Commit b353b241 authored by Csókás Bence's avatar Csókás Bence Committed by Jakub Kicinski
Browse files

net: fec: Use a spinlock to guard `fep->ptp_clk_on` 



Mutexes cannot be taken in a non-preemptible context,
causing a panic in `fec_ptp_save_state()`. Replacing
`ptp_clk_mutex` by `tmreg_lock` fixes this.

Fixes: 6a4d7234 ("net: fec: ptp: avoid register access when ipg clock is disabled")
Fixes: f7995922 ("fec: Restart PPS after link state change")
Reported-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/all/20220827160922.642zlcd5foopozru@pengutronix.de/


Signed-off-by: default avatarCsókás Bence <csokas.bence@prolan.hu>
Tested-by: Francesco Dolcini <francesco.dolcini@toradex.com> # Toradex Apalis iMX6
Link: https://lore.kernel.org/r/20220901140402.64804-1-csokas.bence@prolan.hu


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 7d650df9

drivers/net/ethernet/freescale/fec.h

+0 −1
Original line number Diff line number Diff line
@@ -561,7 +561,6 @@ 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;

drivers/net/ethernet/freescale/fec_main.c

+9 −8
Original line number Diff line number Diff line
@@ -2029,6 +2029,7 @@ 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) {
@@ -2037,15 +2038,15 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) 
			return ret;



		if (fep->clk_ptp) {

			mutex_lock(&fep->ptp_clk_mutex);

			spin_lock_irqsave(&fep->tmreg_lock, flags);

			ret = clk_prepare_enable(fep->clk_ptp);

			if (ret) {

				mutex_unlock(&fep->ptp_clk_mutex);

				spin_unlock_irqrestore(&fep->tmreg_lock, flags);

				goto failed_clk_ptp;

			} else {

				fep->ptp_clk_on = true;

			}

			mutex_unlock(&fep->ptp_clk_mutex);

			spin_unlock_irqrestore(&fep->tmreg_lock, flags);

		}



		ret = clk_prepare_enable(fep->clk_ref);
@@ -2060,10 +2061,10 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) 
	} else {

		clk_disable_unprepare(fep->clk_enet_out);

		if (fep->clk_ptp) {

			mutex_lock(&fep->ptp_clk_mutex);

			spin_lock_irqsave(&fep->tmreg_lock, flags);

			clk_disable_unprepare(fep->clk_ptp);

			fep->ptp_clk_on = false;

			mutex_unlock(&fep->ptp_clk_mutex);

			spin_unlock_irqrestore(&fep->tmreg_lock, flags);

		}

		clk_disable_unprepare(fep->clk_ref);

		clk_disable_unprepare(fep->clk_2x_txclk);
@@ -2076,10 +2077,10 @@ 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) {

		mutex_lock(&fep->ptp_clk_mutex);

		spin_lock_irqsave(&fep->tmreg_lock, flags);

		clk_disable_unprepare(fep->clk_ptp);

		fep->ptp_clk_on = false;

		mutex_unlock(&fep->ptp_clk_mutex);

		spin_unlock_irqrestore(&fep->tmreg_lock, flags);

	}

failed_clk_ptp:

	clk_disable_unprepare(fep->clk_enet_out);
@@ -3914,7 +3915,7 @@ fec_probe(struct platform_device *pdev) 
	}



	fep->ptp_clk_on = false;

	mutex_init(&fep->ptp_clk_mutex);

	spin_lock_init(&fep->tmreg_lock);



	/* clk_ref is optional, depends on board */

	fep->clk_ref = devm_clk_get_optional(&pdev->dev, "enet_clk_ref");

drivers/net/ethernet/freescale/fec_ptp.c

+10 −18
Original line number Diff line number Diff line
@@ -365,21 +365,19 @@ static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta) 
 */

static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)

{

	struct fec_enet_private *adapter =

	struct fec_enet_private *fep =

	    container_of(ptp, struct fec_enet_private, ptp_caps);

	u64 ns;

	unsigned long flags;



	mutex_lock(&adapter->ptp_clk_mutex);

	spin_lock_irqsave(&fep->tmreg_lock, flags);

	/* Check the ptp clock */

	if (!adapter->ptp_clk_on) {

		mutex_unlock(&adapter->ptp_clk_mutex);

	if (!fep->ptp_clk_on) {

		spin_unlock_irqrestore(&fep->tmreg_lock, flags);

		return -EINVAL;

	}

	spin_lock_irqsave(&adapter->tmreg_lock, flags);

	ns = timecounter_read(&adapter->tc);

	spin_unlock_irqrestore(&adapter->tmreg_lock, flags);

	mutex_unlock(&adapter->ptp_clk_mutex);

	ns = timecounter_read(&fep->tc);

	spin_unlock_irqrestore(&fep->tmreg_lock, flags);



	*ts = ns_to_timespec64(ns);
@@ -404,10 +402,10 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp, 
	unsigned long flags;

	u32 counter;



	mutex_lock(&fep->ptp_clk_mutex);

	spin_lock_irqsave(&fep->tmreg_lock, flags);

	/* Check the ptp clock */

	if (!fep->ptp_clk_on) {

		mutex_unlock(&fep->ptp_clk_mutex);

		spin_unlock_irqrestore(&fep->tmreg_lock, flags);

		return -EINVAL;

	}
@@ -417,11 +415,9 @@ 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;

}
@@ -518,13 +514,11 @@ 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;



	mutex_lock(&fep->ptp_clk_mutex);

	if (fep->ptp_clk_on) {

	spin_lock_irqsave(&fep->tmreg_lock, flags);

	if (fep->ptp_clk_on) {

		timecounter_read(&fep->tc);

		spin_unlock_irqrestore(&fep->tmreg_lock, flags);

	}

	mutex_unlock(&fep->ptp_clk_mutex);

	spin_unlock_irqrestore(&fep->tmreg_lock, flags);



	schedule_delayed_work(&fep->time_keep, HZ);

}
@@ -599,8 +593,6 @@ 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);