[PATCH 3/4] irqchip/armada-370-xp: Do not touch IPI registers on platforms without IPI

["Marek Behún" <kabel@kernel.org>]

From: Pali Rohár <pali@kernel.org>

IPI is not available on platforms where MPIC has a parent irq.

On these platforms the IPI registers are used as additional set of MSI
interrupts (currently unused by the driver).

Do not touch these registers if IPI is not available.

Signed-off-by: Pali Rohár <pali@kernel.org>
[ refactored, changed commit message ]
Signed-off-by: Marek Behún <kabel@kernel.org>
---
 drivers/irqchip/irq-armada-370-xp.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index 65f21624263e..0097f7dd36e7 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -506,6 +506,9 @@ static void armada_xp_mpic_smp_cpu_init(void)
 	for (i = 0; i < nr_irqs; i++)
 		writel(i, per_cpu_int_base + ARMADA_370_XP_INT_SET_MASK_OFFS);
 
+	if (!is_ipi_available())
+		return;
+
 	/* Disable all IPIs */
 	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
 
@@ -755,7 +758,7 @@ static void armada_370_xp_mpic_resume(void)
 	/* Reconfigure doorbells for IPIs and MSIs */
 	writel(doorbell_mask_reg,
 	       per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
-	if (doorbell_mask_reg & IPI_DOORBELL_MASK)
+	if (is_ipi_available() && (doorbell_mask_reg & IPI_DOORBELL_MASK))
 		writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
 	if (doorbell_mask_reg & PCI_MSI_DOORBELL_MASK)
 		writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
@@ -805,13 +808,18 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
 	BUG_ON(!armada_370_xp_mpic_domain);
 	irq_domain_update_bus_token(armada_370_xp_mpic_domain, DOMAIN_BUS_WIRED);
 
+	/*
+	 * Initialize parent_irq before calling any other functions, since it is
+	 * used to distinguish between IPI and non-IPI platforms.
+	 */
+	parent_irq = irq_of_parse_and_map(node, 0);
+
 	/* Setup for the boot CPU */
 	armada_xp_mpic_perf_init();
 	armada_xp_mpic_smp_cpu_init();
 
 	armada_370_xp_msi_init(node, main_int_res.start);
 
-	parent_irq = irq_of_parse_and_map(node, 0);
 	if (parent_irq <= 0) {
 		irq_set_default_host(armada_370_xp_mpic_domain);
 		set_handle_irq(armada_370_xp_handle_irq);
-- 
2.44.2