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of/base: Fix PowerPC address parsing hack 

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: <stable@vger.kernel.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
hifive-unleashed-5.1
Benjamin Herrenschmidt 2014-11-14 17:55:03 +11:00 committed by Rob Herring
parent 9b6eab0758
commit 746c9e9f92
1 changed files with 16 additions and 3 deletions
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19
drivers/of/address.c
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@ -450,6 +450,21 @@ static struct of_bus *of_match_bus(struct device_node *np)
return NULL;
}
static int of_empty_ranges_quirk(void)
{
if (IS_ENABLED(CONFIG_PPC)) {
/* To save cycles, we cache the result */
static int quirk_state = -1;
if (quirk_state < 0)
quirk_state =
of_machine_is_compatible("Power Macintosh") ||
of_machine_is_compatible("MacRISC");
return quirk_state;
}
return false;
}
static int of_translate_one(struct device_node *parent, struct of_bus *bus,
struct of_bus *pbus, __be32 *addr,
int na, int ns, int pna, const char *rprop)
@ -475,12 +490,10 @@ 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 (ranges == NULL) {
if (ranges == NULL && !of_empty_ranges_quirk()) {
pr_err("OF: no ranges; cannot translate\n");
return 1;
}
#endif /* !defined(CONFIG_PPC) */
if (ranges == NULL || rlen == 0) {
offset = of_read_number(addr, na);
memset(addr, 0, pna * 4);