[coreboot-gerrit] [S] Change in coreboot[master]: mb/google/herobrine: NVMe id determined by logical (not physical) bit

[Shelley Chen (Code Review)]

Shelley Chen has submitted this change. ( https://review.coreboot.org/c/coreboot/+/70230 )

Change subject: mb/google/herobrine: NVMe id determined by logical (not physical) bit
......................................................................

mb/google/herobrine: NVMe id determined by logical (not physical) bit

NVMe is determined by a logical bit 1, not the physical SKU pin.
Thus, (logical) sku_id & 0x2 == 0x2 would mean that the device has
NVMe enabled on it.  Previously, I thought that it was tied to a
physical pin, but this is not correct.

BUG=b:254281839
BRANCH=None
TEST=flash and boot on villager and make sure that NVMe is not
     initialized in coreboot.

Change-Id: Iaa75d2418d6a2351d874842e8678bd6ad3c92526
Signed-off-by: Shelley Chen 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70230
Reviewed-by: Douglas Anderson 
Tested-by: build bot (Jenkins) 
---
M src/mainboard/google/herobrine/mainboard.c
1 file changed, 29 insertions(+), 14 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Douglas Anderson: Looks good to me, approved

diff --git a/src/mainboard/google/herobrine/mainboard.c b/src/mainboard/google/herobrine/mainboard.c
index c9bca73..8a51b2b 100644
--- a/src/mainboard/google/herobrine/mainboard.c
+++ b/src/mainboard/google/herobrine/mainboard.c
@@ -85,18 +85,14 @@
 }

/*
- * Determine if board need to perform PCIe initialization.  On Herobrine,
- * resistor strapping will be such that bit 0 will be assigned 2 (high Z) if it
- * is an NVMe enabled platform.
+ * Determine if board need to perform PCIe initialization.  Will return true if
+ * NVMe initialization is needed, or false if it is an eMMC device.  On
+ * Herobrine, if it is an NVMe enabled platform, logical sku_id & 2 will be
+ * true.
  */
 bool mainboard_needs_pcie_init(void)
 {
-	/*
-	 * Mask out everything above the actual SKU bits We have 3 sku pins,
-	 * each tristate, so we can represent numbers up to 27, or 5 bits
-	 */
-	uint32_t sku_bits_mask = 0xff;
-	uint32_t sku = sku_id() & sku_bits_mask;
+	uint32_t sku = sku_id();

if (sku == CROS_SKU_UNKNOWN) {
    	printk(BIOS_WARNING, "Unknown SKU (%#x); assuming PCIe", sku);
@@ -106,11 +102,7 @@
    	return true;
    }

-	if ((sku % 3) == 2)
-		return true;
-
-	/* Otherwise, eMMC */
-	return false;
+	return !!(sku & 0x2);
 }

static void mainboard_init(struct device *dev)