From 595e802e53f24642a145cf7f3e4ac9afab4c21ec Mon Sep 17 00:00:00 2001 From: Madalin Bucur Date: Thu, 28 Jun 2018 15:26:51 +0300 Subject: [PATCH] dpaa_eth: DPAA SGT needs to be 256B The DPAA HW requires that at least 256 bytes from the start of the first scatter-gather table entry are allocated and accessible. The hardware reads the maximum size the table can have in one access, thus requiring that the allocation and mapping to be done for the maximum size of 256B even if there is a smaller number of entries in the table. Signed-off-by: Madalin Bucur Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c index 5f4e1ffa7b95..ab02057ac730 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c @@ -125,6 +125,9 @@ MODULE_PARM_DESC(tx_timeout, "The Tx timeout in ms"); /* Default alignment for start of data in an Rx FD */ #define DPAA_FD_DATA_ALIGNMENT 16 +/* The DPAA requires 256 bytes reserved and mapped for the SGT */ +#define DPAA_SGT_SIZE 256 + /* Values for the L3R field of the FM Parse Results */ /* L3 Type field: First IP Present IPv4 */ @@ -1617,8 +1620,8 @@ static struct sk_buff *dpaa_cleanup_tx_fd(const struct dpaa_priv *priv, if (unlikely(qm_fd_get_format(fd) == qm_fd_sg)) { nr_frags = skb_shinfo(skb)->nr_frags; - dma_unmap_single(dev, addr, qm_fd_get_offset(fd) + - sizeof(struct qm_sg_entry) * (1 + nr_frags), + dma_unmap_single(dev, addr, + qm_fd_get_offset(fd) + DPAA_SGT_SIZE, dma_dir); /* The sgt buffer has been allocated with netdev_alloc_frag(), @@ -1903,8 +1906,7 @@ static int skb_to_sg_fd(struct dpaa_priv *priv, void *sgt_buf; /* get a page frag to store the SGTable */ - sz = SKB_DATA_ALIGN(priv->tx_headroom + - sizeof(struct qm_sg_entry) * (1 + nr_frags)); + sz = SKB_DATA_ALIGN(priv->tx_headroom + DPAA_SGT_SIZE); sgt_buf = netdev_alloc_frag(sz); if (unlikely(!sgt_buf)) { netdev_err(net_dev, "netdev_alloc_frag() failed for size %d\n", @@ -1972,9 +1974,8 @@ static int skb_to_sg_fd(struct dpaa_priv *priv, skbh = (struct sk_buff **)buffer_start; *skbh = skb; - addr = dma_map_single(dev, buffer_start, priv->tx_headroom + - sizeof(struct qm_sg_entry) * (1 + nr_frags), - dma_dir); + addr = dma_map_single(dev, buffer_start, + priv->tx_headroom + DPAA_SGT_SIZE, dma_dir); if (unlikely(dma_mapping_error(dev, addr))) { dev_err(dev, "DMA mapping failed"); err = -EINVAL; -- 2.30.2