1 files changed, 30 insertions, 16 deletions

diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index a10c928bbd6b..00cfd95ca59d 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -28,6 +28,16 @@
 
 #include "moxart_ether.h"
 
+static inline void moxart_desc_write(u32 data, u32 *desc)
+{
+        *desc = cpu_to_le32(data);
+}
+
+static inline u32 moxart_desc_read(u32 *desc)
+{
+        return le32_to_cpu(*desc);
+}
+
 static inline void moxart_emac_write(struct net_device *ndev,
                                      unsigned int reg, unsigned long value)
 {
@@ -112,7 +122,7 @@ static void moxart_mac_enable(struct net_device *ndev)
 static void moxart_mac_setup_desc_ring(struct net_device *ndev)
 {
         struct moxart_mac_priv_t *priv = netdev_priv(ndev);
-        void __iomem *desc;
+        void *desc;
         int i;
 
         for (i = 0; i < TX_DESC_NUM; i++) {
@@ -121,7 +131,7 @@ static void moxart_mac_setup_desc_ring(struct net_device *ndev)
 
                 priv->tx_buf[i] = priv->tx_buf_base + priv->tx_buf_size * i;
         }
-        writel(TX_DESC1_END, desc + TX_REG_OFFSET_DESC1);
+        moxart_desc_write(TX_DESC1_END, desc + TX_REG_OFFSET_DESC1);
 
         priv->tx_head = 0;
         priv->tx_tail = 0;
@@ -129,8 +139,8 @@ static void moxart_mac_setup_desc_ring(struct net_device *ndev)
         for (i = 0; i < RX_DESC_NUM; i++) {
                 desc = priv->rx_desc_base + i * RX_REG_DESC_SIZE;
                 memset(desc, 0, RX_REG_DESC_SIZE);
-                writel(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0);
-                writel(RX_BUF_SIZE & RX_DESC1_BUF_SIZE_MASK,
+                moxart_desc_write(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0);
+                moxart_desc_write(RX_BUF_SIZE & RX_DESC1_BUF_SIZE_MASK,
                        desc + RX_REG_OFFSET_DESC1);
 
                 priv->rx_buf[i] = priv->rx_buf_base + priv->rx_buf_size * i;
@@ -141,12 +151,12 @@ static void moxart_mac_setup_desc_ring(struct net_device *ndev)
                 if (dma_mapping_error(&ndev->dev, priv->rx_mapping[i]))
                         netdev_err(ndev, "DMA mapping error\n");
 
-                writel(priv->rx_mapping[i],
+                moxart_desc_write(priv->rx_mapping[i],
                        desc + RX_REG_OFFSET_DESC2 + RX_DESC2_ADDRESS_PHYS);
-                writel(priv->rx_buf[i],
+                moxart_desc_write((uintptr_t)priv->rx_buf[i],
                        desc + RX_REG_OFFSET_DESC2 + RX_DESC2_ADDRESS_VIRT);
         }
-        writel(RX_DESC1_END, desc + RX_REG_OFFSET_DESC1);
+        moxart_desc_write(RX_DESC1_END, desc + RX_REG_OFFSET_DESC1);
 
         priv->rx_head = 0;
 
@@ -201,14 +211,15 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
                                                       napi);
         struct net_device *ndev = priv->ndev;
         struct sk_buff *skb;
-        void __iomem *desc;
+        void *desc;
         unsigned int desc0, len;
         int rx_head = priv->rx_head;
         int rx = 0;
 
         while (rx < budget) {
                 desc = priv->rx_desc_base + (RX_REG_DESC_SIZE * rx_head);
-                desc0 = readl(desc + RX_REG_OFFSET_DESC0);
+                desc0 = moxart_desc_read(desc + RX_REG_OFFSET_DESC0);
+                rmb(); /* ensure desc0 is up to date */
 
                 if (desc0 & RX_DESC0_DMA_OWN)
                         break;
@@ -250,7 +261,8 @@ static int moxart_rx_poll(struct napi_struct *napi, int budget)
                         priv->stats.multicast++;
 
 rx_next:
-                writel(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0);
+                wmb(); /* prevent setting ownership back too early */
+                moxart_desc_write(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0);
 
                 rx_head = RX_NEXT(rx_head);
                 priv->rx_head = rx_head;
@@ -310,7 +322,7 @@ static irqreturn_t moxart_mac_interrupt(int irq, void *dev_id)
 static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
         struct moxart_mac_priv_t *priv = netdev_priv(ndev);
-        void __iomem *desc;
+        void *desc;
         unsigned int len;
         unsigned int tx_head = priv->tx_head;
         u32 txdes1;
@@ -319,11 +331,12 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
         desc = priv->tx_desc_base + (TX_REG_DESC_SIZE * tx_head);
 
         spin_lock_irq(&priv->txlock);
-        if (readl(desc + TX_REG_OFFSET_DESC0) & TX_DESC0_DMA_OWN) {
+        if (moxart_desc_read(desc + TX_REG_OFFSET_DESC0) & TX_DESC0_DMA_OWN) {
                 net_dbg_ratelimited("no TX space for packet\n");
                 priv->stats.tx_dropped++;
                 goto out_unlock;
         }
+        rmb(); /* ensure data is only read that had TX_DESC0_DMA_OWN cleared */
 
         len = skb->len > TX_BUF_SIZE ? TX_BUF_SIZE : skb->len;
 
@@ -337,9 +350,9 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
         priv->tx_len[tx_head] = len;
         priv->tx_skb[tx_head] = skb;
 
-        writel(priv->tx_mapping[tx_head],
+        moxart_desc_write(priv->tx_mapping[tx_head],
                desc + TX_REG_OFFSET_DESC2 + TX_DESC2_ADDRESS_PHYS);
-        writel(skb->data,
+        moxart_desc_write((uintptr_t)skb->data,
                desc + TX_REG_OFFSET_DESC2 + TX_DESC2_ADDRESS_VIRT);
 
         if (skb->len < ETH_ZLEN) {
@@ -354,8 +367,9 @@ static int moxart_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
         txdes1 = TX_DESC1_LTS | TX_DESC1_FTS | (len & TX_DESC1_BUF_SIZE_MASK);
         if (tx_head == TX_DESC_NUM_MASK)
                 txdes1 |= TX_DESC1_END;
-        writel(txdes1, desc + TX_REG_OFFSET_DESC1);
-        writel(TX_DESC0_DMA_OWN, desc + TX_REG_OFFSET_DESC0);
+        moxart_desc_write(txdes1, desc + TX_REG_OFFSET_DESC1);
+        wmb(); /* flush descriptor before transferring ownership */
+        moxart_desc_write(TX_DESC0_DMA_OWN, desc + TX_REG_OFFSET_DESC0);
 
         /* start to send packet */
         writel(0xffffffff, priv->base + REG_TX_POLL_DEMAND);