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-rw-r--r--drivers/acpi/arm64/iort.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 3b23fb775ac4..f2f8f05662de 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1361,9 +1361,17 @@ static void __init arm_smmu_v3_pmcg_init_resources(struct resource *res,
res[0].start = pmcg->page0_base_address;
res[0].end = pmcg->page0_base_address + SZ_4K - 1;
res[0].flags = IORESOURCE_MEM;
- res[1].start = pmcg->page1_base_address;
- res[1].end = pmcg->page1_base_address + SZ_4K - 1;
- res[1].flags = IORESOURCE_MEM;
+ /*
+ * The initial version in DEN0049C lacked a way to describe register
+ * page 1, which makes it broken for most PMCG implementations; in
+ * that case, just let the driver fail gracefully if it expects to
+ * find a second memory resource.
+ */
+ if (node->revision > 0) {
+ res[1].start = pmcg->page1_base_address;
+ res[1].end = pmcg->page1_base_address + SZ_4K - 1;
+ res[1].flags = IORESOURCE_MEM;
+ }
if (pmcg->overflow_gsiv)
acpi_iort_register_irq(pmcg->overflow_gsiv, "overflow",