Re: [PATCH v3] ACPI/IORT: Fix PMCG node always look for a single ID mapping.

[Tuan Phan <tuanphan@amperemail.onmicrosoft.com>]

> On May 14, 2020, at 2:29 AM, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote:
> 
> Please update the subject:
> 
> Subject: "ACPI/IORT: Fix PMCG node single ID mapping handling"
> 
> On Wed, May 13, 2020 at 05:12:02PM -0700, Tuan Phan wrote:
>> PMCG node can have zero ID mapping if its overflow interrupt
>> is wire based. The code to parse PMCG node can not assume it will
>> have a single ID mapping.
> 
> "An IORT PMCG node can have no ID mapping if its overflow interrupt is
> wire based therefore the code that parses the PMCG node can not assume
> the node will always have a single mapping present at index 0.
> 
> Fix iort_get_id_mapping_index() by checking for an overflow interrupt
> and mapping count."

Thanks for the correction. Will update it.
> 
>> Fixes: 24e516049360 ("ACPI/IORT: Add support for PMCG")
>> Reviewed-by: Hanjun Guo <guoahanjun@huawei.com>
>> Signed-off-by: Tuan Phan <tuanphan@os.amperecomputing.com>
>> ---
>> v1 -> v2:
>> - Use pmcg node to detect wired base overflow interrupt.
>> 
>> v2 -> v3:
>> - Address Hanjun and Robin's comments.
>> 
>> drivers/acpi/arm64/iort.c | 5 +++++
>> 1 file changed, 5 insertions(+)
> 
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> 
>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>> index ed3d2d1..12bb70e 100644
>> --- a/drivers/acpi/arm64/iort.c
>> +++ b/drivers/acpi/arm64/iort.c
>> @@ -414,6 +414,7 @@ static struct acpi_iort_node *iort_node_get_id(struct acpi_iort_node *node,
>> static int iort_get_id_mapping_index(struct acpi_iort_node *node)
>> {
>> 	struct acpi_iort_smmu_v3 *smmu;
>> +	struct acpi_iort_pmcg *pmcg;
>> 
>> 	switch (node->type) {
>> 	case ACPI_IORT_NODE_SMMU_V3:
>> @@ -441,6 +442,10 @@ static int iort_get_id_mapping_index(struct acpi_iort_node *node)
>> 
>> 		return smmu->id_mapping_index;
>> 	case ACPI_IORT_NODE_PMCG:
>> +		pmcg = (struct acpi_iort_pmcg *)node->node_data;
>> +		if (pmcg->overflow_gsiv || node->mapping_count == 0)
>> +			return -EINVAL;
>> +
>> 		return 0;
>> 	default:
>> 		return -EINVAL;
>> -- 
>> 2.7.4
>>