soc/skl: set IGD resources only if device is enabled

If the Intel IGD device pci 02.0 is disabled or undefined in
the device tree, then internal graphics pre-allocated memory
and GFX-VT MMIO memory for virtualization won`t be allocated
in the SoC address space.

Thus, patch resolves the FSP-S hang problem on Skylake/ Kaby
Lake processors when the IGD device is disabled. This should
provide to run FSP 2.0-based coreboot on these CPUs families
without integrated graphics card.

The following boards were used for testing:

- Asrock H110M-DVS board (desktop i5-6600) & NVIDIA GTX 1060
  as external GPU.

  Virtualization and GFX 3D acceleration with nouveau driver
  still works well  (tested on VirtualBox 5.1.38 with Ubuntu
  18.04.1 as guest and host OS)

- Intel KBL-R U RVP board (mobile i5-8350u) without GFX.

Payload: tianocore edk2-stable201811-216-g51be9d0.

Change-Id: Id7a0cba582d83e3fe7e8d20342ee219cdd369a53
Signed-off-by: Maxim Polyakov <max.senia.poliak@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32467
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 18 insertions, 12 deletions

diff --git a/src/soc/intel/skylake/romstage/romstage_fsp20.c b/src/soc/intel/skylake/romstage/romstage_fsp20.c
index 1e81d7aa05..c166e3a7c1 100644
--- a/src/soc/intel/skylake/romstage/romstage_fsp20.c
+++ b/src/soc/intel/skylake/romstage/romstage_fsp20.c
@@ -264,14 +264,6 @@ static void soc_memory_init_params(FSP_M_CONFIG *m_cfg,
 	int i;
 	uint32_t mask = 0;
 
-	/*
-	 * Set IGD stolen size to 64MB.  The FBC hardware for skylake does not
-	 * have access to the bios_reserved range so it always assumes 8MB is
-	 * used and so the kernel will avoid the last 8MB of the stolen window.
-	 * With the default stolen size of 32MB(-8MB) there is not enough space
-	 * for FBC to work with a high resolution panel.
-	 */
-	m_cfg->IgdDvmt50PreAlloc = 2;
 	m_cfg->MmioSize = 0x800; /* 2GB in MB */
 	m_cfg->TsegSize = CONFIG_SMM_TSEG_SIZE;
 	m_cfg->IedSize = CONFIG_IED_REGION_SIZE;
@@ -311,12 +303,22 @@ static void soc_primary_gfx_config_params(FSP_M_CONFIG *m_cfg,
 		 * the FSP does not initialize this device
 		 */
 		m_cfg->InternalGfx = 0;
+		m_cfg->IgdDvmt50PreAlloc = 0;
 		if (config->PrimaryDisplay == Display_iGFX)
 			m_cfg->PrimaryDisplay = Display_Auto;
 		else
 			m_cfg->PrimaryDisplay = config->PrimaryDisplay;
 	} else {
 		m_cfg->InternalGfx = 1;
+		/*
+		 * Set IGD stolen size to 64MB.  The FBC hardware for skylake
+		 * does not have access to the bios_reserved range so it always
+		 * assumes 8MB is used and so the kernel will avoid the last
+		 * 8MB of the stolen window. With the default stolen size of
+		 * 32MB(-8MB) there is not enough space for FBC to work with
+		 * a high resolution panel
+		 */
+		m_cfg->IgdDvmt50PreAlloc = 2;
 		m_cfg->PrimaryDisplay = config->PrimaryDisplay;
 	}
 }
diff --git a/src/soc/intel/skylake/romstage/systemagent.c b/src/soc/intel/skylake/romstage/systemagent.c
index 00a2782723..71a9bee1e0 100644
--- a/src/soc/intel/skylake/romstage/systemagent.c
+++ b/src/soc/intel/skylake/romstage/systemagent.c
@@ -26,11 +26,12 @@
 
 static void systemagent_vtd_init(void)
 {
-	const struct device *const dev = dev_find_slot(0, SA_DEVFN_ROOT);
+	const struct device *const root_dev = dev_find_slot(0, SA_DEVFN_ROOT);
+	const struct device *const igd_dev = dev_find_slot(0, SA_DEVFN_IGD);
 	const struct soc_intel_skylake_config *config = NULL;
 
-	if (dev)
-		config = dev->chip_info;
+	if (root_dev)
+		config = root_dev->chip_info;
 	if (config && config->ignore_vtd)
 		return;
 
@@ -39,7 +40,10 @@ static void systemagent_vtd_init(void)
 	if (!vtd_capable)
 		return;
 
-	sa_set_mch_bar(soc_vtd_resources, ARRAY_SIZE(soc_vtd_resources));
+	if (igd_dev && igd_dev->enabled)
+		sa_set_mch_bar(&soc_gfxvt_mmio_descriptor, 1);
+
+	sa_set_mch_bar(&soc_vtvc0_mmio_descriptor, 1);
 }
 
 void systemagent_early_init(void)