Merge a rudimentary gxemul "oldtestmips" port. This consists almost

entirely of one machdep file lifted from the MALTA port, as well as
a low-level console and tty driver for the gxemul debugging console
device (the emulators stdio).  As with many low-level embedded and
hypervisor console devices, it is polled only, so we drive TTY I/O
from a callout; we are perhaps a bit too aware of the MIPS physical
maps in order to attach the console before newbus comes to life.

The sample kernel configuration depends on an MD-based root file
system, which is not provided.  However, any 64-bit, big-endian
userspace image (such as one generated for MALTA) should work.

This will hopefully be supplemented by additional device drivers for
gxemul-specific hardware simulations from Juli Mallett.  We have
found oldtestmips quite useful for testing and improving aspects of
the MIPS port, so it's worth supporting better in FreeBSD.

Requested by:	theraven, jmallett
Sponsored by:	DARPA, AFRL
MFC after:	3 weeks

3 files changed, 200 insertions, 0 deletions

diff --git a/sys/mips/gxemul/files.gxemul b/sys/mips/gxemul/files.gxemul
new file mode 100644
index 0000000..12b7670
--- /dev/null
+++ b/sys/mips/gxemul/files.gxemul
@@ -0,0 +1,5 @@
+# $FreeBSD$
+dev/gxemul/cons/gxemul_cons.c		optional gxemul_cons
+mips/gxemul/gxemul_machdep.c		standard
+mips/mips/intr_machdep.c		standard
+mips/mips/tick.c			standard
diff --git a/sys/mips/gxemul/gxemul_machdep.c b/sys/mips/gxemul/gxemul_machdep.c
new file mode 100644
index 0000000..4789873
--- /dev/null
+++ b/sys/mips/gxemul/gxemul_machdep.c
@@ -0,0 +1,191 @@
+/*-
+ * Copyright (c) 2006 Wojciech A. Koszek <wkoszek@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_ddb.h"
+
+#include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/imgact.h>
+#include <sys/bio.h>
+#include <sys/buf.h>
+#include <sys/bus.h>
+#include <sys/cpu.h>
+#include <sys/cons.h>
+#include <sys/exec.h>
+#include <sys/ucontext.h>
+#include <sys/proc.h>
+#include <sys/kdb.h>
+#include <sys/ptrace.h>
+#include <sys/reboot.h>
+#include <sys/signalvar.h>
+#include <sys/sysent.h>
+#include <sys/sysproto.h>
+#include <sys/user.h>
+
+#include <vm/vm.h>
+#include <vm/vm_object.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pager.h>
+
+#include <machine/clock.h>
+#include <machine/cpu.h>
+#include <machine/cpuregs.h>
+#include <machine/hwfunc.h>
+#include <machine/md_var.h>
+#include <machine/pmap.h>
+#include <machine/trap.h>
+
+extern int	*edata;
+extern int	*end;
+
+void
+platform_cpu_init()
+{
+	/* Nothing special */
+}
+
+static void
+mips_init(void)
+{
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		phys_avail[i] = 0;
+	}
+
+	/* phys_avail regions are in bytes */
+	phys_avail[0] = MIPS_KSEG0_TO_PHYS(kernel_kseg0_end);
+	phys_avail[1] = ctob(realmem);
+
+	dump_avail[0] = phys_avail[0];
+	dump_avail[1] = phys_avail[1];
+
+	physmem = realmem;
+
+	init_param1();
+	init_param2(physmem);
+	mips_cpu_init();
+	pmap_bootstrap();
+	mips_proc0_init();
+	mutex_init();
+	kdb_init();
+#ifdef KDB
+	if (boothowto & RB_KDB)
+		kdb_enter(KDB_WHY_BOOTFLAGS, "Boot flags requested debugger");
+#endif
+}
+
+void
+platform_halt(void)
+{
+
+}
+
+
+void
+platform_identify(void)
+{
+
+}
+
+/*
+ * Perform a board-level soft-reset.
+ *
+ * XXXRW: Does gxemul have a moral equivalent to board-level reset?
+ */
+void
+platform_reset(void)
+{
+
+	panic("%s: not yet", __func__);
+}
+
+void
+platform_trap_enter(void)
+{
+
+}
+
+void
+platform_trap_exit(void)
+{
+
+}
+
+void
+platform_start(__register_t a0, __register_t a1,  __register_t a2, 
+    __register_t a3)
+{
+	vm_offset_t kernend;
+	uint64_t platform_counter_freq;
+	int argc = a0;
+	char **argv = (char **)a1;
+	char **envp = (char **)a2;
+	unsigned int memsize = a3;
+	int i;
+
+	/* clear the BSS and SBSS segments */
+	kernend = (vm_offset_t)&end;
+	memset(&edata, 0, kernend - (vm_offset_t)(&edata));
+
+	mips_postboot_fixup();
+
+	mips_pcpu0_init();
+
+	/*
+	 * XXXRW: Support for the gxemul real-time clock required in order to
+	 * usefully determine our emulated timer frequency.  Go with something
+	 * classic as the default in the mean time.
+	 */
+	platform_counter_freq = MIPS_DEFAULT_HZ;
+	mips_timer_early_init(platform_counter_freq);
+
+	cninit();
+	printf("entry: platform_start()\n");
+
+	bootverbose = 1;
+	if (bootverbose) {
+		printf("cmd line: ");
+		for (i = 0; i < argc; i++)
+			printf("%s ", argv[i]);
+		printf("\n");
+
+		printf("envp:\n");
+		for (i = 0; envp[i]; i += 2)
+			printf("\t%s = %s\n", envp[i], envp[i+1]);
+
+		printf("memsize = %08x\n", memsize);
+	}
+
+	realmem = btoc(memsize);
+	mips_init();
+
+	mips_timer_init_params(platform_counter_freq, 0);
+}
diff --git a/sys/mips/gxemul/std.gxemul b/sys/mips/gxemul/std.gxemul
new file mode 100644
index 0000000..7fad324
--- /dev/null
+++ b/sys/mips/gxemul/std.gxemul
@@ -0,0 +1,4 @@
+# $FreeBSD$
+files	"../gxemul/files.gxemul"
+
+cpu		CPU_MIPS4KC