soc/intel/xeon_sp/uncore: Read VtdBar

Read the VtdBar and add it to the resources of the host bridge PCI
device. The BAR is already marked as PciResourceMem32 in the parent
PCI domain.
This allows easy probing for VTD devices with enabled VtdBars in the
next commit, without the need to look up the stack HOB.

Change-Id: Id579a94e653473f3dd0dccea6e33dc64f792d028
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80550
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

4 files changed, 19 insertions, 4 deletions

diff --git a/src/soc/intel/xeon_sp/cpx/include/soc/pci_devs.h b/src/soc/intel/xeon_sp/cpx/include/soc/pci_devs.h
index d64a0d74139a..587c97cd8b92 100644
--- a/src/soc/intel/xeon_sp/cpx/include/soc/pci_devs.h
+++ b/src/soc/intel/xeon_sp/cpx/include/soc/pci_devs.h
@@ -114,6 +114,7 @@
 #define VTD_CAP_LOW			0x08
 #define VTD_CAP_HIGH			0x0C
 #define VTD_EXT_CAP_HIGH		0x14
+#define VTD_BAR_CSR			0x180
 #define VTD_LTDPR			0x290
 
 /* IMC Devices */
diff --git a/src/soc/intel/xeon_sp/skx/include/soc/pci_devs.h b/src/soc/intel/xeon_sp/skx/include/soc/pci_devs.h
index a5f2f8e674c1..d317d0c47096 100644
--- a/src/soc/intel/xeon_sp/skx/include/soc/pci_devs.h
+++ b/src/soc/intel/xeon_sp/skx/include/soc/pci_devs.h
@@ -108,6 +108,7 @@
 #define VTD_CAP_LOW			0x08
 #define VTD_CAP_HIGH			0x0C
 #define VTD_EXT_CAP_HIGH		0x14
+#define VTD_BAR_CSR			0x180
 #define VTD_LTDPR			0x290
 
 #define PCU_CR1_C2C3TT_REG                                 0xdc
diff --git a/src/soc/intel/xeon_sp/spr/include/soc/pci_devs.h b/src/soc/intel/xeon_sp/spr/include/soc/pci_devs.h
index 9bbe540874f6..158352a8be98 100644
--- a/src/soc/intel/xeon_sp/spr/include/soc/pci_devs.h
+++ b/src/soc/intel/xeon_sp/spr/include/soc/pci_devs.h
@@ -136,6 +136,7 @@
 #define VTD_MMIOL_CSR 0xd8
 #define VTD_NCMEM_BASE_CSR 0xe0
 #define VTD_NCMEM_LIMIT_CSR 0xe8
+#define VTD_BAR_CSR 0x180
 #define VTD_LTDPR 0x290
 
 #define VMD_DEV_NUM 0x00
diff --git a/src/soc/intel/xeon_sp/uncore.c b/src/soc/intel/xeon_sp/uncore.c
index d43b20959168..952ca4db70eb 100644
--- a/src/soc/intel/xeon_sp/uncore.c
+++ b/src/soc/intel/xeon_sp/uncore.c
@@ -45,6 +45,7 @@ enum {
 	ME_LIMIT_REG,
 	TSEG_BASE_REG,
 	TSEG_LIMIT_REG,
+	VTDBAR_REG,
 	/* Must be last. */
 	NUM_MAP_ENTRIES
 };
@@ -64,6 +65,7 @@ static struct map_entry memory_map[NUM_MAP_ENTRIES] = {
 #endif
 		[TSEG_BASE_REG] = MAP_ENTRY_BASE_32(VTD_TSEG_BASE_CSR, "TSEGMB_BASE"),
 		[TSEG_LIMIT_REG] = MAP_ENTRY_LIMIT_32(VTD_TSEG_LIMIT_CSR, 20, "TSEGMB_LIMIT"),
+		[VTDBAR_REG] = MAP_ENTRY_BASE_32(VTD_BAR_CSR, "VTD_BAR"),
 };
 
 static void read_map_entry(struct device *dev, struct map_entry *entry,
@@ -76,6 +78,11 @@ static void read_map_entry(struct device *dev, struct map_entry *entry,
 		*result = 0;
 		return;
 	}
+	if (entry->reg == VTD_BAR_CSR && !(pci_read_config32(dev, entry->reg) & 1)) {
+		/* VTDBAR is not enabled */
+		*result = 0;
+		return;
+	}
 
 	mask = ((1ULL << entry->mask_bits) - 1);
 	mask = ~mask;
@@ -198,14 +205,19 @@ static void mc_add_dram_resources(struct device *dev, int *res_count)
 	int index = *res_count;
 	struct range_entry fsp_mem;
 
-	/* Only add dram resources once. */
-	if (dev->upstream->secondary != 0 || dev->upstream->segment_group != 0)
-		return;
-
 	/* Read in the MAP registers and report their values. */
 	mc_read_map_entries(dev, &mc_values[0]);
 	mc_report_map_entries(dev, &mc_values[0]);
 
+	if (mc_values[VTDBAR_REG]) {
+		res = mmio_range(dev, VTD_BAR_CSR, mc_values[VTDBAR_REG], 8 * KiB);
+		LOG_RESOURCE("vtd_bar", dev, res);
+	}
+
+	/* Only add dram resources once. */
+	if (dev->upstream->secondary != 0 || dev->upstream->segment_group != 0)
+		return;
+
 	/* Conventional Memory (DOS region, 0x0 to 0x9FFFF) */
 	res = ram_from_to(dev, index++, 0, 0xa0000);
 	LOG_RESOURCE("legacy_ram", dev, res);