Commit 91351b5d authored by Sander Vanheule's avatar Sander Vanheule Committed by Marc Zyngier
Browse files

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



There is an offset between routing values (1..6) and the connected MIPS
CPU interrupts (2..7), but no distinction was made between these two
values.

This issue was previously hidden during testing, because an interrupt
mapping was used where for each required interrupt another (unused)
routing was configured, with an offset of +1.

Offset the CPU IRQ numbers by -1 to retrieve the correct routing value.

Fixes: 9f3a0f34 ("irqchip: Add support for Realtek RTL838x/RTL839x interrupt controller")
Signed-off-by: default avatarSander Vanheule <sander@svanheule.net>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/177b920aa8d8610615692d0e657e509f363c85ca.1641739718.git.sander@svanheule.net
parent 291e79c7

drivers/irqchip/irq-realtek-rtl.c

+5 −3
Original line number Diff line number Diff line
@@ -95,7 +95,8 @@ static void realtek_irq_dispatch(struct irq_desc *desc) 
 * 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;

	}