1 files changed, 94 insertions, 0 deletions
diff --git a/src/lib/fw_config.c b/src/lib/fw_config.c
new file mode 100644
index 0000000000..e97cfdc72a
--- /dev/null
+++ b/src/lib/fw_config.c
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <bootstate.h>
+#include <cbfs.h>
+#include <console/console.h>
+#include <device/device.h>
+#include <ec/google/chromeec/ec.h>
+#include <fw_config.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+/**
+ * fw_config_get() - Provide firmware configuration value.
+ *
+ * Return 32bit firmware configuration value determined for the system.
+ */
+static uint32_t fw_config_get(void)
+{
+	static uint32_t fw_config_value;
+	static bool fw_config_value_initialized;
+
+	/* Nothing to prepare if setup is already done. */
+	if (fw_config_value_initialized)
+		return fw_config_value;
+	fw_config_value_initialized = true;
+
+	/* Look in CBFS to allow override of value. */
+	if (CONFIG(FW_CONFIG_SOURCE_CBFS)) {
+		if (cbfs_boot_load_file(CONFIG_CBFS_PREFIX "/fw_config",
+					&fw_config_value, sizeof(fw_config_value),
+					CBFS_TYPE_RAW) != sizeof(fw_config_value)) {
+			printk(BIOS_WARNING, "%s: Could not get fw_config from CBFS\n",
+			       __func__);
+			fw_config_value = 0;
+		} else {
+			printk(BIOS_INFO, "FW_CONFIG value from CBFS is 0x%08x\n",
+			       fw_config_value);
+			return fw_config_value;
+		}
+	}
+
+	/* Read the value from EC CBI. */
+	if (CONFIG(FW_CONFIG_SOURCE_CHROMEEC_CBI)) {
+		if (google_chromeec_cbi_get_fw_config(&fw_config_value))
+			printk(BIOS_WARNING, "%s: Could not get fw_config from EC\n", __func__);
+	}
+
+	printk(BIOS_INFO, "FW_CONFIG value is 0x%08x\n", fw_config_value);
+	return fw_config_value;
+}
+
+bool fw_config_probe(const struct fw_config *match)
+{
+	/* Compare to system value. */
+	if ((fw_config_get() & match->mask) == match->value) {
+		if (match->field_name && match->option_name)
+			printk(BIOS_INFO, "fw_config match found: %s=%s\n", match->field_name,
+			       match->option_name);
+		else
+			printk(BIOS_INFO, "fw_config match found: mask=0x%08x value=0x%08x\n",
+			       match->mask, match->value);
+		return true;
+	}
+
+	return false;
+}
+
+#if ENV_RAMSTAGE
+static void fw_config_init(void *unused)
+{
+	struct device *dev;
+
+	for (dev = all_devices; dev; dev = dev->next) {
+		const struct fw_config *probe;
+		bool match = false;
+
+		if (!dev->probe_list)
+			continue;
+
+		for (probe = dev->probe_list; probe && probe->mask != 0; probe++) {
+			if (fw_config_probe(probe)) {
+				match = true;
+				break;
+			}
+		}
+
+		if (!match) {
+			printk(BIOS_INFO, "%s disabled by fw_config\n", dev_path(dev));
+			dev->enabled = 0;
+		}
+	}
+}
+BOOT_STATE_INIT_ENTRY(BS_DEV_ENUMERATE, BS_ON_ENTRY, fw_config_init, NULL);
+#endif