Re: [PATCH] perf/arm-cmn: don't claim resource during ioremap() for CMN700 with ACPI

From: Robin Murphy
Date: Tue Feb 18 2025 - 05:36:01 EST


On 2025-02-18 1:21 am, Yin Fengwei wrote:
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?

Thanks,
Robin.

Signed-off-by: Yin Fengwei <fengwei_yin@xxxxxxxxxxxxxxxxx>
---
I am also wondering whether we could just drop the CMN600 part id
check here if ACPI companion device claimed the resource?

drivers/perf/arm-cmn.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index ef959e66db7c..8b5322a2aa6e 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -2559,7 +2559,8 @@ static int arm_cmn_probe(struct platform_device *pdev)
cmn->part = (unsigned long)device_get_match_data(cmn->dev);
platform_set_drvdata(pdev, cmn);
- if (cmn->part == PART_CMN600 && has_acpi_companion(cmn->dev)) {
+ if (((cmn->part == PART_CMN600) || (cmn->part == PART_CMN700)) &&
+ has_acpi_companion(cmn->dev)) {
rootnode = arm_cmn600_acpi_probe(pdev, cmn);
} else {
rootnode = 0;
@@ -2649,7 +2650,7 @@ MODULE_DEVICE_TABLE(of, arm_cmn_of_match);
static const struct acpi_device_id arm_cmn_acpi_match[] = {
{ "ARMHC600", PART_CMN600 },
{ "ARMHC650" },
- { "ARMHC700" },
+ { "ARMHC700", PART_CMN700 },
{}
};
MODULE_DEVICE_TABLE(acpi, arm_cmn_acpi_match);