bcm53xx_rng.c revision 1.5.2.2 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 1.5.2.2 2014/02/15 16:18:36 matt 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/mutex.h>
44 #include <sys/rnd.h>
45 #include <sys/systm.h>
46
47 #include <arm/broadcom/bcm53xx_reg.h>
48 #include <arm/broadcom/bcm53xx_var.h>
49
50 static int bcmrng_ccb_match(device_t, cfdata_t, void *);
51 static void bcmrng_ccb_attach(device_t, device_t, void *);
52
53 struct bcmrng_softc {
54 device_t sc_dev;
55 bus_space_tag_t sc_bst;
56 bus_space_handle_t sc_bsh;
57 rndsource_element_t sc_rnd_source;
58 //krndsource_t sc_rnd_source;
59 struct callout sc_rnd_callout;
60 kmutex_t *sc_lock;
61 #ifdef RNG_USE_INTR
62 size_t sc_intr_amount;
63 void *sc_ih;
64 #endif
65 };
66
67 static void bcmrng_callout(void *arg);
68 static size_t bcmrng_empty(struct bcmrng_softc *);
69 #ifdef RNG_USE_INTR
70 static int bcmrng_intr(void *);
71 #endif
72
73 CFATTACH_DECL_NEW(bcmrng_ccb, sizeof(struct bcmrng_softc),
74 bcmrng_ccb_match, bcmrng_ccb_attach, NULL, NULL);
75
76 static int
77 bcmrng_ccb_match(device_t parent, cfdata_t cf, void *aux)
78 {
79 struct bcmccb_attach_args * const ccbaa = aux;
80 const struct bcm_locators * const loc = &ccbaa->ccbaa_loc;
81
82 if (strcmp(cf->cf_name, loc->loc_name))
83 return 0;
84
85 KASSERT(cf->cf_loc[BCMCCBCF_PORT] == BCMCCBCF_PORT_DEFAULT);
86
87 return 1;
88 }
89
90 static inline uint32_t
91 bcmrng_read_4(struct bcmrng_softc *sc, bus_size_t o)
92 {
93 return bus_space_read_4(sc->sc_bst, sc->sc_bsh, o);
94 }
95
96 static inline void
97 bcmrng_read_multi_4(struct bcmrng_softc *sc, bus_size_t o, uint32_t *p,
98 size_t c)
99 {
100 return bus_space_read_multi_4(sc->sc_bst, sc->sc_bsh, o, p, c);
101 }
102
103 __unused static inline void
104 bcmrng_write_4(struct bcmrng_softc *sc, bus_size_t o, uint32_t v)
105 {
106 bus_space_write_4(sc->sc_bst, sc->sc_bsh, o, v);
107 }
108
109 /*
110 * To be called from initarm for an early start.
111 */
112 void
113 bcm53xx_rng_start(bus_space_tag_t bst, bus_space_handle_t bsh)
114 {
115 /*
116 * Disable the interrupt and enable the RNG.
117 */
118 bus_space_write_4(bst, bsh, CCB_BASE + RNG_BASE + RNG_INT_MASK, RNG_INT_OFF);
119 bus_space_write_4(bst, bsh, CCB_BASE + RNG_BASE + RNG_CTRL,
120 bus_space_read_4(bst, bsh, CCB_BASE + RNG_BASE + RNG_CTRL) | RNG_RBGEN);
121 }
122
123 static void
124 bcmrng_ccb_attach(device_t parent, device_t self, void *aux)
125 {
126 struct bcmrng_softc * const sc = device_private(self);
127 struct bcmccb_attach_args * const ccbaa = aux;
128 const struct bcm_locators * const loc = &ccbaa->ccbaa_loc;
129
130 sc->sc_dev = self;
131
132 /* make sure it's running */
133 bcm53xx_rng_start(ccbaa->ccbaa_ccb_bst, ccbaa->ccbaa_ccb_bsh);
134
135 sc->sc_bst = ccbaa->ccbaa_ccb_bst;
136 bus_space_subregion(sc->sc_bst, ccbaa->ccbaa_ccb_bsh,
137 loc->loc_offset, loc->loc_size, &sc->sc_bsh);
138
139 aprint_naive("\n");
140 aprint_normal(": Random Number Generator (%u bit FIFO)\n",
141 32 * bcmrng_read_4(sc, RNG_FF_THRESHOLD));
142
143 sc->sc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SOFTCLOCK);
144
145 callout_init(&sc->sc_rnd_callout, CALLOUT_MPSAFE);
146
147 rnd_attach_source(&sc->sc_rnd_source, device_xname(self), RND_TYPE_RNG,
148 RND_FLAG_NO_ESTIMATE);
149
150 #ifdef RNG_USE_INTR
151 sc->sc_ih = intr_establish(loc->loc_intrs[0], IPL_VM, IST_LEVEL,
152 bcmrng_intr, sc);
153 if (sc->sc_ih == NULL) {
154 aprint_error_dev(self, "failed to establish interrupt %d\n",
155 loc->loc_intrs[0]);
156 } else {
157 aprint_normal_dev(self, "interrupting on irq %d\n", loc->loc_intrs[0]);
158 }
159 #else
160 bcmrng_callout(sc);
161 #endif
162 }
163
164 size_t
165 bcmrng_empty(struct bcmrng_softc *sc)
166 {
167 mutex_enter(sc->sc_lock);
168 size_t nwords = __SHIFTOUT(bcmrng_read_4(sc, RNG_STATUS), RNG_VAL);
169 if (nwords == 0) {
170 mutex_exit(sc->sc_lock);
171 return 0;
172 }
173
174 uint32_t data[nwords];
175
176 bcmrng_read_multi_4(sc, RNG_DATA, data, nwords);
177
178 rnd_add_data(&sc->sc_rnd_source, data, sizeof(data), sizeof(data) * 8);
179 mutex_exit(sc->sc_lock);
180 //aprint_debug_dev(sc->sc_dev, "added %zu words\n", nwords);
181 return nwords;
182 }
183
184 void
185 bcmrng_callout(void *arg)
186 {
187 struct bcmrng_softc * const sc = arg;
188
189 bcmrng_empty(sc);
190
191 callout_reset(&sc->sc_rnd_callout, 1, bcmrng_callout, sc);
192 }
193
194 #ifdef RNG_USE_INTR
195 int
196 bcmrng_intr(void *arg)
197 {
198 struct bcmrng_softc * const sc = arg;
199
200 sc->sc_intr_amount += bcmrng_empty(sc);
201 if (sc->sc_intr_amount >= 0x10000) {
202 bcmrng_callout(sc);
203 bcmrng_write_4(sc, RNG_INT_MASK, RNG_INT_OFF);
204 }
205 return 1;
206 }
207 #endif
208