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From: Amir Vadai <amirv@mellanox•com>
To: Richard Cochran <richardcochran@gmail•com>
Cc: "David S. Miller" <davem@davemloft•net>, <netdev@vger•kernel.org>,
	Or Gerlitz <ogerlitz@mellanox•com>,
	Eugenia Emantayev <eugenia@mellanox•com>
Subject: Re: [PATCH net-next V3 3/5] net/mlx4_en: Add HW timestamping (TS) support
Date: Sun, 28 Apr 2013 09:33:12 +0300	[thread overview]
Message-ID: <517CC2A8.5010303@mellanox.com> (raw)
In-Reply-To: <20130425192627.GA14429@netboy>

On 25/04/2013 22:26, Richard Cochran wrote:
> On Tue, Apr 23, 2013 at 07:06:49PM +0300, Amir Vadai wrote:
> 
>> +u64 mlx4_en_get_cqe_ts(struct mlx4_cqe *cqe)
>> +{
>> +	u64 hi, lo;
>> +	struct mlx4_ts_cqe *ts_cqe = (struct mlx4_ts_cqe *)cqe;
>> +
>> +	lo = (u64)be16_to_cpu(ts_cqe->timestamp_lo);
>> +	hi = ((u64)be32_to_cpu(ts_cqe->timestamp_hi) + !lo) << 16;
>                                                      ^^^^^
> That looks a bit strange. Can you explain?

We need to increment the high order 32bit by one when the low order
16bit value is zero, due to HW limitation.

> 
>> +
>> +	return hi | lo;
>> +}
> 
> Thanks,
> Richard
> 

Amir.

  reply	other threads:[~2013-04-28  6:33 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-23 16:06 [PATCH net-next V3 0/5] net/mlx4: HW timestamping support Amir Vadai
2013-04-23 16:06 ` [PATCH net-next V3 1/5] net/mlx4_core: Add timestamping device capability Amir Vadai
2013-04-23 16:06 ` [PATCH net-next V3 2/5] net/mlx4_core: Read HCA frequency and map internal clock Amir Vadai
2013-04-23 16:06 ` [PATCH net-next V3 3/5] net/mlx4_en: Add HW timestamping (TS) support Amir Vadai
2013-04-25 19:26   ` Richard Cochran
2013-04-28  6:33     ` Amir Vadai [this message]
2013-04-28  7:46       ` Richard Cochran
2013-04-28  8:00         ` Amir Vadai
2013-04-23 16:06 ` [PATCH net-next V3 4/5] net/mlx4_en: Support software timestamping Amir Vadai
2013-04-23 16:06 ` [PATCH net-next V3 5/5] net/mlx4_en: Add a service task Amir Vadai
2013-04-26  0:13   ` Eric Dumazet
2013-04-26  2:24     ` Or Gerlitz
2013-04-26  2:39       ` Eric Dumazet

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