--- /dev/null
+/* $OpenBSD: stfrng.c,v 1.1 2023/09/23 18:29:55 kettenis Exp $ */
+/*
+ * Copyright (c) 2023 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/timeout.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/fdt.h>
+#include <dev/ofw/ofw_clock.h>
+
+/* Registers */
+#define RNG_CTRL 0x0000
+#define RNG_CTRL_RANDOMIZE 0x1
+#define RNG_CTRL_RESEED 0x2
+#define RNG_STAT 0x0004
+#define RNG_STAT_SEEDED (1 << 9)
+#define RNG_MODE 0x000c
+#define RNG_MODE_R256 (1 << 3)
+#define RNG_ISTAT 0x0014
+#define RNG_ISTAT_RAND_RDY (1 << 0)
+#define RNG_ISTAT_LFSR_LOCKUP (1 << 4)
+#define RNG_DATA0 0x0020
+#define RNG_DATA1 0x0024
+#define RNG_DATA2 0x0028
+#define RNG_DATA3 0x002c
+#define RNG_DATA4 0x0030
+#define RNG_DATA5 0x0034
+#define RNG_DATA6 0x0038
+#define RNG_DATA7 0x003c
+
+#define HREAD4(sc, reg) \
+ (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
+#define HWRITE4(sc, reg, val) \
+ bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
+
+struct stfrng_softc {
+ struct device sc_dev;
+ bus_space_tag_t sc_iot;
+ bus_space_handle_t sc_ioh;
+
+ struct timeout sc_to;
+};
+
+int stfrng_match(struct device *, void *, void *);
+void stfrng_attach(struct device *, struct device *, void *);
+
+const struct cfattach stfrng_ca = {
+ sizeof (struct stfrng_softc), stfrng_match, stfrng_attach
+};
+
+struct cfdriver stfrng_cd = {
+ NULL, "stfrng", DV_DULL
+};
+
+void stfrng_rnd(void *);
+
+int
+stfrng_match(struct device *parent, void *match, void *aux)
+{
+ struct fdt_attach_args *faa = aux;
+
+ return OF_is_compatible(faa->fa_node, "starfive,jh7110-trng");
+}
+
+void
+stfrng_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct stfrng_softc *sc = (struct stfrng_softc *)self;
+ struct fdt_attach_args *faa = aux;
+
+ if (faa->fa_nreg < 1) {
+ printf(": no registers\n");
+ return;
+ }
+
+ sc->sc_iot = faa->fa_iot;
+ if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
+ faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
+ printf(": can't map registers\n");
+ return;
+ }
+
+ printf("\n");
+
+ clock_enable(faa->fa_node, "hclk");
+ clock_enable(faa->fa_node, "ahb");
+ reset_deassert(faa->fa_node, NULL);
+
+ /* Clear all interrupts. */
+ HWRITE4(sc, RNG_ISTAT, 0xffffffff);
+
+ HWRITE4(sc, RNG_MODE, RNG_MODE_R256);
+ HWRITE4(sc, RNG_CTRL, RNG_CTRL_RESEED);
+
+ timeout_set(&sc->sc_to, stfrng_rnd, sc);
+ stfrng_rnd(sc);
+}
+
+void
+stfrng_rnd(void *arg)
+{
+ struct stfrng_softc *sc = arg;
+ uint32_t stat, istat;
+
+ stat = HREAD4(sc, RNG_STAT);
+ if (stat & RNG_STAT_SEEDED) {
+ istat = HREAD4(sc, RNG_ISTAT);
+ if (istat & RNG_ISTAT_RAND_RDY) {
+ HWRITE4(sc, RNG_ISTAT, RNG_ISTAT_RAND_RDY);
+ enqueue_randomness(HREAD4(sc, RNG_DATA0));
+ enqueue_randomness(HREAD4(sc, RNG_DATA1));
+ enqueue_randomness(HREAD4(sc, RNG_DATA2));
+ enqueue_randomness(HREAD4(sc, RNG_DATA3));
+ enqueue_randomness(HREAD4(sc, RNG_DATA4));
+ enqueue_randomness(HREAD4(sc, RNG_DATA5));
+ enqueue_randomness(HREAD4(sc, RNG_DATA6));
+ enqueue_randomness(HREAD4(sc, RNG_DATA7));
+ }
+
+ if (istat & RNG_ISTAT_LFSR_LOCKUP)
+ HWRITE4(sc, RNG_CTRL, RNG_CTRL_RESEED);
+ else
+ HWRITE4(sc, RNG_CTRL, RNG_CTRL_RANDOMIZE);
+ }
+
+ timeout_add_sec(&sc->sc_to, 1);
+}
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