149 lines
4.3 KiB
C
149 lines
4.3 KiB
C
/* $NetBSD: ti_rng.c,v 1.4 2020/06/03 15:59:22 jmcneill Exp $ */
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/*-
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* Copyright (c) 2015 Jared D. McNeill <jmcneill@invisible.ca>
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* All rights reserved.
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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, this list of conditions and the following disclaimer.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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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,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: ti_rng.c,v 1.4 2020/06/03 15:59:22 jmcneill Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/device.h>
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#include <sys/conf.h>
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#include <sys/mutex.h>
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#include <sys/bus.h>
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#include <sys/rndsource.h>
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#include <dev/fdt/fdtvar.h>
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#include <arm/ti/ti_prcm.h>
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#include <arm/ti/ti_rngreg.h>
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static const char * const compatible[] = {
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"ti,omap4-rng",
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NULL
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};
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struct ti_rng_softc {
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device_t sc_dev;
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bus_space_tag_t sc_iot;
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bus_space_handle_t sc_ioh;
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kmutex_t sc_lock;
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krndsource_t sc_rndsource;
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};
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static int ti_rng_match(device_t, cfdata_t, void *);
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static void ti_rng_attach(device_t, device_t, void *);
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static void ti_rng_callback(size_t, void *);
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CFATTACH_DECL_NEW(ti_rng, sizeof(struct ti_rng_softc),
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ti_rng_match, ti_rng_attach, NULL, NULL);
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#define RD4(sc, reg) \
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bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg))
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#define WR4(sc, reg, val) \
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bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
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static int
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ti_rng_match(device_t parent, cfdata_t match, void *aux)
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{
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struct fdt_attach_args * const faa = aux;
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return of_match_compatible(faa->faa_phandle, compatible);
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}
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static void
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ti_rng_attach(device_t parent, device_t self, void *aux)
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{
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struct ti_rng_softc *sc = device_private(self);
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struct fdt_attach_args * const faa = aux;
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const int phandle = faa->faa_phandle;
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bus_addr_t addr;
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bus_size_t size;
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if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
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aprint_error(": couldn't get registers\n");
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return;
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}
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if (ti_prcm_enable_hwmod(phandle, 0) != 0) {
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aprint_error(": couldn't enable module\n");
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return;
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}
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sc->sc_dev = self;
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sc->sc_iot = faa->faa_bst;
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if (bus_space_map(sc->sc_iot, addr, size, 0, &sc->sc_ioh) != 0) {
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aprint_error(": couldn't map registers\n");
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return;
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}
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mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_VM);
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if ((RD4(sc, TRNG_CONTROL_REG) & TRNG_CONTROL_ENABLE) == 0) {
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WR4(sc, TRNG_CONFIG_REG,
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__SHIFTIN(0x21, TRNG_CONFIG_MIN_REFILL) |
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__SHIFTIN(0x22, TRNG_CONFIG_MAX_REFILL));
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WR4(sc, TRNG_CONTROL_REG,
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__SHIFTIN(0x21, TRNG_CONTROL_STARTUP_CYCLES) |
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TRNG_CONTROL_ENABLE);
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}
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aprint_naive("\n");
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aprint_normal(": RNG\n");
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rndsource_setcb(&sc->sc_rndsource, ti_rng_callback, sc);
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rnd_attach_source(&sc->sc_rndsource, device_xname(self), RND_TYPE_RNG,
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RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB);
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}
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static void
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ti_rng_callback(size_t bytes_wanted, void *priv)
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{
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struct ti_rng_softc * const sc = priv;
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uint32_t buf[2];
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u_int retry;
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mutex_enter(&sc->sc_lock);
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while (bytes_wanted) {
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for (retry = 10; retry > 0; retry--) {
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if (RD4(sc, TRNG_STATUS_REG) & TRNG_STATUS_READY)
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break;
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delay(10);
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}
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if (retry == 0)
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break;
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buf[0] = RD4(sc, TRNG_OUTPUT_L_REG);
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buf[1] = RD4(sc, TRNG_OUTPUT_H_REG);
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WR4(sc, TRNG_INTACK_REG, TRNG_INTACK_READY);
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rnd_add_data_sync(&sc->sc_rndsource, buf, sizeof(buf),
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sizeof(buf) * NBBY);
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bytes_wanted -= MIN(bytes_wanted, sizeof(buf));
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}
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explicit_memset(buf, 0, sizeof(buf));
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mutex_exit(&sc->sc_lock);
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}
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