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Date:   Tue, 12 May 2020 11:40:30 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To:     Tuan Phan <tuanphan@os.amperecomputing.com>
Cc:     patches@amperecomputing.com, Hanjun Guo <guohanjun@huawei.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>, linux-acpi@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ACPI/IORT: Fix PMCG node always look for a single ID
 mapping.
Message-ID: <20200512104030.GA11555@e121166-lin.cambridge.arm.com>
References: <1589228576-18053-1-git-send-email-tuanphan@os.amperecomputing.com>
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On Mon, May 11, 2020 at 01:22:56PM -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.
> 
> Signed-off-by: Tuan Phan <tuanphan@os.amperecomputing.com>
> ---
>  drivers/acpi/arm64/iort.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index ed3d2d1..72444e1 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -441,7 +441,9 @@ static int iort_get_id_mapping_index(struct acpi_iort_node *node)
>  
>  		return smmu->id_mapping_index;
>  	case ACPI_IORT_NODE_PMCG:
> -		return 0;
> +		if (node->mapping_count)
> +			return 0;

Check struct acpi_iort_pmcg->overflow_gsiv to be coherent with SMMUv3
code.

Lorenzo

> +		return -EINVAL;
>  	default:
>  		return -EINVAL;
>  	}
> -- 
> 2.7.4
>