Cisco has a couple platforms which depend on the domain values getting
set a certain way. We discovered our machines not detecting the pci
devices, and traced it back to this commit,
63a7228 powerpc/pci: Assign fixed PHB number based on device-tree
properties
It seems that the code is expecting the return value of of_property_read_u64()
to be the opposite of what it actually is.. It returns zero on success, and a
negative return value on error. So if you only check when it's non-zero your
going to set Opal for all platforms but Opal, which I assume is not what was
expected.
Fix is just to negate the ret value.
Cc: xe-kernel@external.cisco.com
Cc: Guilherme G. Piccoli <redacted>
Cc: Gavin Shan <redacted>
Cc: Ian Munsie <redacted>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Fixes: 63a72284b159 ("powerpc/pci: Assign fixed PHB number based on device-tree properties")
Signed-off-by: Daniel Walker <redacted>
---
arch/powerpc/kernel/pci-common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index fe9733f..0a1bcbe 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -89,7 +89,7 @@ static int get_phb_number(struct device_node *dn)
* reading "ibm,opal-phbid", only present in OPAL environment.
*/
ret = of_property_read_u64(dn, "ibm,opal-phbid", &prop);
- if (ret) {
+ if (!ret) {
ret = of_property_read_u32_index(dn, "reg", 1, &prop_32);
prop = prop_32;
}--
2.10.3.dirty
On Mon, Jun 18, 2018 at 1:57 PM, Daniel Walker [off-list ref] wrote:
Cisco has a couple platforms which depend on the domain values getting
set a certain way. We discovered our machines not detecting the pci
devices, and traced it back to this commit,
63a7228 powerpc/pci: Assign fixed PHB number based on device-tree
properties
It seems that the code is expecting the return value of of_property_read_u64()
to be the opposite of what it actually is.. It returns zero on success, and a
negative return value on error. So if you only check when it's non-zero your
going to set Opal for all platforms but Opal, which I assume is not what was
expected.
Hi Daniel, thanks for exposing a potential issue and trying to fix.
(And thanks Mauro to point this message, since my email changed).
I disagree with your patch Daniel, I think it's wrong.
Since the logic of my original patch is kind of convoluted, for improve
(even my own) understanding, I tried to over-comment the logic here:
https://pastebin.ubuntu.com/p/4DNvd9b2bY
Please, take a look and see if you agree with the logic now.
Regarding your issue, I'm interested - I think perhaps you have some FW
flaw that might be exposing duplicated "reg" or "ibm,opal-phbid" properties.
Or maybe you somehow rely on the old incremental PHB setting and your
software stack is not working properly with the DT-based PHB values.
Please, elaborate the issue a bit more in order we can try to figure
out. And also, you could try reverting the below two patches and boot
the kernel to be sure it works:
61e8a0d5a02 powerpc/pci: Fix endian bug in fixed PHB numbering
63a72284b15 powerpc/pci: Assign fixed PHB number based on device-tree properties
*Notice* the first is a fix to my patch, and both should be tested together.
Be sure your current kernel has _both or neither_ these patches!
Cheers,
Guilherme