On 07/09/15 22:29, Rafael J. Wysocki wrote:
On Friday, September 04, 2015 06:06:48 PM Marc Zyngier wrote:
IRQ controllers and timers are the two types of device the kernel requires before being able to use the device driver model.
ACPI so far lacks a proper probing infrastructure similar to the one we have with DT, where we're able to declare IRQ chips and clocksources inside the driver code, and let the core code pick it up and call us back on a match. This leads to all kind of really ugly hacks all over the arm64 code and even in the ACPI layer.
In order to allow some basic probing based on the ACPI tables, introduce "struct acpi_probe_entry" which contains just enough data and callbacks to match a table, an optional subtable, and call a probe function. A driver can, at build time, register itself and expect being called if the right entry exists in the ACPI table.
A acpi_probe_device_init() is provided, taking an ACPI table identifier, and iterating over the registered entries.
What about things that are provided by the ACPI namespace (eg. via _MAT) rather than in static tables?
By the time we get to process non-static tables, the whole probing infrastructure (including the ACPI interpreter) should be up and running. I'm not seeing this stuff as a replacement for more dynamic things - quite the opposite. It is only to be used for early bring-up.
Thanks,
M.