2 * Operating System Services (OSS) chip handling
3 * Written by Joshua M. Thompson (funaho@jurai.org)
6 * This chip is used in the IIfx in place of VIA #2. It acts like a fancy
7 * VIA chip with prorammable interrupt levels.
9 * 990502 (jmt) - Major rewrite for new interrupt architecture as well as some
10 * recent insights into OSS operational details.
11 * 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped
12 * to mostly match the A/UX interrupt scheme supported on the
13 * VIA side. Also added support for enabling the ISM irq again
14 * since we now have a functional IOP manager.
17 #include <linux/types.h>
18 #include <linux/kernel.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/irq.h>
24 #include <asm/macintosh.h>
25 #include <asm/macints.h>
26 #include <asm/mac_via.h>
27 #include <asm/mac_oss.h>
30 volatile struct mac_oss *oss;
35 * The OSS "detection" code is actually in via_init() which is always called
36 * before us. Thus we can count on oss_present being valid on entry.
39 void __init oss_init(void)
43 if (!oss_present) return;
45 oss = (struct mac_oss *) OSS_BASE;
47 /* Disable all interrupts. Unlike a VIA it looks like we */
48 /* do this by setting the source's interrupt level to zero. */
50 for (i = 0; i < OSS_NUM_SOURCES; i++)
51 oss->irq_level[i] = 0;
55 * Initialize OSS for Nubus access
58 void __init oss_nubus_init(void)
63 * Handle miscellaneous OSS interrupts.
66 static void oss_irq(unsigned int irq, struct irq_desc *desc)
68 int events = oss->irq_pending &
69 (OSS_IP_IOPSCC | OSS_IP_SCSI | OSS_IP_IOPISM);
72 if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
73 printk("oss_irq: irq %u events = 0x%04X\n", irq,
74 (int) oss->irq_pending);
78 if (events & OSS_IP_IOPSCC) {
79 oss->irq_pending &= ~OSS_IP_IOPSCC;
80 generic_handle_irq(IRQ_MAC_SCC);
83 if (events & OSS_IP_SCSI) {
84 oss->irq_pending &= ~OSS_IP_SCSI;
85 generic_handle_irq(IRQ_MAC_SCSI);
88 if (events & OSS_IP_IOPISM) {
89 oss->irq_pending &= ~OSS_IP_IOPISM;
90 generic_handle_irq(IRQ_MAC_ADB);
95 * Nubus IRQ handler, OSS style
97 * Unlike the VIA/RBV this is on its own autovector interrupt level.
100 static void oss_nubus_irq(unsigned int irq, struct irq_desc *desc)
102 int events, irq_bit, i;
104 events = oss->irq_pending & OSS_IP_NUBUS;
108 #ifdef DEBUG_NUBUS_INT
109 if (console_loglevel > 7) {
110 printk("oss_nubus_irq: events = 0x%04X\n", events);
113 /* There are only six slots on the OSS, not seven */
120 if (events & irq_bit) {
121 oss->irq_pending &= ~irq_bit;
122 generic_handle_irq(NUBUS_SOURCE_BASE + i);
124 } while(events & (irq_bit - 1));
128 * Register the OSS and NuBus interrupt dispatchers.
130 * This IRQ mapping is laid out with two things in mind: first, we try to keep
131 * things on their own levels to avoid having to do double-dispatches. Second,
132 * the levels match as closely as possible the alternate IRQ mapping mode (aka
133 * "A/UX mode") available on some VIA machines.
136 #define OSS_IRQLEV_IOPISM IRQ_AUTO_1
137 #define OSS_IRQLEV_SCSI IRQ_AUTO_2
138 #define OSS_IRQLEV_NUBUS IRQ_AUTO_3
139 #define OSS_IRQLEV_IOPSCC IRQ_AUTO_4
140 #define OSS_IRQLEV_VIA1 IRQ_AUTO_6
142 void __init oss_register_interrupts(void)
144 irq_set_chained_handler(OSS_IRQLEV_IOPISM, oss_irq);
145 irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_irq);
146 irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq);
147 irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_irq);
148 irq_set_chained_handler(OSS_IRQLEV_VIA1, via1_irq);
150 /* OSS_VIA1 gets enabled here because it has no machspec interrupt. */
151 oss->irq_level[OSS_VIA1] = IRQ_AUTO_6;
155 * Enable an OSS interrupt
157 * It looks messy but it's rather straightforward. The switch() statement
158 * just maps the machspec interrupt numbers to the right OSS interrupt
159 * source (if the OSS handles that interrupt) and then sets the interrupt
160 * level for that source to nonzero, thus enabling the interrupt.
163 void oss_irq_enable(int irq) {
165 printk("oss_irq_enable(%d)\n", irq);
169 oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
172 oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
175 oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
183 irq -= NUBUS_SOURCE_BASE;
184 oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
188 if (IRQ_SRC(irq) == 1)
193 * Disable an OSS interrupt
195 * Same as above except we set the source's interrupt level to zero,
196 * to disable the interrupt.
199 void oss_irq_disable(int irq) {
201 printk("oss_irq_disable(%d)\n", irq);
205 oss->irq_level[OSS_IOPSCC] = 0;
208 oss->irq_level[OSS_IOPISM] = 0;
211 oss->irq_level[OSS_SCSI] = 0;
219 irq -= NUBUS_SOURCE_BASE;
220 oss->irq_level[irq] = 0;
224 if (IRQ_SRC(irq) == 1)
225 via_irq_disable(irq);