Re: [PATCH v5] ACPI/IORT: Fix PMCG node single ID mapping handling

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Wed, May 20, 2020 at 10:13:07AM -0700, Tuan Phan wrote:
> 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.
> 
> Fixes: 24e516049360 ("ACPI/IORT: Add support for PMCG")
> 
> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> 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.
> 
> v3 -> v4:
> - Update the title and description as mentioned by Lorenzo.
> 
> v4 -> v5:
> - Remove period in the title and commit references.
> 
>  drivers/acpi/arm64/iort.c | 5 +++++

Hi Will,

is there a chance we can get this patch into v5.8 ? I understand
we are very late in the cycle but I wanted to ask (it applies cleanly
to for-next/acpi).

Thanks !
Lorenzo

>  1 file changed, 5 insertions(+)
> 
> 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
>