1 files changed, 59 insertions, 0 deletions
diff --git a/src/mainboard/emulation/qemu-x86/fw_cfg.c b/src/mainboard/emulation/qemu-x86/fw_cfg.c
new file mode 100644
index 0000000000..5166f83092
--- /dev/null
+++ b/src/mainboard/emulation/qemu-x86/fw_cfg.c
@@ -0,0 +1,59 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <string.h>
+#include <console/console.h>
+#include <arch/io.h>
+
+#include "fw_cfg.h"
+#include "fw_cfg_if.h"
+
+#define FW_CFG_PORT_CTL       0x0510
+#define FW_CFG_PORT_DATA      0x0511
+
+static unsigned char fw_cfg_detected = 0xff;
+
+static int fw_cfg_present(void)
+{
+	static const char qsig[] = "QEMU";
+	unsigned char sig[4];
+
+	if (fw_cfg_detected == 0xff) {
+		fw_cfg_get(FW_CFG_SIGNATURE, sig, sizeof(sig));
+		fw_cfg_detected = (memcmp(sig, qsig, 4) == 0) ? 1 : 0;
+		printk(BIOS_INFO, "QEMU: firmware config interface %s\n",
+		       fw_cfg_detected ? "detected" : "not found");
+	}
+	return fw_cfg_detected;
+}
+
+void fw_cfg_get(int entry, void *dst, int dstlen)
+{
+	outw(entry, FW_CFG_PORT_CTL);
+	insb(FW_CFG_PORT_DATA, dst, dstlen);
+}
+
+int fw_cfg_max_cpus(void)
+{
+	unsigned short max_cpus;
+
+	if (!fw_cfg_present())
+		return -1;
+
+	fw_cfg_get(FW_CFG_MAX_CPUS, &max_cpus, sizeof(max_cpus));
+	return max_cpus;
+}