[PATCHv2] gpio: mvebu: validate ngpios before use

[Rosen Penev <rosenp@gmail.com>]

If ngpios is read as 0 from device tree, it is passed via
irq_alloc_domain_generic_chips() as irqs_per_chip, which leads to a
division by zero in DIV_ROUND_UP(d->revmap_size, irqs_per_chip).
Reject ngpios == 0 early.

Also reject higher than 32, which is the limit.

Fixes: fefe7b0923459 ("gpio: introduce gpio-mvebu driver for Marvell SoCs")
Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 v2: reject higher than 32.
 drivers/gpio/gpio-mvebu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index a863b0bf46ff..73f4bbd2a0cd 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -1176,6 +1176,11 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	if (ngpios == 0 || ngpios > MVEBU_MAX_GPIO_PER_BANK) {
+		dev_err(&pdev->dev, "ngpios must be between 1 and 32\n");
+		return -EINVAL;
+	}
+
 	id = of_alias_get_id(pdev->dev.of_node, "gpio");
 	if (id < 0) {
 		dev_err(&pdev->dev, "Couldn't get OF id\n");
-- 
2.55.0