[PATCH] irqchip/riscv-aplic: Fix crash when MSI domain is missing

[Samuel Holland]

If the APLIC driver is probed before the IMSIC driver, the parent MSI
domain will be missing, which causes a NULL pointer dereference in
msi_create_device_irq_domain(). Avoid this by deferring probe until the
parent MSI domain is available. Use dev_err_probe() to avoid printing an
error message when returning -EPROBE_DEFER.

Fixes: ca8df97fe679 ("irqchip/riscv-aplic: Add support for MSI-mode")
Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
---

 drivers/irqchip/irq-riscv-aplic-main.c | 3 ++-
 drivers/irqchip/irq-riscv-aplic-msi.c  | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-riscv-aplic-main.c b/drivers/irqchip/irq-riscv-aplic-main.c
index 900e72541db9..93e7c51f944a 100644
--- a/drivers/irqchip/irq-riscv-aplic-main.c
+++ b/drivers/irqchip/irq-riscv-aplic-main.c
@@ -207,7 +207,8 @@ static int aplic_probe(struct platform_device *pdev)
 	else
 		rc = aplic_direct_setup(dev, regs);
 	if (rc)
-		dev_err(dev, "failed to setup APLIC in %s mode\n", msi_mode ? "MSI" : "direct");
+		dev_err_probe(dev, rc, "failed to setup APLIC in %s mode\n",
+			      msi_mode ? "MSI" : "direct");
 
 #ifdef CONFIG_ACPI
 	if (!acpi_disabled)
diff --git a/drivers/irqchip/irq-riscv-aplic-msi.c b/drivers/irqchip/irq-riscv-aplic-msi.c
index 945bff28265c..fb8d1838609f 100644
--- a/drivers/irqchip/irq-riscv-aplic-msi.c
+++ b/drivers/irqchip/irq-riscv-aplic-msi.c
@@ -266,6 +266,9 @@ int aplic_msi_setup(struct device *dev, void __iomem *regs)
 			if (msi_domain)
 				dev_set_msi_domain(dev, msi_domain);
 		}
+
+		if (!dev_get_msi_domain(dev))
+			return -EPROBE_DEFER;
 	}
 
 	if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN, &aplic_msi_template,
-- 
2.45.1