[PATCH v2 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>

On platforms where IPI is not available in the MPIC, the IPI registers
instead represent an additional set of MSI interrupt registers (currently
unused by the driver).

Do not touch these registers on platforms where IPI is not available in
the MPIC.

Signed-off-by: Pali Rohár <pali@kernel.org>
[ refactored, changed commit message ]
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
 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 ea95e327f672..aca64de4e3f8 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -508,6 +508,9 @@ 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);
 
@@ -758,7 +761,7 @@ 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);
@@ -809,13 +812,18 @@ 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