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Re: [PATCH v2 3/3] hw/arm/virt_acpi_build: Generate DBG2 table
From: |
Igor Mammedov |
Subject: |
Re: [PATCH v2 3/3] hw/arm/virt_acpi_build: Generate DBG2 table |
Date: |
Tue, 7 Sep 2021 12:18:06 +0200 |
On Mon, 6 Sep 2021 14:31:39 +0200
Eric Auger <eric.auger@redhat.com> wrote:
> ARM SBBR specification mandates DBG2 table (Debug Port Table 2).
^^ revision here, and possibly a pointer [chapter]
to concrete place in spec where it's said.
> this latter allows to describe one or more debug ports.
>
> Generate an DBG2 table featuring a single debug port, the PL011.
>
> The DBG2 specification can be found at:
> https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/acpi-debug-port-table?redirectedfrom=MSDN
links tend to go stale, I'd use a combo of name and optionally link here:
"Microsoft Debug Port Table 2 (DBG2)"
link
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
table looks correct,
so only style related thing to fix to match the common
ACPI code style.
>
> ---
> v1 -> v2:
> - rebased on Igor's refactoring
> ---
> hw/arm/virt-acpi-build.c | 64 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 63 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 488ea04eed7..de604e79779 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -512,6 +512,65 @@ build_gtdt(GArray *table_data, BIOSLinker *linker,
> VirtMachineState *vms)
> acpi_table_composed(linker, &table);
> }
>
> +/* Debug Port Table 2 (DBG2) */
> +static void
> +build_dbg2(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> +{
> + AcpiTable table = { .sig = "DBG2", .rev = 3, .oem_id = vms->oem_id,
> + .oem_table_id = vms->oem_table_id };
> + int dbg2devicelength, baseaddroffset = 22, namespace_length;
> + char name[] = "COM0";
const?
Also I'd move here:
const int namespace_length = sizeof(name);
> +
> + acpi_init_table(&table, table_data);
> +
> + namespace_length = sizeof name;
> + dbg2devicelength = baseaddroffset +
> + sizeof(struct AcpiGenericAddress) + 4 +
> namespace_length;
^^^^, fragile as it's subject to alignment which
depends on target
I suggest following style:
dbg2devicelength = 22 /* BaseAddressRegister[] offset, fixed size table
header */ +
12 /* BaseAddressRegister[] */ +
4 /* AddressSize[] */
namespace_length /* NamespaceString[] */;
and drop 'baseaddroffset' and 'sizeof(struct AcpiGenericAddress)'
to be more consistent with other ACPI code to annotate where lengths
come from
> + /* offset to the first debug struct */
comment should be verbatim field name from spec table, i.e. in this
case
/* OffsetDbgDeviceInfo */
ditto for the rest of field comments
> + build_append_int_noprefix(table_data, 44, 4);
> + /* number of debug device info struct entries */
> + build_append_int_noprefix(table_data, 1, 4);
> +
> + /* debug device info structure */
copy from spec, for ease to find it using just copy/past,
/* Table 2. Debug Device Information structure format */
> + /* revision */
> + build_append_int_noprefix(table_data, 0, 1);
> + /* length */
> + build_append_int_noprefix(table_data, dbg2devicelength, 2);
> + /* register count */
> + build_append_int_noprefix(table_data, 1, 1);
> + /* name path length */
> + build_append_int_noprefix(table_data, namespace_length, 2);
> + /* name path offset */
> + build_append_int_noprefix(table_data, 38, 2);
> + /* oem data length */
> + build_append_int_noprefix(table_data, 0, 2);
> + /* oem data offset (0 means no OEM data) */
> + build_append_int_noprefix(table_data, 0, 2);
> + /* port type (serial port) */
> + build_append_int_noprefix(table_data, 0x8000, 2);
values could be annotated like following, using description from spec:
build_append_int_noprefix(table_data, 0x8000 /* Serial */, 2);
> + /* port subtype (ARM PL011)*/
> + build_append_int_noprefix(table_data, 0x3, 2);
0x3 /* ARM PL011 UART */
it gives checkpatch warning but all APCI code uses this style,
so it's fine
> + /* reserved */
> + build_append_int_noprefix(table_data, 0, 2);
> + /* base address offset */
> + build_append_int_noprefix(table_data, 22, 2);
> + /* address size offset */
> + build_append_int_noprefix(table_data, 34, 2);
> +
> + /* BaseAddressRegister */
> + build_append_gas(table_data, AML_AS_SYSTEM_MEMORY, 8, 0, 1,
> + vms->memmap[VIRT_UART].base);
> +
> + /* AddressSize (PL011 UART length) */
> + build_append_int_noprefix(table_data, 0x1000, 4);
^^^^
at least point out where it comes from or use macro to define
value and use it here and in pl011_init()
> +
> + /* NamespaceString */
> + g_array_append_vals(table_data, name, namespace_length);
> +
> + acpi_table_composed(linker, &table);
> +};
> +
> /*
> * ACPI spec, Revision 5.1 Errata A
> * 5.2.12 Multiple APIC Description Table (MADT)
> @@ -770,7 +829,7 @@ void virt_acpi_build(VirtMachineState *vms,
> AcpiBuildTables *tables)
> dsdt = tables_blob->len;
> build_dsdt(tables_blob, tables->linker, vms);
>
> - /* FADT MADT GTDT MCFG SPCR pointed to by RSDT */
> + /* FADT MADT GTDT MCFG SPCR DBG2 pointed to by RSDT */
> acpi_add_table(table_offsets, tables_blob);
> build_fadt_rev5(tables_blob, tables->linker, vms, dsdt);
>
> @@ -793,6 +852,9 @@ void virt_acpi_build(VirtMachineState *vms,
> AcpiBuildTables *tables)
> acpi_add_table(table_offsets, tables_blob);
> build_spcr(tables_blob, tables->linker, vms);
>
> + acpi_add_table(table_offsets, tables_blob);
> + build_dbg2(tables_blob, tables->linker, vms);
> +
> if (vms->ras) {
> build_ghes_error_table(tables->hardware_errors, tables->linker);
> acpi_add_table(table_offsets, tables_blob);
- [PATCH v2 0/3] hw/arm/virt_acpi_build: Generate DBG2 table, Eric Auger, 2021/09/06
- [PATCH v2 2/3] bios-tables-test: Generate reference table for virt/DBG2, Eric Auger, 2021/09/06
- [PATCH v2 3/3] hw/arm/virt_acpi_build: Generate DBG2 table, Eric Auger, 2021/09/06
- Re: [PATCH v2 3/3] hw/arm/virt_acpi_build: Generate DBG2 table,
Igor Mammedov <=
- [PATCH v2 1/3] tests/acpi: Add void table for virt/DBG2 bios-tables-test, Eric Auger, 2021/09/06
- Re: [PATCH v2 0/3] hw/arm/virt_acpi_build: Generate DBG2 table, Igor Mammedov, 2021/09/07
- Re: [PATCH v2 0/3] hw/arm/virt_acpi_build: Generate DBG2 table, Andrew Jones, 2021/09/08