Re: [PATCH] Revert "arm64: Increase the max granular size"

From: Timur Tabi
Date: Thu Mar 17 2016 - 10:50:52 EST

Catalin Marinas wrote:
>Yes, that's exactly it. Ours is an ACPI system, and so we have to have our
>own defconfig for now. We're holding off on pushing our own defconfig
>changes (enabling drivers, etc) until ACPI is enabled in

Is there anything that prevents you from providing a dtb/dts for this

We don't have a boot loader capable of passing a device tree to the kernel. It's an ARM Server chip. It doesn't do device tree. It's 100% ACPI. We boot with UEFI that configures the system and generates ACPI tables.

I just want to make this crystal clear, because it comes up every now and then. The QDF2432 is an ACPI-only SOC with no device tree support whatsoever. Zero. Zip. Nada. It's not an option.

Keep in mind that on an ACPI system like ours, the boot loader (UEFI in our case) configures the system extensively. It does a lot of things that the kernel would normally do on a device tree system. For example, pin control is handled completely by UEFI. The kernel does not set the pin muxes or GPIO directions. That means we don't support dynamic pin muxing. Before the kernel is booted, the GPIO pins are fixed.

We're not going to create an entire device tree from scratch for this chip, and then make the extensive modifications necessary to our boot loader for parsing and modifying that device tree. That would take months of work, and it would be all throw-away code.

Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the
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