[PATCH kernel] powerpc/pci: Fix broken INTx configuration via OF

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Commit 59f47eff03a0 ("powerpc/pci: Use of_irq_parse_and_map_pci() helper")
correctly states that of_irq_parse_and_map_pci() does the same thing as
of_irq_parse_pci() does as it simply calls
of_irq_parse_pci() and irq_create_of_mapping().

However of_irq_parse_and_map_pci() not only returns 0 for success and
negative value for an error but also a positive virq value from
irq_create_of_mapping() which the mentioned commit ignores and
INTx config fails.

This fixes the of_irq_parse_and_map_pci() return value handling.

Fixes: 59f47eff03a0 "powerpc/pci: Use of_irq_parse_and_map_pci() helper"
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---

Found it on POWER9 + powernv system - almost all devices suddenly lost
INTx support.
---
 arch/powerpc/kernel/pci-common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index ae2ede4..acbb44f2 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -370,7 +370,8 @@ static int pci_read_irq_line(struct pci_dev *pci_dev)
 	memset(&oirq, 0xff, sizeof(oirq));
 #endif
 	/* Try to get a mapping from the device-tree */
-	if (!of_irq_parse_and_map_pci(pci_dev, 0, 0)) {
+	virq = of_irq_parse_and_map_pci(pci_dev, 0, 0);
+	if (virq <= 0) {
 		u8 line, pin;
 
 		/* If that fails, lets fallback to what is in the config
-- 
2.11.0