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Commit 5f186c25 authored by Joakim Zhang's avatar Joakim Zhang Committed by Marc Kleine-Budde
Browse files

can: flexcan: fix stop mode acknowledgment 



To enter stop mode, the CPU should manually assert a global Stop Mode
request and check the acknowledgment asserted by FlexCAN. The CPU must
only consider the FlexCAN in stop mode when both request and
acknowledgment conditions are satisfied.

Fixes: de3578c1 ("can: flexcan: add self wakeup support")
Reported-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: default avatarJoakim Zhang <qiangqing.zhang@nxp.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v5.0
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent e9f2a856

drivers/net/can/flexcan.c

+27 −4
Original line number Diff line number Diff line
@@ -400,9 +400,10 @@ static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable) 
	priv->write(reg_mcr, &regs->mcr);

}



static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv)

static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)

{

	struct flexcan_regs __iomem *regs = priv->regs;

	unsigned int ackval;

	u32 reg_mcr;



	reg_mcr = priv->read(&regs->mcr);
@@ -412,20 +413,37 @@ static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv) 
	/* enable stop request */

	regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,

			   1 << priv->stm.req_bit, 1 << priv->stm.req_bit);



	/* get stop acknowledgment */

	if (regmap_read_poll_timeout(priv->stm.gpr, priv->stm.ack_gpr,

				     ackval, ackval & (1 << priv->stm.ack_bit),

				     0, FLEXCAN_TIMEOUT_US))

		return -ETIMEDOUT;



	return 0;

}



static inline void flexcan_exit_stop_mode(struct flexcan_priv *priv)

static inline int flexcan_exit_stop_mode(struct flexcan_priv *priv)

{

	struct flexcan_regs __iomem *regs = priv->regs;

	unsigned int ackval;

	u32 reg_mcr;



	/* remove stop request */

	regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,

			   1 << priv->stm.req_bit, 0);



	/* get stop acknowledgment */

	if (regmap_read_poll_timeout(priv->stm.gpr, priv->stm.ack_gpr,

				     ackval, !(ackval & (1 << priv->stm.ack_bit)),

				     0, FLEXCAN_TIMEOUT_US))

		return -ETIMEDOUT;



	reg_mcr = priv->read(&regs->mcr);

	reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;

	priv->write(reg_mcr, &regs->mcr);



	return 0;

}



static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv)
@@ -1614,7 +1632,9 @@ static int __maybe_unused flexcan_suspend(struct device *device) 
		 */

		if (device_may_wakeup(device)) {

			enable_irq_wake(dev->irq);

			flexcan_enter_stop_mode(priv);

			err = flexcan_enter_stop_mode(priv);

			if (err)

				return err;

		} else {

			err = flexcan_chip_disable(priv);

			if (err)
@@ -1664,10 +1684,13 @@ static int __maybe_unused flexcan_noirq_resume(struct device *device) 
{

	struct net_device *dev = dev_get_drvdata(device);

	struct flexcan_priv *priv = netdev_priv(dev);

	int err;



	if (netif_running(dev) && device_may_wakeup(device)) {

		flexcan_enable_wakeup_irq(priv, false);

		flexcan_exit_stop_mode(priv);

		err = flexcan_exit_stop_mode(priv);

		if (err)

			return err;

	}



	return 0;