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      1 /* $NetBSD: fdt_syscon.c,v 1.3 2018/06/30 20:16:56 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2018 Jared McNeill <jmcneill (at) invisible.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: fdt_syscon.c,v 1.3 2018/06/30 20:16:56 jmcneill Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/kmem.h>
     35 #include <sys/queue.h>
     36 
     37 #include <libfdt.h>
     38 #include <dev/fdt/fdtvar.h>
     39 
     40 struct syscon;
     41 
     42 struct fdtbus_syscon {
     43 	device_t sc_dev;
     44 	int sc_phandle;
     45 	struct syscon *sc_syscon;
     46 
     47 	LIST_ENTRY(fdtbus_syscon) sc_next;
     48 };
     49 
     50 static LIST_HEAD(, fdtbus_syscon) fdtbus_syscons =
     51     LIST_HEAD_INITIALIZER(fdtbus_syscons);
     52 
     53 int
     54 fdtbus_register_syscon(device_t dev, int phandle,
     55     struct syscon *syscon)
     56 {
     57 	struct fdtbus_syscon *sc;
     58 
     59 	sc = kmem_alloc(sizeof(*sc), KM_SLEEP);
     60 	sc->sc_dev = dev;
     61 	sc->sc_phandle = phandle;
     62 	sc->sc_syscon = syscon;
     63 
     64 	LIST_INSERT_HEAD(&fdtbus_syscons, sc, sc_next);
     65 
     66 	return 0;
     67 }
     68 
     69 static struct fdtbus_syscon *
     70 fdtbus_get_syscon(int phandle)
     71 {
     72 	struct fdtbus_syscon *sc;
     73 
     74 	LIST_FOREACH(sc, &fdtbus_syscons, sc_next) {
     75 		if (sc->sc_phandle == phandle)
     76 			return sc;
     77 	}
     78 
     79 	return NULL;
     80 }
     81 
     82 struct syscon *
     83 fdtbus_syscon_acquire(int phandle, const char *prop)
     84 {
     85 	struct fdtbus_syscon *sc;
     86 	int sc_phandle;
     87 
     88 	sc_phandle = fdtbus_get_phandle(phandle, prop);
     89 	if (sc_phandle < 0)
     90 		return NULL;
     91 
     92 	sc = fdtbus_get_syscon(sc_phandle);
     93 	if (sc == NULL)
     94 		return NULL;
     95 
     96 	return sc->sc_syscon;
     97 }
     98 
     99 struct syscon *
    100 fdtbus_syscon_lookup(int phandle)
    101 {
    102 	struct fdtbus_syscon *sc;
    103 
    104 	sc = fdtbus_get_syscon(phandle);
    105 	if (sc == NULL)
    106 		return NULL;
    107 
    108 	return sc->sc_syscon;
    109 }
    110