On Mon, Oct 10, 2011 at 01:42:23PM -0300, Thadeu Lima de Souza Cascardo wrote:
> The doorbell register was being unconditionally swapped. In x86, that
> meant it was being swapped to BE and written to the descriptor and to
> memory, depending on the case of blue frame support or writing to
> doorbell register. On PPC, this meant it was being swapped to LE and
> then swapped back to BE while writing to the register. But in the blue
> frame case, it was being written as LE to the descriptor.
>
> The fix is not to swap doorbell unconditionally, write it to the
> register as BE and convert it to BE when writing it to the descriptor.
>
> Signed-off-by: Thadeu Lima de Souza Cascardo <casca...@linux.vnet.ibm.com>
> Reported-by: Richard Hendrickson <richh...@us.ibm.com>
> Cc: Eli Cohen <e...@dev.mellanox.co.il>
> Cc: Yevgeny Petrilin <yevge...@mellanox.co.il>
> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> ---
So I tested this patch and it works for me. Thanks Ben and Eli for
finding out the problem with doorbell in the descriptor.
Regards,
Cascardo.
> drivers/net/mlx4/en_tx.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/mlx4/en_tx.c b/drivers/net/mlx4/en_tx.c
> index 6e03de0..f76ab6b 100644
> --- a/drivers/net/mlx4/en_tx.c
> +++ b/drivers/net/mlx4/en_tx.c
> @@ -172,7 +172,7 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
> memset(ring->buf, 0, ring->buf_size);
>
> ring->qp_state = MLX4_QP_STATE_RST;
> - ring->doorbell_qpn = swab32(ring->qp.qpn << 8);
> + ring->doorbell_qpn = ring->qp.qpn << 8;
>
> mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn,
> ring->cqn, &ring->context);
> @@ -791,7 +791,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct
> net_device *dev)
> skb_orphan(skb);
>
> if (ring->bf_enabled && desc_size <= MAX_BF && !bounce && !vlan_tag) {
> - *(u32 *) (&tx_desc->ctrl.vlan_tag) |= ring->doorbell_qpn;
> + *(__be32 *) (&tx_desc->ctrl.vlan_tag) |=
> cpu_to_be32(ring->doorbell_qpn);
> op_own |= htonl((bf_index & 0xffff) << 8);
> /* Ensure new descirptor hits memory
> * before setting ownership of this descriptor to HW */
> @@ -812,7 +812,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct
> net_device *dev)
> wmb();
> tx_desc->ctrl.owner_opcode = op_own;
> wmb();
> - writel(ring->doorbell_qpn, ring->bf.uar->map +
> MLX4_SEND_DOORBELL);
> + iowrite32be(ring->doorbell_qpn, ring->bf.uar->map +
> MLX4_SEND_DOORBELL);
> }
>
> /* Poll CQ here */
> --
> 1.7.4.4
>
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