[U-Boot] [PATCH v2] Initial support for ACPI Tables for qemu-x86 target.

[Bin Meng]

Hi Saket,

On Thu, Jun 25, 2015 at 3:38 AM, Saket Sinha <saket.sinha89 at gmail.com> wrote:
> Hi Simon,
>
> Please find my comments inline -
>

[snip]

>>> +static unsigned long acpi_fill_mcfg(unsigned long current)
>>> +{
>>> +       pci_dev_t qemu_dev;
>>> +       struct pci_device_id qemu_id[] = { { 0x8086, 0x29c0 } };
>>> +        u32 reg;
>>> +
>>> +        qemu_dev = pci_find_devices(qemu_id, 0);
>>> +        if (!qemu_dev)
>>> +                return current;
>>> +
>>> +        reg = pci_read_config_dword(qemu_dev, 0x60, &reg);
>>> +        if ((reg & 0x07) != 0x01)  // require enabled + 256MB size
>>> +                return current;
>>> +
>>> +        current += acpi_create_mcfg_mmconfig((struct acpi_mcfg_mmconfig *) current,
>>> +                                             reg & 0xf0000000, 0x0, 0x0, 255);
>>
>> We need actually programming the chipset to enable the ECAM. This
>> needs to be done in the arch/x86/cpu/qemu/qemu.c.
>>
>
> Would be needing your guidance for this. Would need some info about
> qemu working and  ECAM's role.

ECAM is PCIe enhanced configuration access mechanism. QEMU i440FX is a
PCI chipset, which does not support ECAM. For QEMU Q35 which supports
PCIe, you need check the Q35 chipset. I just checked that, it's on
D0:F0:R60h a register called PCIEXBAR. You need hook U-Boot's PCI
configuration RW routines to actually use ECAM to verify it is really
working.

[snip]

>>> +static void acpi_create_fadt(struct acpi_fadt *fadt, struct acpi_facs *facs, void *dsdt)
>>> +{
>>> +       acpi_header_t *header = &(fadt->header);
>>> +       u16 pmbase;
>>> +
>>> +       pci_dev_t bdf = PCI_BDF(0, 0x1f, 0);
>>> +       pci_read_config_word(bdf, 0x40, &pmbase);
>>> +
>>> +       memset((void *) fadt, 0, sizeof(struct acpi_fadt));
>>> +       memcpy(header->signature, "FACP", 4);
>>> +       header->length = sizeof(struct acpi_fadt);
>>> +       header->revision = 3;
>>> +       memcpy(header->oem_id, OEM_ID, 6);
>>> +       memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
>>> +       memcpy(header->asl_compiler_id, ASLC, 4);
>>> +       header->asl_compiler_revision = 0;
>>
>> We should use this field to indicate which compiler we used to compile
>> the ASL. Could be Intel (INTL) or Microsoft (MSFT). We also need put
>> the compiler version into header->asl_compiler_revision. You will need
>> get the compiler version generated by some shell scripts
>> automatically. Note we should only put ASL compiler id/rev when it
>> comes to definition block. For others, we still need to use creator id
>> and revision.
>>
> Details of the compiler I am using can be found below -
>
> Intel ACPI Component Architecture
> ASL+ Optimizing Compiler version 20141107-64 [Dec 17 2014]
> Copyright (c) 2000 - 2014 Intel Corporation
>
> I am not sure about the id but the revision number 20141107-64 cab be parsed.
>

The id should be "INTL" for Intel compiler and "MSFT" for Microsoft compiler.

[snip]

Regards,
Bin