Re: [PATCH 3/3] net: hisilicon: new hip04 ethernet driver

2014-03-24 10:23 GMT-07:00 Arnd Bergmann [off-list ref]:

On Monday 24 March 2014 09:32:17 Florian Fainelli wrote:

quoted

quoted

+       priv->tx_skb[tx_head] = skb;
+       priv->tx_phys[tx_head] = phys;
+       desc->send_addr = cpu_to_be32(phys);
+       desc->send_size = cpu_to_be16(skb->len);
+       desc->cfg = cpu_to_be32(DESC_DEF_CFG);
+       phys = priv->tx_desc_dma + tx_head * sizeof(struct tx_desc);
+       desc->wb_addr = cpu_to_be32(phys);

Don't we need a barrier here to ensure that all stores are completed
before we hand this descriptor address to hip40_set_xmit_desc() which
should make DMA start processing it?

I would think the writel() in set_xmit_desc() implies the barrier.

Right, which means that this should be properly documented to make
sure that this simplification is well understood and produces the
expected result.
-- 
Florian