linux-kernel - [PATCH net-next v3 2/4] net: ti: icss-iep: Remove spinlock-based synchronization

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Message-Id: <20240607-iep-v3-2-4824224105bc@siemens.com>
Date: Fri, 07 Jun 2024 14:02:43 +0100
From: Diogo Ivo <diogo.ivo@...mens.com>
To: MD Danish Anwar <danishanwar@...com>, Roger Quadros <rogerq@...nel.org>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Richard Cochran <richardcochran@...il.com>, Nishanth Menon <nm@...com>, 
 Vignesh Raghavendra <vigneshr@...com>, Tero Kristo <kristo@...nel.org>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Jan Kiszka <jan.kiszka@...mens.com>, 
 Jacob Keller <jacob.e.keller@...el.com>, Simon Horman <horms@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, netdev@...r.kernel.org, 
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, 
 Diogo Ivo <diogo.ivo@...mens.com>
Subject: [PATCH net-next v3 2/4] net: ti: icss-iep: Remove spinlock-based
 synchronization

As all sources of concurrency in hardware register access occur in
non-interrupt context eliminate spinlock-based synchronization and
rely on the mutex-based synchronization that is already present.

Signed-off-by: Diogo Ivo <diogo.ivo@...mens.com>
---
 drivers/net/ethernet/ti/icssg/icss_iep.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/drivers/net/ethernet/ti/icssg/icss_iep.c b/drivers/net/ethernet/ti/icssg/icss_iep.c
index 3025e9c18970..1d6ccdf2583f 100644
--- a/drivers/net/ethernet/ti/icssg/icss_iep.c
+++ b/drivers/net/ethernet/ti/icssg/icss_iep.c
@@ -110,7 +110,6 @@ struct icss_iep {
 	struct ptp_clock_info ptp_info;
 	struct ptp_clock *ptp_clock;
 	struct mutex ptp_clk_mutex;	/* PHC access serializer */
-	spinlock_t irq_lock; /* CMP IRQ vs icss_iep_ptp_enable access */
 	u32 def_inc;
 	s16 slow_cmp_inc;
 	u32 slow_cmp_count;
@@ -199,7 +198,6 @@ static void icss_iep_settime(struct icss_iep *iep, u64 ns)
 		return;
 	}

-	spin_lock_irqsave(&iep->irq_lock, flags);
 	if (iep->pps_enabled || iep->perout_enabled)
 		writel(0, iep->base + iep->plat_data->reg_offs[ICSS_IEP_SYNC_CTRL_REG]);

@@ -210,7 +208,6 @@ static void icss_iep_settime(struct icss_iep *iep, u64 ns)
 		writel(IEP_SYNC_CTRL_SYNC_N_EN(0) | IEP_SYNC_CTRL_SYNC_EN,
 		       iep->base + iep->plat_data->reg_offs[ICSS_IEP_SYNC_CTRL_REG]);
 	}
-	spin_unlock_irqrestore(&iep->irq_lock, flags);
 }

 /**
@@ -559,11 +556,9 @@ static int icss_iep_perout_enable(struct icss_iep *iep,
 	if (iep->perout_enabled == !!on)
 		goto exit;

-	spin_lock_irqsave(&iep->irq_lock, flags);
 	ret = icss_iep_perout_enable_hw(iep, req, on);
 	if (!ret)
 		iep->perout_enabled = !!on;
-	spin_unlock_irqrestore(&iep->irq_lock, flags);

 exit:
 	mutex_unlock(&iep->ptp_clk_mutex);
@@ -589,8 +584,6 @@ static int icss_iep_pps_enable(struct icss_iep *iep, int on)
 	if (iep->pps_enabled == !!on)
 		goto exit;

-	spin_lock_irqsave(&iep->irq_lock, flags);
-
 	rq.perout.index = 0;
 	if (on) {
 		ns = icss_iep_gettime(iep, NULL);
@@ -607,8 +600,6 @@ static int icss_iep_pps_enable(struct icss_iep *iep, int on)
 	if (!ret)
 		iep->pps_enabled = !!on;

-	spin_unlock_irqrestore(&iep->irq_lock, flags);
-
 exit:
 	mutex_unlock(&iep->ptp_clk_mutex);

@@ -853,7 +844,6 @@ static int icss_iep_probe(struct platform_device *pdev)

 	iep->ptp_info = icss_iep_ptp_info;
 	mutex_init(&iep->ptp_clk_mutex);
-	spin_lock_init(&iep->irq_lock);
 	dev_set_drvdata(dev, iep);
 	icss_iep_disable(iep);

-- 
2.45.2