elcr.c revision 140451
1128928Sjhb/*- 2128928Sjhb * Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org> 3128928Sjhb * All rights reserved. 4128928Sjhb * 5128928Sjhb * Redistribution and use in source and binary forms, with or without 6128928Sjhb * modification, are permitted provided that the following conditions 7128928Sjhb * are met: 8128928Sjhb * 1. Redistributions of source code must retain the above copyright 9128928Sjhb * notice, this list of conditions and the following disclaimer. 10128928Sjhb * 2. Redistributions in binary form must reproduce the above copyright 11128928Sjhb * notice, this list of conditions and the following disclaimer in the 12128928Sjhb * documentation and/or other materials provided with the distribution. 13128928Sjhb * 3. Neither the name of the author nor the names of any co-contributors 14128928Sjhb * may be used to endorse or promote products derived from this software 15128928Sjhb * without specific prior written permission. 16128928Sjhb * 17128928Sjhb * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18128928Sjhb * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19128928Sjhb * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20128928Sjhb * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21128928Sjhb * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22128928Sjhb * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23128928Sjhb * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24128928Sjhb * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25128928Sjhb * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26128928Sjhb * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27128928Sjhb * SUCH DAMAGE. 28128928Sjhb */ 29128928Sjhb 30128928Sjhb#include <sys/cdefs.h> 31128928Sjhb__FBSDID("$FreeBSD: head/sys/i386/isa/elcr.c 140451 2005-01-18 20:24:47Z jhb $"); 32128928Sjhb 33128928Sjhb/* 34128928Sjhb * The ELCR is a register that controls the trigger mode and polarity of 35128928Sjhb * EISA and ISA interrupts. In FreeBSD 3.x and 4.x, the ELCR was only 36128928Sjhb * consulted for determining the appropriate trigger mode of EISA 37128928Sjhb * interrupts when using an APIC. However, it seems that almost all 38128928Sjhb * systems that include PCI also include an ELCR that manages the ISA 39128928Sjhb * IRQs 0 through 15. Thus, we check for the presence of an ELCR on 40128928Sjhb * every machine by checking to see if the values found at bootup are 41128928Sjhb * sane. Note that the polarity of ISA and EISA IRQs are linked to the 42128928Sjhb * trigger mode. All edge triggered IRQs use active-hi polarity, and 43128928Sjhb * all level triggered interrupts use active-lo polarity. 44128928Sjhb * 45128928Sjhb * The format of the ELCR is simple: it is a 16-bit bitmap where bit 0 46128928Sjhb * controls IRQ 0, bit 1 controls IRQ 1, etc. If the bit is zero, the 47128928Sjhb * associated IRQ is edge triggered. If the bit is one, the IRQ is 48128928Sjhb * level triggered. 49128928Sjhb */ 50128928Sjhb 51128928Sjhb#include <sys/param.h> 52128928Sjhb#include <sys/bus.h> 53128928Sjhb#include <sys/systm.h> 54128928Sjhb#include <machine/intr_machdep.h> 55128928Sjhb 56128928Sjhb#define ELCR_PORT 0x4d0 57128928Sjhb#define ELCR_MASK(irq) (1 << (irq)) 58128928Sjhb 59128928Sjhbstatic int elcr_status; 60140451Sjhbint elcr_found; 61128928Sjhb 62128928Sjhb/* 63128928Sjhb * Check to see if we have what looks like a valid ELCR. We do this by 64128928Sjhb * verifying that IRQs 0, 1, 2, and 13 are all edge triggered. 65128928Sjhb */ 66128928Sjhbint 67128928Sjhbelcr_probe(void) 68128928Sjhb{ 69128928Sjhb int i; 70128928Sjhb 71128928Sjhb elcr_status = inb(ELCR_PORT) | inb(ELCR_PORT + 1) << 8; 72128928Sjhb if ((elcr_status & (ELCR_MASK(0) | ELCR_MASK(1) | ELCR_MASK(2) | 73128928Sjhb ELCR_MASK(8) | ELCR_MASK(13))) != 0) 74128928Sjhb return (ENXIO); 75128928Sjhb if (bootverbose) { 76128928Sjhb printf("ELCR Found. ISA IRQs programmed as:\n"); 77128928Sjhb for (i = 0; i < 16; i++) 78128928Sjhb printf(" %2d", i); 79128928Sjhb printf("\n"); 80128928Sjhb for (i = 0; i < 16; i++) 81128928Sjhb if (elcr_status & ELCR_MASK(i)) 82128928Sjhb printf(" L"); 83128928Sjhb else 84128928Sjhb printf(" E"); 85128928Sjhb printf("\n"); 86128928Sjhb } 87128928Sjhb if (resource_disabled("elcr", 0)) 88128928Sjhb return (ENXIO); 89128928Sjhb elcr_found = 1; 90128928Sjhb return (0); 91128928Sjhb} 92128928Sjhb 93128928Sjhb/* 94128928Sjhb * Returns 1 for level trigger, 0 for edge. 95128928Sjhb */ 96128928Sjhbenum intr_trigger 97128928Sjhbelcr_read_trigger(u_int irq) 98128928Sjhb{ 99128928Sjhb 100128928Sjhb KASSERT(elcr_found, ("%s: no ELCR was found!", __func__)); 101128928Sjhb KASSERT(irq <= 15, ("%s: invalid IRQ %u", __func__, irq)); 102128928Sjhb if (elcr_status & ELCR_MASK(irq)) 103128928Sjhb return (INTR_TRIGGER_LEVEL); 104128928Sjhb else 105128928Sjhb return (INTR_TRIGGER_EDGE); 106128928Sjhb} 107128928Sjhb 108128928Sjhb/* 109128928Sjhb * Set the trigger mode for a specified IRQ. Mode of 0 means edge triggered, 110128928Sjhb * and a mode of 1 means level triggered. 111128928Sjhb */ 112128928Sjhbvoid 113128928Sjhbelcr_write_trigger(u_int irq, enum intr_trigger trigger) 114128928Sjhb{ 115128928Sjhb int new_status; 116128928Sjhb 117128928Sjhb KASSERT(elcr_found, ("%s: no ELCR was found!", __func__)); 118128928Sjhb KASSERT(irq <= 15, ("%s: invalid IRQ %u", __func__, irq)); 119128928Sjhb if (trigger == INTR_TRIGGER_LEVEL) 120128928Sjhb new_status = elcr_status | ELCR_MASK(irq); 121128928Sjhb else 122128928Sjhb new_status = elcr_status & ~ELCR_MASK(irq); 123128928Sjhb if (new_status == elcr_status) 124128928Sjhb return; 125128928Sjhb elcr_status = new_status; 126128928Sjhb if (irq >= 8) 127128928Sjhb outb(ELCR_PORT + 1, elcr_status >> 8); 128128928Sjhb else 129128928Sjhb outb(ELCR_PORT, elcr_status & 0xff); 130128928Sjhb} 131128928Sjhb 132128928Sjhbvoid 133128928Sjhbelcr_resume(void) 134128928Sjhb{ 135128928Sjhb 136128928Sjhb KASSERT(elcr_found, ("%s: no ELCR was found!", __func__)); 137128928Sjhb outb(ELCR_PORT, elcr_status & 0xff); 138128928Sjhb outb(ELCR_PORT + 1, elcr_status >> 8); 139128928Sjhb} 140