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",