qcom_rnd: add initial qualcomm prng driver.
This is the MVP required to initialise and consume random data from the QCA PRNG hardware found on the IPQ401x. Reviewed by: andrew, manu, imp Differential Revision: https://reviews.freebsd.org/D32723
This commit is contained in:
Adrian Chadd
parent
6325f105aa
commit
1492c8c0d8
257
sys/dev/qcom_rnd/qcom_rnd.c
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257
sys/dev/qcom_rnd/qcom_rnd.c
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@ -0,0 +1,257 @@
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/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2021, Adrian Chadd <adrian@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* Driver for Qualcomm MSM entropy device. */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/sglist.h>
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#include <sys/random.h>
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#include <sys/stdatomic.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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#include <sys/bus.h>
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#include <dev/fdt/fdt_common.h>
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <dev/random/randomdev.h>
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#include <dev/random/random_harvestq.h>
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#include <dev/qcom_rnd/qcom_rnd_reg.h>
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struct qcom_rnd_softc {
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device_t dev;
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int reg_rid;
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struct resource *reg;
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};
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static int qcom_rnd_modevent(module_t, int, void *);
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static int qcom_rnd_probe(device_t);
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static int qcom_rnd_attach(device_t);
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static int qcom_rnd_detach(device_t);
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static int qcom_rnd_harvest(struct qcom_rnd_softc *, void *, size_t *);
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static unsigned qcom_rnd_read(void *, unsigned);
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static struct random_source random_qcom_rnd = {
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.rs_ident = "Qualcomm Entropy Adapter",
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.rs_source = RANDOM_PURE_QUALCOMM,
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.rs_read = qcom_rnd_read,
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};
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/* Kludge for API limitations of random(4). */
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static _Atomic(struct qcom_rnd_softc *) g_qcom_rnd_softc;
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static int
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qcom_rnd_modevent(module_t mod, int type, void *unused)
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{
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int error;
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switch (type) {
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case MOD_LOAD:
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case MOD_QUIESCE:
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case MOD_UNLOAD:
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case MOD_SHUTDOWN:
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error = 0;
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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static int
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qcom_rnd_probe(device_t dev)
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{
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if (! ofw_bus_status_okay(dev)) {
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return (ENXIO);
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}
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if (ofw_bus_is_compatible(dev, "qcom,prng") == 0) {
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return (ENXIO);
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}
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return (0);
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}
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static int
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qcom_rnd_attach(device_t dev)
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{
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struct qcom_rnd_softc *sc, *exp;
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uint32_t reg;
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sc = device_get_softc(dev);
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/* Found a compatible device! */
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sc->dev = dev;
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exp = NULL;
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if (!atomic_compare_exchange_strong_explicit(&g_qcom_rnd_softc, &exp,
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sc, memory_order_release, memory_order_acquire)) {
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return (ENXIO);
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}
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sc->reg_rid = 0;
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sc->reg = bus_alloc_resource_anywhere(dev, SYS_RES_MEMORY,
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&sc->reg_rid, 0x140, RF_ACTIVE);
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if (sc->reg == NULL) {
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device_printf(dev, "Couldn't allocate memory resource!\n");
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return (ENXIO);
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}
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device_set_desc(dev, "Qualcomm PRNG");
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/*
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* Check to see whether the PRNG has already been setup or not.
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*/
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bus_barrier(sc->reg, 0, 0x120, BUS_SPACE_BARRIER_READ);
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reg = bus_read_4(sc->reg, QCOM_RND_PRNG_CONFIG);
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if (reg & QCOM_RND_PRNG_CONFIG_HW_ENABLE) {
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device_printf(dev, "PRNG HW already enabled\n");
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} else {
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/*
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* Do PRNG setup and then enable it.
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*/
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reg = bus_read_4(sc->reg, QCOM_RND_PRNG_LFSR_CFG);
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reg &= QCOM_RND_PRNG_LFSR_CFG_MASK;
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reg |= QCOM_RND_PRNG_LFSR_CFG_CLOCKS;
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bus_write_4(sc->reg, QCOM_RND_PRNG_LFSR_CFG, reg);
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bus_barrier(sc->reg, 0, 0x120, BUS_SPACE_BARRIER_WRITE);
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reg = bus_read_4(sc->reg, QCOM_RND_PRNG_CONFIG);
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reg |= QCOM_RND_PRNG_CONFIG_HW_ENABLE;
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bus_write_4(sc->reg, QCOM_RND_PRNG_CONFIG, reg);
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bus_barrier(sc->reg, 0, 0x120, BUS_SPACE_BARRIER_WRITE);
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}
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random_source_register(&random_qcom_rnd);
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return (0);
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}
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static int
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qcom_rnd_detach(device_t dev)
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{
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struct qcom_rnd_softc *sc;
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sc = device_get_softc(dev);
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KASSERT(
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atomic_load_explicit(&g_qcom_rnd_softc, memory_order_acquire) == sc,
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("only one global instance at a time"));
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random_source_deregister(&random_qcom_rnd);
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if (sc->reg != NULL) {
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bus_release_resource(sc->dev, SYS_RES_MEMORY, sc->reg_rid, sc->reg);
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}
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atomic_store_explicit(&g_qcom_rnd_softc, NULL, memory_order_release);
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return (0);
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}
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static int
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qcom_rnd_harvest(struct qcom_rnd_softc *sc, void *buf, size_t *sz)
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{
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/*
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* Add data to buf until we either run out of entropy or we
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* fill the buffer.
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*
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* Note - be mindful of the provided buffer size; we're reading
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* 4 bytes at a time but we only want to supply up to the max
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* buffer size, so don't write past it!
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*/
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size_t rz = 0;
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uint32_t reg;
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while (rz < *sz) {
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bus_barrier(sc->reg, 0, 0x120, BUS_SPACE_BARRIER_READ);
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reg = bus_read_4(sc->reg, QCOM_RND_PRNG_STATUS);
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if ((reg & QCOM_RND_PRNG_STATUS_DATA_AVAIL) == 0)
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break;
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reg = bus_read_4(sc->reg, QCOM_RND_PRNG_DATA_OUT);
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memcpy(((char *) buf) + rz, ®, sizeof(uint32_t));
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rz += sizeof(uint32_t);
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}
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if (rz == 0)
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return (EAGAIN);
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*sz = rz;
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return (0);
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}
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static unsigned
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qcom_rnd_read(void *buf, unsigned usz)
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{
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struct qcom_rnd_softc *sc;
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size_t sz;
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int error;
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sc = g_qcom_rnd_softc;
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if (sc == NULL)
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return (0);
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sz = usz;
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error = qcom_rnd_harvest(sc, buf, &sz);
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if (error != 0)
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return (0);
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return (sz);
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}
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static device_method_t qcom_rnd_methods[] = {
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/* Device methods. */
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DEVMETHOD(device_probe, qcom_rnd_probe),
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DEVMETHOD(device_attach, qcom_rnd_attach),
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DEVMETHOD(device_detach, qcom_rnd_detach),
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DEVMETHOD_END
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};
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static driver_t qcom_rnd_driver = {
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"qcom_rnd",
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qcom_rnd_methods,
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sizeof(struct qcom_rnd_softc)
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};
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static devclass_t qcom_rnd_devclass;
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DRIVER_MODULE(qcom_rnd_random, simplebus, qcom_rnd_driver, qcom_rnd_devclass,
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qcom_rnd_modevent, 0);
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DRIVER_MODULE(qcom_rnd_random, ofwbus, qcom_rnd_driver, qcom_rnd_devclass,
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qcom_rnd_modevent, 0);
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MODULE_DEPEND(qcom_rnd_random, random_device, 1, 1, 1);
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MODULE_VERSION(qcom_rnd_random, 1);
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43
sys/dev/qcom_rnd/qcom_rnd_reg.h
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43
sys/dev/qcom_rnd/qcom_rnd_reg.h
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@ -0,0 +1,43 @@
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/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2021, Adrian Chadd <adrian@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __QCOM_RND_REG_H__
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#define __QCOM_RND_REG_H__
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#define QCOM_RND_PRNG_DATA_OUT 0x0000
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#define QCOM_RND_PRNG_STATUS 0x0004
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#define QCOM_RND_PRNG_STATUS_DATA_AVAIL (1 << 0)
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#define QCOM_RND_PRNG_LFSR_CFG 0x0100
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#define QCOM_RND_PRNG_LFSR_CFG_MASK 0x0000ffff
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#define QCOM_RND_PRNG_LFSR_CFG_CLOCKS 0x0000dddd
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#define QCOM_RND_PRNG_CONFIG 0x0104
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#define QCOM_RND_PRNG_CONFIG_HW_ENABLE (1 << 1)
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#endif /* __QCOM_RND_REG_H__ */
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@ -102,6 +102,7 @@ enum random_entropy_source {
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RANDOM_PURE_DARN,
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RANDOM_PURE_TPM,
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RANDOM_PURE_VMGENID,
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RANDOM_PURE_QUALCOMM,
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ENTROPYSOURCE
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};
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_Static_assert(ENTROPYSOURCE <= 32,
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