294 lines
6.7 KiB
C
294 lines
6.7 KiB
C
/*
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* OSS handling
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* Written by Joshua M. Thompson (funaho@jurai.org)
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*
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*
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* This chip is used in the IIfx in place of VIA #2. It acts like a fancy
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* VIA chip with prorammable interrupt levels.
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*
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* 990502 (jmt) - Major rewrite for new interrupt architecture as well as some
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* recent insights into OSS operational details.
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* 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped
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* to mostly match the A/UX interrupt scheme supported on the
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* VIA side. Also added support for enabling the ISM irq again
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* since we now have a functional IOP manager.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <asm/bootinfo.h>
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#include <asm/macintosh.h>
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#include <asm/macints.h>
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#include <asm/mac_via.h>
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#include <asm/mac_oss.h>
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int oss_present;
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volatile struct mac_oss *oss;
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static irqreturn_t oss_irq(int, void *);
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static irqreturn_t oss_nubus_irq(int, void *);
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extern irqreturn_t via1_irq(int, void *);
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/*
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* Initialize the OSS
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*
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* The OSS "detection" code is actually in via_init() which is always called
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* before us. Thus we can count on oss_present being valid on entry.
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*/
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void __init oss_init(void)
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{
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int i;
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if (!oss_present) return;
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oss = (struct mac_oss *) OSS_BASE;
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/* Disable all interrupts. Unlike a VIA it looks like we */
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/* do this by setting the source's interrupt level to zero. */
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for (i = 0; i <= OSS_NUM_SOURCES; i++) {
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oss->irq_level[i] = OSS_IRQLEV_DISABLED;
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}
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/* If we disable VIA1 here, we never really handle it... */
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oss->irq_level[OSS_VIA1] = OSS_IRQLEV_VIA1;
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}
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/*
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* Register the OSS and NuBus interrupt dispatchers.
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*/
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void __init oss_register_interrupts(void)
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{
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if (request_irq(OSS_IRQLEV_SCSI, oss_irq, IRQ_FLG_LOCK,
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"scsi", (void *) oss))
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pr_err("Couldn't register %s interrupt\n", "scsi");
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if (request_irq(OSS_IRQLEV_NUBUS, oss_nubus_irq, IRQ_FLG_LOCK,
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"nubus", (void *) oss))
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pr_err("Couldn't register %s interrupt\n", "nubus");
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if (request_irq(OSS_IRQLEV_SOUND, oss_irq, IRQ_FLG_LOCK,
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"sound", (void *) oss))
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pr_err("Couldn't register %s interrupt\n", "sound");
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if (request_irq(OSS_IRQLEV_VIA1, via1_irq, IRQ_FLG_LOCK,
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"via1", (void *) via1))
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pr_err("Couldn't register %s interrupt\n", "via1");
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}
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/*
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* Initialize OSS for Nubus access
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*/
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void __init oss_nubus_init(void)
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{
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}
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/*
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* Handle miscellaneous OSS interrupts. Right now that's just sound
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* and SCSI; everything else is routed to its own autovector IRQ.
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*/
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static irqreturn_t oss_irq(int irq, void *dev_id)
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{
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int events;
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events = oss->irq_pending & (OSS_IP_SOUND|OSS_IP_SCSI);
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if (!events)
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return IRQ_NONE;
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#ifdef DEBUG_IRQS
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if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
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printk("oss_irq: irq %d events = 0x%04X\n", irq,
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(int) oss->irq_pending);
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}
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#endif
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/* FIXME: how do you clear a pending IRQ? */
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if (events & OSS_IP_SOUND) {
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oss->irq_pending &= ~OSS_IP_SOUND;
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/* FIXME: call sound handler */
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} else if (events & OSS_IP_SCSI) {
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oss->irq_pending &= ~OSS_IP_SCSI;
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m68k_handle_int(IRQ_MAC_SCSI);
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} else {
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/* FIXME: error check here? */
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}
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return IRQ_HANDLED;
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}
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/*
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* Nubus IRQ handler, OSS style
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*
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* Unlike the VIA/RBV this is on its own autovector interrupt level.
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*/
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static irqreturn_t oss_nubus_irq(int irq, void *dev_id)
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{
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int events, irq_bit, i;
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events = oss->irq_pending & OSS_IP_NUBUS;
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if (!events)
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return IRQ_NONE;
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#ifdef DEBUG_NUBUS_INT
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if (console_loglevel > 7) {
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printk("oss_nubus_irq: events = 0x%04X\n", events);
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}
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#endif
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/* There are only six slots on the OSS, not seven */
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i = 6;
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irq_bit = 0x40;
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do {
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--i;
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irq_bit >>= 1;
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if (events & irq_bit) {
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oss->irq_pending &= ~irq_bit;
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m68k_handle_int(NUBUS_SOURCE_BASE + i);
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}
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} while(events & (irq_bit - 1));
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return IRQ_HANDLED;
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}
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/*
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* Enable an OSS interrupt
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*
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* It looks messy but it's rather straightforward. The switch() statement
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* just maps the machspec interrupt numbers to the right OSS interrupt
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* source (if the OSS handles that interrupt) and then sets the interrupt
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* level for that source to nonzero, thus enabling the interrupt.
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*/
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void oss_irq_enable(int irq) {
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#ifdef DEBUG_IRQUSE
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printk("oss_irq_enable(%d)\n", irq);
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#endif
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switch(irq) {
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case IRQ_MAC_SCC:
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oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
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break;
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case IRQ_MAC_ADB:
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oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
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break;
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case IRQ_MAC_SCSI:
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oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
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break;
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case IRQ_NUBUS_9:
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case IRQ_NUBUS_A:
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case IRQ_NUBUS_B:
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case IRQ_NUBUS_C:
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case IRQ_NUBUS_D:
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case IRQ_NUBUS_E:
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irq -= NUBUS_SOURCE_BASE;
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oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
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break;
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#ifdef DEBUG_IRQUSE
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default:
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printk("%s unknown irq %d\n", __func__, irq);
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break;
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#endif
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}
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}
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/*
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* Disable an OSS interrupt
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*
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* Same as above except we set the source's interrupt level to zero,
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* to disable the interrupt.
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*/
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void oss_irq_disable(int irq) {
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#ifdef DEBUG_IRQUSE
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printk("oss_irq_disable(%d)\n", irq);
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#endif
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switch(irq) {
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case IRQ_MAC_SCC:
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oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_DISABLED;
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break;
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case IRQ_MAC_ADB:
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oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_DISABLED;
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break;
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case IRQ_MAC_SCSI:
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oss->irq_level[OSS_SCSI] = OSS_IRQLEV_DISABLED;
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break;
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case IRQ_NUBUS_9:
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case IRQ_NUBUS_A:
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case IRQ_NUBUS_B:
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case IRQ_NUBUS_C:
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case IRQ_NUBUS_D:
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case IRQ_NUBUS_E:
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irq -= NUBUS_SOURCE_BASE;
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oss->irq_level[irq] = OSS_IRQLEV_DISABLED;
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break;
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#ifdef DEBUG_IRQUSE
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default:
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printk("%s unknown irq %d\n", __func__, irq);
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break;
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#endif
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}
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}
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/*
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* Clear an OSS interrupt
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*
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* Not sure if this works or not but it's the only method I could
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* think of based on the contents of the mac_oss structure.
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*/
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void oss_irq_clear(int irq) {
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/* FIXME: how to do this on OSS? */
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switch(irq) {
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case IRQ_MAC_SCC:
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oss->irq_pending &= ~OSS_IP_IOPSCC;
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break;
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case IRQ_MAC_ADB:
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oss->irq_pending &= ~OSS_IP_IOPISM;
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break;
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case IRQ_MAC_SCSI:
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oss->irq_pending &= ~OSS_IP_SCSI;
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break;
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case IRQ_NUBUS_9:
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case IRQ_NUBUS_A:
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case IRQ_NUBUS_B:
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case IRQ_NUBUS_C:
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case IRQ_NUBUS_D:
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case IRQ_NUBUS_E:
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irq -= NUBUS_SOURCE_BASE;
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oss->irq_pending &= ~(1 << irq);
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break;
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}
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}
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/*
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* Check to see if a specific OSS interrupt is pending
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*/
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int oss_irq_pending(int irq)
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{
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switch(irq) {
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case IRQ_MAC_SCC:
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return oss->irq_pending & OSS_IP_IOPSCC;
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break;
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case IRQ_MAC_ADB:
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return oss->irq_pending & OSS_IP_IOPISM;
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break;
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case IRQ_MAC_SCSI:
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return oss->irq_pending & OSS_IP_SCSI;
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break;
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case IRQ_NUBUS_9:
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case IRQ_NUBUS_A:
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case IRQ_NUBUS_B:
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case IRQ_NUBUS_C:
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case IRQ_NUBUS_D:
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case IRQ_NUBUS_E:
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irq -= NUBUS_SOURCE_BASE;
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return oss->irq_pending & (1 << irq);
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break;
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}
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return 0;
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}
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