[POWERPC] Add new interrupt mapping core and change platforms to use it

This adds the new irq remapper core and removes the old one.  Because
there are some fundamental conflicts with the old code, like the value
of NO_IRQ which I'm now setting to 0 (as per discussions with Linus),
etc..., this commit also changes the relevant platform and driver code
over to use the new remapper (so as not to cause difficulties later
in bisecting).

This patch removes the old pre-parsing of the open firmware interrupt
tree along with all the bogus assumptions it made to try to renumber
interrupts according to the platform. This is all to be handled by the
new code now.

For the pSeries XICS interrupt controller, a single remapper host is
created for the whole machine regardless of how many interrupt
presentation and source controllers are found, and it's set to match
any device node that isn't a 8259.  That works fine on pSeries and
avoids having to deal with some of the complexities of split source
controllers vs. presentation controllers in the pSeries device trees.

The powerpc i8259 PIC driver now always requests the legacy interrupt
range. It also has the feature of being able to match any device node
(including NULL) if passed no device node as an input. That will help
porting over platforms with broken device-trees like Pegasos who don't
have a proper interrupt tree.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 112 insertions, 29 deletions

diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
index c2e9465..72c73a6 100644
--- a/arch/powerpc/sysdev/i8259.c
+++ b/arch/powerpc/sysdev/i8259.c
@@ -6,11 +6,16 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#undef DEBUG
+
 #include <linux/init.h>
 #include <linux/ioport.h>
 #include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
 #include <asm/io.h>
 #include <asm/i8259.h>
+#include <asm/prom.h>
 
 static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
 
@@ -20,7 +25,8 @@ static unsigned char cached_8259[2] = { 0xff, 0xff };
 
 static DEFINE_SPINLOCK(i8259_lock);
 
-static int i8259_pic_irq_offset;
+static struct device_node *i8259_node;
+static struct irq_host *i8259_host;
 
 /*
  * Acknowledge the IRQ using either the PCI host bridge's interrupt
@@ -28,16 +34,18 @@ static int i8259_pic_irq_offset;
  * 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)
+unsigned int i8259_irq(struct pt_regs *regs)
 {
 	int irq;
-
-	spin_lock(&i8259_lock);
+	int lock = 0;
 
 	/* Either int-ack or poll for the IRQ */
 	if (pci_intack)
 		irq = readb(pci_intack);
 	else {
+		spin_lock(&i8259_lock);
+		lock = 1;
+
 		/* Perform an interrupt acknowledge cycle on controller 1. */
 		outb(0x0C, 0x20);		/* prepare for poll */
 		irq = inb(0x20) & 7;
@@ -62,11 +70,13 @@ int i8259_irq(struct pt_regs *regs)
 		if (!pci_intack)
 			outb(0x0B, 0x20);	/* ISR register */
 		if(~inb(0x20) & 0x80)
-			irq = -1;
-	}
+			irq = NO_IRQ;
+	} else if (irq == 0xff)
+		irq = NO_IRQ;
 
-	spin_unlock(&i8259_lock);
-	return irq + i8259_pic_irq_offset;
+	if (lock)
+		spin_unlock(&i8259_lock);
+	return irq;
 }
 
 static void i8259_mask_and_ack_irq(unsigned int irq_nr)
@@ -74,7 +84,6 @@ static void i8259_mask_and_ack_irq(unsigned int irq_nr)
 	unsigned long flags;
 
 	spin_lock_irqsave(&i8259_lock, flags);
-	irq_nr -= i8259_pic_irq_offset;
 	if (irq_nr > 7) {
 		cached_A1 |= 1 << (irq_nr-8);
 		inb(0xA1); 	/* DUMMY */
@@ -100,8 +109,9 @@ static void i8259_mask_irq(unsigned int irq_nr)
 {
 	unsigned long flags;
 
+	pr_debug("i8259_mask_irq(%d)\n", irq_nr);
+
 	spin_lock_irqsave(&i8259_lock, flags);
-	irq_nr -= i8259_pic_irq_offset;
 	if (irq_nr < 8)
 		cached_21 |= 1 << irq_nr;
 	else
@@ -114,8 +124,9 @@ static void i8259_unmask_irq(unsigned int irq_nr)
 {
 	unsigned long flags;
 
+	pr_debug("i8259_unmask_irq(%d)\n", irq_nr);
+
 	spin_lock_irqsave(&i8259_lock, flags);
-	irq_nr -= i8259_pic_irq_offset;
 	if (irq_nr < 8)
 		cached_21 &= ~(1 << irq_nr);
 	else
@@ -152,25 +163,84 @@ static struct resource pic_edgectrl_iores = {
 	.flags = IORESOURCE_BUSY,
 };
 
-static struct irqaction i8259_irqaction = {
-	.handler = no_action,
-	.flags = IRQF_DISABLED,
-	.mask = CPU_MASK_NONE,
-	.name = "82c59 secondary cascade",
+static int i8259_host_match(struct irq_host *h, struct device_node *node)
+{
+	return i8259_node == NULL || i8259_node == node;
+}
+
+static int i8259_host_map(struct irq_host *h, unsigned int virq,
+			  irq_hw_number_t hw, unsigned int flags)
+{
+	pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
+
+	/* We block the internal cascade */
+	if (hw == 2)
+		get_irq_desc(virq)->status |= IRQ_NOREQUEST;
+
+	/* We use the level stuff only for now, we might want to
+	 * be more cautious here but that works for now
+	 */
+	get_irq_desc(virq)->status |= IRQ_LEVEL;
+	set_irq_chip_and_handler(virq, &i8259_pic, handle_level_irq);
+	return 0;
+}
+
+static void i8259_host_unmap(struct irq_host *h, unsigned int virq)
+{
+	/* Make sure irq is masked in hardware */
+	i8259_mask_irq(virq);
+
+	/* remove chip and handler */
+	set_irq_chip_and_handler(virq, NULL, NULL);
+
+	/* Make sure it's completed */
+	synchronize_irq(virq);
+}
+
+static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
+			    u32 *intspec, unsigned int intsize,
+			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+{
+	static unsigned char map_isa_senses[4] = {
+		IRQ_TYPE_LEVEL_LOW,
+		IRQ_TYPE_LEVEL_HIGH,
+		IRQ_TYPE_EDGE_FALLING,
+		IRQ_TYPE_EDGE_RISING,
+	};
+
+	*out_hwirq = intspec[0];
+	if (intsize > 1 && intspec[1] < 4)
+		*out_flags = map_isa_senses[intspec[1]];
+	else
+		*out_flags = IRQ_TYPE_NONE;
+
+	return 0;
+}
+
+static struct irq_host_ops i8259_host_ops = {
+	.match = i8259_host_match,
+	.map = i8259_host_map,
+	.unmap = i8259_host_unmap,
+	.xlate = i8259_host_xlate,
 };
 
-/*
- * i8259_init()
- * intack_addr - PCI interrupt acknowledge (real) address which will return
- *               the active irq from the 8259
+/****
+ * i8259_init - Initialize the legacy controller
+ * @node: device node of the legacy PIC (can be NULL, but then, it will match
+ *        all interrupts, so beware)
+ * @intack_addr: PCI interrupt acknowledge (real) address which will return
+ *             	 the active irq from the 8259
  */
-void __init i8259_init(unsigned long intack_addr, int offset)
+void i8259_init(struct device_node *node, unsigned long intack_addr)
 {
 	unsigned long flags;
-	int i;
 
+	/* initialize the controller */
 	spin_lock_irqsave(&i8259_lock, flags);
-	i8259_pic_irq_offset = offset;
+
+	/* Mask all first */
+	outb(0xff, 0xA1);
+	outb(0xff, 0x21);
 
 	/* init master interrupt controller */
 	outb(0x11, 0x20); /* Start init sequence */
@@ -184,24 +254,36 @@ void __init i8259_init(unsigned long intack_addr, int offset)
 	outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
 	outb(0x01, 0xA1); /* Select 8086 mode */
 
+	/* That thing is slow */
+	udelay(100);
+
 	/* always read ISR */
 	outb(0x0B, 0x20);
 	outb(0x0B, 0xA0);
 
-	/* Mask all interrupts */
+	/* Unmask the internal cascade */
+	cached_21 &= ~(1 << 2);
+
+	/* Set interrupt masks */
 	outb(cached_A1, 0xA1);
 	outb(cached_21, 0x21);
 
 	spin_unlock_irqrestore(&i8259_lock, flags);
 
-	for (i = 0; i < NUM_ISA_INTERRUPTS; ++i) {
-		set_irq_chip_and_handler(offset + i, &i8259_pic,
-					 handle_level_irq);
-		irq_desc[offset + i].status |= IRQ_LEVEL;
+	/* create a legacy host */
+	if (node)
+		i8259_node = of_node_get(node);
+	i8259_host = irq_alloc_host(IRQ_HOST_MAP_LEGACY, 0, &i8259_host_ops, 0);
+	if (i8259_host == NULL) {
+		printk(KERN_ERR "i8259: failed to allocate irq host !\n");
+		return;
 	}
 
 	/* reserve our resources */
-	setup_irq(offset + 2, &i8259_irqaction);
+	/* XXX should we continue doing that ? it seems to cause problems
+	 * with further requesting of PCI IO resources for that range...
+	 * need to look into it.
+	 */
 	request_resource(&ioport_resource, &pic1_iores);
 	request_resource(&ioport_resource, &pic2_iores);
 	request_resource(&ioport_resource, &pic_edgectrl_iores);
@@ -209,4 +291,5 @@ void __init i8259_init(unsigned long intack_addr, int offset)
 	if (intack_addr != 0)
 		pci_intack = ioremap(intack_addr, 1);
 
+	printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
 }