[PATCH v8 4/4] drivers: net: Add APM X-Gene SoC ethernet driver support.

On Tue, Jun 24, 2014 at 10:34 PM, David Miller [off-list ref] wrote:

From: Iyappan Subramanian <redacted>
Date: Fri, 20 Jun 2014 16:18:16 -0700

quoted

This patch adds network driver for APM X-Gene SoC ethernet.

Signed-off-by: Iyappan Subramanian <redacted>
Signed-off-by: Ravi Patel <redacted>
Signed-off-by: Keyur Chudgar <redacted>

I really don't like how you handle the hardware descriptors in this
driver.

You copy back and forth between a software format and the hardware
format.  That's extremely wasteful and will hurt performance.

Just use the raw format throughout, you can extract the fields when
you need them.

I agree and I will fix this and resubmit the patches.

You also make two passes when building a hardware descriptor:

1) write the values
2) endian swap

This means you make three memory accesses on every 64-bit word
in every descriptor you setup, this is really inefficient.

You should just byte swap them in-situ as you build the raw
descriptors.