On Fri, 16 Aug 2019 20:41:22 +0200
Lubomir Rintel [off-list ref] wrote:

On Fri, 2019-08-09 at 13:12 +0100, Marc Zyngier wrote:

quoted

On 09/08/2019 10:31, Lubomir Rintel wrote:  

quoted

The "regs" property of the "mrvl,mmp2-mux-intc" devices are silly. They
are offsets from intc's base, not addresses on the parent bus. At this
point it probably can't be fixed.

On an OLPC XO-1.75 machine, the muxes are children of the intc, not the
axi bus, and thus of_address_to_resource() won't work. We should treat
the values as mere integers as opposed to bus addresses.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <redacted>

---
 drivers/irqchip/irq-mmp.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/irqchip/irq-mmp.c b/drivers/irqchip/irq-mmp.c
index 14618dc0bd396..af9cba4a51c2e 100644
--- a/drivers/irqchip/irq-mmp.c
+++ b/drivers/irqchip/irq-mmp.c

@@ -424,9 +424,9 @@ IRQCHIP_DECLARE(mmp2_intc, "mrvl,mmp2-intc", mmp2_of_init);
 static int __init mmp2_mux_of_init(struct device_node *node,
 				   struct device_node *parent)
 {
-	struct resource res;
 	int i, ret, irq, j = 0;
 	u32 nr_irqs, mfp_irq;
+	u32 reg[4];
 
 	if (!parent)
 		return -ENODEV;

@@ -438,18 +438,20 @@ static int __init mmp2_mux_of_init(struct device_node *node,
 		pr_err("Not found mrvl,intc-nr-irqs property\n");
 		return -EINVAL;
 	}
-	ret = of_address_to_resource(node, 0, &res);
+
+	/*
+	 * For historical reasonsm, the "regs" property of the
+	 * mrvl,mmp2-mux-intc is not a regular * "regs" property containing
+	 * addresses on the parent bus, but offsets from the intc's base.
+	 * That is why we can't use of_address_to_resource() here.
+	 */
+	ret = of_property_read_u32_array(node, "reg", reg, ARRAY_SIZE(reg));  

This will return 0 even if you've read less than your expected 4 u32s.
You may want to try of_property_read_variable_u32_array instead.  

Will it? Unless I'm reading the of_property_read_u32_array()
documentation wrong, it suggests that would return -EOVERFLOW in that
case.

You're appear to be right, and I read it wrong.

It ignores the extra values it the property is larger. I guess that is
not a good thing and we still want to use
of_property_read_variable_u32_array() though.

It doesn't hurt to check for all possible problems, specially given
that this machine doesn't appear to have a mainline DT (and its OF
implementation looks a bit buggy).

Thanks,

	M.
-- 
Without deviation from the norm, progress is not possible.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel