. */
buf_len = ALIGN(mdp->rx_buf_sz, 32);
- rxdesc->len = cpu_to_le32(buf_len << 16);
+ rxdesc->len = buf_len << 16;
if (mdp->rx_skbuff[entry] == NULL) {
skb = netdev_alloc_skb(ndev, skbuff_size);
@@ -1589,14 +1586,13 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
mdp->rx_skbuff[entry] = skb;
skb_checksum_none_assert(skb);
- rxdesc->addr = cpu_to_le32(dma_addr);
+ rxdesc->addr = dma_addr;
}
dma_wmb(); /* RACT bit must be set after all the above writes */
if (entry >= mdp->num_rx_ring - 1)
- rxdesc->status |=
- cpu_to_le32(RD_RACT | RD_RFP | RD_RDLE);
+ rxdesc->status |= RD_RACT | RD_RFP | RD_RDLE;
else
- rxdesc->status |= cpu_to_le32(RD_RACT | RD_RFP);
+ rxdesc->status |= RD_RACT | RD_RFP;
}
/* Restart Rx engine if stopped. */
@@ -2426,8 +2422,8 @@ static void sh_eth_tx_timeout(struct net_device *ndev)
/* Free all the skbuffs in the Rx queue. */
for (i = 0; i < mdp->num_rx_ring; i++) {
rxdesc = &mdp->rx_ring[i];
- rxdesc->status = cpu_to_le32(0);
- rxdesc->addr = cpu_to_le32(0xBADF00D0);
+ rxdesc->status = 0;
+ rxdesc->addr = 0xBADF00D0;
dev_kfree_skb(mdp->rx_skbuff[i]);
mdp->rx_skbuff[i] = NULL;
}
@@ -2477,14 +2473,14 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev)
kfree_skb(skb);
return NETDEV_TX_OK;
}
- txdesc->addr = cpu_to_le32(dma_addr);
- txdesc->len = cpu_to_le32(skb->len << 16);
+ txdesc->addr = dma_addr;
+ txdesc->len = skb->len << 16;
dma_wmb(); /* TACT bit must be set after all the above writes */
if (entry >= mdp->num_tx_ring - 1)
- txdesc->status |= cpu_to_le32(TD_TACT | TD_TDLE);
+ txdesc->status |= TD_TACT | TD_TDLE;
else
- txdesc->status |= cpu_to_le32(TD_TACT);
+ txdesc->status |= TD_TACT;
mdp->cur_tx++;
--
2.13.6
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