util/intelmetool: Add support for platforms without RCBA

Only try to unhide MEI if the PCI device wasn't found and
probe for RCBA before trying to use it.

Allows to run the utility on Skylake and newer hardware that
do not have RCBA any more.

TODO: Use sideband interface to unhide MEI.

Change-Id: I7926aa80b132d5be9fece0724516701d74dd4d3d
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/25399
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>

3 files changed, 56 insertions, 37 deletions

diff --git a/util/intelmetool/intelmetool.c b/util/intelmetool/intelmetool.c
index bc5f26c4b5..66353bc0a9 100644
--- a/util/intelmetool/intelmetool.c
+++ b/util/intelmetool/intelmetool.c
@@ -179,38 +179,45 @@ static int pci_platform_scan(void)
 
 static int activate_me(void)
 {
-	if (read_rcba32(FD2, &fd2)) {
-		printf("Error reading RCBA\n");
-		return 1;
-	}
-	if (write_rcba32(FD2, fd2 & ~0x2)) {
-		printf("Error writing RCBA\n");
-		return 1;
-	}
-	if (debug) {
-		if (fd2 & 0x2)
+	const uint32_t rcba = get_rcba_phys();
+	if (debug)
+		printf("RCBA addr: 0x%08x\n", rcba);
+	if (rcba > 0) {
+		if (read_rcba32(FD2, &fd2)) {
+			printf("Error reading RCBA\n");
+			return 1;
+		}
+		if (write_rcba32(FD2, fd2 & ~0x2)) {
+			printf("Error writing RCBA\n");
+			return 1;
+		}
+		if (debug && (fd2 & 0x2))
 			printf("MEI was hidden on PCI, now unlocked\n");
-		else
+		else if (debug)
 			printf("MEI not hidden on PCI, checking if visible\n");
 	}
+
 	return 0;
 }
 
 static void rehide_me(void)
 {
-	if (fd2 & 0x2) {
-		if (debug)
-			printf("Re-hiding MEI device...");
-		if (read_rcba32(FD2, &fd2)) {
-			printf("Error reading RCBA\n");
-			return;
-		}
-		if (write_rcba32(FD2, fd2 | 0x2)) {
-			printf("Error writing RCBA\n");
-			return;
+	const uint32_t rcba = get_rcba_phys();
+	if (rcba > 0) {
+		if (fd2 & 0x2) {
+			if (debug)
+				printf("Re-hiding MEI device...");
+			if (read_rcba32(FD2, &fd2)) {
+				printf("Error reading RCBA\n");
+				return;
+			}
+			if (write_rcba32(FD2, fd2 | 0x2)) {
+				printf("Error writing RCBA\n");
+				return;
+			}
+			if (debug)
+				printf("done\n");
 		}
-		if (debug)
-			printf("done\n");
 	}
 }
 
@@ -244,7 +251,6 @@ static struct pci_dev *pci_me_interface_scan(const char **name, char *namebuf,
 	if (!me) {
 		rehide_me();
 
-		printf("MEI device not found\n");
 		pci_cleanup(pacc);
 		return NULL;
 	}
@@ -260,14 +266,21 @@ static void dump_me_info(void)
 	const char *name = NULL;
 
 	if (pci_platform_scan())
-		exit(1);
-
-	if (activate_me())
-		exit(1);
+		return;
 
 	dev = pci_me_interface_scan(&name, namebuf, sizeof(namebuf));
-	if (!dev)
-		exit(1);
+	if (!dev) {
+		if (debug)
+			printf("ME PCI device is hidden\n");
+
+		if (activate_me())
+			return;
+		dev = pci_me_interface_scan(&name, namebuf, sizeof(namebuf));
+		if (!dev) {
+			printf("Can't find ME PCI device\n");
+			return;
+		}
+	}
 
 	if (name == NULL)
 		name = "<unknown>";
@@ -314,15 +327,20 @@ static void dump_bootguard_info(void)
 	uint64_t bootguard = 0;
 
 	if (pci_platform_scan())
-		exit(1);
-
-	if (activate_me())
-		exit(1);
+		return;
 
 	dev = pci_me_interface_scan(&name, namebuf, sizeof(namebuf));
 	if (!dev) {
-		printf("Can't access ME PCI device\n");
-		return;
+		if (debug)
+			printf("ME PCI device is hidden\n");
+
+		if (activate_me())
+			return;
+		dev = pci_me_interface_scan(&name, namebuf, sizeof(namebuf));
+		if (!dev) {
+			printf("Can't find ME PCI device\n");
+			return;
+		}
 	}
 
 	if (debug) {
diff --git a/util/intelmetool/rcba.c b/util/intelmetool/rcba.c
index fcc9bc59c9..c138e89fd3 100644
--- a/util/intelmetool/rcba.c
+++ b/util/intelmetool/rcba.c
@@ -22,7 +22,7 @@
 static const int size = 0x4000;
 
 /* Returns the physical RCBA base address or zero on error. */
-static u32 get_rcba_phys(void)
+u32 get_rcba_phys(void)
 {
 	struct pci_access *pacc;
 	struct pci_dev *sb;
diff --git a/util/intelmetool/rcba.h b/util/intelmetool/rcba.h
index e1a22be1c2..e349d3d7fd 100644
--- a/util/intelmetool/rcba.h
+++ b/util/intelmetool/rcba.h
@@ -13,3 +13,4 @@
 
 int write_rcba32(uint32_t addr, uint32_t val);
 int read_rcba32(uint32_t addr, uint32_t *val);
+u32 get_rcba_phys(void);