| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | From 59876225748221d7ebbdb9c892a2086420ddd80d Mon Sep 17 00:00:00 2001 |
| 2 | From: Sean Nyekjaer <sean@geanix.com> |
| 3 | Date: Thu, 14 Nov 2019 19:56:28 +0800 |
| 4 | Subject: [PATCH] can: flexcan: fix deadlock when using self wakeup |
| 5 | |
| 6 | When suspending, when there is still can traffic on the interfaces the |
| 7 | flexcan immediately wakes the platform again. As it should :-). But it |
| 8 | throws this error msg: |
| 9 | [ 3169.378661] PM: noirq suspend of devices failed |
| 10 | |
| 11 | On the way down to suspend the interface that throws the error message does |
| 12 | call flexcan_suspend but fails to call flexcan_noirq_suspend. That means the |
| 13 | flexcan_enter_stop_mode is called, but on the way out of suspend the driver |
| 14 | only calls flexcan_resume and skips flexcan_noirq_resume, thus it doesn't call |
| 15 | flexcan_exit_stop_mode. This leaves the flexcan in stop mode, and with the |
| 16 | current driver it can't recover from this even with a soft reboot, it requires |
| 17 | a hard reboot. |
| 18 | |
| 19 | This patch can fix deadlock when using self wakeup, it happenes to be |
| 20 | able to fix another issue that frames out-of-order in first IRQ handler |
| 21 | run after wakeup. |
| 22 | |
| 23 | In wakeup case, after system resume, frames received out-of-order,the |
| 24 | problem is wakeup latency from frame reception to IRQ handler is much |
| 25 | bigger than the counter overflow. This means it's impossible to sort the |
| 26 | CAN frames by timestamp. The reason is that controller exits stop mode |
| 27 | during noirq resume, then it can receive the frame immediately. If |
| 28 | noirq reusme stage consumes much time, it will extend interrupt response |
| 29 | time. |
| 30 | |
| 31 | Fixes: de3578c198c6 ("can: flexcan: add self wakeup support") |
| 32 | Signed-off-by: Sean Nyekjaer <sean@geanix.com> |
| 33 | Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com> |
| 34 | --- |
| 35 | drivers/net/can/flexcan.c | 9 +++++++-- |
| 36 | 1 file changed, 7 insertions(+), 2 deletions(-) |
| 37 | |
| 38 | --- a/drivers/net/can/flexcan.c |
| 39 | +++ b/drivers/net/can/flexcan.c |
| 40 | @@ -137,8 +137,7 @@ |
| 41 | (FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE) |
| 42 | #define FLEXCAN_ESR_ALL_INT \ |
| 43 | (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \ |
| 44 | - FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT | \ |
| 45 | - FLEXCAN_ESR_WAK_INT) |
| 46 | + FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT) |
| 47 | |
| 48 | /* FLEXCAN Bit Timing register (CBT) bits */ |
| 49 | #define FLEXCAN_CBT_BTF BIT(31) |
| 50 | @@ -1062,6 +1061,12 @@ static irqreturn_t flexcan_irq(int irq, |
| 51 | |
| 52 | reg_esr = priv->read(®s->esr); |
| 53 | |
| 54 | + /* ACK wakeup interrupt */ |
| 55 | + if (reg_esr & FLEXCAN_ESR_WAK_INT) { |
| 56 | + handled = IRQ_HANDLED; |
| 57 | + priv->write(reg_esr & FLEXCAN_ESR_WAK_INT, ®s->esr); |
| 58 | + } |
| 59 | + |
| 60 | /* ACK all bus error and state change IRQ sources */ |
| 61 | if (reg_esr & FLEXCAN_ESR_ALL_INT) { |
| 62 | handled = IRQ_HANDLED; |