Re: [Qemu-devel] [PATCH v2 2/2] hw/arm/virt-acpi-build: Add DBG2 table

[Shannon Zhao <shannon.zhao@linaro.org>]

On 2015/9/15 0:35, Andrew Jones wrote:
> On Sun, Sep 13, 2015 at 04:06:33PM +0100, Leif Lindholm wrote:
>> Add a DBG2 table, describing the pl011 UART.
>>
>> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
>> ---
>>  hw/arm/virt-acpi-build.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 59 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>> index 9088248..0ea7023 100644
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -352,6 +352,61 @@ build_rsdp(GArray *rsdp_table, GArray *linker, unsigned rsdt)
>>  }
>>  
>>  static void
>> +build_dbg2(GArray *table_data, GArray *linker, VirtGuestInfo *guest_info)
>> +{
>> +    AcpiDebugPort2Header *dbg2;
>> +    AcpiDebugPort2Device *dev;
>> +    struct AcpiGenericAddress *addr;
>> +    uint32_t *addr_size;
>> +    char *name;
>> +    const MemMapEntry *uart_memmap = &guest_info->memmap[VIRT_UART];
>> +    int table_size, dev_size, namepath_length;
>> +    const char namepath[] = ".";
>> +
>> +    namepath_length = strlen(namepath) + 1;
>> +    dev_size = sizeof(*dev) + sizeof(*addr) * 1 + sizeof(uint32_t) * 1 +
>> +        namepath_length;
>> +    table_size = dev_size + sizeof(AcpiDebugPort2Header);
>> +
>> +    dbg2 = acpi_data_push(table_data, table_size);
>> +    dev = (void *)dbg2 + sizeof(*dbg2);
>> +    addr = (void *)dev + sizeof(*dev);
>> +    addr_size = (void *)addr + sizeof(*addr);
>> +    name = (void *)addr_size + sizeof(*addr_size);
>> +

This looks hard to read.

>> +    dbg2->devices_offset = sizeof(*dbg2);
>> +    dbg2->devices_count = 1;
>> +
>> +    /* First (only) debug device */
>> +    dev->revision = 0;
>> +    dev->length = cpu_to_le16(dev_size);
>> +    dev->address_count = 1;
>> +    dev->namepath_length = cpu_to_le16(namepath_length);
>> +    dev->namepath_offset = cpu_to_le16((void *)name - (void *)dev);
>> +    dev->oem_data_length = 0;
>> +    dev->oem_data_offset = 0;
>> +    dev->port_type = cpu_to_le16(0x8000);    /* Serial */
>> +    dev->port_subtype = cpu_to_le16(0x3);    /* ARM PL011 UART */
>> +    dev->base_address_offset = cpu_to_le16((void *)addr - (void *)dev);
>> +    dev->address_size_offset = cpu_to_le16((void *)addr_size - (void *)dev);
>> +
>> +    /* First (only) address */
>> +    addr->space_id = AML_SYSTEM_MEMORY;
>> +    addr->bit_width = 8;
>> +    addr->bit_offset = 0;
>> +    addr->access_width = 1;
>> +    addr->address = cpu_to_le64(uart_memmap->base);
>> +
>> +    /* Size of first (only) address */
>> +    *addr_size = cpu_to_le32(sizeof(*addr));
>> +
>> +    /* Namespace String for first (only) device */
>> +    strcpy(name, namepath);
>> +
>> +    build_header(linker, table_data, (void *)dbg2, "DBG2", table_size, 0);
>> +}
>> +
>> +static void
>>  build_spcr(GArray *table_data, GArray *linker, VirtGuestInfo *guest_info)
>>  {
>>      AcpiSerialPortConsoleRedirection *spcr;
>> @@ -577,7 +632,7 @@ void virt_acpi_build(VirtGuestInfo *guest_info, AcpiBuildTables *tables)
>>      dsdt = tables_blob->len;
>>      build_dsdt(tables_blob, tables->linker, guest_info);
>>  
>> -    /* FADT MADT GTDT MCFG SPCR pointed to by RSDT */
>> +    /* FADT MADT GTDT MCFG DBG2 SPCR pointed to by RSDT */
>>      acpi_add_table(table_offsets, tables_blob);
>>      build_fadt(tables_blob, tables->linker, dsdt);
>>  
>> @@ -591,6 +646,9 @@ void virt_acpi_build(VirtGuestInfo *guest_info, AcpiBuildTables *tables)
>>      build_mcfg(tables_blob, tables->linker, guest_info);
>>  
>>      acpi_add_table(table_offsets, tables_blob);
>> +    build_dbg2(tables_blob, tables->linker, guest_info);
>> +
>> +    acpi_add_table(table_offsets, tables_blob);
>>      build_spcr(tables_blob, tables->linker, guest_info);
>>  
>>      /* RSDT is pointed to by RSDP */
>> -- 
>> 2.1.4
>>
>>
> 
> This looks good to me, since it's pretty unlikely we'll ever want
> more than one device, so
> 
> Reviewed-by: Andrew Jones <drjones@redhat.com>
> 
> But, when I read that the table generation had become dynamic, I was sort
> of expecting something like
> 

Leif, you can have a look at build_madt.

-- 
Shannon