Change in coreboot[master]: soc/intel/alderlake: Enable VT-d

[Angel Pons (Code Review)]

Attention is currently required from: Furquan Shaikh, Maulik V Vaghela, Tim Wawrzynczak, Subrata Banik, Meera Ravindranath, Ronak Kanabar, Patrick Rudolph.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/51849 )

Change subject: soc/intel/alderlake: Enable VT-d
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Patch Set 7:

(4 comments)

File src/soc/intel/alderlake/romstage/fsp_params.c:

https://review.coreboot.org/c/coreboot/+/51849/comment/1be0f867_c9b6c53a 
PS5, Line 204: 		#if (GFXVT_BASE_ADDRESS == 0)
             : 			#error "Error: GFXVT_BASE_ADDRESS should be non-zero for enabling VT-d!"
             : 		#endif
> perfect Tim. […]

I would do this as follows:

m_cfg->VtdBaseAddress[0] = GFXVT_BASE_ADDRESS;
 m_cfg->VtdBaseAddress[1] = IPUVT_BASE_ADDRESS;
 m_cfg->VtdBaseAddress[2] = VTVC0_BASE_ADDRESS;

m_cfg->VtdDisable = 0;
 m_cfg->VtdIgdEnable = m_cfg->InternalGfx;
 m_cfg->VtdIpuEnable = m_cfg->SaIpuEnable;

if (m_cfg->VtdIgdEnable && m_cfg->VtdBaseAddress[0] == 0) {
    m_cfg->VtdIgdEnable = 0;
    printk(BIOS_ERR, "ERROR: Requested IGD VT-d, but GFXVT_BASE_ADDRESS is 0\n");
 }
 if (m_cfg->VtdIpuEnable && m_cfg->VtdBaseAddress[1] == 0) {
    m_cfg->VtdIpuEnable = 0;
    printk(BIOS_ERR, "ERROR: Requested IPU VT-d, but IPUVT_BASE_ADDRESS is 0\n");
 }
 if (!m_cfg->VtdDisable && m_cfg->VtdBaseAddress[2] == 0) {
    m_cfg->VtdDisable = 1;
    printk(BIOS_ERR, "ERROR: Requested VT-d, but VTVCO_BASE_ADDRESS is 0\n");
 }
 m_cfg->VtdIopEnable = !m_cfg->VtdDisable;

Aside, it would be good to define an enum to index the `VtdBaseAddress` array.

File src/soc/intel/alderlake/romstage/fsp_params.c:

https://review.coreboot.org/c/coreboot/+/51849/comment/e9e7dbe2_519b46d3 
PS7, Line 201: GFXVT_BASE_ADDRESS == 0
What does this check achieve? This value is a #define and is not zero.

https://review.coreboot.org/c/coreboot/+/51849/comment/2757072d_bd270ff1 
PS7, Line 209: IPUVT_BASE_ADDRESS == 0
What does this check achieve? This value is a #define and is not zero.

https://review.coreboot.org/c/coreboot/+/51849/comment/0b9537f2_a9e18de7 
PS7, Line 217: VTVC0_BASE_ADDRESS == 0
What does this check achieve? This value is a #define and is not zero.