Re: [PATCH] powerpc/microwatt: Add mmu bits to device tree
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2022-05-20 00:06:57
Excerpts from Joel Stanley's message of May 19, 2022 10:57 pm:
In commit 5402e239d09f ("powerpc/64s: Get LPID bit width from device
tree") the kernel tried to determine the pid and lpid bits from the
device tree. If they are not found, there is a fallback, but Microwatt
wasn't covered as has the unusual configuration of being both !HV and bare
metal.
Set the values in the device tree to avoid having to add a special case.
The lpid value is the only one required, but add both for completeness.
Fixes: 5402e239d09f ("powerpc/64s: Get LPID bit width from device tree")
Signed-off-by: Joel Stanley <joel@jms.id.au>LGTM... does Microwatt actually need 12 lpid bits, or does it just need the LPID 0 partition table entry? I wonder if you set it to 1. That's a minor nit though. Acked-by: Nicholas Piggin <npiggin@gmail.com>
quoted hunk ↗ jump to hunk
--- arch/powerpc/boot/dts/microwatt.dts | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts index 65b270a90f94..b69db1d275cd 100644 --- a/arch/powerpc/boot/dts/microwatt.dts +++ b/arch/powerpc/boot/dts/microwatt.dts@@ -90,6 +90,8 @@ PowerPC,Microwatt@0 { 64-bit; d-cache-size = <0x1000>; ibm,chip-id = <0>; + ibm,mmu-lpid-bits = <12>; + ibm,mmu-pid-bits = <20>; }; };-- 2.35.1