[PATCH] mailbox: mtk-cmdq: Fix sleeping function called from invalid context

[Jason-JH.Lin]

When we run kernel with lockdebug option, we will get the BUG below:
[  106.692124] BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1164
[  106.692190] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 3616, name: kworker/u17:3
[  106.692226] preempt_count: 1, expected: 0
[  106.692254] RCU nest depth: 0, expected: 0
[  106.692282] INFO: lockdep is turned off.
[  106.692306] irq event stamp: 0
[  106.692331] hardirqs last  enabled at (0): [<0000000000000000>] 0x0
[  106.692376] hardirqs last disabled at (0): [<ffffffee15d37fa0>] copy_process+0xc90/0x2ac0
[  106.692429] softirqs last  enabled at (0): [<ffffffee15d37fc4>] copy_process+0xcb4/0x2ac0
[  106.692473] softirqs last disabled at (0): [<0000000000000000>] 0x0
[  106.692513] CPU: 1 PID: 3616 Comm: kworker/u17:3 Not tainted 6.1.87-lockdep-14133-g26e933aca785 #1 6839942e1cf34914b0a366137843dd2366f52aa9
[  106.692556] Hardware name: Google Ciri sku0/unprovisioned board (DT)
[  106.692586] Workqueue: imgsys_runner imgsys_runner_func
[  106.692638] Call trace:
[  106.692662]  dump_backtrace+0x100/0x120
[  106.692702]  show_stack+0x20/0x2c
[  106.692737]  dump_stack_lvl+0x84/0xb4
[  106.692775]  dump_stack+0x18/0x48
[  106.692809]  __might_resched+0x354/0x4c0
[  106.692847]  __might_sleep+0x98/0xe4
[  106.692883]  __pm_runtime_resume+0x70/0x124
[  106.692921]  cmdq_mbox_send_data+0xe4/0xb1c
[  106.692964]  msg_submit+0x194/0x2dc
[  106.693003]  mbox_send_message+0x190/0x330
[  106.693043]  imgsys_cmdq_sendtask+0x1618/0x2224
[  106.693082]  imgsys_runner_func+0xac/0x11c
[  106.693118]  process_one_work+0x638/0xf84
[  106.693158]  worker_thread+0x808/0xcd0
[  106.693196]  kthread+0x24c/0x324
[  106.693231]  ret_from_fork+0x10/0x20

We found that there is a spin_lock_irqsave protection in msg_submit()
of mailbox.c.
So when cmdq driver calls pm_runtime_get_sync() in cmdq_mbox_send_data(),
it will get this BUG report.

Add pm_runtime_irq_safe() to let pm_runtime callbacks is safe in atomic
context with interrupts disabled.

Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
Signed-off-by: Jason-JH.Lin <jason-jh.lin at mediatek.com>
---
 drivers/mailbox/mtk-cmdq-mailbox.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
index ead2200f39ba..3b4f19633c83 100644
--- a/drivers/mailbox/mtk-cmdq-mailbox.c
+++ b/drivers/mailbox/mtk-cmdq-mailbox.c
@@ -694,6 +694,7 @@ static int cmdq_probe(struct platform_device *pdev)
 
 	pm_runtime_set_autosuspend_delay(dev, CMDQ_MBOX_AUTOSUSPEND_DELAY_MS);
 	pm_runtime_use_autosuspend(dev);
+	pm_runtime_irq_safe(dev);
 
 	return 0;
 }
-- 
2.18.0