Re: [PATCH v3 2/2] ACPI: AGDI: Add driver for Arm Generic Diagnostic Dump and Reset device

Ilkka Koskinen
2022-01-14T02:19:11Z

Hi Lorenzo,

On Wed, 5 Jan 2022, Ilkka Koskinen wrote:
>
> Hi Lorenzo,
>
> On Wed, 5 Jan 2022, Lorenzo Pieralisi wrote:
>> [+James, for SDEI bits]
>>
>> On Thu, Dec 30, 2021 at 07:37:25PM -0800, Ilkka Koskinen wrote:
>>> ACPI for Arm Components 1.1 Platform Design Document v1.1 [0] specifices
>>> Arm Generic Diagnostic Device Interface (AGDI). It allows an admin to
>>> issue diagnostic dump and reset via an SDEI event or an interrupt.
>>> This patch implements SDEI path.
>>>
>>> [0] https://developer.arm.com/documentation/den0093/latest/
>>>
>>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
>>> ---
>>> drivers/acpi/arm64/Kconfig | 8 +++
>>> drivers/acpi/arm64/Makefile | 1 +
>>> drivers/acpi/arm64/agdi.c | 125 ++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 134 insertions(+)
>>> create mode 100644 drivers/acpi/arm64/agdi.c

<snip>

>>> diff --git a/drivers/acpi/arm64/agdi.c b/drivers/acpi/arm64/agdi.c
>>> new file mode 100644
>>> index 000000000000..6525ccbae5c1
>>> --- /dev/null
>>> +++ b/drivers/acpi/arm64/agdi.c

<snip>

>>>
>>> +static int __init agdi_init(void)
>>> +{
>>> + int ret;
>>> + acpi_status status;
>>> + struct acpi_table_agdi *agdi_table;
>>> + struct agdi_data pdata;
>>> + struct platform_device *pdev;
>>> +
>>> + if (acpi_disabled)
>>> + return 0;
>>
>> Why don't we call agdi_init() from acpi_init() as we do for IORT/VIOT ?
>>
>> I don't think it is necessary to add a device_initcall(), with related
>> ordering dependencies.
>
> That's a good point. I change it.

Actually, I looked at this more carefully. acpi_init() is called in
subsys_initcall() while sdei_init() is called in subsys_initcall_sync().
That is, if I call this function in acpi_init(), SDEI driver won't be
ready and this driver fails to register the event.

Cheers, Ilkka