Add Jing Zhang as we will continue discussion in this thread.
On Tue, Feb 18, 2025 at 12:31:10PM +0800, Robin Murphy wrote:
On 2025-02-18 10:58 am, YinFengwei wrote:My bad. I will attatch the full patch at the end of this mail.
On Tue, Feb 18, 2025 at 10:31:42AM +0800, Robin Murphy wrote:
On 2025-02-18 1:21 am, Yin Fengwei wrote:Sorry. Forgot the link for the new proposed fix:
Currently, arm-cmn PMU driver assumes ACPI claim resource
for CMN600 + ACPI. But with CMN700 + ACPI, the device probe
failed because of resource claim failes when ioremap() is
called:
[ 10.837300] arm-cmn ARMHC700:00: error -EBUSY: can't request region for resource [mem 0x40000000-0x4fffffff]
[ 10.847310] arm-cmn ARMHC700:00: probe with driver arm-cmn failed with error -16
[ 10.854726] arm-cmn ARMHC700:02: error -EBUSY: can't request region for resource [mem 0x40040000000-0x4004fffffff]
[ 10.865085] arm-cmn ARMHC700:02: probe with driver arm-cmn failed with error -16
Let CMN700 + ACPI do same as CMN600 + ACPI to allow CMN700
work in ACPI env.
No, the CMN-600 routine is a special case for CMN-600 having two nested
memory resources of its own. CMN-700 and everything else only have one
memory resource, so that is not appropriate. What else is claiming the
region to cause a conflict?
https://lore.kernel.org/all/Z7QYlUP6nfBNMXsv@U-V2QX163P-2032.local/
Yes, I saw that. It's a broken diff that won't even compile, with no
explanation of what it's supposed to be trying to achieve or why. I'm not
sure what you're asking me to comment on.
I believe this works only for parents/children resource node. Otherwise,
My understanding is that there are two problems here:
1. ACPI claim the memory range and that's why we see this -EBUSY error
with correct code path for CMN700 + ACPI table.
No, it's fine to claim the exact *same* range that the ACPI companion owns;
the identical requests just nest inside each other. I don't have a CMN-700
to hand but here's a selection of other drivers doing just that from
/proc/iomem on my system:
12600000-12600fff : ARMH0011:00
12600000-12600fff : ARMH0011:00 ARMH0011:00
12610000-12610fff : ARMH0011:01
12610000-12610fff : ARMH0011:01 ARMH0011:01
126b0000-126b0fff : APMC0D0F:00
126b0000-126b0fff : APMC0D0F:00 APMC0D0F:00
126f0000-126f0fff : APMC0D81:00
126f0000-126f0fff : APMC0D81:00 APMC0D81:00
there will be conflict.
No. It's not ACPI table problem. The problem is mentioned in comments of
And I know people are using the CMN-700 PMU on other ACPI systems without
issue, so there's nothing wrong with the binding or the driver in general.
The resource conflict only arises when a request overlaps an existing region
inexactly. Either your firmware is describing the CMN incorrectly, or some
other driver is claiming conflicting iomem regions for some reason.
function arm_cmn600_acpi_probe():
/*
* Note that devm_ioremap_resource() is dumb and won't let the platform
* device claim cfg when the ACPI companion device has already claimed
* root within it. But since they *are* already both claimed in the
* appropriate name, we don't really need to do it again here anyway.
*/
So I suppose for ACPI env, we should use devm_ioremap() as cmn600 does.
And make CMN700 handling follow spec exactly.