From 4c7577314f19e934d690c4cce3642fe693400c07 Mon Sep 17 00:00:00 2001
From: Leah Rowe <info@minifree.org>
Date: Sat, 2 Mar 2024 22:51:09 +0000
Subject: [PATCH 21/51] nb/intel/haswell: make IOMMU a runtime option

When I tested graphics cards on a coreboot port for Dell
OptiPlex 9020 SFF, I could not use a graphics card unless
I set iommu=off on the Linux cmdline.

Coreboot's current behaviour is to check whether the CPU
has vt-d support and, if it does, initialise the IOMMU.

This patch maintains the current behaviour by default, but
allows the user to turn *off* the IOMMU, even if vt-d is
supported by the host CPU.

If iommu=Disable is specified, the check will not be
performed, and the IOMMU will be left disabled. This option
has been added to all current Haswell boards, though it is
recommended to leave the IOMMU turned on in most setups.

Signed-off-by: Leah Rowe <info@minifree.org>
---
 src/mainboard/asrock/b85m_pro4/cmos.default    | 1 +
 src/mainboard/asrock/b85m_pro4/cmos.layout     | 3 +++
 src/mainboard/asrock/h81m-hds/cmos.default     | 1 +
 src/mainboard/asrock/h81m-hds/cmos.layout      | 6 ++++++
 src/mainboard/dell/optiplex_9020/cmos.default  | 1 +
 src/mainboard/dell/optiplex_9020/cmos.layout   | 6 ++++++
 src/mainboard/google/beltino/cmos.layout       | 5 +++++
 src/mainboard/google/slippy/cmos.layout        | 5 +++++
 src/mainboard/intel/baskingridge/cmos.layout   | 4 ++++
 src/mainboard/lenovo/haswell/cmos.default      | 1 +
 src/mainboard/lenovo/haswell/cmos.layout       | 3 +++
 src/mainboard/supermicro/x10slm-f/cmos.default | 1 +
 src/mainboard/supermicro/x10slm-f/cmos.layout  | 6 ++++++
 src/northbridge/intel/haswell/early_init.c     | 5 +++++
 14 files changed, 48 insertions(+)

diff --git a/src/mainboard/asrock/b85m_pro4/cmos.default b/src/mainboard/asrock/b85m_pro4/cmos.default
index 01bf20ad16..dfc8b80fb0 100644
--- a/src/mainboard/asrock/b85m_pro4/cmos.default
+++ b/src/mainboard/asrock/b85m_pro4/cmos.default
@@ -4,3 +4,4 @@ boot_option=Fallback
 debug_level=Debug
 nmi=Enable
 power_on_after_fail=Disable
+iommu=Enable
diff --git a/src/mainboard/asrock/b85m_pro4/cmos.layout b/src/mainboard/asrock/b85m_pro4/cmos.layout
index efdc333fc2..c9883ea71d 100644
--- a/src/mainboard/asrock/b85m_pro4/cmos.layout
+++ b/src/mainboard/asrock/b85m_pro4/cmos.layout
@@ -11,6 +11,7 @@
 	395	4	e	4	debug_level
 	408	1	e	1	nmi
 	409	2	e	5	power_on_after_fail
+	412	1	e	6	iommu
 	984	16	h	0	check_sum
 # -----------------------------------------------------------------
 
@@ -38,6 +39,8 @@
 	5	0	Disable
 	5	1	Enable
 	5	2	Keep
+	6	0	Disable
+	6	1	Enable
 # -----------------------------------------------------------------
 
 # -----------------------------------------------------------------
diff --git a/src/mainboard/asrock/h81m-hds/cmos.default b/src/mainboard/asrock/h81m-hds/cmos.default
index 01bf20ad16..dfc8b80fb0 100644
--- a/src/mainboard/asrock/h81m-hds/cmos.default
+++ b/src/mainboard/asrock/h81m-hds/cmos.default
@@ -4,3 +4,4 @@ boot_option=Fallback
 debug_level=Debug
 nmi=Enable
 power_on_after_fail=Disable
+iommu=Enable
diff --git a/src/mainboard/asrock/h81m-hds/cmos.layout b/src/mainboard/asrock/h81m-hds/cmos.layout
index c9ba76c78f..95ee3d36fb 100644
--- a/src/mainboard/asrock/h81m-hds/cmos.layout
+++ b/src/mainboard/asrock/h81m-hds/cmos.layout
@@ -21,6 +21,9 @@ entries
 408	1	e	1	nmi
 409	2	e	5	power_on_after_fail
 
+# enable or disable iommu
+412	1	e	6	iommu
+
 # coreboot config options: check sums
 984	16	h	0	check_sum
 
@@ -52,6 +55,9 @@ enumerations
 5	1	Enable
 5	2	Keep
 
+6	0	Disable
+6	1	Enable
+
 # -----------------------------------------------------------------
 checksums
 
diff --git a/src/mainboard/dell/optiplex_9020/cmos.default b/src/mainboard/dell/optiplex_9020/cmos.default
index 6c4a2a1be7..8000eea8c0 100644
--- a/src/mainboard/dell/optiplex_9020/cmos.default
+++ b/src/mainboard/dell/optiplex_9020/cmos.default
@@ -4,3 +4,4 @@ debug_level=Debug
 nmi=Disable
 power_on_after_fail=Disable
 fan_full_speed=Disable
+iommu=Enable
diff --git a/src/mainboard/dell/optiplex_9020/cmos.layout b/src/mainboard/dell/optiplex_9020/cmos.layout
index d10ad95b23..4a1496a878 100644
--- a/src/mainboard/dell/optiplex_9020/cmos.layout
+++ b/src/mainboard/dell/optiplex_9020/cmos.layout
@@ -21,6 +21,9 @@ entries
 408	1	e	1	nmi
 409	2	e	5	power_on_after_fail
 
+# turn iommu on or off
+411	1	e	6	iommu
+
 # coreboot config options: EC
 412	1	e	1	fan_full_speed
 
@@ -55,6 +58,9 @@ enumerations
 5	1	Enable
 5	2	Keep
 
+6	0	Disable
+6	1	Enable
+
 # -----------------------------------------------------------------
 checksums
 
diff --git a/src/mainboard/google/beltino/cmos.layout b/src/mainboard/google/beltino/cmos.layout
index 78d44c1415..c143979ae1 100644
--- a/src/mainboard/google/beltino/cmos.layout
+++ b/src/mainboard/google/beltino/cmos.layout
@@ -19,6 +19,9 @@ entries
 408	1	e	1	nmi
 409	2	e	7	power_on_after_fail
 
+# enable or disable iommu
+412	1	e	8	iommu
+
 # coreboot config options: bootloader
 #Used by ChromeOS:
 416	128	r	0	vbnv
@@ -47,6 +50,8 @@ enumerations
 7	0	Disable
 7	1	Enable
 7	2	Keep
+8	0	Disable
+8	1	Enable
 # -----------------------------------------------------------------
 checksums
 
diff --git a/src/mainboard/google/slippy/cmos.layout b/src/mainboard/google/slippy/cmos.layout
index 78d44c1415..c143979ae1 100644
--- a/src/mainboard/google/slippy/cmos.layout
+++ b/src/mainboard/google/slippy/cmos.layout
@@ -19,6 +19,9 @@ entries
 408	1	e	1	nmi
 409	2	e	7	power_on_after_fail
 
+# enable or disable iommu
+412	1	e	8	iommu
+
 # coreboot config options: bootloader
 #Used by ChromeOS:
 416	128	r	0	vbnv
@@ -47,6 +50,8 @@ enumerations
 7	0	Disable
 7	1	Enable
 7	2	Keep
+8	0	Disable
+8	1	Enable
 # -----------------------------------------------------------------
 checksums
 
diff --git a/src/mainboard/intel/baskingridge/cmos.layout b/src/mainboard/intel/baskingridge/cmos.layout
index 78d44c1415..f2c602f541 100644
--- a/src/mainboard/intel/baskingridge/cmos.layout
+++ b/src/mainboard/intel/baskingridge/cmos.layout
@@ -19,6 +19,8 @@ entries
 408	1	e	1	nmi
 409	2	e	7	power_on_after_fail
 
+412	1	e	8	iommu
+
 # coreboot config options: bootloader
 #Used by ChromeOS:
 416	128	r	0	vbnv
@@ -47,6 +49,8 @@ enumerations
 7	0	Disable
 7	1	Enable
 7	2	Keep
+8	0	Disable
+8	1	Enable
 # -----------------------------------------------------------------
 checksums
 
diff --git a/src/mainboard/lenovo/haswell/cmos.default b/src/mainboard/lenovo/haswell/cmos.default
index 08db97c5a9..cc6b363cd9 100644
--- a/src/mainboard/lenovo/haswell/cmos.default
+++ b/src/mainboard/lenovo/haswell/cmos.default
@@ -14,3 +14,4 @@ trackpoint=Enable
 backlight=Keyboard
 enable_dual_graphics=Disable
 usb_always_on=Disable
+iommu=Enable
diff --git a/src/mainboard/lenovo/haswell/cmos.layout b/src/mainboard/lenovo/haswell/cmos.layout
index 27915d3ab7..59df76b64c 100644
--- a/src/mainboard/lenovo/haswell/cmos.layout
+++ b/src/mainboard/lenovo/haswell/cmos.layout
@@ -23,6 +23,7 @@ entries
 
 # coreboot config options: EC
 411	1	e	8	first_battery
+413	1	e	14	iommu
 415	1	e	1	wlan
 416	1	e	1	trackpoint
 417	1	e	1	fn_ctrl_swap
@@ -72,6 +73,8 @@ enumerations
 13	0	Disable
 13	1	AC and battery
 13	2	AC only
+14	0	Disable
+14	1	Enable
 
 # -----------------------------------------------------------------
 checksums
diff --git a/src/mainboard/supermicro/x10slm-f/cmos.default b/src/mainboard/supermicro/x10slm-f/cmos.default
index 7ce38fb5d7..6049e7938a 100644
--- a/src/mainboard/supermicro/x10slm-f/cmos.default
+++ b/src/mainboard/supermicro/x10slm-f/cmos.default
@@ -5,3 +5,4 @@ debug_level=Debug
 nmi=Enable
 power_on_after_fail=Keep
 hide_ast2400=Disable
+iommu=Enable
diff --git a/src/mainboard/supermicro/x10slm-f/cmos.layout b/src/mainboard/supermicro/x10slm-f/cmos.layout
index 38ba87aa45..24d39e97ee 100644
--- a/src/mainboard/supermicro/x10slm-f/cmos.layout
+++ b/src/mainboard/supermicro/x10slm-f/cmos.layout
@@ -21,6 +21,9 @@ entries
 408	1	e	1	nmi
 409	2	e	5	power_on_after_fail
 
+# enable or disable iommu
+412	1	e	6	iommu
+
 # coreboot config options: mainboard
 416	1	e	1	hide_ast2400
 
@@ -55,6 +58,9 @@ enumerations
 5	1	Enable
 5	2	Keep
 
+6	0	Disable
+6	1	Enable
+
 # -----------------------------------------------------------------
 checksums
 
diff --git a/src/northbridge/intel/haswell/early_init.c b/src/northbridge/intel/haswell/early_init.c
index e47deb5da6..1a7e0b1076 100644
--- a/src/northbridge/intel/haswell/early_init.c
+++ b/src/northbridge/intel/haswell/early_init.c
@@ -5,6 +5,7 @@
 #include <device/mmio.h>
 #include <device/pci_def.h>
 #include <device/pci_ops.h>
+#include <option.h>
 
 #include "haswell.h"
 
@@ -157,6 +158,10 @@ static void haswell_setup_misc(void)
 static void haswell_setup_iommu(void)
 {
 	const u32 capid0_a = pci_read_config32(HOST_BRIDGE, CAPID0_A);
+	u8 enable_iommu = get_uint_option("iommu", 1);
+
+	if (!enable_iommu)
+		return;
 
 	if (capid0_a & VTD_DISABLE)
 		return;
-- 
2.39.5

