Initial import

1 files changed, 226 insertions, 0 deletions

diff --git a/arch/m68k/mac/oss.c b/arch/m68k/mac/oss.c
new file mode 100644
index 000000000..bb11dceed
--- /dev/null
+++ b/arch/m68k/mac/oss.c
@@ -0,0 +1,226 @@
+/*
+ *	Operating System Services (OSS) chip handling
+ *	Written by Joshua M. Thompson (funaho@jurai.org)
+ *
+ *
+ *	This chip is used in the IIfx in place of VIA #2. It acts like a fancy
+ *	VIA chip with prorammable interrupt levels.
+ *
+ * 990502 (jmt) - Major rewrite for new interrupt architecture as well as some
+ *		  recent insights into OSS operational details.
+ * 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped
+ *		  to mostly match the A/UX interrupt scheme supported on the
+ *		  VIA side. Also added support for enabling the ISM irq again
+ *		  since we now have a functional IOP manager.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+
+#include <asm/macintosh.h>
+#include <asm/macints.h>
+#include <asm/mac_via.h>
+#include <asm/mac_oss.h>
+
+int oss_present;
+volatile struct mac_oss *oss;
+
+/*
+ * Initialize the OSS
+ *
+ * The OSS "detection" code is actually in via_init() which is always called
+ * before us. Thus we can count on oss_present being valid on entry.
+ */
+
+void __init oss_init(void)
+{
+	int i;
+
+	if (!oss_present) return;
+
+	oss = (struct mac_oss *) OSS_BASE;
+
+	/* Disable all interrupts. Unlike a VIA it looks like we    */
+	/* do this by setting the source's interrupt level to zero. */
+
+	for (i = 0; i < OSS_NUM_SOURCES; i++)
+		oss->irq_level[i] = 0;
+}
+
+/*
+ * Initialize OSS for Nubus access
+ */
+
+void __init oss_nubus_init(void)
+{
+}
+
+/*
+ * Handle miscellaneous OSS interrupts.
+ */
+
+static void oss_irq(unsigned int irq, struct irq_desc *desc)
+{
+	int events = oss->irq_pending &
+	             (OSS_IP_IOPSCC | OSS_IP_SCSI | OSS_IP_IOPISM);
+
+#ifdef DEBUG_IRQS
+	if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
+		printk("oss_irq: irq %u events = 0x%04X\n", irq,
+			(int) oss->irq_pending);
+	}
+#endif
+
+	if (events & OSS_IP_IOPSCC) {
+		oss->irq_pending &= ~OSS_IP_IOPSCC;
+		generic_handle_irq(IRQ_MAC_SCC);
+	}
+
+	if (events & OSS_IP_SCSI) {
+		oss->irq_pending &= ~OSS_IP_SCSI;
+		generic_handle_irq(IRQ_MAC_SCSI);
+	}
+
+	if (events & OSS_IP_IOPISM) {
+		oss->irq_pending &= ~OSS_IP_IOPISM;
+		generic_handle_irq(IRQ_MAC_ADB);
+	}
+}
+
+/*
+ * Nubus IRQ handler, OSS style
+ *
+ * Unlike the VIA/RBV this is on its own autovector interrupt level.
+ */
+
+static void oss_nubus_irq(unsigned int irq, struct irq_desc *desc)
+{
+	int events, irq_bit, i;
+
+	events = oss->irq_pending & OSS_IP_NUBUS;
+	if (!events)
+		return;
+
+#ifdef DEBUG_NUBUS_INT
+	if (console_loglevel > 7) {
+		printk("oss_nubus_irq: events = 0x%04X\n", events);
+	}
+#endif
+	/* There are only six slots on the OSS, not seven */
+
+	i = 6;
+	irq_bit = 0x40;
+	do {
+		--i;
+		irq_bit >>= 1;
+		if (events & irq_bit) {
+			oss->irq_pending &= ~irq_bit;
+			generic_handle_irq(NUBUS_SOURCE_BASE + i);
+		}
+	} while(events & (irq_bit - 1));
+}
+
+/*
+ * Register the OSS and NuBus interrupt dispatchers.
+ *
+ * This IRQ mapping is laid out with two things in mind: first, we try to keep
+ * things on their own levels to avoid having to do double-dispatches. Second,
+ * the levels match as closely as possible the alternate IRQ mapping mode (aka
+ * "A/UX mode") available on some VIA machines.
+ */
+
+#define OSS_IRQLEV_IOPISM    IRQ_AUTO_1
+#define OSS_IRQLEV_SCSI      IRQ_AUTO_2
+#define OSS_IRQLEV_NUBUS     IRQ_AUTO_3
+#define OSS_IRQLEV_IOPSCC    IRQ_AUTO_4
+#define OSS_IRQLEV_VIA1      IRQ_AUTO_6
+
+void __init oss_register_interrupts(void)
+{
+	irq_set_chained_handler(OSS_IRQLEV_IOPISM, oss_irq);
+	irq_set_chained_handler(OSS_IRQLEV_SCSI,   oss_irq);
+	irq_set_chained_handler(OSS_IRQLEV_NUBUS,  oss_nubus_irq);
+	irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_irq);
+	irq_set_chained_handler(OSS_IRQLEV_VIA1,   via1_irq);
+
+	/* OSS_VIA1 gets enabled here because it has no machspec interrupt. */
+	oss->irq_level[OSS_VIA1] = IRQ_AUTO_6;
+}
+
+/*
+ * Enable an OSS interrupt
+ *
+ * It looks messy but it's rather straightforward. The switch() statement
+ * just maps the machspec interrupt numbers to the right OSS interrupt
+ * source (if the OSS handles that interrupt) and then sets the interrupt
+ * level for that source to nonzero, thus enabling the interrupt.
+ */
+
+void oss_irq_enable(int irq) {
+#ifdef DEBUG_IRQUSE
+	printk("oss_irq_enable(%d)\n", irq);
+#endif
+	switch(irq) {
+		case IRQ_MAC_SCC:
+			oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
+			return;
+		case IRQ_MAC_ADB:
+			oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
+			return;
+		case IRQ_MAC_SCSI:
+			oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
+			return;
+		case IRQ_NUBUS_9:
+		case IRQ_NUBUS_A:
+		case IRQ_NUBUS_B:
+		case IRQ_NUBUS_C:
+		case IRQ_NUBUS_D:
+		case IRQ_NUBUS_E:
+			irq -= NUBUS_SOURCE_BASE;
+			oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
+			return;
+	}
+
+	if (IRQ_SRC(irq) == 1)
+		via_irq_enable(irq);
+}
+
+/*
+ * Disable an OSS interrupt
+ *
+ * Same as above except we set the source's interrupt level to zero,
+ * to disable the interrupt.
+ */
+
+void oss_irq_disable(int irq) {
+#ifdef DEBUG_IRQUSE
+	printk("oss_irq_disable(%d)\n", irq);
+#endif
+	switch(irq) {
+		case IRQ_MAC_SCC:
+			oss->irq_level[OSS_IOPSCC] = 0;
+			return;
+		case IRQ_MAC_ADB:
+			oss->irq_level[OSS_IOPISM] = 0;
+			return;
+		case IRQ_MAC_SCSI:
+			oss->irq_level[OSS_SCSI] = 0;
+			return;
+		case IRQ_NUBUS_9:
+		case IRQ_NUBUS_A:
+		case IRQ_NUBUS_B:
+		case IRQ_NUBUS_C:
+		case IRQ_NUBUS_D:
+		case IRQ_NUBUS_E:
+			irq -= NUBUS_SOURCE_BASE;
+			oss->irq_level[irq] = 0;
+			return;
+	}
+
+	if (IRQ_SRC(irq) == 1)
+		via_irq_disable(irq);
+}