[PATCH 3/6] risc-v: add support for QEMU provided ACPI tables

[Tom Rini]

On Thu, Nov 16, 2023 at 08:54:44PM +0100, Heinrich Schuchardt wrote:
> On 11/16/23 19:35, Tom Rini wrote:
> > On Wed, Nov 15, 2023 at 03:23:52PM +0100, Heinrich Schuchardt wrote:
> > > If U-Boot provides ACPI tables on RISC-V QEMU, we need to copy what QEMU
> > > provides.
> > > 
> > > Provide the qfw command to retrieve information from the QEMU firmware.
> > > 
> > > Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> > > ---
> > >   board/emulation/qemu-riscv/Kconfig | 2 ++
> > >   lib/Kconfig                        | 2 +-
> > >   2 files changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/board/emulation/qemu-riscv/Kconfig b/board/emulation/qemu-riscv/Kconfig
> > > index d56b4b5bc1..933b035991 100644
> > > --- a/board/emulation/qemu-riscv/Kconfig
> > > +++ b/board/emulation/qemu-riscv/Kconfig
> > > @@ -33,6 +33,8 @@ config BOARD_SPECIFIC_OPTIONS # dummy
> > >   	def_bool y
> > >   	select GENERIC_RISCV
> > >   	select SUPPORT_SPL
> > > +	select CMD_QFW if GENERATE_ACPI_TABLE
> > > +	select QFW_MMIO if GENERATE_ACPI_TABLE
> > >   	imply AHCI
> > >   	imply SMP
> > >   	imply BOARD_LATE_INIT
> > > diff --git a/lib/Kconfig b/lib/Kconfig
> > > index 19649517a3..a94adc388f 100644
> > > --- a/lib/Kconfig
> > > +++ b/lib/Kconfig
> > > @@ -300,7 +300,7 @@ config SPL_ACPI
> > >   config GENERATE_ACPI_TABLE
> > >   	bool "Generate an ACPI (Advanced Configuration and Power Interface) table"
> > >   	depends on ACPI
> > > -	select QFW if QEMU
> > > +	select QFW if QEMU || TARGET_QEMU_VIRT
> > >   	help
> > >   	  The Advanced Configuration and Power Interface (ACPI) specification
> > >   	  provides an open standard for device configuration and management
> > 
> > In this case we aren't "generating" the table, we're using the table
> > we've been passed, yes? I think that further shows the need to add a
> > symbol which means that, and use it where appropriate. Or am I
> > misunderstanding the GENERATE_ACPI_TABLE symbol?
> > 
> 
> If you look at drivers/misc/qfw.c you will find, that we only read ACPI
> tables created in QEMU if CONFIG_GNERATE_ACPI_TABLE=y. This contradicts the
> long text of the configuration symbol.
> 
> CONFIG_GNERATE_ACPI_TABLE is used to decide if we publish a device-tree in
> the EFI sub-system.
> 
> Simon tried to clean up EFI a bit in 53e8e6f98679 ("efi: x86: Correct the
> condition for installing ACPI tables") but did not change cmd/bootefi.c.
> 
> I would agree to calling the current usage of the symbol incoherent.

Yes, we need to start by making our ACPI-related symbols coherent. We
need a symbol for "create ACPI tables" such as we seem to be doing in
for example arch/x86/cpu/baytrail/acpi.c. And then a different symbol
for utilizing pass-through tables. And then probably another symbol or
two to handle what U-Boot does with these tables once U-Boot has access
to a populated table.

-- 
Tom
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