text: /*-
   * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   *
   * Copyright (c) 2017 Kyle Evans <kevans@FreeBSD.org>
   *
   * 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.
   */
  
  /*
   * This is a generic syscon driver, whose purpose is to provide access to
   * various unrelated bits packed in a single register space. It is usually used
   * as a fallback to more specific driver, but works well enough for simple
   * access.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  #include "opt_platform.h"
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/bus.h>
  #include <sys/kernel.h>
  #include <sys/kobj.h>
  #include <sys/lock.h>
  #include <sys/module.h>
  #include <sys/rman.h>
  #include <sys/sx.h>
  #include <sys/queue.h>
  
  #include <machine/bus.h>
  
  #ifdef FDT
  #include <dev/ofw/ofw_bus.h>
  #include <dev/ofw/ofw_bus_subr.h>
  #endif
  
  #include "syscon_if.h"
  #include "syscon.h"
  
  /*
   * Syscon interface details
   */
  typedef TAILQ_HEAD(syscon_list, syscon) syscon_list_t;
  
  /*
   * Declarations
   */
  static int syscon_method_init(struct syscon *syscon);
  static int syscon_method_uninit(struct syscon *syscon);
  
  MALLOC_DEFINE(M_SYSCON, "syscon", "Syscon driver");
  
  static syscon_list_t syscon_list = TAILQ_HEAD_INITIALIZER(syscon_list);
  static struct sx		syscon_topo_lock;
  SX_SYSINIT(syscon_topology, &syscon_topo_lock, "Syscon topology lock");
  
  /*
   * Syscon methods.
   */
  static syscon_method_t syscon_methods[] = {
  	SYSCONMETHOD(syscon_init,	syscon_method_init),
  	SYSCONMETHOD(syscon_uninit,	syscon_method_uninit),
  
  	SYSCONMETHOD_END
  };
  DEFINE_CLASS_0(syscon, syscon_class, syscon_methods, 0);
  
  #define SYSCON_TOPO_SLOCK()	sx_slock(&syscon_topo_lock)
  #define SYSCON_TOPO_XLOCK()	sx_xlock(&syscon_topo_lock)
  #define SYSCON_TOPO_UNLOCK()	sx_unlock(&syscon_topo_lock)
  #define SYSCON_TOPO_ASSERT()	sx_assert(&syscon_topo_lock, SA_LOCKED)
  #define SYSCON_TOPO_XASSERT()	sx_assert(&syscon_topo_lock, SA_XLOCKED)
  
  /*
   * Default syscon methods for base class.
   */
  static int
  syscon_method_init(struct syscon *syscon)
  {
  
  	return (0);
  };
  
  static int
  syscon_method_uninit(struct syscon *syscon)
  {
  
  	return (0);
  };
  
  void *
  syscon_get_softc(struct syscon *syscon)
  {
  
  	return (syscon->softc);
  };
  
  /*
   * Create and initialize syscon object, but do not register it.
   */
  struct syscon *
  syscon_create(device_t pdev, syscon_class_t syscon_class)
  {
  	struct syscon *syscon;
  
  	/* Create object and initialize it. */
  	syscon = malloc(sizeof(struct syscon), M_SYSCON,
  	    M_WAITOK | M_ZERO);
  	kobj_init((kobj_t)syscon, (kobj_class_t)syscon_class);
  
  	/* Allocate softc if required. */
  	if (syscon_class->size > 0)
  		syscon->softc = malloc(syscon_class->size, M_SYSCON,
  		    M_WAITOK | M_ZERO);
  
  	/* Rest of init. */
  	syscon->pdev = pdev;
  	return (syscon);
  }
  
  /* Register syscon object. */
  struct syscon *
  syscon_register(struct syscon *syscon)
  {
  	int rv;
  
  #ifdef FDT
  	if (syscon->ofw_node <= 0)
  		syscon->ofw_node = ofw_bus_get_node(syscon->pdev);
  	if (syscon->ofw_node <= 0)
  		return (NULL);
  #endif
  
  	rv = SYSCON_INIT(syscon);
  	if (rv != 0) {
  		printf("SYSCON_INIT failed: %d\n", rv);
  		return (NULL);
  	}
  
  #ifdef FDT
  	OF_device_register_xref(OF_xref_from_node(syscon->ofw_node),
  	    syscon->pdev);
  #endif
  	SYSCON_TOPO_XLOCK();
  	TAILQ_INSERT_TAIL(&syscon_list, syscon, syscon_link);
  	SYSCON_TOPO_UNLOCK();
  	return (syscon);
  }
  
  int
  syscon_unregister(struct syscon *syscon)
  {
  
  	SYSCON_TOPO_XLOCK();
  	TAILQ_REMOVE(&syscon_list, syscon, syscon_link);
  	SYSCON_TOPO_UNLOCK();
  #ifdef FDT
  	OF_device_register_xref(OF_xref_from_node(syscon->ofw_node), NULL);
  #endif
  	return (SYSCON_UNINIT(syscon));
  }
  
  /**
   * Provider methods
   */
  #ifdef FDT
  static struct syscon *
  syscon_find_by_ofw_node(phandle_t node)
  {
  	struct syscon *entry;
  
  	SYSCON_TOPO_ASSERT();
  
  	TAILQ_FOREACH(entry, &syscon_list, syscon_link) {
  		if (entry->ofw_node == node)
  			return (entry);
  	}
  
  	return (NULL);
  }
  
  struct syscon *
  syscon_create_ofw_node(device_t pdev, syscon_class_t syscon_class,
      phandle_t node)
  {
  	struct syscon *syscon;
  
  	syscon = syscon_create(pdev, syscon_class);
  	if (syscon == NULL)
  		return (NULL);
  	syscon->ofw_node = node;
  	if (syscon_register(syscon) == NULL)
  		return (NULL);
  	return (syscon);
  }
  
  phandle_t
  syscon_get_ofw_node(struct syscon *syscon)
  {
  
  	return (syscon->ofw_node);
  }
  
  int
  syscon_get_by_ofw_property(device_t cdev, phandle_t cnode, char *name,
      struct syscon **syscon)
  {
  	pcell_t *cells;
  	int ncells;
  
  	if (cnode <= 0)
  		cnode = ofw_bus_get_node(cdev);
  	if (cnode <= 0) {
  		device_printf(cdev,
  		    "%s called on not ofw based device\n", __func__);
  		return (ENXIO);
  	}
  	ncells = OF_getencprop_alloc_multi(cnode, name, sizeof(pcell_t),
  	    (void **)&cells);
  	if (ncells < 1)
  		return (ENOENT);
  
  	/* Translate to syscon node. */
  	SYSCON_TOPO_SLOCK();
  	*syscon = syscon_find_by_ofw_node(OF_node_from_xref(cells[0]));
  	if (*syscon == NULL) {
  		SYSCON_TOPO_UNLOCK();
  		device_printf(cdev, "Failed to find syscon node\n");
  		OF_prop_free(cells);
  		return (ENODEV);
  	}
  	SYSCON_TOPO_UNLOCK();
  	OF_prop_free(cells);
  	return (0);
  }
  #endif
  
  int
  syscon_get_handle_default(device_t dev, struct syscon **syscon)
  {
  	device_t parent;
  
  	parent = device_get_parent(dev);
  	if (parent == NULL)
  		return (ENODEV);
  	return (SYSCON_GET_HANDLE(parent, syscon));
  }
  