Commit c45ded7e1135 ("mailbox: pcc: Add support for PCCT extended PCC
subspaces(type 3/4)") enabled the type3/4 of PCCT, but the change in
pcc_mbox_irq breaks the other PCC subtypes.
The kernel reports a warning on an Ampere eMag server
-->8
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-rc4 #127
Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019
Call trace:
dump_backtrace+0x0/0x200
show_stack+0x20/0x30
dump_stack_lvl+0x68/0x84
dump_stack+0x18/0x34
__report_bad_irq+0x54/0x17c
note_interrupt+0x330/0x428
handle_irq_event_percpu+0x90/0x98
handle_irq_event+0x4c/0x148
handle_fasteoi_irq+0xc4/0x188
generic_handle_domain_irq+0x44/0x68
gic_handle_irq+0x84/0x2ec
call_on_irq_stack+0x28/0x34
do_interrupt_handler+0x88/0x90
el1_interrupt+0x48/0xb0
el1h_64_irq_handler+0x18/0x28
el1h_64_irq+0x7c/0x80
---
The main reason for that is the command complete register is read as 0
if the GAS register doesn't exist for the same which is the case for
PCC subtypes 0-2. Fix it by checking for non-zero value before masking
with the status flag and checking for command completion.
Fixes: c45ded7e1135 ("mailbox: pcc: Add support for PCCT extended PCC subspaces(type 3/4)")
Cc: Jassi Brar <jassisinghbrar@xxxxxxxxx>
Reported-by: Justin He <justin.he@xxxxxxx>
Tested-by: Justin He <justin.he@xxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
drivers/mailbox/pcc.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index e0a1ab3861f0..ed18936b8ce6 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -241,9 +241,11 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
if (ret)
return IRQ_NONE;
- val &= pchan->cmd_complete.status_mask;
- if (!val)
- return IRQ_NONE;
+ if (val) { /* Ensure GAS exists and value is non-zero */
+ val &= pchan->cmd_complete.status_mask;
+ if (!val)
+ return IRQ_NONE;
+ }
ret = pcc_chan_reg_read(&pchan->error, &val);
if (ret)
--
2.25.1
