63 lines
2.5 KiB
Diff
63 lines
2.5 KiB
Diff
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From 59876225748221d7ebbdb9c892a2086420ddd80d Mon Sep 17 00:00:00 2001
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From: Sean Nyekjaer <sean@geanix.com>
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Date: Thu, 14 Nov 2019 19:56:28 +0800
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Subject: [PATCH] can: flexcan: fix deadlock when using self wakeup
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When suspending, when there is still can traffic on the interfaces the
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flexcan immediately wakes the platform again. As it should :-). But it
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throws this error msg:
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[ 3169.378661] PM: noirq suspend of devices failed
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On the way down to suspend the interface that throws the error message does
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call flexcan_suspend but fails to call flexcan_noirq_suspend. That means the
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flexcan_enter_stop_mode is called, but on the way out of suspend the driver
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only calls flexcan_resume and skips flexcan_noirq_resume, thus it doesn't call
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flexcan_exit_stop_mode. This leaves the flexcan in stop mode, and with the
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current driver it can't recover from this even with a soft reboot, it requires
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a hard reboot.
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This patch can fix deadlock when using self wakeup, it happenes to be
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able to fix another issue that frames out-of-order in first IRQ handler
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run after wakeup.
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In wakeup case, after system resume, frames received out-of-order,the
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problem is wakeup latency from frame reception to IRQ handler is much
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bigger than the counter overflow. This means it's impossible to sort the
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CAN frames by timestamp. The reason is that controller exits stop mode
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during noirq resume, then it can receive the frame immediately. If
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noirq reusme stage consumes much time, it will extend interrupt response
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time.
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Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
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Signed-off-by: Sean Nyekjaer <sean@geanix.com>
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Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
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---
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drivers/net/can/flexcan.c | 9 +++++++--
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1 file changed, 7 insertions(+), 2 deletions(-)
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--- a/drivers/net/can/flexcan.c
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+++ b/drivers/net/can/flexcan.c
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@@ -137,8 +137,7 @@
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(FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE)
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#define FLEXCAN_ESR_ALL_INT \
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(FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
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- FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT | \
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- FLEXCAN_ESR_WAK_INT)
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+ FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
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/* FLEXCAN Bit Timing register (CBT) bits */
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#define FLEXCAN_CBT_BTF BIT(31)
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@@ -1055,6 +1054,12 @@ static irqreturn_t flexcan_irq(int irq,
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reg_esr = priv->read(®s->esr);
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+ /* ACK wakeup interrupt */
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+ if (reg_esr & FLEXCAN_ESR_WAK_INT) {
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+ handled = IRQ_HANDLED;
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+ priv->write(reg_esr & FLEXCAN_ESR_WAK_INT, ®s->esr);
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+ }
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+
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/* ACK all bus error and state change IRQ sources */
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if (reg_esr & FLEXCAN_ESR_ALL_INT) {
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handled = IRQ_HANDLED;
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