187 lines
4.5 KiB
C
187 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Operating System Services (OSS) chip 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 <linux/irq.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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/*
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* Initialize the OSS
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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 (macintosh_config->ident != MAC_MODEL_IIFX)
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return;
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oss = (struct mac_oss *) OSS_BASE;
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pr_debug("OSS detected at %p", oss);
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oss_present = 1;
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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] = 0;
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}
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/*
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* Handle OSS interrupts.
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* XXX how do you clear a pending IRQ? is it even necessary?
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*/
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static void oss_iopism_irq(struct irq_desc *desc)
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{
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generic_handle_irq(IRQ_MAC_ADB);
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}
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static void oss_scsi_irq(struct irq_desc *desc)
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{
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generic_handle_irq(IRQ_MAC_SCSI);
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}
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static void oss_nubus_irq(struct irq_desc *desc)
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{
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u16 events, irq_bit;
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int irq_num;
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events = oss->irq_pending & OSS_IP_NUBUS;
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irq_num = NUBUS_SOURCE_BASE + 5;
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irq_bit = OSS_IP_NUBUS5;
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do {
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if (events & irq_bit) {
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events &= ~irq_bit;
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generic_handle_irq(irq_num);
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}
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--irq_num;
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irq_bit >>= 1;
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} while (events);
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}
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static void oss_iopscc_irq(struct irq_desc *desc)
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{
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generic_handle_irq(IRQ_MAC_SCC);
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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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* This IRQ mapping is laid out with two things in mind: first, we try to keep
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* things on their own levels to avoid having to do double-dispatches. Second,
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* the levels match as closely as possible the alternate IRQ mapping mode (aka
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* "A/UX mode") available on some VIA machines.
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*/
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#define OSS_IRQLEV_IOPISM IRQ_AUTO_1
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#define OSS_IRQLEV_SCSI IRQ_AUTO_2
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#define OSS_IRQLEV_NUBUS IRQ_AUTO_3
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#define OSS_IRQLEV_IOPSCC IRQ_AUTO_4
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#define OSS_IRQLEV_VIA1 IRQ_AUTO_6
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void __init oss_register_interrupts(void)
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{
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irq_set_chained_handler(OSS_IRQLEV_IOPISM, oss_iopism_irq);
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irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_scsi_irq);
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irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq);
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irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_iopscc_irq);
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irq_set_chained_handler(OSS_IRQLEV_VIA1, via1_irq);
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/* OSS_VIA1 gets enabled here because it has no machspec interrupt. */
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oss->irq_level[OSS_VIA1] = OSS_IRQLEV_VIA1;
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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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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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return;
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case IRQ_MAC_ADB:
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oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
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return;
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case IRQ_MAC_SCSI:
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oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
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return;
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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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return;
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}
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if (IRQ_SRC(irq) == 1)
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via_irq_enable(irq);
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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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switch(irq) {
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case IRQ_MAC_SCC:
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oss->irq_level[OSS_IOPSCC] = 0;
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return;
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case IRQ_MAC_ADB:
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oss->irq_level[OSS_IOPISM] = 0;
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return;
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case IRQ_MAC_SCSI:
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oss->irq_level[OSS_SCSI] = 0;
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return;
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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] = 0;
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return;
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}
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if (IRQ_SRC(irq) == 1)
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via_irq_disable(irq);
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}
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