irqchip/mbigen: Don't clear eventid when freeing an MSI

mbigen_write_msg clears eventid bits of a mbigen register
when free a interrupt, because msi_domain_deactivate memset
struct msg to zero. Then multiple mbigen pins with zero eventid
will report the same interrupt number.

The eventid clear call trace:
                free_irq
                __free_irq
                irq_shutdown
                irq_domain_deactivate_irq
                __irq_domain_deactivate_irq
                __irq_domain_deactivate_irq
                msi_domain_deactivate
                platform_msi_write_msg
                mbigen_write_msg

Signed-off-by: Jianguo Chen <chenjianguo3@huawei.com>
[maz: massaged subject]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-mbigen.c b/drivers/irqchip/irq-mbigen.c
index 567b29c47608..98b6e1d4b1a6 100644
--- a/drivers/irqchip/irq-mbigen.c
+++ b/drivers/irqchip/irq-mbigen.c
@@ -161,6 +161,9 @@ static void mbigen_write_msg(struct msi_desc *desc, struct msi_msg *msg)
         void __iomem *base = d->chip_data;
         u32 val;
 
+        if (!msg->address_lo && !msg->address_hi)
+                return;
+ 
         base += get_mbigen_vec_reg(d->hwirq);
         val = readl_relaxed(base);