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can: flexcan: fix stop mode acknowledgment

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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: de3578c198 ("can: flexcan: add self wakeup support")
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v5.0
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Joakim Zhang 2019-07-02 01:45:41 +00:00 • committed by Marc Kleine-Budde
parent e9f2a856e1
commit 5f186c257f
1 changed files with 27 additions and 4 deletions
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31
drivers/net/can/flexcan.c
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@ -400,9 +400,10 @@ static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
priv->write(reg_mcr, &regs->mcr); 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; struct flexcan_regs __iomem *regs = priv->regs;
unsigned int ackval;
u32 reg_mcr; u32 reg_mcr;
reg_mcr = priv->read(&regs->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 */ /* enable stop request */
regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr, regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
1 << priv->stm.req_bit, 1 << priv->stm.req_bit); 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; struct flexcan_regs __iomem *regs = priv->regs;
unsigned int ackval;
u32 reg_mcr; u32 reg_mcr;
/* remove stop request */ /* remove stop request */
regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr, regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
1 << priv->stm.req_bit, 0); 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 = priv->read(&regs->mcr);
reg_mcr &= ~FLEXCAN_MCR_SLF_WAK; reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;
priv->write(reg_mcr, &regs->mcr); priv->write(reg_mcr, &regs->mcr);
return 0;
} }
static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv) 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)) { if (device_may_wakeup(device)) {
enable_irq_wake(dev->irq); enable_irq_wake(dev->irq);
flexcan_enter_stop_mode(priv); err = flexcan_enter_stop_mode(priv);
if (err)
return err;
} else { } else {
err = flexcan_chip_disable(priv); err = flexcan_chip_disable(priv);
if (err) 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 net_device *dev = dev_get_drvdata(device);
struct flexcan_priv *priv = netdev_priv(dev); struct flexcan_priv *priv = netdev_priv(dev);
int err;
if (netif_running(dev) && device_may_wakeup(device)) { if (netif_running(dev) && device_may_wakeup(device)) {
flexcan_enable_wakeup_irq(priv, false); flexcan_enable_wakeup_irq(priv, false);
flexcan_exit_stop_mode(priv); err = flexcan_exit_stop_mode(priv);
if (err)
return err;
} }
return 0; return 0;