[PATCH v2] remoteproc: qcom: q6v5_pas: Don't enable handover IRQ on attach

qcom_pas_attach() unmasks the handover IRQ and marks handover_issued
even though this driver instance never runs qcom_q6v5_prepare() for
the boot it is attaching to. This was believed necessary to flush a
stale interrupt latched at the interrupt controller while masked, but
the handover IRQ is a Qualcomm SMP2P soft IRQ, not a real edge-latched
hardware interrupt. The Linux SMP2P driver updates its cached value
unconditionally on every notification and only delivers the nested IRQ
for bits currently enabled in its own software bitmap, so a transition
that happens while masked is simply dropped, never replayed on a later
unmask.

Since there is nothing to flush, and this driver instance never takes
the proxy power-domain/clock/regulator votes that the handover
callback would tear down, there is no need to unmask the IRQ in
attach() at all. Drop the enable_irq()/disable_irq() pair; setting
handover_issued = true is sufficient to keep the flag consistent for
the eventual qcom_q6v5_unprepare()/qcom_q6v5_prepare() cycle.

It fixes the following unbalanced runtime PM usage and IRQ enable
warnings seen on Nord ADSP (probed as attached), after commit bb7c5d6f5b41
("remoteproc: qcom: q6v5: Make handover IRQ one-shot") comes in place.

root@iq10-rrd:~# cat /sys/class/remoteproc/remoteproc0/state
attached
root@iq10-rrd:~# echo stop > /sys/class/remoteproc/remoteproc0/state
[   40.004874] genpd genpd:0:4c00000.remoteproc: Runtime PM usage count underflow!
[   40.012409] genpd genpd:1:4c00000.remoteproc: Runtime PM usage count underflow!
[   40.050074] remoteproc remoteproc0: stopped remote processor adsp
root@iq10-rrd:~# echo start > /sys/class/remoteproc/remoteproc0/state
[   44.350298] remoteproc remoteproc0: powering up adsp
[   44.375769] remoteproc remoteproc0: Booting fw image qcom/nord/adsp.mbn, size 8241816
[   44.389850] PDM: no support for the platform, userspace daemon might be required.
[   44.397864] ------------[ cut here ]------------
[   44.402633] Unbalanced enable for IRQ 363
[   44.406779] WARNING: kernel/irq/manage.c:775 at __enable_irq+0x4c/0x7c, CPU#9: sh/791
...

Suggested-by: Stephan Gerhold <[email protected]>
Signed-off-by: Shawn Guo <[email protected]>
---
Changes for v2:
- Fix the warnings by dropping handover IRQ enable in qcom_pas_attach()
  (Thanks Stephan!)
- Link to v1: https://lore.kernel.org/all/[email protected]/

 drivers/remoteproc/qcom_q6v5_pas.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/remoteproc/qcom_q6v5_pas.c b/drivers/remoteproc/qcom_q6v5_pas.c
index a4b233d92efb..bc565979a5a7 100644
--- a/drivers/remoteproc/qcom_q6v5_pas.c
+++ b/drivers/remoteproc/qcom_q6v5_pas.c
@@ -521,7 +521,6 @@ static int qcom_pas_attach(struct rproc *rproc)
 	int ret;
 
 	pas->q6v5.handover_issued = true;
-	enable_irq(pas->q6v5.handover_irq);
 
 	pas->q6v5.running = true;
 	ret = irq_get_irqchip_state(pas->q6v5.fatal_irq,
@@ -567,7 +566,6 @@ static int qcom_pas_attach(struct rproc *rproc)
 	pas->rproc->state = RPROC_OFFLINE;
 	ret = -EINVAL;
 disable_running:
-	disable_irq(pas->q6v5.handover_irq);
 	pas->q6v5.running = false;
 
 	return ret;
-- 
2.43.0