On Mon, 6 Sep 2021 14:31:39 +0200 Eric Auger <eric.au...@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.au...@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);