linux-kernel - Re: [PATCH v3 1/7] ACPI/PPTT: Add Processor Properties Topology Table parsing

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Date:   Mon, 23 Oct 2017 16:14:22 -0500
From:   Jeremy Linton <jeremy.linton@....com>
To:     "Christ, Austin" <austinwc@...eaurora.org>,
        linux-acpi@...r.kernel.org
Cc:     linux-arm-kernel@...ts.infradead.org, sudeep.holla@....com,
        hanjun.guo@...aro.org, lorenzo.pieralisi@....com,
        rjw@...ysocki.net, will.deacon@....com, catalin.marinas@....com,
        gregkh@...uxfoundation.org, viresh.kumar@...aro.org,
        mark.rutland@....com, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, jhugo@...eaurora.org,
        wangxiongfeng2@...wei.com, Jonathan.Zhang@...ium.com,
        ahs3@...hat.com, Jayachandran.Nair@...ium.com
Subject: Re: [PATCH v3 1/7] ACPI/PPTT: Add Processor Properties Topology Table
 parsing

Hi,

On 10/20/2017 02:53 PM, Christ, Austin wrote:
> Hey Jeremy,
> 
> Quick comment below.
> 
> On 10/12/2017 1:48 PM, Jeremy Linton wrote:
>> +static int topology_setup_acpi_cpu(struct acpi_table_header *table,
>> +                    unsigned int cpu, int level)
>> +{
>> +    struct acpi_pptt_processor *cpu_node;
>> +    u32 acpi_cpu_id = acpi_cpu_get_madt_gicc(cpu)->uid;
> 
> This lookup for the acpi id is architecture dependent. Can you use a 
> function that would work for any user of PPTT and MADT? It may require 
> writing and exporting the inverse lookup of the function 
> acpi_get_cpuid() which is exported from processor_core.c

Sure, I was actually thinking about just passing it into the function, 
so it becomes the responsibility of the caller to do the platform 
specific reverse lookup.

> 
>> +
>> +    cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
>> +    if (cpu_node) {
>> +        cpu_node = acpi_find_processor_package_id(table, cpu_node, 
>> level);
>> +        /* Only the first level has a guaranteed id */
>> +        if (level == 0)
>> +            return cpu_node->acpi_processor_id;
>> +        return (int)((u8 *)cpu_node - (u8 *)table);
>> +    }
>> +    pr_err_once("PPTT table found, but unable to locate core for %d\n",
>> +            cpu);
>> +    return -ENOENT;
>> +}
>