On Thu, Dec 7, 2017 at 11:29 AM, Prarit Bhargava <pra...@redhat.com> wrote:
> Other architectures can use SPCR to setup an early console or console but
> the current code is ARM64 specific.
>
> Change the name of parse_spcr() to acpi_parse_spcr(). Add a weak
> function acpi_arch_setup_console() that can be used for arch-specific
> setup. Move SPCR initialization flag into ACPI code. Update the
> Documention on the use of the SPCR earlycon.
>
> This patch does not change arm64 behaviour.
Let's hope so. Our E44 erratum work-around has caused lots of
problems in the past, so the code is a bit fragile.
> +static bool qdf2400_erratum_44_present(struct acpi_table_header *h)
> +{
> + if (memcmp(h->oem_id, "QCOM ", ACPI_OEM_ID_SIZE))
> + return false;
> +
> + if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE))
> + return true;
> +
> + if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) &&
> + h->oem_revision == 1)
> + return true;
> +
> + return false;
> +}
Please give us a chance to test this patch before merging. We've had a
lot of problems with our E44 work-around, and we need to make sure
that qdf2400_erratum_44_present function is called before the pl011
driver is probed.
> +
> +/*
> + * APM X-Gene v1 and v2 UART hardware is an 16550 like device but has its
> + * register aligned to 32-bit. In addition, the BIOS also encoded the
> + * access width to be 8 bits. This function detects this errata condition.
> + */
> +static bool xgene_8250_erratum_present(struct acpi_table_spcr *tb)
> +{
> + bool xgene_8250 = false;
> +
> + if (tb->interface_type != ACPI_DBG2_16550_COMPATIBLE)
> + return false;
> +
> + if (memcmp(tb->header.oem_id, "APMC0D", ACPI_OEM_ID_SIZE) &&
> + memcmp(tb->header.oem_id, "HPE ", ACPI_OEM_ID_SIZE))
> + return false;
> +
> + if (!memcmp(tb->header.oem_table_id, "XGENESPC",
> + ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 0)
> + xgene_8250 = true;
> +
> + if (!memcmp(tb->header.oem_table_id, "ProLiant",
> + ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 1)
> + xgene_8250 = true;
> +
> + return xgene_8250;
> +}
I suspect that this function has the same issues as
qdf2400_erratum_44_present().
> +config ACPI_SPCR_TABLE
> + bool "ACPI Serial Port Console Redirection Support"
> + default y if ARM64
> + help
> + Enable support for Serial Port Console Redirection (SPCR) Table.
> + This table provides information about the configuration of the
> + earlycon console.
> +
So ACPI without SPCR has never been tested by us. Making it optional
makes me a little nervous. We'll have to evaluate this change.
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