1 /*-
2 * Copyright (c) 2012 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Matt Thomas of 3am Software Foundry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #define RNG_PRIVATE
31
32 #include "locators.h"
33
34 #include <sys/cdefs.h>
35
36 __KERNEL_RCSID(1, "$NetBSD: bcm53xx_rng.c,v 1.10 2017/01/08 05:05:27 christos Exp $");
37
38 #include <sys/param.h>
39 #include <sys/bus.h>
40 #include <sys/callout.h>
41 #include <sys/device.h>
42 #include <sys/intr.h>
43 #include <sys/rndsource.h>
44 #include <sys/systm.h>
45
46 #include <arm/broadcom/bcm53xx_reg.h>
47 #include <arm/broadcom/bcm53xx_var.h>
48
49 static int bcmrng_ccb_match(device_t, cfdata_t, void *);
50 static void bcmrng_ccb_attach(device_t, device_t, void *);
51
52 struct bcmrng_softc {
53 device_t sc_dev;
54 bus_space_tag_t sc_bst;
55 bus_space_handle_t sc_bsh;
56 krndsource_t sc_rnd_source;
57 struct callout sc_rnd_callout;
58 kmutex_t *sc_lock;
59 #ifdef RNG_USE_INTR
60 size_t sc_intr_amount;
61 void *sc_ih;
62 #endif
63 };
64
65 static void bcmrng_callout(void *arg);
66 static size_t bcmrng_empty(struct bcmrng_softc *);
67 #ifdef RNG_USE_INTR
68 static int bcmrng_intr(void *);
69 #endif
70
71 CFATTACH_DECL_NEW(bcmrng_ccb, sizeof(struct bcmrng_softc),
72 bcmrng_ccb_match, bcmrng_ccb_attach, NULL, NULL);
73
74 static int
bcmrng_ccb_match(device_t parent,cfdata_t cf,void * aux)75 bcmrng_ccb_match(device_t parent, cfdata_t cf, void *aux)
76 {
77 struct bcmccb_attach_args * const ccbaa = aux;
78 const struct bcm_locators * const loc = &ccbaa->ccbaa_loc;
79
80 if (strcmp(cf->cf_name, loc->loc_name))
81 return 0;
82
83 KASSERT(cf->cf_loc[BCMCCBCF_PORT] == BCMCCBCF_PORT_DEFAULT);
84
85 return 1;
86 }
87
88 static inline uint32_t
bcmrng_read_4(struct bcmrng_softc * sc,bus_size_t o)89 bcmrng_read_4(struct bcmrng_softc *sc, bus_size_t o)
90 {
91 return bus_space_read_4(sc->sc_bst, sc->sc_bsh, o);
92 }
93
94 static inline void
bcmrng_read_multi_4(struct bcmrng_softc * sc,bus_size_t o,uint32_t * p,size_t c)95 bcmrng_read_multi_4(struct bcmrng_softc *sc, bus_size_t o, uint32_t *p,
96 size_t c)
97 {
98 return bus_space_read_multi_4(sc->sc_bst, sc->sc_bsh, o, p, c);
99 }
100
101 __unused static inline void
bcmrng_write_4(struct bcmrng_softc * sc,bus_size_t o,uint32_t v)102 bcmrng_write_4(struct bcmrng_softc *sc, bus_size_t o, uint32_t v)
103 {
104 bus_space_write_4(sc->sc_bst, sc->sc_bsh, o, v);
105 }
106
107 /*
108 * To be called from initarm for an early start.
109 */
110 void
bcm53xx_rng_start(bus_space_tag_t bst,bus_space_handle_t bsh)111 bcm53xx_rng_start(bus_space_tag_t bst, bus_space_handle_t bsh)
112 {
113 /*
114 * Disable the interrupt and enable the RNG.
115 */
116 bus_space_write_4(bst, bsh, CCB_BASE + RNG_BASE + RNG_INT_MASK, RNG_INT_OFF);
117 bus_space_write_4(bst, bsh, CCB_BASE + RNG_BASE + RNG_CTRL,
118 bus_space_read_4(bst, bsh, CCB_BASE + RNG_BASE + RNG_CTRL) | RNG_RBGEN);
119 }
120
121 static void
bcmrng_ccb_attach(device_t parent,device_t self,void * aux)122 bcmrng_ccb_attach(device_t parent, device_t self, void *aux)
123 {
124 struct bcmrng_softc * const sc = device_private(self);
125 struct bcmccb_attach_args * const ccbaa = aux;
126 const struct bcm_locators * const loc = &ccbaa->ccbaa_loc;
127
128 sc->sc_dev = self;
129
130 /* make sure it's running */
131 bcm53xx_rng_start(ccbaa->ccbaa_ccb_bst, ccbaa->ccbaa_ccb_bsh);
132
133 sc->sc_bst = ccbaa->ccbaa_ccb_bst;
134 bus_space_subregion(sc->sc_bst, ccbaa->ccbaa_ccb_bsh,
135 loc->loc_offset, loc->loc_size, &sc->sc_bsh);
136
137 aprint_naive("\n");
138 aprint_normal(": Random Number Generator (%u bit FIFO)\n",
139 32 * bcmrng_read_4(sc, RNG_FF_THRESHOLD));
140
141 sc->sc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SOFTCLOCK);
142
143 callout_init(&sc->sc_rnd_callout, CALLOUT_MPSAFE);
144
145 rnd_attach_source(&sc->sc_rnd_source, device_xname(self), RND_TYPE_RNG,
146 RND_FLAG_COLLECT_VALUE);
147
148 #ifdef RNG_USE_INTR
149 sc->sc_ih = intr_establish(loc->loc_intrs[0], IPL_VM, IST_LEVEL,
150 bcmrng_intr, sc);
151 if (sc->sc_ih == NULL) {
152 aprint_error_dev(self, "failed to establish interrupt %d\n",
153 loc->loc_intrs[0]);
154 } else {
155 aprint_normal_dev(self, "interrupting on irq %d\n", loc->loc_intrs[0]);
156 }
157 #else
158 bcmrng_callout(sc);
159 #endif
160 }
161
162 size_t
bcmrng_empty(struct bcmrng_softc * sc)163 bcmrng_empty(struct bcmrng_softc *sc)
164 {
165 mutex_enter(sc->sc_lock);
166 uint32_t data[128];
167 size_t nwords = __SHIFTOUT(bcmrng_read_4(sc, RNG_STATUS), RNG_VAL);
168 if (nwords == 0) {
169 mutex_exit(sc->sc_lock);
170 return 0;
171 }
172 if (nwords > __arraycount(data))
173 nwords = __arraycount(data);
174
175 bcmrng_read_multi_4(sc, RNG_DATA, data, nwords);
176
177 rnd_add_data(&sc->sc_rnd_source, data, sizeof(data), sizeof(data) * 8);
178 mutex_exit(sc->sc_lock);
179 //aprint_debug_dev(sc->sc_dev, "added %zu words\n", nwords);
180 return nwords;
181 }
182
183 void
bcmrng_callout(void * arg)184 bcmrng_callout(void *arg)
185 {
186 struct bcmrng_softc * const sc = arg;
187
188 bcmrng_empty(sc);
189
190 callout_reset(&sc->sc_rnd_callout, 1, bcmrng_callout, sc);
191 }
192
193 #ifdef RNG_USE_INTR
194 int
bcmrng_intr(void * arg)195 bcmrng_intr(void *arg)
196 {
197 struct bcmrng_softc * const sc = arg;
198
199 sc->sc_intr_amount += bcmrng_empty(sc);
200 if (sc->sc_intr_amount >= 0x10000) {
201 bcmrng_callout(sc);
202 bcmrng_write_4(sc, RNG_INT_MASK, RNG_INT_OFF);
203 }
204 return 1;
205 }
206 #endif
207