Re: [net-next 09/14] ptp: mlx5: convert to .adjfine and adjust_by_scaled_ppm

From: Gal Pressman <gal@nvidia.com>
To: Jacob Keller <jacob.e.keller@intel.com>, netdev@vger.kernel.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Shyam Sundar S K <Shyam-sundar.S-k@amd.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Siva Reddy Kallam <siva.kallam@broadcom.com>,
	Prashant Sreedharan <prashant@broadcom.com>,
	Michael Chan <mchan@broadcom.com>,
	Yisen Zhuang <yisen.zhuang@huawei.com>,
	Salil Mehta <salil.mehta@huawei.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	Tariq Toukan <tariqt@nvidia.com>,
	Saeed Mahameed <saeedm@nvidia.com>,
	Leon Romanovsky <leon@kernel.org>,
	Bryan Whitehead <bryan.whitehead@microchip.com>,
	Sergey Shtylyov <s.shtylyov@omp.ru>,
	Giuseppe Cavallaro <peppe.cavallaro@st.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Richard Cochran <richardcochran@gmail.com>,
	Vivek Thampi <vithampi@vmware.com>,
	VMware PV-Drivers Reviewers <pv-drivers@vmware.com>,
	Jie Wang <wangjie125@huawei.com>,
	Guangbin Huang <huangguangbin2@huawei.com>,
	Eran Ben Elisha <eranbe@nvidia.com>, Aya Levin <ayal@nvidia.com>,
	Cai Huoqing <cai.huoqing@linux.dev>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Phil Edworthy <phil.edworthy@renesas.com>,
	Jiasheng Jiang <jiasheng@iscas.ac.cn>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Wan Jiabing <wanjiabing@vivo.com>, Lv Ruyi <lv.ruyi@zte.com.cn>,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [net-next 09/14] ptp: mlx5: convert to .adjfine and adjust_by_scaled_ppm
Date: Tue, 23 Aug 2022 18:30:39 +0300	[thread overview]
Message-ID: <ae6132bc-7b7c-8f31-7854-8e451f57cdc7@nvidia.com> (raw)
In-Reply-To: <20220818222742.1070935-10-jacob.e.keller@intel.com>

On 19/08/2022 01:27, Jacob Keller wrote:
> The mlx5 implementation of .adjfreq is implemented in terms of a
> straight forward "base * ppb / 1 billion" calculation.
>
> Convert this to the .adjfine interface and use adjust_by_scaled_ppm for the
> calculation  of the new mult value.
>
> Note that the mlx5_ptp_adjfreq_real_time function expects input in terms of
> ppb, so use the scaled_ppm_to_ppb to convert before passing to this
> function.
>
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Saeed Mahameed <saeedm@nvidia.com>
> Cc: Leon Romanovsky <leon@kernel.org>
> Cc: Aya Levin <ayal@nvidia.com>
> ---
>
> I do not have this hardware, and have only compile tested the change.
>
>  .../ethernet/mellanox/mlx5/core/lib/clock.c   | 22 +++++--------------
>  1 file changed, 6 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
> index 91e806c1aa21..34871ab659d9 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
> @@ -330,35 +330,25 @@ static int mlx5_ptp_adjfreq_real_time(struct mlx5_core_dev *mdev, s32 freq)
>  	return mlx5_set_mtutc(mdev, in, sizeof(in));
>  }
>  
> -static int mlx5_ptp_adjfreq(struct ptp_clock_info *ptp, s32 delta)
> +static int mlx5_ptp_adjfine(struct ptp_clock_info *ptp, long delta)

Small nit, please rename delta to scaled_ppm.
I'll try to get this tested in our regression soon.