Nikolai Artemiev has uploaded this change for review.

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ichspi: Handle EC region permissions

WIP. Not sure if we need this.

BUG=b:260440773
BRANCH=none
TEST=todo

Change-Id: Ieaf2a960ec0c72d7b576dc3733260592c7c1f766
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
---
M ichspi.c
1 file changed, 53 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/69/70169/1

diff --git a/ichspi.c b/ichspi.c
index 06f94c7..5bf8790 100644
--- a/ichspi.c
+++ b/ichspi.c
@@ -1806,6 +1806,40 @@
 	"read-write", "write-only", "read-only", "locked"
 };
 
+#define EMBEDDED_CONTROLLER_REGION	8
+
+static enum ich_access_protection ec_region_rwperms(unsigned int i)
+{
+	/*
+	 * Use Flash Descriptor Observe register to determine if
+	 * the EC region can be written by the BIOS master.
+	 */
+	int rwperms = NO_PROT;
+
+	struct ich_descriptors desc;
+	memset(&desc, 0, sizeof(desc));
+
+	/* Region is RW if flash descriptor override is set */
+	uint16_t freg = REGREAD16(ICH9_REG_HSFS);
+	if ((freg & HSFS_FDV) && !(freg & HSFS_FDOPSS)) {
+		rwperms = NO_PROT;
+	} else if (read_ich_descriptors_via_fdo(ich_generation, ich_spibar, &desc) == ICH_RET_OK) {
+		const struct ich_desc_master *const mstr = &desc.master;
+		int bios_ec_r = mstr->mstr[i].read  & BIT(16); /* BIOS_EC_r in PCH100+ */
+		int bios_ec_w = mstr->mstr[i].write & BIT(28); /* BIOS_EC_w in PCH100+ */
+		if (bios_ec_r && bios_ec_w)
+			rwperms = NO_PROT;
+		else if (bios_ec_r && !bios_ec_w)
+			rwperms = WRITE_PROT;
+		else if (!bios_ec_r && bios_ec_w)
+			rwperms = READ_PROT;
+		else
+			rwperms = LOCKED;
+	}
+
+	return rwperms;
+}
+
 static enum ich_access_protection ich9_handle_frap(uint32_t frap, unsigned int i)
 {
 	static const char *const region_names[] = {
@@ -1833,10 +1867,12 @@
 	}
 	msg_pdbg("0x%02X: 0x%08x ", offset, freg);
 
-	if (i < 8) {
+	if (i < EMBEDDED_CONTROLLER_REGION) {
 		rwperms_idx = (((ICH_BRWA(frap) >> i) & 1) << 1) |
 			      (((ICH_BRRA(frap) >> i) & 1) << 0);
 		rwperms = access_perms_to_protection[rwperms_idx];
+	} else if (i == EMBEDDED_CONTROLLER_REGION && ich_generation >= CHIPSET_100_SERIES_SUNRISE_POINT) {
+		rwperms = ec_region_rwperms(i);
 	} else {
 		/* Datasheets don't define any access bits for regions > 7. We
 		   can't rely on the actual descriptor settings either as there

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