2 * Copyright (c) 2015, 2016, Stephen J. Kiernan
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
31 #include <sys/param.h>
32 #include <sys/kernel.h>
34 #include <sys/malloc.h>
35 #include <sys/module.h>
36 #include <sys/random.h>
38 #include <sys/sysctl.h>
39 #include <sys/selinfo.h>
40 #include <sys/systm.h>
44 #include <machine/bus.h>
45 #include <machine/resource.h>
47 #include <dev/ofw/openfirm.h>
48 #include <dev/ofw/ofw_bus.h>
49 #include <dev/ofw/ofw_bus_subr.h>
51 #include <dev/random/randomdev.h>
52 #include <dev/random/random_harvestq.h>
54 #if !defined(BCM2835_RNG_USE_CALLOUT)
55 #define BCM2835_RNG_USE_INTERRUPT
58 static device_attach_t bcm2835_rng_attach;
59 static device_detach_t bcm2835_rng_detach;
60 static device_probe_t bcm2835_rng_probe;
62 #define RNG_CTRL 0x00 /* RNG Control Register */
63 #define RNG_COMBLK1_OSC 0x003f0000 /* Combiner Blk 1 Oscillator */
64 #define RNG_COMBLK1_OSC_SHIFT 16
65 #define RNG_COMBLK2_OSC 0x0fc00000 /* Combiner Blk 2 Oscillator */
66 #define RNG_COMBLK2_OSC_SHIFT 22
67 #define RNG_JCLK_BYP_DIV_CNT 0x0000ff00 /* Jitter clk bypass divider
69 #define RNG_JCLK_BYP_DIV_CNT_SHIFT 8
70 #define RNG_JCLK_BYP_SRC 0x00000020 /* Jitter clk bypass source */
71 #define RNG_JCLK_BYP_SEL 0x00000010 /* Jitter clk bypass select */
72 #define RNG_RBG2X 0x00000002 /* RBG 2X SPEED */
73 #define RNG_RBGEN_BIT 0x00000001 /* Enable RNG bit */
75 #define RNG_STATUS 0x04 /* RNG status register */
76 #define RND_VAL_SHIFT 24 /* Shift for valid words */
77 #define RND_VAL_MASK 0x000000ff /* Number valid words mask */
78 #define RND_VAL_WARM_CNT 0x40000 /* RNG Warm Up count */
79 #define RND_WARM_CNT 0xfffff /* RNG Warm Up Count mask */
81 #define RNG_DATA 0x08 /* RNG Data Register */
82 #define RNG_FF_THRES 0x0c
83 #define RNG_FF_THRES_MASK 0x0000001f
85 #define RNG_INT_MASK 0x10
86 #define RNG_INT_OFF_BIT 0x00000001
88 #define RNG_FF_DEFAULT 0x10 /* FIFO threshold default */
90 #define RNG_FIFO_WORDS (RNG_FF_DEFAULT / sizeof(uint32_t))
92 #define RNG_NUM_OSCILLATORS 6
93 #define RNG_STALL_COUNT_DEFAULT 10
95 struct bcm2835_rng_softc {
97 struct resource * sc_mem_res;
98 struct resource * sc_irq_res;
100 #if defined(BCM2835_RNG_USE_CALLOUT) || defined(BCM2835_RNG_USE_INTERRUPT)
101 uint32_t sc_buf[RNG_FIFO_WORDS];
103 #if defined(BCM2835_RNG_USE_CALLOUT)
104 struct callout sc_rngto;
113 bcm2835_rng_stat_inc_underrun(struct bcm2835_rng_softc *sc)
116 atomic_add_long(&sc->sc_underrun, 1);
119 static __inline uint32_t
120 bcm2835_rng_read4(struct bcm2835_rng_softc *sc, bus_size_t off)
123 return bus_read_4(sc->sc_mem_res, off);
127 bcm2835_rng_read_multi4(struct bcm2835_rng_softc *sc, bus_size_t off,
128 uint32_t *datap, bus_size_t count)
131 bus_read_multi_4(sc->sc_mem_res, off, datap, count);
135 bcm2835_rng_write4(struct bcm2835_rng_softc *sc, bus_size_t off, uint32_t val)
138 bus_write_4(sc->sc_mem_res, off, val);
142 bcm2835_rng_dump_registers(struct bcm2835_rng_softc *sc, struct sbuf *sbp)
144 uint32_t comblk2_osc, comblk1_osc, jclk_byp_div, val;
147 /* Display RNG control register contents */
148 val = bcm2835_rng_read4(sc, RNG_CTRL);
149 sbuf_printf(sbp, "RNG_CTRL (%08x)\n", val);
151 comblk2_osc = (val & RNG_COMBLK2_OSC) >> RNG_COMBLK2_OSC_SHIFT;
152 sbuf_printf(sbp, " RNG_COMBLK2_OSC (%02x)\n", comblk2_osc);
153 for (i = 0; i < RNG_NUM_OSCILLATORS; i++)
154 if ((comblk2_osc & (1 << i)) == 0)
155 sbuf_printf(sbp, " Oscillator %d enabled\n", i + 1);
157 comblk1_osc = (val & RNG_COMBLK1_OSC) >> RNG_COMBLK1_OSC_SHIFT;
158 sbuf_printf(sbp, " RNG_COMBLK1_OSC (%02x)\n", comblk1_osc);
159 for (i = 0; i < RNG_NUM_OSCILLATORS; i++)
160 if ((comblk1_osc & (1 << i)) == 0)
161 sbuf_printf(sbp, " Oscillator %d enabled\n", i + 1);
163 jclk_byp_div = (val & RNG_JCLK_BYP_DIV_CNT) >>
164 RNG_JCLK_BYP_DIV_CNT_SHIFT;
166 " RNG_JCLK_BYP_DIV_CNT (%02x)\n APB clock frequency / %d\n",
167 jclk_byp_div, 2 * (jclk_byp_div + 1));
169 sbuf_printf(sbp, " RNG_JCLK_BYP_SRC:\n %s\n",
170 (val & RNG_JCLK_BYP_SRC) ? "Use divided down APB clock" :
171 "Use RNG clock (APB clock)");
173 sbuf_printf(sbp, " RNG_JCLK_BYP_SEL:\n %s\n",
174 (val & RNG_JCLK_BYP_SEL) ? "Bypass internal jitter clock" :
175 "Use internal jitter clock");
177 if ((val & RNG_RBG2X) != 0)
178 sbuf_cat(sbp, " RNG_RBG2X: RNG 2X SPEED enabled\n");
180 if ((val & RNG_RBGEN_BIT) != 0)
181 sbuf_cat(sbp, " RNG_RBGEN_BIT: RBG enabled\n");
183 /* Display RNG status register contents */
184 val = bcm2835_rng_read4(sc, RNG_STATUS);
185 sbuf_printf(sbp, "RNG_CTRL (%08x)\n", val);
186 sbuf_printf(sbp, " RND_VAL: %02x\n",
187 (val >> RND_VAL_SHIFT) & RND_VAL_MASK);
188 sbuf_printf(sbp, " RND_WARM_CNT: %05x\n", val & RND_WARM_CNT);
190 /* Display FIFO threshold register contents */
191 val = bcm2835_rng_read4(sc, RNG_FF_THRES);
192 sbuf_printf(sbp, "RNG_FF_THRES: %05x\n", val & RNG_FF_THRES_MASK);
194 /* Display interrupt mask register contents */
195 val = bcm2835_rng_read4(sc, RNG_INT_MASK);
196 sbuf_printf(sbp, "RNG_INT_MASK: interrupt %s\n",
197 ((val & RNG_INT_OFF_BIT) != 0) ? "disabled" : "enabled");
201 bcm2835_rng_disable_intr(struct bcm2835_rng_softc *sc)
205 /* Set the interrupt off bit in the interrupt mask register */
206 mask = bcm2835_rng_read4(sc, RNG_INT_MASK);
207 mask |= RNG_INT_OFF_BIT;
208 bcm2835_rng_write4(sc, RNG_INT_MASK, mask);
211 #if defined(BCM2835_RNG_USE_INTERRUPT)
213 bcm2835_rng_enable_intr(struct bcm2835_rng_softc *sc)
217 /* Clear the interrupt off bit in the interrupt mask register */
218 mask = bcm2835_rng_read4(sc, RNG_INT_MASK);
219 mask &= ~RNG_INT_OFF_BIT;
220 bcm2835_rng_write4(sc, RNG_INT_MASK, mask);
225 bcm2835_rng_start(struct bcm2835_rng_softc *sc)
229 /* Disable the interrupt */
230 bcm2835_rng_disable_intr(sc);
232 /* Set the warmup count */
233 bcm2835_rng_write4(sc, RNG_STATUS, RND_VAL_WARM_CNT);
236 ctrl = bcm2835_rng_read4(sc, RNG_CTRL);
237 ctrl |= RNG_RBGEN_BIT;
240 bcm2835_rng_write4(sc, RNG_CTRL, ctrl);
242 #if defined(BCM2835_RNG_USE_INTERRUPT)
243 /* Enable the interrupt */
244 bcm2835_rng_enable_intr(sc);
249 bcm2835_rng_stop(struct bcm2835_rng_softc *sc)
253 /* Disable the RNG */
254 ctrl = bcm2835_rng_read4(sc, RNG_CTRL);
255 ctrl &= ~RNG_RBGEN_BIT;
256 bcm2835_rng_write4(sc, RNG_CTRL, ctrl);
260 bcm2835_rng_harvest(struct bcm2835_rng_softc *sc)
264 u_int cnt, nread, num_avail, num_words;
265 int seen_underrun, num_stalls;
268 nread = num_words = 0;
269 seen_underrun = num_stalls = 0;
270 for (cnt = sizeof(sc->sc_buf) / sizeof(uint32_t); cnt > 0;
272 /* Read status register to find out how many words available */
273 status = bcm2835_rng_read4(sc, RNG_STATUS);
274 num_avail = (status >> RND_VAL_SHIFT) & RND_VAL_MASK;
276 /* If we have none... */
277 if (num_avail == 0) {
278 bcm2835_rng_stat_inc_underrun(sc);
279 if (++seen_underrun >= sc->sc_stall_count) {
280 if (num_stalls++ > 0) {
281 device_printf(sc->sc_dev,
282 "RNG stalled, disabling device\n");
283 bcm2835_rng_stop(sc);
286 device_printf(sc->sc_dev,
287 "Too many underruns, resetting\n");
288 bcm2835_rng_stop(sc);
289 bcm2835_rng_start(sc);
297 CTR2(KTR_DEV, "%s: %d words available in RNG FIFO",
298 device_get_nameunit(sc->sc_dev), num_avail);
300 /* Pull MIN(num_avail, cnt) words from the FIFO */
301 num_words = (num_avail > cnt) ? cnt : num_avail;
302 bcm2835_rng_read_multi4(sc, RNG_DATA, dest,
308 cnt = nread * sizeof(uint32_t);
310 random_harvest_queue(sc->sc_buf, cnt, cnt * NBBY / 2,
311 RANDOM_PURE_BROADCOM);
313 #if defined(BCM2835_RNG_USE_CALLOUT)
314 callout_reset(&sc->sc_rngto, sc->sc_rnghz, bcm2835_rng_harvest, sc);
319 sysctl_bcm2835_rng_2xspeed(SYSCTL_HANDLER_ARGS)
321 struct bcm2835_rng_softc *sc = arg1;
324 rbg2x = sc->sc_rbg2x;
325 error = sysctl_handle_int(oidp, &rbg2x, 0, req);
328 if (req->newptr == NULL)
330 if (rbg2x == sc->sc_rbg2x)
334 bcm2835_rng_stop(sc);
335 sc->sc_rbg2x = rbg2x;
336 bcm2835_rng_start(sc);
341 #ifdef BCM2835_RNG_DEBUG_REGISTERS
343 sysctl_bcm2835_rng_dump(SYSCTL_HANDLER_ARGS)
346 struct bcm2835_rng_softc *sc = arg1;
349 error = sysctl_wire_old_buffer(req, 0);
352 sbuf_new_for_sysctl(&sb, NULL, 128, req);
353 bcm2835_rng_dump_registers(sc, &sb);
354 error = sbuf_finish(&sb);
361 bcm2835_rng_probe(device_t dev)
364 if (!ofw_bus_status_okay(dev))
367 if (!ofw_bus_is_compatible(dev, "broadcom,bcm2835-rng"))
370 device_set_desc(dev, "Broadcom BCM2835 RNG");
372 return (BUS_PROBE_DEFAULT);
376 bcm2835_rng_attach(device_t dev)
378 struct bcm2835_rng_softc *sc;
379 struct sysctl_ctx_list *sysctl_ctx;
380 struct sysctl_oid *sysctl_tree;
384 sc = device_get_softc(dev);
386 sc->sc_stall_count = RNG_STALL_COUNT_DEFAULT;
387 #ifdef BCM2835_RNG_USE_CALLOUT
388 /* Initialize callout */
389 callout_init(&sc->sc_rngto, CALLOUT_MPSAFE);
391 TUNABLE_INT_FETCH("bcmrng.2xspeed", &sc->sc_rbg2x);
392 TUNABLE_INT_FETCH("bcmrng.stall_count", &sc->sc_stall_count);
394 /* Allocate memory resources */
396 sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
398 if (sc->sc_mem_res == NULL) {
399 bcm2835_rng_detach(dev);
403 #if defined(BCM2835_RNG_USE_INTERRUPT)
404 /* Allocate interrupt resource */
406 sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
407 RF_SHAREABLE | RF_ACTIVE);
408 if (sc->sc_irq_res == NULL) {
409 bcm2835_rng_detach(dev);
413 /* Set up the interrupt handler */
414 error = bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_BIO | INTR_MPSAFE,
415 NULL, (driver_intr_t *)bcm2835_rng_harvest, sc, &sc->sc_intr_hdl);
417 device_printf(dev, "Failed to set up IRQ\n");
418 sc->sc_intr_hdl = NULL;
419 bcm2835_rng_detach(dev);
425 bcm2835_rng_start(sc);
427 /* Dump the registers if booting verbose */
431 (void) sbuf_new(&sb, NULL, 256,
432 SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
433 bcm2835_rng_dump_registers(sc, &sb);
435 error = sbuf_finish(&sb);
437 device_printf(dev, "%s", sbuf_data(&sb));
441 sysctl_ctx = device_get_sysctl_ctx(dev);
442 sysctl_tree = device_get_sysctl_tree(dev);
443 SYSCTL_ADD_LONG(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
444 "underrun", CTLFLAG_RD, &sc->sc_underrun,
445 "Number of FIFO underruns");
446 SYSCTL_ADD_PROC(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
447 "2xspeed", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
448 sysctl_bcm2835_rng_2xspeed, "I", "Enable RBG 2X SPEED");
449 SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
450 "stall_count", CTLFLAG_RW, &sc->sc_stall_count,
451 RNG_STALL_COUNT_DEFAULT, "Number of underruns to assume RNG stall");
452 #ifdef BCM2835_RNG_DEBUG_REGISTERS
453 SYSCTL_ADD_PROC(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
454 "dumpregs", CTLTYPE_STRING | CTLFLAG_RD, sc, 0,
455 sysctl_bcm2835_rng_dump, "S", "Dump RNG registers");
458 #if defined(BCM2835_RNG_USE_CALLOUT)
461 sc->sc_rnghz = hz / 100;
464 callout_reset(&sc->sc_rngto, sc->sc_rnghz, bcm2835_rng_harvest, sc);
471 bcm2835_rng_detach(device_t dev)
473 struct bcm2835_rng_softc *sc;
474 #if defined(BCM2835_RNG_USE_INTERRUPT)
478 sc = device_get_softc(dev);
481 bcm2835_rng_stop(sc);
483 /* Drain the callout it */
484 #if defined(BCM2835_RNG_USE_CALLOUT)
485 callout_drain(&sc->sc_rngto);
488 #if defined(BCM2835_RNG_USE_INTERRUPT)
489 /* Tear down the interrupt */
490 if (sc->sc_irq_res && sc->sc_intr_hdl) {
491 error = bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr_hdl);
493 device_printf(dev, "could not tear down IRQ\n");
496 sc->sc_intr_hdl = NULL;
499 /* Release interrupt resource */
500 if (sc->sc_irq_res) {
501 bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
502 sc->sc_irq_res = NULL;
506 /* Release memory resource */
507 if (sc->sc_mem_res != NULL)
508 bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
513 static device_method_t bcm2835_rng_methods[] = {
514 /* Device interface */
515 DEVMETHOD(device_probe, bcm2835_rng_probe),
516 DEVMETHOD(device_attach, bcm2835_rng_attach),
517 DEVMETHOD(device_detach, bcm2835_rng_detach),
522 static driver_t bcm2835_rng_driver = {
525 sizeof(struct bcm2835_rng_softc)
527 static devclass_t bcm2835_rng_devclass;
529 DRIVER_MODULE(bcm2835_rng, simplebus, bcm2835_rng_driver,
530 bcm2835_rng_devclass, 0, 0);
531 DRIVER_MODULE(bcm2835_rng, ofwbus, bcm2835_rng_driver, bcm2835_rng_devclass, 0,
533 MODULE_VERSION(bcm2835_rng, 1);
534 MODULE_DEPEND(bcm2835_rng, randomdev, 1, 1, 1);