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      1 /* $NetBSD: fdt_reset.c,v 1.4 2019/02/27 16:56:00 jakllsch Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015 Jared D. 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_reset.c,v 1.4 2019/02/27 16:56:00 jakllsch 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 fdtbus_reset_controller {
     41 	device_t rc_dev;
     42 	int rc_phandle;
     43 	const struct fdtbus_reset_controller_func *rc_funcs;
     44 
     45 	LIST_ENTRY(fdtbus_reset_controller) rc_next;
     46 };
     47 
     48 static LIST_HEAD(, fdtbus_reset_controller) fdtbus_reset_controllers =
     49     LIST_HEAD_INITIALIZER(fdtbus_reset_controllers);
     50 
     51 int
     52 fdtbus_register_reset_controller(device_t dev, int phandle,
     53     const struct fdtbus_reset_controller_func *funcs)
     54 {
     55 	struct fdtbus_reset_controller *rc;
     56 
     57 	rc = kmem_alloc(sizeof(*rc), KM_SLEEP);
     58 	rc->rc_dev = dev;
     59 	rc->rc_phandle = phandle;
     60 	rc->rc_funcs = funcs;
     61 
     62 	LIST_INSERT_HEAD(&fdtbus_reset_controllers, rc, rc_next);
     63 
     64 	return 0;
     65 }
     66 
     67 static struct fdtbus_reset_controller *
     68 fdtbus_get_reset_controller(int phandle)
     69 {
     70 	struct fdtbus_reset_controller *rc;
     71 
     72 	LIST_FOREACH(rc, &fdtbus_reset_controllers, rc_next) {
     73 		if (rc->rc_phandle == phandle)
     74 			return rc;
     75 	}
     76 
     77 	return NULL;
     78 }
     79 
     80 struct fdtbus_reset *
     81 fdtbus_reset_get_index(int phandle, u_int index)
     82 {
     83 	struct fdtbus_reset_controller *rc;
     84 	struct fdtbus_reset *rst = NULL;
     85 	void *rst_priv = NULL;
     86 	uint32_t *resets = NULL;
     87 	uint32_t *p;
     88 	u_int n, reset_cells;
     89 	int len, resid;
     90 
     91 	len = OF_getproplen(phandle, "resets");
     92 	if (len <= 0)
     93 		return NULL;
     94 
     95 	resets = kmem_alloc(len, KM_SLEEP);
     96 	if (OF_getprop(phandle, "resets", resets, len) != len) {
     97 		kmem_free(resets, len);
     98 		return NULL;
     99 	}
    100 
    101 	p = resets;
    102 	for (n = 0, resid = len; resid > 0; n++) {
    103 		const int rc_phandle =
    104 		    fdtbus_get_phandle_from_native(be32toh(p[0]));
    105 		if (of_getprop_uint32(rc_phandle, "#reset-cells", &reset_cells))
    106 			break;
    107 		if (n == index) {
    108 			rc = fdtbus_get_reset_controller(rc_phandle);
    109 			if (rc == NULL)
    110 				goto done;
    111 			rst_priv = rc->rc_funcs->acquire(rc->rc_dev,
    112 			    reset_cells > 0 ? &p[1] : NULL, reset_cells * 4);
    113 			if (rst_priv) {
    114 				rst = kmem_alloc(sizeof(*rst), KM_SLEEP);
    115 				rst->rst_rc = rc;
    116 				rst->rst_priv = rst_priv;
    117 			}
    118 			break;
    119 		}
    120 		resid -= (reset_cells + 1) * 4;
    121 		p += reset_cells + 1;
    122 	}
    123 
    124 done:
    125 	if (resets)
    126 		kmem_free(resets, len);
    127 
    128 	return rst;
    129 }
    130 
    131 struct fdtbus_reset *
    132 fdtbus_reset_get(int phandle, const char *rstname)
    133 {
    134 	u_int index;
    135 	int err;
    136 
    137 	err = fdtbus_get_index(phandle, "reset-names", rstname, &index);
    138 	if (err != 0)
    139 		return NULL;
    140 
    141 	return fdtbus_reset_get_index(phandle, index);
    142 }
    143 
    144 void
    145 fdtbus_reset_put(struct fdtbus_reset *rst)
    146 {
    147 	struct fdtbus_reset_controller *rc = rst->rst_rc;
    148 
    149 	rc->rc_funcs->release(rc->rc_dev, rst->rst_priv);
    150 	kmem_free(rst, sizeof(*rst));
    151 }
    152 
    153 int
    154 fdtbus_reset_assert(struct fdtbus_reset *rst)
    155 {
    156 	struct fdtbus_reset_controller *rc = rst->rst_rc;
    157 
    158 	return rc->rc_funcs->reset_assert(rc->rc_dev, rst->rst_priv);
    159 }
    160 
    161 int
    162 fdtbus_reset_deassert(struct fdtbus_reset *rst)
    163 {
    164 	struct fdtbus_reset_controller *rc = rst->rst_rc;
    165 
    166 	return rc->rc_funcs->reset_deassert(rc->rc_dev, rst->rst_priv);
    167 }
    168