[PATCH 1/2] perf/arm-cmn: don't claim resource during ioremap() for CMN700 with ACPI

[Yin Fengwei]

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 function
devm_platform_ioremap_resource(pdev, 0) 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 all ACPI cases call devm_ioremap(cmn->dev, cfg) just
like current CMN600 does.

Signed-off-by: Yin Fengwei <fengwei_yin@xxxxxxxxxxxxxxxxx>
---
 drivers/perf/arm-cmn.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index ef959e66db7c..5993a46c5560 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -2510,20 +2510,26 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset)
 	return 0;
 }
 
-static int arm_cmn600_acpi_probe(struct platform_device *pdev, struct arm_cmn *cmn)
+static int arm_acpi_probe(struct platform_device *pdev, struct arm_cmn *cmn)
 {
-	struct resource *cfg, *root;
+	struct resource *cfg, *root = NULL;
 
 	cfg = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!cfg)
 		return -EINVAL;
 
-	root = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-	if (!root)
-		return -EINVAL;
+	if (cmn->part == PART_CMN600) {
+		/* Per "ACPI for Arm Components" Table 16, CMN600 has
+		 * nested root node memory range.
+		 */
+		root = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+		if (!root)
+			return -EINVAL;
+
+		if (!resource_contains(cfg, root))
+			swap(cfg, root);
+	}
 
-	if (!resource_contains(cfg, root))
-		swap(cfg, root);
 	/*
 	 * Note that devm_ioremap_resource() is dumb and won't let the platform
 	 * device claim cfg when the ACPI companion device has already claimed
@@ -2534,7 +2540,7 @@ static int arm_cmn600_acpi_probe(struct platform_device *pdev, struct arm_cmn *c
 	if (!cmn->base)
 		return -ENOMEM;
 
-	return root->start - cfg->start;
+	return root ? (root->start - cfg->start) : 0;
 }
 
 static int arm_cmn600_of_probe(struct device_node *np)
@@ -2559,9 +2565,9 @@ 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)) {
-		rootnode = arm_cmn600_acpi_probe(pdev, cmn);
-	} else {
+	if (has_acpi_companion(cmn->dev))
+		rootnode = arm_acpi_probe(pdev, cmn);
+	else {
 		rootnode = 0;
 		cmn->base = devm_platform_ioremap_resource(pdev, 0);
 		if (IS_ERR(cmn->base))
-- 
2.43.5