[PATCH 3/3] net: hisilicon: add hix5hd2 mac driver
Arnd Bergmann
arnd at arndb.de
Mon May 26 07:51:15 PDT 2014
On Monday 19 May 2014, Zhangfei Gao wrote:
I only noticed one real issue with the driver:
> +struct hix5hd2_desc {
> + __le32 buff_addr;
> + __le32 buff_len:11;
> + __le32 reserve2:5;
> + __le32 data_len:11;
> + __le32 reserve1:2;
> + __le32 fl:2;
> + __le32 descvid:1;
> +} __aligned(32);
> +
You should generall not use bitfields in hardware data structures, as that is
not endian safe and will prevent running a big-endian kernel on this machine.
Better convert this to a set of __le32 fields and explicit shifts and masks.
Two smaller things you should think about, I'm not entirely sure about these:
> +static int hix5hd2_rx(struct net_device *dev, int limit)
> +{
> + struct hix5hd2_priv *priv = netdev_priv(dev);
> + struct sk_buff *skb;
> + struct hix5hd2_desc *desc;
> + dma_addr_t dma_addr;
> + u32 start, end, num, pos, i, len;
> +
> + /* software read pointer */
> + start = dma_cnt(readl_relaxed(priv->base + RX_BQ_RD_ADDR));
> + /* logic write pointer */
> + end = dma_cnt(readl_relaxed(priv->base + RX_BQ_WR_ADDR));
I think one of these needs to be readl() instead of readl_relaxed(),
to ensure the data is correctly ordered with regard to the pointer
access.
> + if (pos != start)
> + writel(dma_byte(pos), priv->base + TX_RQ_RD_ADDR);
While this looks like it could be writel_relaxed().
Arnd
More information about the linux-arm-kernel
mailing list