freebsd-skq/sys/arm/amlogic/aml8726/aml8726_rng.c
jkim 318c4f97e6 CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten
years for head.  However, it is continuously misused as the mpsafe argument
for callout_init(9).  Deprecate the flag and clean up callout_init() calls
to make them more consistent.

Differential Revision:	https://reviews.freebsd.org/D2613
Reviewed by:	jhb
MFC after:	2 weeks
2015-05-22 17:05:21 +00:00

156 lines
3.9 KiB
C

/*-
* Copyright 2014 John Wehle <john@feith.com>
* 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.
*/
/*
* Amlogic aml8726 random number generator driver.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/random.h>
#include <machine/bus.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
struct aml8726_rng_softc {
device_t dev;
struct resource *res[1];
struct callout co;
int ticks;
};
static struct resource_spec aml8726_rng_spec[] = {
{ SYS_RES_MEMORY, 0, RF_ACTIVE },
{ -1, 0 }
};
#define AML_RNG_0_REG 0
#define AML_RNG_1_REG 4
#define CSR_READ_4(sc, reg) bus_read_4((sc)->res[0], reg)
static void
aml8726_rng_harvest(void *arg)
{
struct aml8726_rng_softc *sc = arg;
uint32_t rn[2];
rn[0] = CSR_READ_4(sc, AML_RNG_0_REG);
rn[1] = CSR_READ_4(sc, AML_RNG_1_REG);
random_harvest(rn, sizeof(rn), sizeof(rn) * NBBY / 2,
RANDOM_PURE_AML8726);
callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc);
}
static int
aml8726_rng_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (!ofw_bus_is_compatible(dev, "amlogic,aml8726-rng"))
return (ENXIO);
device_set_desc(dev, "Amlogic aml8726 RNG");
return (BUS_PROBE_DEFAULT);
}
static int
aml8726_rng_attach(device_t dev)
{
struct aml8726_rng_softc *sc = device_get_softc(dev);
sc->dev = dev;
if (bus_alloc_resources(dev, aml8726_rng_spec, sc->res)) {
device_printf(dev, "can not allocate resources for device\n");
return (ENXIO);
}
/* Install a periodic collector for the RNG */
if (hz > 100)
sc->ticks = hz / 100;
else
sc->ticks = 1;
callout_init(&sc->co, 1);
callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc);
return (0);
}
static int
aml8726_rng_detach(device_t dev)
{
struct aml8726_rng_softc *sc = device_get_softc(dev);
callout_drain(&sc->co);
bus_release_resources(dev, aml8726_rng_spec, sc->res);
return (0);
}
static device_method_t aml8726_rng_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, aml8726_rng_probe),
DEVMETHOD(device_attach, aml8726_rng_attach),
DEVMETHOD(device_detach, aml8726_rng_detach),
DEVMETHOD_END
};
static driver_t aml8726_rng_driver = {
"rng",
aml8726_rng_methods,
sizeof(struct aml8726_rng_softc),
};
static devclass_t aml8726_rng_devclass;
DRIVER_MODULE(aml8726_rng, simplebus, aml8726_rng_driver,
aml8726_rng_devclass, 0, 0);
MODULE_DEPEND(aml8726_rng, random, 1, 1, 1);