PPC32: Cleanup the i8259 code slightly. Allow for polling of interrupts again

and combine i8259_poll() and i8259_irq().

arch/ppc/kernel/Makefile

@@ -67,7 +67,7 @@ obj-$(CONFIG_ADIR)		+= i8259.o indirect_pci.o pci_auto.o \
 					todc_time.o
 obj-$(CONFIG_EV64260)		+= gt64260_common.o gt64260_pic.o \
 					indirect_pci.o todc_time.o pci_auto.o
-obj-$(CONFIG_GEMINI)		+= open_pic.o
+obj-$(CONFIG_GEMINI)		+= open_pic.o i8259.o
 obj-$(CONFIG_K2)		+= i8259.o indirect_pci.o todc_time.o \
 					pci_auto.o
 obj-$(CONFIG_LOPEC)		+= mpc10x_common.o indirect_pci.o pci_auto.o \

arch/ppc/kernel/i8259.c

@@ -21,17 +21,37 @@ static spinlock_t i8259_lock = SPIN_LOCK_UNLOCKED;
 
 int i8259_pic_irq_offset;
 
-/* Acknowledge the irq using the PCI host bridge's interrupt acknowledge
- * feature. (Polling is somehow broken on some IBM and Motorola PReP boxes.)
+/*
+ * Acknowledge the IRQ using either the PCI host bridge's interrupt
+ * acknowledge feature or poll.  How i8259_init() is called determines
+ * which is called.  It should be noted that polling is broken on some
+ * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
  */
-int i8259_irq(struct pt_regs *regs)
+int
+i8259_irq(struct pt_regs *regs)
 {
 	int irq;
 
-	spin_lock/*_irqsave*/(&i8259_lock/*, flags*/);
+	spin_lock(&i8259_lock);
+
+	/* Either int-ack or poll for the IRQ */
+	if (pci_intack)
+		irq = *pci_intack;
+	else {
+		/* Perform an interrupt acknowledge cycle on controller 1. */
+		outb(0x0C, 0x20);		/* prepare for poll */
+		irq = inb(0x20) & 7;
+		if (irq == 2 ) {
+			/*
+			 * Interrupt is cascaded so perform interrupt
+			 * acknowledge on controller 2.
+			 */
+			outb(0x0C, 0xA0);	/* prepare for poll */
+			irq = (inb(0xA0) & 7) + 8;
+		}
+	}
 
-	irq = *pci_intack;
-	if (irq==7) {
+	if (irq == 7) {
 		/*
 		 * This may be a spurious interrupt.
 		 *
@@ -39,47 +59,13 @@ int i8259_irq(struct pt_regs *regs)
 		 * significant bit is not set then there is no valid
 		 * interrupt.
 		 */
-		if(~inb(0x20)&0x80) {
+		if (!pci_intack)
+			outb(0x0B, 0x20);	/* ISR register */
+		if(~inb(0x20) & 0x80)
 			irq = -1;
-		}
 	}
-	spin_unlock/*_irqrestore*/(&i8259_lock/*, flags*/);
-	return irq;
-}
 
-/* Poke the 8259's directly using poll commands. */
-int i8259_poll(void)
-{
-	int irq;
-
-	spin_lock/*_irqsave*/(&i8259_lock/*, flags*/);
-	/*
-	 * Perform an interrupt acknowledge cycle on controller 1
-	 */
-	outb(0x0C, 0x20); /* prepare for poll */
-	irq = inb(0x20) & 7;
-	if (irq == 2) {
-		/*
-		 * Interrupt is cascaded so perform interrupt
-		 * acknowledge on controller 2
-		 */
-		outb(0x0C, 0xA0); /* prepare for poll */
-		irq = (inb(0xA0) & 7) + 8;
-	} else if (irq==7) {
-		/*
-		 * This may be a spurious interrupt
-		 *
-		 * Read the interrupt status register. If the most
-		 * significant bit is not set then there is no valid
-		 * interrupt
-		 */
-		outb(0x0b, 0x20);
-		if(~inb(0x20)&0x80) {
-			spin_unlock/*_irqrestore*/(&i8259_lock/*, flags*/);
-			return -1;
-		}
-	}
-	spin_unlock/*_irqrestore*/(&i8259_lock/*, flags*/);
+	spin_unlock(&i8259_lock);
 	return irq;
 }
 
@@ -171,11 +157,13 @@ static struct resource pic_edgectrl_iores = {
 	"8259 edge control", 0x4d0, 0x4d1, IORESOURCE_BUSY
 };
 
-/* i8259_init()
+/*
+ * i8259_init()
  * intack_addr - PCI interrupt acknowledge (real) address which will return
  *               the active irq from the 8259
  */
-void __init i8259_init(long intack_addr)
+void __init
+i8259_init(long intack_addr)
 {
 	unsigned long flags;
 
@@ -209,9 +197,6 @@ void __init i8259_init(long intack_addr)
 	request_resource(&ioport_resource, &pic2_iores);
 	request_resource(&ioport_resource, &pic_edgectrl_iores);
 
-	/* XXX remove me after board maintainers fix their i8259_init calls */
-	if (intack_addr == 0)
-		panic("You must supply a PCI interrupt acknowledge address to i8259_init()\n");
-
-	pci_intack = ioremap(intack_addr, 1);
+	if (intack_addr != 0)
+		pci_intack = ioremap(intack_addr, 1);
 }

arch/ppc/kernel/open_pic.c

@@ -799,26 +799,20 @@ static void openpic_ipi_action(int cpl, void *dev_id, struct pt_regs *regs)
 
 #endif /* CONFIG_SMP */
 
-/* This one may be merged with PReP and CHRP */
 int
 openpic_get_irq(struct pt_regs *regs)
 {
-/*
- * Clean up needed. -VAL
- */
 	int irq = openpic_irq();
 
-	/* Management of the cascade should be moved out of here */
-
-	/* Yep - because openpic !=> i8259, for one thing. -VAL */
-	if (open_pic_irq_offset && irq == open_pic_irq_offset)
-	{
-#ifndef CONFIG_GEMINI
-		irq = i8259_irq(regs); /* get IRQ from cascade */
-#endif
+	/*
+	 * This needs to be cleaned up.  We don't necessarily have
+	 * an i8259 cascaded or even a cascade.
+	 */
+	if (open_pic_irq_offset && irq == open_pic_irq_offset) {
+		/* Get the IRQ from the cascade. */
+		irq = i8259_irq(regs);
 		openpic_eoi();
-	}
-	if (irq == OPENPIC_VEC_SPURIOUS + open_pic_irq_offset)
+	} else if (irq == OPENPIC_VEC_SPURIOUS + open_pic_irq_offset)
 		irq = -1;
 	return irq;
 }

include/asm-ppc/i8259.h

@@ -9,8 +9,7 @@
 
 extern struct hw_interrupt_type i8259_pic;
 
-void i8259_init(long);
-int i8259_irq(struct pt_regs *regs);
-int i8259_poll(void);
+extern void i8259_init(long intack_addr);
+extern int i8259_irq(struct pt_regs *regs);
 
 #endif /* _PPC_KERNEL_i8259_H */