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

[Ilkka Koskinen]

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@xxxxxxxxxxxxxxxxxxxxxx>
> > > ---
> > >  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