# HG changeset patch
# User Taylor R Campbell <riastradh@NetBSD.org>
# Date 1589249103 0
#      Tue May 12 02:05:03 2020 +0000
# Branch trunk
# Node ID be0dd54edaf17793e88148e3d7ecc6ffbbf319dc
# Parent  33c1fbd3107ad65e9cd05de97ce0a7e49c3e0e2e
WIP: octeon rnm(4) rework

diff -r 33c1fbd3107a -r be0dd54edaf1 sys/arch/mips/cavium/dev/octeon_rnm.c
--- a/sys/arch/mips/cavium/dev/octeon_rnm.c	Mon May 11 21:51:25 2020 +0000
+++ b/sys/arch/mips/cavium/dev/octeon_rnm.c	Tue May 12 02:05:03 2020 +0000
@@ -45,26 +45,18 @@
 #include <sys/bus.h>
 
 #define RNG_DELAY_CLOCK 91
-#define RNG_DEF_BURST_COUNT 10
-
-int octeon_rnm_burst_count = RNG_DEF_BURST_COUNT;
 
 struct octeon_rnm_softc {
-	device_t sc_dev;
-
 	bus_space_tag_t		sc_bust;
 	bus_space_handle_t	sc_regh;
-
+	kmutex_t		sc_lock;
 	krndsource_t		sc_rndsrc;	/* /dev/random source */
-	struct callout		sc_rngto;	/* rng timeout */
-	int			sc_rnghz;	/* rng poll time */
 };
 
 static int octeon_rnm_match(device_t, struct cfdata *, void *);
 static void octeon_rnm_attach(device_t, device_t, void *);
-static void octeon_rnm_rng(void *);
-static inline uint64_t octeon_rnm_load(struct octeon_rnm_softc *);
-static inline int octeon_rnm_iobdma(struct octeon_rnm_softc *);
+static void octeon_rnm_rng(size_t, void *);
+static uint64_t octeon_rnm_load(struct octeon_rnm_softc *);
 
 CFATTACH_DECL_NEW(octeon_rnm, sizeof(struct octeon_rnm_softc),
     octeon_rnm_match, octeon_rnm_attach, NULL, NULL);
@@ -94,40 +86,37 @@ octeon_rnm_attach(device_t parent, devic
 
 	aprint_normal("\n");
 
-	sc->sc_dev = self;
 	sc->sc_bust = aa->aa_bust;
 	status = bus_space_map(aa->aa_bust, aa->aa_unit->addr, RNM_SIZE,
 	    0, &sc->sc_regh);
 	if (status != 0)
 		panic(": can't map i/o space");
 
-	bus_space_write_8(sc->sc_bust, sc->sc_regh, RNM_CTL_STATUS_OFFSET,
-	    RNM_CTL_STATUS_RNG_EN | RNM_CTL_STATUS_ENT_EN);
-
-	if (hz >= 100)
-		sc->sc_rnghz = hz / 100;
-	else 
-		sc->sc_rnghz = 1;
+	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_VM);
 
-	rnd_attach_source(&sc->sc_rndsrc, device_xname(sc->sc_dev),
-	    RND_TYPE_RNG, RND_FLAG_NO_ESTIMATE);
-
-	callout_init(&sc->sc_rngto, 0);
+	/*
+	 * Enable the internal ring oscillator entropy source (ENT),
+	 * but disable the LFSR/SHA-1 engine (RNG) so we get the raw RO
+	 * samples.
+	 */
+	bus_space_write_8(sc->sc_bust, sc->sc_regh, RNM_CTL_STATUS_OFFSET,
+	    RNM_CTL_STATUS_ENT_EN);
 
-	octeon_rnm_rng(sc);
-
-	aprint_normal("%s: random number generator enabled: %dhz\n",
-	    device_xname(sc->sc_dev), sc->sc_rnghz);
+	rndsource_setcb(&sc->sc_rndsrc, octeon_rnm_rng, sc);
+	rnd_attach_source(&sc->sc_rndsrc, device_xname(self), RND_TYPE_RNG,
+	    RND_FLAG_DEFAULT);
 }
 
 static void
-octeon_rnm_rng(void *vsc)
+octeon_rnm_rng(size_t nbytes, void *vsc)
 {
 	struct octeon_rnm_softc *sc = vsc;
 	uint64_t rn;
 	int i;
 
-	for (i = 0; i < octeon_rnm_burst_count; i++) {
+	/* Prevent concurrent access from emptying the FIFO.  */
+	mutex_enter(&sc->sc_lock);
+	for (i = 0; i < howmany(nbytes, sizeof(rn)); i++) {
 		rn = octeon_rnm_load(sc);
 		rnd_add_data(&sc->sc_rndsrc,
 				&rn, sizeof(rn), sizeof(rn) * NBBY);
@@ -138,11 +127,10 @@ octeon_rnm_rng(void *vsc)
 		 */
 		delay(1);
 	}
-
-	callout_reset(&sc->sc_rngto, sc->sc_rnghz, octeon_rnm_rng, sc);
+	mutex_exit(&sc->sc_lock);
 }
 
-static inline uint64_t
+static uint64_t
 octeon_rnm_load(struct octeon_rnm_softc *sc)
 {
 	uint64_t addr =
@@ -152,45 +140,3 @@ octeon_rnm_load(struct octeon_rnm_softc 
 
 	return octeon_xkphys_read_8(addr);
 }
-
-static inline int
-octeon_rnm_iobdma(struct octeon_rnm_softc *sc)
-{
-
-	/* XXX */
-	return 0;
-}
-
-SYSCTL_SETUP(octeon_rnm_sysctl, "sysctl octeon_rnm subtree setup")
-{
-	int rc, root_num;
-	const struct sysctlnode *node;
-
-	if ( (rc = sysctl_createv(clog, 0, NULL, NULL,
-			CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL,
-			NULL, 0, NULL, 0, CTL_HW, CTL_EOL)) != 0) {
-		goto err;
-	}
-
-	if ( (rc = sysctl_createv(clog, 0, NULL, &node,
-			CTLFLAG_PERMANENT, CTLTYPE_NODE, "octeon_rnm",
-			SYSCTL_DESCR("octeon_rnm controls"),
-			NULL, 0, NULL, 0, CTL_HW, CTL_CREATE, CTL_EOL)) != 0) {
-		goto err;
-	}
-
-	root_num = node->sysctl_num;
-
-	if ( (rc = sysctl_createv(clog, 0, NULL, NULL,
-			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
-			CTLTYPE_INT, "burst_count",
-			SYSCTL_DESCR("Burst read count per callout"),
-			NULL, 0, &octeon_rnm_burst_count,
-			0, CTL_HW, root_num, CTL_CREATE, CTL_EOL)) != 0) {
-		goto err;
-	}
-
-	return;
-err:
-	printf("%s: sysctl_createv failed (rc = %d)\n", __func__, rc);
-}