[PATCH 1/2] irqchip/qcom-pdc: don't read version register if it is not available

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On Qualcomm SM8150 the PDC resource has size 0x400. When PDC driver
tries to read the version register (0x1000), it reads past the end of
this resource, causing kernel crash.

Check the size of PDC resource before reading the PDC_VERSION register.

Fixes: bc82cc42644b ("irqchip/qcom-pdc: Add support for v3.2 HW")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/irqchip/qcom-pdc.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
index 9bb6951257c2..431b213b5abb 100644
--- a/drivers/irqchip/qcom-pdc.c
+++ b/drivers/irqchip/qcom-pdc.c
@@ -324,6 +324,7 @@ static int pdc_setup_pin_mapping(struct device_node *np)
 static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
 {
 	struct irq_domain *parent_domain, *pdc_domain;
+	struct resource res;
 	int ret;
 
 	pdc_base = of_iomap(node, 0);
@@ -332,7 +333,14 @@ static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
 		return -ENXIO;
 	}
 
-	pdc_version = pdc_reg_read(PDC_VERSION, 0);
+	if (of_address_to_resource(node, 0, &res))
+		return -EINVAL;
+
+	/* compat with old sm8150 DT which had very small region for PDC */
+	if (resource_size(&res) > PDC_VERSION)
+		pdc_version = pdc_reg_read(PDC_VERSION, 0);
+	else
+		pdc_version = 0;
 
 	parent_domain = irq_find_host(parent);
 	if (!parent_domain) {
-- 
2.39.2