freebsd-dev/sys/arm/broadcom/bcm2835/bcm2835_rng.c
Pawel Biernacki 7029da5c36 Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE.  All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Approved by:	kib (mentor, blanket)
Commented by:	kib, gallatin, melifaro
Differential Revision:	https://reviews.freebsd.org/D23718
2020-02-26 14:26:36 +00:00

468 lines
13 KiB
C

/*
* Copyright (c) 2015, 2016, Stephen J. Kiernan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/random.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/selinfo.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/rman.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/random/randomdev.h>
#include <dev/random/random_harvestq.h>
static device_attach_t bcm2835_rng_attach;
static device_detach_t bcm2835_rng_detach;
static device_probe_t bcm2835_rng_probe;
#define RNG_CTRL 0x00 /* RNG Control Register */
#define RNG_COMBLK1_OSC 0x003f0000 /* Combiner Blk 1 Oscillator */
#define RNG_COMBLK1_OSC_SHIFT 16
#define RNG_COMBLK2_OSC 0x0fc00000 /* Combiner Blk 2 Oscillator */
#define RNG_COMBLK2_OSC_SHIFT 22
#define RNG_JCLK_BYP_DIV_CNT 0x0000ff00 /* Jitter clk bypass divider
count */
#define RNG_JCLK_BYP_DIV_CNT_SHIFT 8
#define RNG_JCLK_BYP_SRC 0x00000020 /* Jitter clk bypass source */
#define RNG_JCLK_BYP_SEL 0x00000010 /* Jitter clk bypass select */
#define RNG_RBG2X 0x00000002 /* RBG 2X SPEED */
#define RNG_RBGEN_BIT 0x00000001 /* Enable RNG bit */
#define RNG_STATUS 0x04 /* RNG status register */
#define RND_VAL_SHIFT 24 /* Shift for valid words */
#define RND_VAL_MASK 0x000000ff /* Number valid words mask */
#define RND_VAL_WARM_CNT 0x40000 /* RNG Warm Up count */
#define RND_WARM_CNT 0xfffff /* RNG Warm Up Count mask */
#define RNG_DATA 0x08 /* RNG Data Register */
#define RNG_FF_THRES 0x0c
#define RNG_FF_THRES_MASK 0x0000001f
#define RNG_INT_MASK 0x10
#define RNG_INT_OFF_BIT 0x00000001
#define RNG_FF_DEFAULT 0x10 /* FIFO threshold default */
#define RNG_FIFO_WORDS (RNG_FF_DEFAULT / sizeof(uint32_t))
#define RNG_NUM_OSCILLATORS 6
#define RNG_STALL_COUNT_DEFAULT 10
#define RNG_CALLOUT_TICKS (hz * 4)
struct bcm2835_rng_softc {
device_t sc_dev;
struct resource * sc_mem_res;
struct resource * sc_irq_res;
void * sc_intr_hdl;
uint32_t sc_buf[RNG_FIFO_WORDS];
struct callout sc_rngto;
int sc_stall_count;
int sc_rbg2x;
long sc_underrun;
};
static struct ofw_compat_data compat_data[] = {
{"broadcom,bcm2835-rng", 1},
{"brcm,bcm2835-rng", 1},
{NULL, 0}
};
static __inline void
bcm2835_rng_stat_inc_underrun(struct bcm2835_rng_softc *sc)
{
atomic_add_long(&sc->sc_underrun, 1);
}
static __inline uint32_t
bcm2835_rng_read4(struct bcm2835_rng_softc *sc, bus_size_t off)
{
return bus_read_4(sc->sc_mem_res, off);
}
static __inline void
bcm2835_rng_read_multi4(struct bcm2835_rng_softc *sc, bus_size_t off,
uint32_t *datap, bus_size_t count)
{
bus_read_multi_4(sc->sc_mem_res, off, datap, count);
}
static __inline void
bcm2835_rng_write4(struct bcm2835_rng_softc *sc, bus_size_t off, uint32_t val)
{
bus_write_4(sc->sc_mem_res, off, val);
}
static void
bcm2835_rng_dump_registers(struct bcm2835_rng_softc *sc, struct sbuf *sbp)
{
uint32_t comblk2_osc, comblk1_osc, jclk_byp_div, val;
int i;
/* Display RNG control register contents */
val = bcm2835_rng_read4(sc, RNG_CTRL);
sbuf_printf(sbp, "RNG_CTRL (%08x)\n", val);
comblk2_osc = (val & RNG_COMBLK2_OSC) >> RNG_COMBLK2_OSC_SHIFT;
sbuf_printf(sbp, " RNG_COMBLK2_OSC (%02x)\n", comblk2_osc);
for (i = 0; i < RNG_NUM_OSCILLATORS; i++)
if ((comblk2_osc & (1 << i)) == 0)
sbuf_printf(sbp, " Oscillator %d enabled\n", i + 1);
comblk1_osc = (val & RNG_COMBLK1_OSC) >> RNG_COMBLK1_OSC_SHIFT;
sbuf_printf(sbp, " RNG_COMBLK1_OSC (%02x)\n", comblk1_osc);
for (i = 0; i < RNG_NUM_OSCILLATORS; i++)
if ((comblk1_osc & (1 << i)) == 0)
sbuf_printf(sbp, " Oscillator %d enabled\n", i + 1);
jclk_byp_div = (val & RNG_JCLK_BYP_DIV_CNT) >>
RNG_JCLK_BYP_DIV_CNT_SHIFT;
sbuf_printf(sbp,
" RNG_JCLK_BYP_DIV_CNT (%02x)\n APB clock frequency / %d\n",
jclk_byp_div, 2 * (jclk_byp_div + 1));
sbuf_printf(sbp, " RNG_JCLK_BYP_SRC:\n %s\n",
(val & RNG_JCLK_BYP_SRC) ? "Use divided down APB clock" :
"Use RNG clock (APB clock)");
sbuf_printf(sbp, " RNG_JCLK_BYP_SEL:\n %s\n",
(val & RNG_JCLK_BYP_SEL) ? "Bypass internal jitter clock" :
"Use internal jitter clock");
if ((val & RNG_RBG2X) != 0)
sbuf_cat(sbp, " RNG_RBG2X: RNG 2X SPEED enabled\n");
if ((val & RNG_RBGEN_BIT) != 0)
sbuf_cat(sbp, " RNG_RBGEN_BIT: RBG enabled\n");
/* Display RNG status register contents */
val = bcm2835_rng_read4(sc, RNG_STATUS);
sbuf_printf(sbp, "RNG_CTRL (%08x)\n", val);
sbuf_printf(sbp, " RND_VAL: %02x\n",
(val >> RND_VAL_SHIFT) & RND_VAL_MASK);
sbuf_printf(sbp, " RND_WARM_CNT: %05x\n", val & RND_WARM_CNT);
/* Display FIFO threshold register contents */
val = bcm2835_rng_read4(sc, RNG_FF_THRES);
sbuf_printf(sbp, "RNG_FF_THRES: %05x\n", val & RNG_FF_THRES_MASK);
/* Display interrupt mask register contents */
val = bcm2835_rng_read4(sc, RNG_INT_MASK);
sbuf_printf(sbp, "RNG_INT_MASK: interrupt %s\n",
((val & RNG_INT_OFF_BIT) != 0) ? "disabled" : "enabled");
}
static void
bcm2835_rng_disable_intr(struct bcm2835_rng_softc *sc)
{
uint32_t mask;
/* Set the interrupt off bit in the interrupt mask register */
mask = bcm2835_rng_read4(sc, RNG_INT_MASK);
mask |= RNG_INT_OFF_BIT;
bcm2835_rng_write4(sc, RNG_INT_MASK, mask);
}
static void
bcm2835_rng_start(struct bcm2835_rng_softc *sc)
{
uint32_t ctrl;
/* Disable the interrupt */
bcm2835_rng_disable_intr(sc);
/* Set the warmup count */
bcm2835_rng_write4(sc, RNG_STATUS, RND_VAL_WARM_CNT);
/* Enable the RNG */
ctrl = bcm2835_rng_read4(sc, RNG_CTRL);
ctrl |= RNG_RBGEN_BIT;
if (sc->sc_rbg2x)
ctrl |= RNG_RBG2X;
bcm2835_rng_write4(sc, RNG_CTRL, ctrl);
}
static void
bcm2835_rng_stop(struct bcm2835_rng_softc *sc)
{
uint32_t ctrl;
/* Disable the RNG */
ctrl = bcm2835_rng_read4(sc, RNG_CTRL);
ctrl &= ~RNG_RBGEN_BIT;
bcm2835_rng_write4(sc, RNG_CTRL, ctrl);
}
static void
bcm2835_rng_harvest(void *arg)
{
uint32_t *dest;
uint32_t status;
u_int cnt, nread, num_avail, num_words;
int seen_underrun, num_stalls;
struct bcm2835_rng_softc *sc = arg;
dest = sc->sc_buf;
nread = num_words = 0;
seen_underrun = num_stalls = 0;
for (cnt = sizeof(sc->sc_buf) / sizeof(uint32_t); cnt > 0;
cnt -= num_words) {
/* Read status register to find out how many words available */
status = bcm2835_rng_read4(sc, RNG_STATUS);
num_avail = (status >> RND_VAL_SHIFT) & RND_VAL_MASK;
/* If we have none... */
if (num_avail == 0) {
bcm2835_rng_stat_inc_underrun(sc);
if (++seen_underrun >= sc->sc_stall_count) {
if (num_stalls++ > 0) {
device_printf(sc->sc_dev,
"RNG stalled, disabling device\n");
bcm2835_rng_stop(sc);
break;
} else {
device_printf(sc->sc_dev,
"Too many underruns, resetting\n");
bcm2835_rng_stop(sc);
bcm2835_rng_start(sc);
seen_underrun = 0;
}
}
/* Try again */
continue;
}
CTR2(KTR_DEV, "%s: %d words available in RNG FIFO",
device_get_nameunit(sc->sc_dev), num_avail);
/* Pull MIN(num_avail, cnt) words from the FIFO */
num_words = (num_avail > cnt) ? cnt : num_avail;
bcm2835_rng_read_multi4(sc, RNG_DATA, dest,
num_words);
dest += num_words;
nread += num_words;
}
cnt = nread * sizeof(uint32_t);
if (cnt > 0)
random_harvest_queue(sc->sc_buf, cnt, RANDOM_PURE_BROADCOM);
callout_reset(&sc->sc_rngto, RNG_CALLOUT_TICKS, bcm2835_rng_harvest, sc);
}
static int
sysctl_bcm2835_rng_2xspeed(SYSCTL_HANDLER_ARGS)
{
struct bcm2835_rng_softc *sc = arg1;
int error, rbg2x;
rbg2x = sc->sc_rbg2x;
error = sysctl_handle_int(oidp, &rbg2x, 0, req);
if (error)
return (error);
if (req->newptr == NULL)
return (error);
if (rbg2x == sc->sc_rbg2x)
return (0);
/* Reset the RNG */
bcm2835_rng_stop(sc);
sc->sc_rbg2x = rbg2x;
bcm2835_rng_start(sc);
return (0);
}
#ifdef BCM2835_RNG_DEBUG_REGISTERS
static int
sysctl_bcm2835_rng_dump(SYSCTL_HANDLER_ARGS)
{
struct sbuf sb;
struct bcm2835_rng_softc *sc = arg1;
int error;
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
sbuf_new_for_sysctl(&sb, NULL, 128, req);
bcm2835_rng_dump_registers(sc, &sb);
error = sbuf_finish(&sb);
sbuf_delete(&sb);
return (error);
}
#endif
static int
bcm2835_rng_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
return (ENXIO);
device_set_desc(dev, "Broadcom BCM2835 RNG");
return (BUS_PROBE_DEFAULT);
}
static int
bcm2835_rng_attach(device_t dev)
{
struct bcm2835_rng_softc *sc;
struct sysctl_ctx_list *sysctl_ctx;
struct sysctl_oid *sysctl_tree;
int error, rid;
error = 0;
sc = device_get_softc(dev);
sc->sc_dev = dev;
sc->sc_stall_count = RNG_STALL_COUNT_DEFAULT;
/* Initialize callout */
callout_init(&sc->sc_rngto, CALLOUT_MPSAFE);
TUNABLE_INT_FETCH("bcmrng.2xspeed", &sc->sc_rbg2x);
TUNABLE_INT_FETCH("bcmrng.stall_count", &sc->sc_stall_count);
/* Allocate memory resources */
rid = 0;
sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
RF_ACTIVE);
if (sc->sc_mem_res == NULL) {
bcm2835_rng_detach(dev);
return (ENXIO);
}
/* Start the RNG */
bcm2835_rng_start(sc);
/* Dump the registers if booting verbose */
if (bootverbose) {
struct sbuf sb;
(void) sbuf_new(&sb, NULL, 256,
SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
bcm2835_rng_dump_registers(sc, &sb);
sbuf_trim(&sb);
error = sbuf_finish(&sb);
if (error == 0)
device_printf(dev, "%s", sbuf_data(&sb));
sbuf_delete(&sb);
}
sysctl_ctx = device_get_sysctl_ctx(dev);
sysctl_tree = device_get_sysctl_tree(dev);
SYSCTL_ADD_LONG(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"underrun", CTLFLAG_RD, &sc->sc_underrun,
"Number of FIFO underruns");
SYSCTL_ADD_PROC(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"2xspeed", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
sysctl_bcm2835_rng_2xspeed, "I", "Enable RBG 2X SPEED");
SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"stall_count", CTLFLAG_RW, &sc->sc_stall_count,
RNG_STALL_COUNT_DEFAULT, "Number of underruns to assume RNG stall");
#ifdef BCM2835_RNG_DEBUG_REGISTERS
SYSCTL_ADD_PROC(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"dumpregs", CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NEEDGIANT, sc, 0,
sysctl_bcm2835_rng_dump, "S", "Dump RNG registers");
#endif
/*
* Schedule the initial harvesting one second from now, which should give the
* hardware RNG plenty of time to generate the first random bytes.
*/
callout_reset(&sc->sc_rngto, hz, bcm2835_rng_harvest, sc);
return (0);
}
static int
bcm2835_rng_detach(device_t dev)
{
struct bcm2835_rng_softc *sc;
sc = device_get_softc(dev);
/* Stop the RNG */
bcm2835_rng_stop(sc);
/* Drain the callout it */
callout_drain(&sc->sc_rngto);
/* Release memory resource */
if (sc->sc_mem_res != NULL)
bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
return (0);
}
static device_method_t bcm2835_rng_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, bcm2835_rng_probe),
DEVMETHOD(device_attach, bcm2835_rng_attach),
DEVMETHOD(device_detach, bcm2835_rng_detach),
DEVMETHOD_END
};
static driver_t bcm2835_rng_driver = {
"bcmrng",
bcm2835_rng_methods,
sizeof(struct bcm2835_rng_softc)
};
static devclass_t bcm2835_rng_devclass;
DRIVER_MODULE(bcm2835_rng, simplebus, bcm2835_rng_driver,
bcm2835_rng_devclass, 0, 0);
DRIVER_MODULE(bcm2835_rng, ofwbus, bcm2835_rng_driver, bcm2835_rng_devclass, 0,
0);
MODULE_VERSION(bcm2835_rng, 1);
MODULE_DEPEND(bcm2835_rng, randomdev, 1, 1, 1);