From: Anssi Hannula anssi.hannula@bitwise.fi
There are several issues with the suspend/resume handling code of the driver:
- The device is attached and detached in the runtime_suspend() and runtime_resume() callbacks if the interface is running. However, during xcan_chip_start() the interface is considered running, causing the resume handler to incorrectly call netif_start_queue() at the beginning of xcan_chip_start(), and on xcan_chip_start() error return the suspend handler detaches the device leaving the user unable to bring-up the device anymore.
- The device is not brought properly up on system resume. A reset is done and the code tries to determine the bus state after that. However, after reset the device is always in Configuration mode (down), so the state checking code does not make sense and communication will also not work.
- The suspend callback tries to set the device to sleep mode (low-power mode which monitors the bus and brings the device back to normal mode on activity), but then immediately disables the clocks (possibly before the device reaches the sleep mode), which does not make sense to me. If a clean shutdown is wanted before disabling clocks, we can just bring it down completely instead of only sleep mode.
Reorganize the PM code so that only the clock logic remains in the runtime PM callbacks and the system PM callbacks contain the device bring-up/down logic. This makes calling the runtime PM callbacks during e.g. xcan_chip_start() safe.
The system PM callbacks now simply call common code to start/stop the HW if the interface was running, replacing the broken code from before.
xcan_chip_stop() is updated to use the common reset code so that it will wait for the reset to complete. Reset also disables all interrupts so do not do that separately.
Also, the device_may_wakeup() checks are removed as the driver does not have wakeup support.
Tested on Zynq-7000 integrated CAN.
Signed-off-by: Anssi Hannula anssi.hannula@bitwise.fi Cc: Michal Simek michal.simek@xilinx.com Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- drivers/net/can/xilinx_can.c | 69 +++++++++++++++--------------------- 1 file changed, 28 insertions(+), 41 deletions(-)
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index cb80a9aa7281..5a24039733ef 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -984,13 +984,9 @@ static irqreturn_t xcan_interrupt(int irq, void *dev_id) static void xcan_chip_stop(struct net_device *ndev) { struct xcan_priv *priv = netdev_priv(ndev); - u32 ier;
/* Disable interrupts and leave the can in configuration mode */ - ier = priv->read_reg(priv, XCAN_IER_OFFSET); - ier &= ~XCAN_INTR_ALL; - priv->write_reg(priv, XCAN_IER_OFFSET, ier); - priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK); + set_reset_mode(ndev); priv->can.state = CAN_STATE_STOPPED; }
@@ -1123,10 +1119,15 @@ static const struct net_device_ops xcan_netdev_ops = { */ static int __maybe_unused xcan_suspend(struct device *dev) { - if (!device_may_wakeup(dev)) - return pm_runtime_force_suspend(dev); + struct net_device *ndev = dev_get_drvdata(dev);
- return 0; + if (netif_running(ndev)) { + netif_stop_queue(ndev); + netif_device_detach(ndev); + xcan_chip_stop(ndev); + } + + return pm_runtime_force_suspend(dev); }
/** @@ -1138,11 +1139,27 @@ static int __maybe_unused xcan_suspend(struct device *dev) */ static int __maybe_unused xcan_resume(struct device *dev) { - if (!device_may_wakeup(dev)) - return pm_runtime_force_resume(dev); + struct net_device *ndev = dev_get_drvdata(dev); + int ret;
- return 0; + ret = pm_runtime_force_resume(dev); + if (ret) { + dev_err(dev, "pm_runtime_force_resume failed on resume\n"); + return ret; + } + + if (netif_running(ndev)) { + ret = xcan_chip_start(ndev); + if (ret) { + dev_err(dev, "xcan_chip_start failed on resume\n"); + return ret; + }
+ netif_device_attach(ndev); + netif_start_queue(ndev); + } + + return 0; }
/** @@ -1157,14 +1174,6 @@ static int __maybe_unused xcan_runtime_suspend(struct device *dev) struct net_device *ndev = dev_get_drvdata(dev); struct xcan_priv *priv = netdev_priv(ndev);
- if (netif_running(ndev)) { - netif_stop_queue(ndev); - netif_device_detach(ndev); - } - - priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_SLEEP_MASK); - priv->can.state = CAN_STATE_SLEEPING; - clk_disable_unprepare(priv->bus_clk); clk_disable_unprepare(priv->can_clk);
@@ -1183,7 +1192,6 @@ static int __maybe_unused xcan_runtime_resume(struct device *dev) struct net_device *ndev = dev_get_drvdata(dev); struct xcan_priv *priv = netdev_priv(ndev); int ret; - u32 isr, status;
ret = clk_prepare_enable(priv->bus_clk); if (ret) { @@ -1197,27 +1205,6 @@ static int __maybe_unused xcan_runtime_resume(struct device *dev) return ret; }
- priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK); - isr = priv->read_reg(priv, XCAN_ISR_OFFSET); - status = priv->read_reg(priv, XCAN_SR_OFFSET); - - if (netif_running(ndev)) { - if (isr & XCAN_IXR_BSOFF_MASK) { - priv->can.state = CAN_STATE_BUS_OFF; - priv->write_reg(priv, XCAN_SRR_OFFSET, - XCAN_SRR_RESET_MASK); - } else if ((status & XCAN_SR_ESTAT_MASK) == - XCAN_SR_ESTAT_MASK) { - priv->can.state = CAN_STATE_ERROR_PASSIVE; - } else if (status & XCAN_SR_ERRWRN_MASK) { - priv->can.state = CAN_STATE_ERROR_WARNING; - } else { - priv->can.state = CAN_STATE_ERROR_ACTIVE; - } - netif_device_attach(ndev); - netif_start_queue(ndev); - } - return 0; }