port-arm/58194: Resurrect vmt(4) from bitrot

On this architecture vmt(4) used to search for a node "/hypervisor" in the
FDT and probed the VMware hypervisor call only when the node was
found. However, things appear to have changed and VMware no longer provides
the FDT node.

Since vmt(4) doesn't actually need to read anything from FDT, and the
hypervisor call logically resides in virtual CPUs themselves, it would be
better to attach it directly to cpu, just like how it's probed on x86.


(pho)

/* $NetBSD */

/*
 * Copyright (c) 2024 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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/device.h>
#include <sys/module.h>

#include <dev/vmt/vmtreg.h>
#include <dev/vmt/vmtvar.h>

static int	vmt_match(device_t, cfdata_t, void *);
static void	vmt_attach(device_t, device_t, void *);
static int	vmt_detach(device_t, int);

CFATTACH_DECL_NEW(vmt, sizeof(struct vmt_softc),
	vmt_match, vmt_attach, vmt_detach, NULL);

static bool vmt_attached = false;

static int
vmt_match(device_t parent, cfdata_t match, void *aux)
{
	/* vmt should not attach to more than a single CPU. */
	if (vmt_attached)
		return 0;

	return vmt_probe();
}

static void
vmt_attach(device_t parent, device_t self, void *aux)
{
	struct vmt_softc *sc = device_private(self);

	aprint_naive("\n");
	aprint_normal(": VMware Tools driver\n");

	sc->sc_dev = self;
	vmt_common_attach(sc);

	vmt_attached = true;
}

static int
vmt_detach(device_t self, int flags)
{
	struct vmt_softc *sc = device_private(self);
	int rv;

	rv = vmt_common_detach(sc);
	if (rv != 0)
		return rv;

	vmt_attached = false;
	return 0;
}

MODULE(MODULE_CLASS_DRIVER, vmt, "sysmon_power,sysmon_taskq");

#ifdef _MODULE
#include "ioconf.c"
#endif

static int
vmt_modcmd(modcmd_t cmd, void *aux)
{
	int error = 0;

	switch (cmd) {
	case MODULE_CMD_INIT:
#ifdef _MODULE
		error = config_init_component(cfdriver_ioconf_vmt,
		    cfattach_ioconf_vmt, cfdata_ioconf_vmt);
#endif
		break;
	case MODULE_CMD_FINI:
#ifdef _MODULE
		error = config_fini_component(cfdriver_ioconf_vmt,
		    cfattach_ioconf_vmt, cfdata_ioconf_vmt);
#endif
		break;
	case MODULE_CMD_AUTOUNLOAD:
		error = EBUSY;
		break;
	default:
		error = ENOTTY;
		break;
	}

	return error;
}