/* * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009 * The President and Fellows of Harvard College. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <types.h> #include <lib.h> #include <spinlock.h> #include <platform/bus.h> #include <lamebus/lser.h> #include "autoconf.h" /* Registers (offsets within slot) */ #define LSER_REG_CHAR 0 /* Character in/out */ #define LSER_REG_WIRQ 4 /* Write interrupt status */ #define LSER_REG_RIRQ 8 /* Read interrupt status */ /* Bits in the IRQ registers */ #define LSER_IRQ_ENABLE 1 #define LSER_IRQ_ACTIVE 2 #define LSER_IRQ_FORCE 4 void lser_irq(void *vsc) { struct lser_softc *sc = vsc; uint32_t x; bool clear_to_write = false; bool got_a_read = false; uint32_t ch = 0; spinlock_acquire(&sc->ls_lock); x = bus_read_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ); if (x & LSER_IRQ_ACTIVE) { x = LSER_IRQ_ENABLE; sc->ls_wbusy = 0; clear_to_write = true; bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ, x); } x = bus_read_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_RIRQ); if (x & LSER_IRQ_ACTIVE) { x = LSER_IRQ_ENABLE; ch = bus_read_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_CHAR); got_a_read = true; bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_RIRQ, x); } spinlock_release(&sc->ls_lock); if (clear_to_write && sc->ls_start != NULL) { sc->ls_start(sc->ls_devdata); } if (got_a_read && sc->ls_input != NULL) { sc->ls_input(sc->ls_devdata, ch); } } void lser_write(void *vls, int ch) { struct lser_softc *ls = vls; spinlock_acquire(&ls->ls_lock); if (ls->ls_wbusy) { /* * We're not clear to write. * * This should not happen. It's the job of the driver * attached to us to not write until we call * ls->ls_start. * * (Note: if we're the console, the panic will go to * lser_writepolled for printing, because we hold a * spinlock and interrupts are off; it won't recurse.) */ panic("lser: Not clear to write\n"); } ls->ls_wbusy = true; bus_write_register(ls->ls_busdata, ls->ls_buspos, LSER_REG_CHAR, ch); spinlock_release(&ls->ls_lock); } static void lser_poll_until_write(struct lser_softc *sc) { uint32_t val; KASSERT(spinlock_do_i_hold(&sc->ls_lock)); do { val = bus_read_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ); } while ((val & LSER_IRQ_ACTIVE) == 0); } void lser_writepolled(void *vsc, int ch) { struct lser_softc *sc = vsc; bool irqpending; spinlock_acquire(&sc->ls_lock); if (sc->ls_wbusy) { irqpending = true; lser_poll_until_write(sc); /* Clear the ready condition, but leave the IRQ asserted */ bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ, LSER_IRQ_FORCE|LSER_IRQ_ENABLE); } else { irqpending = false; /* Clear the interrupt enable bit */ bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ, 0); } /* Send the character. */ bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_CHAR, ch); /* Wait until it's done. */ lser_poll_until_write(sc); /* * If there wasn't already an IRQ pending, clear the ready * condition and turn interruption back on. But if there was, * leave the register alone, with the ready condition set (and * the force bit still on); in due course we'll get to the * interrupt handler and they'll be cleared. */ if (!irqpending) { bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ, LSER_IRQ_ENABLE); } spinlock_release(&sc->ls_lock); } int config_lser(struct lser_softc *sc, int lserno) { (void)lserno; /* * Enable interrupting. */ spinlock_init(&sc->ls_lock); sc->ls_wbusy = false; bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_RIRQ, LSER_IRQ_ENABLE); bus_write_register(sc->ls_busdata, sc->ls_buspos, LSER_REG_WIRQ, LSER_IRQ_ENABLE); return 0; }