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Date: Mon, 12 Sep 2022 07:31:04 +0000
From: Bence Csókás <bence98@....bme.hu>
To: <netdev@...r.kernel.org>
CC: Richard Cochran <richardcochran@...il.com>,
"David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Francesco Dolcini <francesco.dolcini@...adex.com>,
Andrew Lunn <andrew@...n.ch>,
Guenter Roeck <linux@...ck-us.net>, <kernel@...gutronix.de>,
Marc Kleine-Budde <mkl@...gutronix.de>,
Csókás Bence <csokas.bence@...lan.hu>
Subject: [PATCH 1/2] Revert "net: fec: Use a spinlock to guard `fep->ptp_clk_on`"
From: Csókás Bence <csokas.bence@...lan.hu>
`clk_prepare_enable()` gets called in atomic context (holding a spinlock),
which may sleep, causing a BUG on certain platforms.
This reverts commit b353b241f1eb9b6265358ffbe2632fdcb563354f.
Reported-by: Marc Kleine-Budde <mkl@...gutronix.de>
Link: https://lore.kernel.org/all/20220907143915.5w65kainpykfobte@pengutronix.de/
Signed-off-by: Csókás Bence <csokas.bence@...lan.hu>
---
drivers/net/ethernet/freescale/fec.h | 1 +
drivers/net/ethernet/freescale/fec_main.c | 17 ++++++++---------
drivers/net/ethernet/freescale/fec_ptp.c | 20 ++++++++++++++------
3 files changed, 23 insertions(+), 15 deletions(-)
diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 99cfe6ab41fc..b7b8c4ddac5b 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -563,6 +563,7 @@ struct fec_enet_private {
struct clk *clk_2x_txclk;
bool ptp_clk_on;
+ struct mutex ptp_clk_mutex;
unsigned int num_tx_queues;
unsigned int num_rx_queues;
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index ad01db156972..f5ba133468f5 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -2059,7 +2059,6 @@ static void fec_enet_phy_reset_after_clk_enable(struct net_device *ndev)
static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
{
struct fec_enet_private *fep = netdev_priv(ndev);
- unsigned long flags;
int ret;
if (enable) {
@@ -2068,15 +2067,15 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
return ret;
if (fep->clk_ptp) {
- spin_lock_irqsave(&fep->tmreg_lock, flags);
+ mutex_lock(&fep->ptp_clk_mutex);
ret = clk_prepare_enable(fep->clk_ptp);
if (ret) {
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
goto failed_clk_ptp;
} else {
fep->ptp_clk_on = true;
}
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
}
ret = clk_prepare_enable(fep->clk_ref);
@@ -2091,10 +2090,10 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
} else {
clk_disable_unprepare(fep->clk_enet_out);
if (fep->clk_ptp) {
- spin_lock_irqsave(&fep->tmreg_lock, flags);
+ mutex_lock(&fep->ptp_clk_mutex);
clk_disable_unprepare(fep->clk_ptp);
fep->ptp_clk_on = false;
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
}
clk_disable_unprepare(fep->clk_ref);
clk_disable_unprepare(fep->clk_2x_txclk);
@@ -2107,10 +2106,10 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable)
clk_disable_unprepare(fep->clk_ref);
failed_clk_ref:
if (fep->clk_ptp) {
- spin_lock_irqsave(&fep->tmreg_lock, flags);
+ mutex_lock(&fep->ptp_clk_mutex);
clk_disable_unprepare(fep->clk_ptp);
fep->ptp_clk_on = false;
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
}
failed_clk_ptp:
clk_disable_unprepare(fep->clk_enet_out);
@@ -3949,7 +3948,7 @@ fec_probe(struct platform_device *pdev)
}
fep->ptp_clk_on = false;
- spin_lock_init(&fep->tmreg_lock);
+ mutex_init(&fep->ptp_clk_mutex);
/* clk_ref is optional, depends on board */
fep->clk_ref = devm_clk_get_optional(&pdev->dev, "enet_clk_ref");
diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c
index 7be97ab84e50..ae2c786dc130 100644
--- a/drivers/net/ethernet/freescale/fec_ptp.c
+++ b/drivers/net/ethernet/freescale/fec_ptp.c
@@ -370,14 +370,16 @@ static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
u64 ns;
unsigned long flags;
- spin_lock_irqsave(&fep->tmreg_lock, flags);
+ mutex_lock(&fep->ptp_clk_mutex);
/* Check the ptp clock */
if (!fep->ptp_clk_on) {
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
return -EINVAL;
}
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
ns = timecounter_read(&fep->tc);
spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
*ts = ns_to_timespec64(ns);
@@ -402,10 +404,10 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp,
unsigned long flags;
u32 counter;
- spin_lock_irqsave(&fep->tmreg_lock, flags);
+ mutex_lock(&fep->ptp_clk_mutex);
/* Check the ptp clock */
if (!fep->ptp_clk_on) {
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
return -EINVAL;
}
@@ -415,9 +417,11 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp,
*/
counter = ns & fep->cc.mask;
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
writel(counter, fep->hwp + FEC_ATIME);
timecounter_init(&fep->tc, &fep->cc, ns);
spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
return 0;
}
@@ -514,11 +518,13 @@ static void fec_time_keep(struct work_struct *work)
struct fec_enet_private *fep = container_of(dwork, struct fec_enet_private, time_keep);
unsigned long flags;
- spin_lock_irqsave(&fep->tmreg_lock, flags);
+ mutex_lock(&fep->ptp_clk_mutex);
if (fep->ptp_clk_on) {
+ spin_lock_irqsave(&fep->tmreg_lock, flags);
timecounter_read(&fep->tc);
+ spin_unlock_irqrestore(&fep->tmreg_lock, flags);
}
- spin_unlock_irqrestore(&fep->tmreg_lock, flags);
+ mutex_unlock(&fep->ptp_clk_mutex);
schedule_delayed_work(&fep->time_keep, HZ);
}
@@ -593,6 +599,8 @@ void fec_ptp_init(struct platform_device *pdev, int irq_idx)
}
fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed;
+ spin_lock_init(&fep->tmreg_lock);
+
fec_ptp_start_cyclecounter(ndev);
INIT_DELAYED_WORK(&fep->time_keep, fec_time_keep);
--
2.37.3
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