[PATCH v1] ASoC: meson: axg-fifo: set option to use raw spinlock

Arseniy Krasnov
2024-07-29T13:29:33Z

Raw spinlock is needed here, because with enabled PREEMPT_RT,
spinlock_t become preemptible, but this regmap lock could be
acquired in IRQ handler. Found by lockdep:

[ ] =============================
[ ] [ BUG: Invalid wait context ]
[ ] 6.9.9-sdkernel #1 Tainted: G O
[ ] -----------------------------
[ ] aplay/413 is trying to lock:
[ ] ffff000003930018 (axg_fifo:356:(&axg_fifo_regmap_cfg)->lock){....}-{3:3},c
[ ] other info that might help us debug this:
[ ] context-{2:2}
[ ] no locks held by aplay/413.
[ ] stack backtrace:
[ ] CPU: 0 PID: 413 Comm: aplay Tainted: G O 6.9.9-kernel #1
[ ] Hardware name: SberDevices SberBoom Mini (DT)
[ ] Call trace:
[ ] dump_backtrace+0x98/0xf0
[ ] show_stack+0x18/0x24
[ ] dump_stack_lvl+0x90/0xd0
[ ] dump_stack+0x18/0x24
[ ] __lock_acquire+0x9dc/0x1f10
[ ] lock_acquire.part.0+0xe8/0x228
[ ] lock_acquire+0x68/0x84
[ ] _raw_spin_lock_irqsave+0x60/0x88
[ ] regmap_lock_spinlock+0x18/0x2c
[ ] regmap_read+0x3c/0x78
[ ] axg_fifo_pcm_irq_block+0x4c/0xc8
[ ] __handle_irq_event_percpu+0xa4/0x2f8
[ ] handle_irq_event+0x4c/0xbc
[ ] handle_fasteoi_irq+0xa4/0x23c
[ ] generic_handle_domain_irq+0x2c/0x44
[ ] gic_handle_irq+0x40/0xc4
[ ] call_on_irq_stack+0x24/0x4c
[ ] do_interrupt_handler+0x80/0x84
[ ] el0_interrupt+0x5c/0x124
[ ] __el0_irq_handler_common+0x18/0x24
[ ] el0t_32_irq_handler+0x10/0x1c
[ ] el0t_32_irq+0x194/0x198

Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
---
sound/soc/meson/axg-fifo.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/sound/soc/meson/axg-fifo.c b/sound/soc/meson/axg-fifo.c
index ecb3eb7a9723d..a22298f74b35a 100644
--- a/sound/soc/meson/axg-fifo.c
+++ b/sound/soc/meson/axg-fifo.c
@@ -328,6 +328,7 @@ static const struct regmap_config axg_fifo_regmap_cfg = {
.val_bits = 32,
.reg_stride = 4,
.max_register = FIFO_CTRL2,
+ .use_raw_spinlock = true,
};

int axg_fifo_probe(struct platform_device *pdev)
--
2.30.1