Hi Jeremy,
Thanks for the patch. However I played with booting with ACPI with and
without your patch - I may be missing something, but I don't see a
difference, when using earlycon (both
'earlycon=uart,mmio32,0xf0512000' and
'earlycon=uart8250,mmio32,0xf0512000'). Can you please show what
booting scenario is fixed with the patch?
Thanks,
Marcin
wt., 9 kwi 2019 o 02:33 Jeremy Linton <jeremy.lin...@arm.com> napisał(a):
>
> The mcbin (and likely others) have a nonstandard uart clock.
> This means that the earlycon programming will incorrectly set
> the baud rate if it is specified. The way around this is to tell
> the kernel to continue using the preprogrammed baud rate. This
> is done by setting the baud to 0.
>
> Further, the SPCR and DSDT serial port need to match the port
> address and port access type for the kernel to conclude they
> are the same.
>
> So while ARM_GAS32 is correct for earlycon (it can be used alone
> on the kernel command line) by providing the reg-shift=2 value,
> it also sets the io type to MMIO32, which doesn't match the DSDT
> defined MMIO. This means that the actual console will never appear.
> The obvious fix is to set reg-width=4 in DSDT, but that also changes
> the accesssors to 32-bits (similarly to earlycon) and results in
> console failure.
>
> So the less obvious fix, is to use the GAS8 specifier. This means
> that earlycon needs to be fully specified as
> earlycon=uart,mmio32,0xf0512000, but has the extremely useful feature
> that the console default works without any user interaction.
>
> If in the future marvell decides to define their own ACPI id for the
> console and upstream a quirk, the ARM_GAS8 portion of this should
> be reverted.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jeremy Linton <jeremy.lin...@arm.com>
> ---
> Silicon/Marvell/Armada7k8k/AcpiTables/Spcr.aslc | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Silicon/Marvell/Armada7k8k/AcpiTables/Spcr.aslc
> b/Silicon/Marvell/Armada7k8k/AcpiTables/Spcr.aslc
> index e78bb9036f..06c7af069c 100644
> --- a/Silicon/Marvell/Armada7k8k/AcpiTables/Spcr.aslc
> +++ b/Silicon/Marvell/Armada7k8k/AcpiTables/Spcr.aslc
> @@ -30,11 +30,11 @@ EFI_ACPI_SERIAL_PORT_CONSOLE_REDIRECTION_TABLE Spcr = {
> { EFI_ACPI_RESERVED_BYTE,
> EFI_ACPI_RESERVED_BYTE,
> EFI_ACPI_RESERVED_BYTE }, //
> Reserved1[3]
> - ARM_GAS32 (FixedPcdGet64(PcdSerialRegisterBase)), //
> BaseAddress
> + ARM_GAS8 (FixedPcdGet64(PcdSerialRegisterBase)), //
> BaseAddress
> EFI_ACPI_SERIAL_PORT_CONSOLE_REDIRECTION_TABLE_INTERRUPT_TYPE_GIC, //
> InterruptType
> 0, //
> Irq
> 51, //
> GlobalSystemInterrupt
> - EFI_ACPI_SERIAL_PORT_CONSOLE_REDIRECTION_TABLE_BAUD_RATE_115200, //
> BaudRate
> + 0, //
> Keep Firmware Baud
> EFI_ACPI_SERIAL_PORT_CONSOLE_REDIRECTION_TABLE_PARITY_NO_PARITY, //
> Parity
> EFI_ACPI_SERIAL_PORT_CONSOLE_REDIRECTION_TABLE_STOP_BITS_1, //
> StopBits
> 0, //
> FlowControl
> --
> 2.20.1
>
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