Change in coreboot[master]: mb/google/octopus: Dynamically disable CNVi/PCIe device

[Furquan Shaikh (Code Review)]

Furquan Shaikh has uploaded this change for review. ( https://review.coreboot.org/27961

Change subject: mb/google/octopus: Dynamically disable CNVi/PCIe device
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mb/google/octopus: Dynamically disable CNVi/PCIe device

This change checks to see if CNVi module is out of reset:
1. If yes, then PCIe device for WiFi is disabled.
2. If no, then CNVi device is disabled.

BUG=b:112371978

Change-Id: I6e6cf2e646c897df017913056db87ac0cffa1a8e
Signed-off-by: Furquan Shaikh 
---
M src/mainboard/google/octopus/mainboard.c
1 file changed, 28 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/61/27961/1

diff --git a/src/mainboard/google/octopus/mainboard.c b/src/mainboard/google/octopus/mainboard.c
index 5c10d94..344596f 100644
--- a/src/mainboard/google/octopus/mainboard.c
+++ b/src/mainboard/google/octopus/mainboard.c
@@ -19,6 +19,8 @@
 #include <compiler.h>
 #include <console/console.h>
 #include <device/device.h>
+#include <device/pci_def.h>
+#include <device/pci_ops.h>
 #include <ec/google/chromeec/ec.h>
 #include <ec/ec.h>
 #include <nhlt.h>
@@ -26,6 +28,7 @@
 #include <soc/cpu.h>
 #include <soc/gpio.h>
 #include <soc/nhlt.h>
+#include <soc/pci_devs.h>
 #include <string.h>
 #include <vendorcode/google/chromeos/chromeos.h>
 #include <variant/ec.h>
@@ -122,8 +125,33 @@
    /* Place holder for common updates. */
 }

+/*
+ * Check if CNVi PCI device is released from reset. If yes, then the system is
+ * booting with CNVi module. In this case, the PCIe device for WiFi needs to
+ * be disabled. If CNVi device is held in reset, then disable it.
+ */
+static void wifi_device_update(void)
+{
+	struct device *dev = dev_find_slot(0, PCH_DEVFN_CNVI);
+	uint32_t reg = pci_read_config32(dev, PCI_VENDOR_ID);
+
+	/*
+	 * If vendor/device ID for CNVi reads as 0xffffffff, then it is safe to
+	 * assume that it is being held in reset.
+	 */
+	if (reg == 0xffffffff)
+		dev->enabled = 0;
+	else {
+		dev = dev_find_slot(0, PCH_DEVFN_PCIE1);
+		dev->enabled = 0;
+	}
+}
+
 void mainboard_devtree_update(struct device *dev)
 {
+	/* Apply common devtree updates. */
+	wifi_device_update();
+
    /* Defer to variant for board-specific updates. */
    variant_update_devtree(dev);
 }