From 59a557be385b66c1da20e9cfc6ff6c2e676c6804 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 28 Jan 2016 17:54:33 +0100 Subject: [PATCH] net: moxart: use correct accessors for DMA memory The moxart ethernet driver confuses coherent DMA buffers with MMIO registers. moxart_ether.c: In function 'moxart_mac_setup_desc_ring': moxart_ether.c:146:428: error: passing argument 1 of '__fswab32' makes integer from pointer without a cast [-Werror=int-conversion] moxart_ether.c:74:39: warning: incorrect type in argument 3 (different address spaces) moxart_ether.c:74:39: expected void *cpu_addr moxart_ether.c:74:39: got void [noderef] *tx_desc_base This leaves the basic logic alone and uses normal pointers for the virtual address of the descriptor. As we cannot use readl/writel to access them, we also introduce our own moxart_desc_read moxart_desc_write helpers that perform the same endianess swap as the original code, but without the address space conversion. The barriers are made explicit here where needed: Even in the worst-case scenario, we just have to use a rmb() after checking ownership so we don't read any input data before we are sure it is value, and we use wmb() before transferring ownership back to the device. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller --- drivers/net/ethernet/moxa/moxart_ether.c | 46 +++++++++++++++--------- drivers/net/ethernet/moxa/moxart_ether.h | 4 +-- 2 files changed, 32 insertions(+), 18 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); diff --git a/drivers/net/ethernet/moxa/moxart_ether.h b/drivers/net/ethernet/moxa/moxart_ether.h index 2be9280d608c..93a9563ac7c6 100644 --- a/drivers/net/ethernet/moxa/moxart_ether.h +++ b/drivers/net/ethernet/moxa/moxart_ether.h @@ -300,7 +300,7 @@ struct moxart_mac_priv_t { dma_addr_t rx_base; dma_addr_t rx_mapping[RX_DESC_NUM]; - void __iomem *rx_desc_base; + void *rx_desc_base; unsigned char *rx_buf_base; unsigned char *rx_buf[RX_DESC_NUM]; unsigned int rx_head; @@ -308,7 +308,7 @@ struct moxart_mac_priv_t { dma_addr_t tx_base; dma_addr_t tx_mapping[TX_DESC_NUM]; - void __iomem *tx_desc_base; + void *tx_desc_base; unsigned char *tx_buf_base; unsigned char *tx_buf[RX_DESC_NUM]; unsigned int tx_head; -- 2.20.1