Skip to content

Commit

Permalink
net: fec: Use a spinlock to guard fep->ptp_clk_on
Browse files Browse the repository at this point in the history 
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: 6a4d723 ("net: fec: ptp: avoid register access when ipg clock is disabled")
Fixes: f799592 ("fec: Restart PPS after link state change")
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/all/20220827160922.642zlcd5foopozru@pengutronix.de/
Signed-off-by: Csókás 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: Jakub Kicinski <kuba@kernel.org>
  • Loading branch information
Csókás Bence authored and Jakub Kicinski committed Sep 3, 2022
1 parent 7d650df commit b353b24
Show file tree
Hide file tree
Showing 3 changed files with 19 additions and 27 deletions.
1 change: 0 additions & 1 deletion drivers/net/ethernet/freescale/fec.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand Down
17 changes: 9 additions & 8 deletions drivers/net/ethernet/freescale/fec_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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) {
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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);
Expand Down Expand Up @@ -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");
Expand Down
28 changes: 10 additions & 18 deletions drivers/net/ethernet/freescale/fec_ptp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand All @@ -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;
}

Expand All @@ -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;
}

Expand Down Expand Up @@ -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);
spin_lock_irqsave(&fep->tmreg_lock, flags);
if (fep->ptp_clk_on) {
spin_lock_irqsave(&fep->tmreg_lock, flags);
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);
}
Expand Down Expand Up @@ -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);
Expand Down

0 comments on commit b353b24

Please sign in to comment.