Change in coreboot[master]: soc/intel/common/block: Add PAM locking function

[Tim Wawrzynczak (Code Review)]

Tim Wawrzynczak has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/57145 )

Change subject: soc/intel/common/block: Add PAM locking function
......................................................................

soc/intel/common/block: Add PAM locking function

Some FSPs provide a UPD to allow the bootloader to set the PAM lock bit
instead of the FSP, therefore add a function in the common code to do
this. Source: ADL & TGL FSP integration guides

Signed-off-by: Tim Wawrzynczak 
Change-Id: I1d6642b496617b6e8ccda8a0aa6bfd88ea9dc3ba
---
M src/soc/intel/common/block/include/intelblocks/systemagent.h
M src/soc/intel/common/block/systemagent/systemagent.c
M src/soc/intel/common/block/systemagent/systemagent_def.h
3 files changed, 15 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/45/57145/1

diff --git a/src/soc/intel/common/block/include/intelblocks/systemagent.h b/src/soc/intel/common/block/include/intelblocks/systemagent.h
index fe14c18..f708fae 100644
--- a/src/soc/intel/common/block/include/intelblocks/systemagent.h
+++ b/src/soc/intel/common/block/include/intelblocks/systemagent.h
@@ -79,6 +79,9 @@
 size_t sa_get_tseg_size(void);
 /* Fill MMIO resource above 4GB into GNVS */
 void sa_fill_gnvs(struct global_nvs *gnvs);
+/* API to lock PAM registers */
+void sa_lock_pam(void);
+
 /*
  * SoC overrides
  *
diff --git a/src/soc/intel/common/block/systemagent/systemagent.c b/src/soc/intel/common/block/systemagent/systemagent.c
index 6e02c81..45e1d42 100644
--- a/src/soc/intel/common/block/systemagent/systemagent.c
+++ b/src/soc/intel/common/block/systemagent/systemagent.c
@@ -306,6 +306,15 @@
    MCHBAR8(MCH_PAIR) = pair;
 }

+void sa_lock_pam(void)
+{
+	const struct device *dev = pcidev_path_on_root(SA_DEVFN_ROOT);
+	if (!dev)
+		return;
+
+	pci_or_config8(dev, PAM0, PAM_LOCK);
+}
+
 static struct device_operations systemagent_ops = {
    .read_resources   = systemagent_read_resources,
    .set_resources    = pci_dev_set_resources,
diff --git a/src/soc/intel/common/block/systemagent/systemagent_def.h b/src/soc/intel/common/block/systemagent/systemagent_def.h
index 7517b14..0add13e 100644
--- a/src/soc/intel/common/block/systemagent/systemagent_def.h
+++ b/src/soc/intel/common/block/systemagent/systemagent_def.h
@@ -35,6 +35,9 @@
 #define PAM5	0x85
 #define PAM6	0x86

+/* PAM0 contains the lock bit */
+#define PAM_LOCK	(1 << 0)
+
 /* Device 0:0.0 MMIO space */
 #define MCH_PAIR	0x5418