soc/intel/skylake: Add RMRRs after all DRHDs

The VT-d architecture specification (Doc. D51397-011, Rev. 3.1) says:

 BIOS implementations must report these remapping structure types in
 numerical order. i.e., All remapping structures of type 0 (DRHD)
 enumerated before remapping structures of type 1 (RMRR), and so forth.

So, update the corresponding code to adhere to the specification.

Change-Id: I2446d536603559f637f3f8b1b44e9d712aa35492
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44112
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

1 files changed, 18 insertions, 11 deletions

diff --git a/src/soc/intel/skylake/acpi.c b/src/soc/intel/skylake/acpi.c
index 1beff3d3af..ae9d78436c 100644
--- a/src/soc/intel/skylake/acpi.c
+++ b/src/soc/intel/skylake/acpi.c
@@ -425,22 +425,19 @@ static unsigned long acpi_fill_dmar(unsigned long current)
 	const bool gfxvten = MCHBAR32(GFXVTBAR) & 1;
 
 	/* iGFX has to be enabled, GFXVTBAR set and in 32-bit space. */
-	if (igfx_dev && igfx_dev->enabled && gfxvten &&
-	    gfx_vtbar && !MCHBAR32(GFXVTBAR + 4)) {
-		unsigned long tmp = current;
+	const bool emit_igd =
+			igfx_dev && igfx_dev->enabled &&
+			gfx_vtbar && gfxvten &&
+			!MCHBAR32(GFXVTBAR + 4);
+
+	/* First, add DRHD entries */
+	if (emit_igd) {
+		const unsigned long tmp = current;
 
 		current += acpi_create_dmar_drhd(current, 0, 0, gfx_vtbar);
 		current += acpi_create_dmar_ds_pci(current, 0, 2, 0);
 
 		acpi_dmar_drhd_fixup(tmp, current);
-
-		/* Add RMRR entry */
-		tmp = current;
-
-		current += acpi_create_dmar_rmrr(current, 0,
-				sa_get_gsm_base(), sa_get_tolud_base() - 1);
-		current += acpi_create_dmar_ds_pci(current, 0, 2, 0);
-		acpi_dmar_rmrr_fixup(tmp, current);
 	}
 
 	const u32 vtvc0bar = MCHBAR32(VTVC0BAR) & ~0xfff;
@@ -461,6 +458,16 @@ static unsigned long acpi_fill_dmar(unsigned long current)
 		acpi_dmar_drhd_fixup(tmp, current);
 	}
 
+	/* Then, add RMRR entries after all DRHD entries */
+	if (emit_igd) {
+		const unsigned long tmp = current;
+
+		current += acpi_create_dmar_rmrr(current, 0,
+				sa_get_gsm_base(), sa_get_tolud_base() - 1);
+		current += acpi_create_dmar_ds_pci(current, 0, 2, 0);
+		acpi_dmar_rmrr_fixup(tmp, current);
+	}
+
 	return current;
 }