soc/intel/skylake: Enable VT-d and X2APIC

We use the usual static addresses 0xfed90000/0xfed91000 for the GFX
IOMMU and the general IOMMU respectively. These addresses have to be
configured in MCHBAR registers (maybe, who knows, the blob is undocu-
mented), advertised to FSP and reserved from the OS.

The new devicetree option `ignore_vtd` allows to retain the old beha-
viour (do whatever pre-set UPD values suggest).

We also let FSP set up distinct BDFs for messages originating from the
I/O-APIC and the HPET.

Change-Id: I77f87c385736615c127143760bbd144f97986b37
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/21597
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Youness Alaoui <snifikino@gmail.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/src/soc/intel/skylake/romstage/systemagent.c b/src/soc/intel/skylake/romstage/systemagent.c
index a262462a09..0c8e9e7b9e 100644
--- a/src/soc/intel/skylake/romstage/systemagent.c
+++ b/src/soc/intel/skylake/romstage/systemagent.c
@@ -18,8 +18,28 @@
 #include <device/device.h>
 #include <intelblocks/systemagent.h>
 #include <soc/iomap.h>
+#include <soc/pci_devs.h>
 #include <soc/romstage.h>
 #include <soc/systemagent.h>
+#include "chip.h"
+
+static void systemagent_vtd_init(void)
+{
+	const struct device *const dev = dev_find_slot(0, SA_DEVFN_ROOT);
+	const struct soc_intel_skylake_config *config = NULL;
+
+	if (dev)
+		config = dev->chip_info;
+	if (config && config->ignore_vtd)
+		return;
+
+	const bool vtd_capable =
+		!(pci_read_config32(SA_DEV_ROOT, CAPID0_A) & VTD_DISABLE);
+	if (!vtd_capable)
+		return;
+
+	sa_set_mch_bar(soc_vtd_resources, ARRAY_SIZE(soc_vtd_resources));
+}
 
 void systemagent_early_init(void)
 {
@@ -40,6 +60,9 @@ void systemagent_early_init(void)
 	/* Set Fixed MMIO address into MCH base address */
 	sa_set_mch_bar(soc_fixed_mch_resources,
 			ARRAY_SIZE(soc_fixed_mch_resources));
+
+	systemagent_vtd_init();
+
 	/* Enable PAM registers */
 	enable_pam_region();
 }