Subject: [PATCH v2 05/18] ARM64 / ACPI: Parse FADT table to get PSCI flags for PSCI init

From: [email-masked] (Hanjun Guo)
Date: Tue, 19 Aug 2014 20:13:46 +0800

On 2014-8-19 19:10, Mark Rutland wrote:
>>>> @@ -47,6 +49,26 @@ void __init __acpi_unmap_table(char *map, unsigned long size)
>>>>  	early_memunmap(map, size);
>>>>  }
>>>>  
>>>> +static int __init acpi_parse_fadt(struct acpi_table_header *table)
>>>> +{
>>>> +	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
>>>> +
>>>> +	/*
>>>> +	 * Revision in table header is the FADT Major version,
>>>> +	 * and there is a minor version of FADT which was introduced
>>>> +	 * by ACPI 5.1, we only deal with ACPI 5.1 or higher version
>>>> +	 * to get arm boot flags, or we will disable ACPI.
>>>> +	 */
>>>> +	if (table->revision < 5 || fadt->minor_revision < 1) {
>>>
>>> If we ever get revision 6.0, this would trigger.
>>
>> Yes, good catch, actually I already fixed that in my local git repo,
>>
>> +       if (table->revision > 5 ||
>> +           (table->revision == 5 && fadt->minor_revision >= 1)) {
>> +               return 0;
>> +       } else {
>> +               pr_info("FADT revision is %d.%d, no PSCI support, should be 5.1
>> or higher\n",
>> +                       table->revision, fadt->minor_revision);
>> +               disable_acpi();
>> +               return -EINVAL;
>> +       }
> 
> Given you return in the first path, you don't need the remaining code to
> live in an else block.

Agreed, I will update it, and move disable_acpi() outside this function and keep
it in one place as Sudeep suggested.

Thanks
Hanjun