Re: [PATCH for-6.2] hw/arm/virt_acpi_build: Generate DBG2 table

[Igor Mammedov]

On Tue, 10 Aug 2021 10:30:57 +0200
Eric Auger <eric.auger@redhat.com> wrote:

> ARM SBBR specification mandates DBG2 table (Debug Port Table 2).
> 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
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>

using packed structures for composing ACPI tables is discouraged,
pls use build_append_int_noprefix() API instead. You can look at
build_amd_iommu() as an example.

PS:
Also note field comments format.
/it should be verbatim copy of entry name from respective table in spec/

> 
> ---
> 
> Tested by comparing the content with the table generated
> by EDK2 along with the SBSA-REF machine (code generated by
> DynamicTablesPkg/Library/Acpi/Arm/AcpiDbg2LibArm/Dbg2Generator.c).
> 
> I reused the Generic Address Structure filled by QEMU in the SPCR, ie.
> bit_width = 8 and byte access. While EDK2 sets bit_width = 32 and
> dword access. Also the name exposed by acpica tools is different:
> 'COM0' in my case where '\_SB.COM0' in SBSA-REF case?
> ---
>  hw/arm/virt-acpi-build.c    | 77 ++++++++++++++++++++++++++++++++++++-
>  include/hw/acpi/acpi-defs.h | 50 ++++++++++++++++++++++++
>  2 files changed, 126 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 037cc1fd82..35f27b41df 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -563,6 +563,78 @@ build_gtdt(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>                   vms->oem_table_id);
>  }
>  
> +#define ACPI_DBG2_PL011_UART_LENGTH 0x1000
> +
> +/* DBG2 */
> +static void
> +build_dbg2(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> +{
> +    int addr_offset, addrsize_offset, namespace_offset, namespace_length;
> +    const MemMapEntry *uart_memmap = &vms->memmap[VIRT_UART];
> +    struct AcpiGenericAddress *base_address;
> +    int dbg2_start = table_data->len;
> +    AcpiDbg2Device *dbg2dev;
> +    char name[] = "COM0";
> +    AcpiDbg2Table *dbg2;
> +    uint32_t *addr_size;
> +    uint8_t *namespace;
> +
> +    dbg2 = acpi_data_push(table_data, sizeof *dbg2);
> +    dbg2->info_offset = sizeof *dbg2;
> +    dbg2->info_count = 1;
> +
> +    /* debug device info structure */
> +
> +    dbg2dev = acpi_data_push(table_data, sizeof(AcpiDbg2Device));
> +
> +    dbg2dev->revision = 0;
> +    namespace_length = sizeof name;
> +    dbg2dev->length = sizeof *dbg2dev + sizeof(struct AcpiGenericAddress) +
> +                      4 + namespace_length;
> +    dbg2dev->register_count = 1;
> +
> +    addr_offset = sizeof *dbg2dev;
> +    addrsize_offset = addr_offset + sizeof(struct AcpiGenericAddress);
> +    namespace_offset = addrsize_offset + 4;
> +
> +    dbg2dev->namepath_length = cpu_to_le16(namespace_length);
> +    dbg2dev->namepath_offset = cpu_to_le16(namespace_offset);
> +    dbg2dev->oem_data_length = cpu_to_le16(0);
> +    dbg2dev->oem_data_offset = cpu_to_le16(0); /* No OEM data is present */
> +    dbg2dev->port_type = cpu_to_le16(ACPI_DBG2_SERIAL_PORT);
> +    dbg2dev->port_subtype = cpu_to_le16(ACPI_DBG2_ARM_PL011);
> +
> +    dbg2dev->base_address_offset = cpu_to_le16(addr_offset);
> +    dbg2dev->address_size_offset = cpu_to_le16(addrsize_offset);
> +
> +    /*
> +     * variable length content:
> +     * BaseAddressRegister[1]
> +     * AddressSize[1]
> +     * NamespaceString[1]
> +     */
> +
> +    base_address = acpi_data_push(table_data,
> +                                  sizeof(struct AcpiGenericAddress));
> +
> +    base_address->space_id = AML_SYSTEM_MEMORY;
> +    base_address->bit_width = 8;
> +    base_address->bit_offset = 0;
> +    base_address->access_width = 1;
> +    base_address->address = cpu_to_le64(uart_memmap->base);
> +
> +    addr_size = acpi_data_push(table_data, sizeof *addr_size);
> +    *addr_size = cpu_to_le32(ACPI_DBG2_PL011_UART_LENGTH);
> +
> +    namespace = acpi_data_push(table_data, namespace_length);
> +    memcpy(namespace, name, namespace_length);
> +
> +    build_header(linker, table_data,
> +                 (void *)(table_data->data + dbg2_start), "DBG2",
> +                 table_data->len - dbg2_start, 3, vms->oem_id,
> +                 vms->oem_table_id);
> +}
> +
>  /* MADT */
>  static void
>  build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> @@ -790,7 +862,7 @@ 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);
>  
> @@ -813,6 +885,9 @@ 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);
> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> index cf9f44299c..bdb2ebed2c 100644
> --- a/include/hw/acpi/acpi-defs.h
> +++ b/include/hw/acpi/acpi-defs.h
> @@ -618,4 +618,54 @@ struct AcpiIortRC {
>  } QEMU_PACKED;
>  typedef struct AcpiIortRC AcpiIortRC;
>  
> +/* DBG2 */
> +
> +/* Types for port_type field above */
> +
> +#define ACPI_DBG2_SERIAL_PORT       0x8000
> +#define ACPI_DBG2_1394_PORT         0x8001
> +#define ACPI_DBG2_USB_PORT          0x8002
> +#define ACPI_DBG2_NET_PORT          0x8003
> +
> +/* Subtypes for port_subtype field above */
> +
> +#define ACPI_DBG2_16550_COMPATIBLE  0x0000
> +#define ACPI_DBG2_16550_SUBSET      0x0001
> +#define ACPI_DBG2_ARM_PL011         0x0003
> +#define ACPI_DBG2_ARM_SBSA_32BIT    0x000D
> +#define ACPI_DBG2_ARM_SBSA_GENERIC  0x000E
> +#define ACPI_DBG2_ARM_DCC           0x000F
> +#define ACPI_DBG2_BCM2835           0x0010
> +
> +#define ACPI_DBG2_1394_STANDARD     0x0000
> +
> +#define ACPI_DBG2_USB_XHCI          0x0000
> +#define ACPI_DBG2_USB_EHCI          0x0001
> +
> +/* Debug Device Information Subtable */
> +
> +struct AcpiDbg2Device {
> +    uint8_t  revision;
> +    uint16_t length;
> +    uint8_t  register_count; /* Number of base_address registers */
> +    uint16_t namepath_length;
> +    uint16_t namepath_offset;
> +    uint16_t oem_data_length;
> +    uint16_t oem_data_offset;
> +    uint16_t port_type;
> +    uint16_t port_subtype;
> +    uint8_t  reserved[2];
> +    uint16_t base_address_offset;
> +    uint16_t address_size_offset;
> +}  QEMU_PACKED;
> +typedef struct AcpiDbg2Device AcpiDbg2Device;
> +
> +struct AcpiDbg2Table {
> +    ACPI_TABLE_HEADER_DEF /* ACPI common table header */
> +    uint32_t info_offset; /* offset to the first debug struct */
> +    uint32_t info_count;  /* number of debug device info struct entries */
> +    uint8_t  dbg2_device_info[];
> +} QEMU_PACKED;
> +typedef struct AcpiDbg2Table AcpiDbg2Table;
> +
>  #endif