lynxpoint: Avoid any ME device communication in S3 path

The management engine is occasionally hanging the system on resume
when it is accessed.  Since we actually don't need to do anything
with it on resume it can be disabled early in the resume path and
avoid assigning resources just to remove them later.

suspend/resume on falco and check /sys/firmware/log
to ensure that device 00:16.0 is disabled early and that no
resources are probed or assigned and that the device init path
does not execute.

Change-Id: I35573681e3a1d43d816d24954842cbe9c61f3484
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/62897
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/4376
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

1 files changed, 13 insertions, 19 deletions

diff --git a/src/southbridge/intel/lynxpoint/me_9.x.c b/src/southbridge/intel/lynxpoint/me_9.x.c
index 5aa74f015d..eebc451bfe 100644
--- a/src/southbridge/intel/lynxpoint/me_9.x.c
+++ b/src/southbridge/intel/lynxpoint/me_9.x.c
@@ -574,13 +574,6 @@ static me_bios_path intel_me_path(device_t dev)
 	struct me_hfs hfs;
 	struct me_hfs2 hfs2;
 
-#if CONFIG_HAVE_ACPI_RESUME
-	/* S3 wake skips all MKHI messages */
-	if (acpi_slp_type == 3) {
-		return ME_S3WAKE_BIOS_PATH;
-	}
-#endif
-
 	pci_read_dword_ptr(dev, &hfs, PCI_ME_HFS);
 	pci_read_dword_ptr(dev, &hfs2, PCI_ME_HFS2);
 
@@ -721,13 +714,6 @@ static int intel_me_extend_valid(device_t dev)
 	return 0;
 }
 
-/* Hide the ME virtual PCI devices */
-static void intel_me_hide(device_t dev)
-{
-	dev->enabled = 0;
-	pch_enable(dev);
-}
-
 /* Check whether ME is present and do basic init */
 static void intel_me_init(device_t dev)
 {
@@ -737,10 +723,7 @@ static void intel_me_init(device_t dev)
 	/* Do initial setup and determine the BIOS path */
 	printk(BIOS_NOTICE, "ME: BIOS path: %s\n", me_bios_path_values[path]);
 
-	if (path == ME_S3WAKE_BIOS_PATH) {
-		intel_me_hide(dev);
-		return;
-	} else if (path == ME_NORMAL_BIOS_PATH) {
+	if (path == ME_NORMAL_BIOS_PATH) {
 		/* Validate the extend register */
 		/* FIXME: force recovery mode on failure. */
 		intel_me_extend_valid(dev);
@@ -794,12 +777,23 @@ static struct pci_operations pci_ops = {
 	.set_subsystem = set_subsystem,
 };
 
+static void intel_me_enable(device_t dev)
+{
+#if CONFIG_HAVE_ACPI_RESUME
+	/* Avoid talking to the device in S3 path */
+	if (acpi_slp_type == 3) {
+		dev->enabled = 0;
+		pch_disable_devfn(dev);
+	}
+#endif
+}
+
 static struct device_operations device_ops = {
 	.read_resources		= pci_dev_read_resources,
 	.set_resources		= pci_dev_set_resources,
 	.enable_resources	= pci_dev_enable_resources,
+	.enable			= intel_me_enable,
 	.init			= intel_me_init,
-	.scan_bus		= scan_static_bus,
 	.ops_pci		= &pci_ops,
 };