1 files changed, 72 insertions, 0 deletions
diff --git a/drivers/eisa/virtual_root.c b/drivers/eisa/virtual_root.c
new file mode 100644
index 0000000000..37e6dd219c
--- /dev/null
+++ b/drivers/eisa/virtual_root.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Virtual EISA root driver.
+ * Acts as a placeholder if we don't have a proper EISA bridge.
+ *
+ * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/eisa.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+
+#if defined(CONFIG_ALPHA_JENSEN) || defined(CONFIG_EISA_VLB_PRIMING)
+#define EISA_FORCE_PROBE_DEFAULT 1
+#else
+#define EISA_FORCE_PROBE_DEFAULT 0
+#endif
+
+static int force_probe = EISA_FORCE_PROBE_DEFAULT;
+static void virtual_eisa_release (struct device *);
+
+/* The default EISA device parent (virtual root device).
+ * Now use a platform device, since that's the obvious choice. */
+
+static struct platform_device eisa_root_dev = {
+	.name = "eisa",
+	.id   = 0,
+	.dev  = {
+		.release = virtual_eisa_release,
+	},
+};
+
+static struct eisa_root_device eisa_bus_root = {
+	.dev		= &eisa_root_dev.dev,
+	.bus_base_addr	= 0,
+	.res		= &ioport_resource,
+	.slots		= EISA_MAX_SLOTS,
+	.dma_mask	= 0xffffffff,
+};
+
+static void virtual_eisa_release (struct device *dev)
+{
+	/* nothing really to do here */
+}
+
+static int __init virtual_eisa_root_init (void)
+{
+	int r;
+
+	if ((r = platform_device_register (&eisa_root_dev)))
+		return r;
+
+	eisa_bus_root.force_probe = force_probe;
+
+	dev_set_drvdata(&eisa_root_dev.dev, &eisa_bus_root);
+
+	if (eisa_root_register (&eisa_bus_root)) {
+		/* A real bridge may have been registered before
+		 * us. So quietly unregister. */
+		platform_device_unregister (&eisa_root_dev);
+		return -1;
+	}
+
+	return 0;
+}
+
+module_param (force_probe, int, 0444);
+
+device_initcall (virtual_eisa_root_init);