netdev - [net-next v2 4/9] ptp: mlx4: convert to .adjfine and adjust_by_scaled

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Message-Id: <20220930204851.1910059-5-jacob.e.keller@intel.com>
Date:   Fri, 30 Sep 2022 13:48:46 -0700
From:   Jacob Keller <jacob.e.keller@...el.com>
To:     netdev@...r.kernel.org
Cc:     Jacob Keller <jacob.e.keller@...el.com>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Siva Reddy Kallam <siva.kallam@...adcom.com>,
        Prashant Sreedharan <prashant@...adcom.com>,
        Michael Chan <mchan@...adcom.com>,
        Yisen Zhuang <yisen.zhuang@...wei.com>,
        Salil Mehta <salil.mehta@...wei.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        Tony Nguyen <anthony.l.nguyen@...el.com>,
        Tariq Toukan <tariqt@...dia.com>,
        Saeed Mahameed <saeedm@...dia.com>,
        Leon Romanovsky <leon@...nel.org>,
        Bryan Whitehead <bryan.whitehead@...rochip.com>,
        Sergey Shtylyov <s.shtylyov@....ru>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Richard Cochran <richardcochran@...il.com>,
        Vivek Thampi <vithampi@...are.com>,
        VMware PV-Drivers Reviewers <pv-drivers@...are.com>,
        Jie Wang <wangjie125@...wei.com>,
        Guangbin Huang <huangguangbin2@...wei.com>,
        Eran Ben Elisha <eranbe@...dia.com>,
        Aya Levin <ayal@...dia.com>,
        Cai Huoqing <cai.huoqing@...ux.dev>,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Phil Edworthy <phil.edworthy@...esas.com>,
        Jiasheng Jiang <jiasheng@...as.ac.cn>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Wan Jiabing <wanjiabing@...o.com>,
        Lv Ruyi <lv.ruyi@....com.cn>, Arnd Bergmann <arnd@...db.de>
Subject: [net-next v2 4/9] ptp: mlx4: convert to .adjfine and adjust_by_scaled_ppm

The mlx4 implementation of .adjfreq is implemented in terms of a
straight forward "base * ppb / 1 billion" calculation.

Convert this driver to .adjfine and use adjust_by_scaled_ppm to perform the
calculation.

Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Cc: Tariq Toukan <tariqt@...dia.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_clock.c | 29 +++++++------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 024788549c25..98b5ffb4d729 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -111,34 +111,27 @@ void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
 }
 
 /**
- * mlx4_en_phc_adjfreq - adjust the frequency of the hardware clock
+ * mlx4_en_phc_adjfine - adjust the frequency of the hardware clock
  * @ptp: ptp clock structure
- * @delta: Desired frequency change in parts per billion
+ * @scaled_ppm: Desired frequency change in scaled parts per million
  *
- * Adjust the frequency of the PHC cycle counter by the indicated delta from
- * the base frequency.
+ * Adjust the frequency of the PHC cycle counter by the indicated scaled_ppm
+ * from the base frequency.
+ *
+ * Scaled parts per million is ppm with a 16-bit binary fractional field.
  **/
-static int mlx4_en_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)
+static int mlx4_en_phc_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 {
-	u64 adj;
-	u32 diff, mult;
-	int neg_adj = 0;
+	u32 mult;
 	unsigned long flags;
 	struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
 						ptp_clock_info);
 
-	if (delta < 0) {
-		neg_adj = 1;
-		delta = -delta;
-	}
-	mult = mdev->nominal_c_mult;
-	adj = mult;
-	adj *= delta;
-	diff = div_u64(adj, 1000000000ULL);
+	mult = (u32)adjust_by_scaled_ppm(mdev->nominal_c_mult, scaled_ppm);
 
 	write_seqlock_irqsave(&mdev->clock_lock, flags);
 	timecounter_read(&mdev->clock);
-	mdev->cycles.mult = neg_adj ? mult - diff : mult + diff;
+	mdev->cycles.mult = mult;
 	write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 
 	return 0;
@@ -237,7 +230,7 @@ static const struct ptp_clock_info mlx4_en_ptp_clock_info = {
 	.n_per_out	= 0,
 	.n_pins		= 0,
 	.pps		= 0,
-	.adjfreq	= mlx4_en_phc_adjfreq,
+	.adjfine	= mlx4_en_phc_adjfine,
 	.adjtime	= mlx4_en_phc_adjtime,
 	.gettime64	= mlx4_en_phc_gettime,
 	.settime64	= mlx4_en_phc_settime,
-- 
2.37.1.394.gc50926e1f488