[rpi] remove IRQ support for BCM233x RNG
Upstream DTBs don't provide IRQ lines for the RNG. Moreover, harvesting bytes as often as the RNG interrupt is triggered (87 times per sec) is an overkill. For these reasons, get rid of the interrupt mode and make callout mode the default, with random bits harvested every 4 seconds. Submitted by: Sylvain Garrigues <sylgar@gmail.com> Reviewed by: ian, imp, manu, mmel Approved by: emaste MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D14541
This commit is contained in:
Oleksandr Tymoshenko
parent
71b126549d
commit
8e6a67d5be
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=330727
@ -51,10 +51,6 @@ __FBSDID("$FreeBSD$");
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#include <dev/random/randomdev.h>
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#include <dev/random/random_harvestq.h>
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#if !defined(BCM2835_RNG_USE_CALLOUT)
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#define BCM2835_RNG_USE_INTERRUPT
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#endif
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static device_attach_t bcm2835_rng_attach;
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static device_detach_t bcm2835_rng_detach;
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static device_probe_t bcm2835_rng_probe;
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@ -92,18 +88,15 @@ static device_probe_t bcm2835_rng_probe;
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#define RNG_NUM_OSCILLATORS 6
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#define RNG_STALL_COUNT_DEFAULT 10
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#define RNG_CALLOUT_TICKS (hz * 4)
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struct bcm2835_rng_softc {
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device_t sc_dev;
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struct resource * sc_mem_res;
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struct resource * sc_irq_res;
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void * sc_intr_hdl;
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#if defined(BCM2835_RNG_USE_CALLOUT) || defined(BCM2835_RNG_USE_INTERRUPT)
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uint32_t sc_buf[RNG_FIFO_WORDS];
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#endif
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#if defined(BCM2835_RNG_USE_CALLOUT)
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struct callout sc_rngto;
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int sc_rnghz;
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#endif
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int sc_stall_count;
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int sc_rbg2x;
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long sc_underrun;
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@ -214,19 +207,6 @@ bcm2835_rng_disable_intr(struct bcm2835_rng_softc *sc)
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bcm2835_rng_write4(sc, RNG_INT_MASK, mask);
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}
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#if defined(BCM2835_RNG_USE_INTERRUPT)
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static void
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bcm2835_rng_enable_intr(struct bcm2835_rng_softc *sc)
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{
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uint32_t mask;
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/* Clear the interrupt off bit in the interrupt mask register */
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mask = bcm2835_rng_read4(sc, RNG_INT_MASK);
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mask &= ~RNG_INT_OFF_BIT;
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bcm2835_rng_write4(sc, RNG_INT_MASK, mask);
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}
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#endif
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static void
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bcm2835_rng_start(struct bcm2835_rng_softc *sc)
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{
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@ -244,11 +224,6 @@ bcm2835_rng_start(struct bcm2835_rng_softc *sc)
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if (sc->sc_rbg2x)
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ctrl |= RNG_RBG2X;
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bcm2835_rng_write4(sc, RNG_CTRL, ctrl);
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#if defined(BCM2835_RNG_USE_INTERRUPT)
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/* Enable the interrupt */
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bcm2835_rng_enable_intr(sc);
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#endif
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}
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static void
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@ -263,12 +238,13 @@ bcm2835_rng_stop(struct bcm2835_rng_softc *sc)
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}
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static void
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bcm2835_rng_harvest(struct bcm2835_rng_softc *sc)
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bcm2835_rng_harvest(void *arg)
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{
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uint32_t *dest;
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uint32_t status;
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u_int cnt, nread, num_avail, num_words;
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int seen_underrun, num_stalls;
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struct bcm2835_rng_softc *sc = arg;
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dest = sc->sc_buf;
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nread = num_words = 0;
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@ -316,9 +292,7 @@ bcm2835_rng_harvest(struct bcm2835_rng_softc *sc)
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random_harvest_queue(sc->sc_buf, cnt, cnt * NBBY / 2,
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RANDOM_PURE_BROADCOM);
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#if defined(BCM2835_RNG_USE_CALLOUT)
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callout_reset(&sc->sc_rngto, sc->sc_rnghz, bcm2835_rng_harvest, sc);
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#endif
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callout_reset(&sc->sc_rngto, RNG_CALLOUT_TICKS, bcm2835_rng_harvest, sc);
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}
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static int
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@ -390,10 +364,10 @@ bcm2835_rng_attach(device_t dev)
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sc = device_get_softc(dev);
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sc->sc_dev = dev;
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sc->sc_stall_count = RNG_STALL_COUNT_DEFAULT;
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#ifdef BCM2835_RNG_USE_CALLOUT
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/* Initialize callout */
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callout_init(&sc->sc_rngto, CALLOUT_MPSAFE);
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#endif
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TUNABLE_INT_FETCH("bcmrng.2xspeed", &sc->sc_rbg2x);
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TUNABLE_INT_FETCH("bcmrng.stall_count", &sc->sc_stall_count);
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@ -406,27 +380,6 @@ bcm2835_rng_attach(device_t dev)
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return (ENXIO);
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}
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#if defined(BCM2835_RNG_USE_INTERRUPT)
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/* Allocate interrupt resource */
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rid = 0;
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sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
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RF_SHAREABLE | RF_ACTIVE);
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if (sc->sc_irq_res == NULL) {
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bcm2835_rng_detach(dev);
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return (ENXIO);
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}
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/* Set up the interrupt handler */
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error = bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_BIO | INTR_MPSAFE,
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NULL, (driver_intr_t *)bcm2835_rng_harvest, sc, &sc->sc_intr_hdl);
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if (error) {
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device_printf(dev, "Failed to set up IRQ\n");
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sc->sc_intr_hdl = NULL;
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bcm2835_rng_detach(dev);
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return (error);
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}
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#endif
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/* Start the RNG */
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bcm2835_rng_start(sc);
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@ -461,14 +414,11 @@ bcm2835_rng_attach(device_t dev)
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sysctl_bcm2835_rng_dump, "S", "Dump RNG registers");
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#endif
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#if defined(BCM2835_RNG_USE_CALLOUT)
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/* Reset callout */
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if (hz >= 100)
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sc->sc_rnghz = hz / 100;
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else
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sc->sc_rnghz = 1;
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callout_reset(&sc->sc_rngto, sc->sc_rnghz, bcm2835_rng_harvest, sc);
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#endif
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/*
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* Schedule the initial harvesting one second from now, which should give the
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* hardware RNG plenty of time to generate the first random bytes.
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*/
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callout_reset(&sc->sc_rngto, hz, bcm2835_rng_harvest, sc);
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return (0);
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}
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@ -477,9 +427,6 @@ static int
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bcm2835_rng_detach(device_t dev)
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{
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struct bcm2835_rng_softc *sc;
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#if defined(BCM2835_RNG_USE_INTERRUPT)
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int error;
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#endif
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sc = device_get_softc(dev);
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@ -487,27 +434,7 @@ bcm2835_rng_detach(device_t dev)
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bcm2835_rng_stop(sc);
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/* Drain the callout it */
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#if defined(BCM2835_RNG_USE_CALLOUT)
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callout_drain(&sc->sc_rngto);
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#endif
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#if defined(BCM2835_RNG_USE_INTERRUPT)
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/* Tear down the interrupt */
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if (sc->sc_irq_res && sc->sc_intr_hdl) {
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error = bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr_hdl);
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if (error != 0) {
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device_printf(dev, "could not tear down IRQ\n");
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return (error);
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}
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sc->sc_intr_hdl = NULL;
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}
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/* Release interrupt resource */
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if (sc->sc_irq_res) {
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bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
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sc->sc_irq_res = NULL;
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}
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#endif
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/* Release memory resource */
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if (sc->sc_mem_res != NULL)
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@ -51,10 +51,6 @@
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status = "okay";
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};
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rng@7e104000 {
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interrupts = <2 29>;
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}
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spi@7e204000 {
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status = "okay";
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};
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@ -51,10 +51,6 @@
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status = "okay";
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};
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rng@7e104000 {
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interrupts = <2 29>;
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}
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spi@7e204000 {
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status = "okay";
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};
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