MIPS: Add generic support for multiple machines within a single kernel

This patch adds a generic solution to support multiple machines based on
a given SoC within a single kernel image. It is implemented already for
several other architectures but MIPS has no generic support for that yet.

[Ralf: This competes with DT but DT is a much more complex solution and this
code has been used by OpenWRT for a long time so for now DT is a bad reason
to stop the merge but longer term this should be migrated to DT.]

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: kaloz@openwrt.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1814/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 86 insertions, 0 deletions

diff --git a/arch/mips/kernel/mips_machine.c b/arch/mips/kernel/mips_machine.c
new file mode 100644
index 0000000..411a058
--- /dev/null
+++ b/arch/mips/kernel/mips_machine.c
@@ -0,0 +1,86 @@
+/*
+ *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ */
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+
+#include <asm/mips_machine.h>
+
+static struct mips_machine *mips_machine __initdata;
+static char *mips_machine_name = "Unknown";
+
+#define for_each_machine(mach) \
+	for ((mach) = (struct mips_machine *)&__mips_machines_start; \
+	     (mach) && \
+	     (unsigned long)(mach) < (unsigned long)&__mips_machines_end; \
+	     (mach)++)
+
+__init void mips_set_machine_name(const char *name)
+{
+	char *p;
+
+	if (name == NULL)
+		return;
+
+	p = kstrdup(name, GFP_KERNEL);
+	if (!p)
+		pr_err("MIPS: no memory for machine_name\n");
+
+	mips_machine_name = p;
+}
+
+char *mips_get_machine_name(void)
+{
+	return mips_machine_name;
+}
+
+__init int mips_machtype_setup(char *id)
+{
+	struct mips_machine *mach;
+
+	for_each_machine(mach) {
+		if (mach->mach_id == NULL)
+			continue;
+
+		if (strcmp(mach->mach_id, id) == 0) {
+			mips_machtype = mach->mach_type;
+			return 0;
+		}
+	}
+
+	pr_err("MIPS: no machine found for id '%s', supported machines:\n", id);
+	pr_err("%-24s %s\n", "id", "name");
+	for_each_machine(mach)
+		pr_err("%-24s %s\n", mach->mach_id, mach->mach_name);
+
+	return 1;
+}
+
+__setup("machtype=", mips_machtype_setup);
+
+__init void mips_machine_setup(void)
+{
+	struct mips_machine *mach;
+
+	for_each_machine(mach) {
+		if (mips_machtype == mach->mach_type) {
+			mips_machine = mach;
+			break;
+		}
+	}
+
+	if (!mips_machine)
+		return;
+
+	mips_set_machine_name(mips_machine->mach_name);
+	pr_info("MIPS: machine is %s\n", mips_machine_name);
+
+	if (mips_machine->mach_setup)
+		mips_machine->mach_setup();
+}