Re: [PATCH] of/base: Fix PowerPC address parsing hack

On Wed, 12 Nov 2014 08:39:32 -0600
, Rob Herring [off-list ref]
 wrote:

On Tue, Nov 11, 2014 at 11:51 PM, Benjamin Herrenschmidt
[off-list ref] wrote:

quoted

We have a historical hack that treats missing ranges properties as the
equivalent of an empty one. This is needed for ancient PowerMac "bad"
device-trees, and shouldn't be enabled for any other PowerPC platform,
otherwise we get some nasty layout of devices in sysfs or even
duplication when a set of otherwise identically named devices is
created multiple times under a different parent node with no ranges
property.

This fix is needed for the PowerNV i2c busses to be exposed properly
and will fix a number of other embedded cases.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <redacted>
---

diff --git a/drivers/of/address.c b/drivers/of/address.c
index e371825..e37f017 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c

@@ -7,6 +7,10 @@
 #include <linux/pci_regs.h>
 #include <linux/string.h>

+#ifdef CONFIG_PPC
+#include <asm/machdep.h>
+#endif
+
 /* Max address size we deal with */
 #define OF_MAX_ADDR_CELLS      4
 #define OF_CHECK_ADDR_COUNT(na)        ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS)

@@ -428,12 +432,13 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus,
         * This code is only enabled on powerpc. --gcl
         */
        ranges = of_get_property(parent, rprop, &rlen);
-#if !defined(CONFIG_PPC)
+#if defined(CONFIG_PPC)
+       if (!machine_is(powermac))

Can we use a machine compatible here or something not PPC specific?
Then we can use IS_ENABLED(CONFIG_PPC) instead of ifdefs.

Yeah, that's kind of nasty!

g.