Hi Simon, On Sat, Dec 7, 2019 at 12:54 PM Simon Glass <s...@chromium.org> wrote: > > This driver handles communication with the systemagent which needs to be > told when U-Boot has completed its init. > > Signed-off-by: Simon Glass <s...@chromium.org> > > --- > > Changes in v6: None > Changes in v5: None > Changes in v4: > - Add a comment for enable_bios_reset_cpl() > - Tidy up header guards > - use GENMASK() for VTBAR_MASK > > Changes in v3: None > Changes in v2: None > > arch/x86/cpu/apollolake/Makefile | 2 + > arch/x86/cpu/apollolake/systemagent.c | 19 ++++++++++ > .../include/asm/arch-apollolake/systemagent.h | 37 +++++++++++++++++++ > 3 files changed, 58 insertions(+) > create mode 100644 arch/x86/cpu/apollolake/systemagent.c > create mode 100644 arch/x86/include/asm/arch-apollolake/systemagent.h > > diff --git a/arch/x86/cpu/apollolake/Makefile > b/arch/x86/cpu/apollolake/Makefile > index fdda748ea3..3a8c2f66a3 100644 > --- a/arch/x86/cpu/apollolake/Makefile > +++ b/arch/x86/cpu/apollolake/Makefile > @@ -2,5 +2,7 @@ > # > # Copyright 2019 Google LLC > > +obj-$(CONFIG_SPL_BUILD) += systemagent.o > + > obj-y += pmc.o > obj-y += uart.o > diff --git a/arch/x86/cpu/apollolake/systemagent.c > b/arch/x86/cpu/apollolake/systemagent.c > new file mode 100644 > index 0000000000..3a41b329c3 > --- /dev/null > +++ b/arch/x86/cpu/apollolake/systemagent.c > @@ -0,0 +1,19 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2017 Intel Corporation. > + * Take from coreboot project file of the same name > + */ > + > +#include <common.h> > +#include <asm/intel_regs.h> > +#include <asm/io.h> > +#include <asm/arch/systemagent.h> > + > +void enable_bios_reset_cpl(void) > +{ > + /* > + * Set bits 0+1 of BIOS_RESET_CPL to indicate to the CPU > + * that BIOS has initialised memory and power management > + */
Could you put more comments here, like what you mentioned in the v5 comments: "The FSP-S does not do it. If we leave this as zero then I believe the power-aware interrupts don't work in Linux, and cpu 0 always gets the interrupt." > + setbits_8(MCHBAR_REG(BIOS_RESET_CPL), 3); > +} [snip] Regards, Bin