irqchip/realtek-rtl: Fix off-by-one in routing

[mirror_ubuntu-jammy-kernel.git] / drivers / irqchip / irq-realtek-rtl.c

diff --git a/drivers/irqchip/irq-realtek-rtl.c b/drivers/irqchip/irq-realtek-rtl.c
index d6788dd93c7bb3b70ae3fa67891612d4d50f5572..568614edd88f4f2b25d6817d4e3ed16d87e90d68 100644 (file)
--- a/drivers/irqchip/irq-realtek-rtl.c
+++ b/drivers/irqchip/irq-realtek-rtl.c
@@ -95,7 +95,8 @@ out:
  * SoC interrupts are cascaded to MIPS CPU interrupts according to the
  * interrupt-map in the device tree. Each SoC interrupt gets 4 bits for
  * the CPU interrupt in an Interrupt Routing Register. Max 32 SoC interrupts
- * thus go into 4 IRRs.
+ * thus go into 4 IRRs. A routing value of '0' means the interrupt is left
+ * disconnected. Routing values {1..15} connect to output lines {0..14}.
  */
 static int __init map_interrupts(struct device_node *node, struct irq_domain *domain)
 {
@@ -134,7 +135,7 @@ static int __init map_interrupts(struct device_node *node, struct irq_domain *do
                of_node_put(cpu_ictl);
 
                cpu_int = be32_to_cpup(imap + 2);
-               if (cpu_int > 7)
+               if (cpu_int > 7 || cpu_int < 2)
                        return -EINVAL;
 
                if (!(mips_irqs_set & BIT(cpu_int))) {
@@ -143,7 +144,8 @@ static int __init map_interrupts(struct device_node *node, struct irq_domain *do
                        mips_irqs_set |= BIT(cpu_int);
                }
 
-               regs[(soc_int * 4) / 32] |= cpu_int << (soc_int * 4) % 32;
+               /* Use routing values (1..6) for CPU interrupts (2..7) */
+               regs[(soc_int * 4) / 32] |= (cpu_int - 1) << (soc_int * 4) % 32;
                imap += 3;
        }