[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>

3 files changed, 59 insertions, 43 deletions

diff --git a/arch/powerpc/platforms/iseries/irq.c b/arch/powerpc/platforms/iseries/irq.c
index 7fb6a08786c0..2275e64f3152 100644
--- a/arch/powerpc/platforms/iseries/irq.c
+++ b/arch/powerpc/platforms/iseries/irq.c
@@ -162,27 +162,6 @@ static void pci_event_handler(struct HvLpEvent *event, struct pt_regs *regs)
 		printk(KERN_ERR "pci_event_handler: NULL event received\n");
 }
 
-/*
- * This is called by init_IRQ.  set in ppc_md.init_IRQ by iSeries_setup.c
- * It must be called before the bus walk.
- */
-void __init iSeries_init_IRQ(void)
-{
-	/* Register PCI event handler and open an event path */
-	int ret;
-
-	ret = HvLpEvent_registerHandler(HvLpEvent_Type_PciIo,
-			&pci_event_handler);
-	if (ret == 0) {
-		ret = HvLpEvent_openPath(HvLpEvent_Type_PciIo, 0);
-		if (ret != 0)
-			printk(KERN_ERR "iseries_init_IRQ: open event path "
-					"failed with rc 0x%x\n", ret);
-	} else
-		printk(KERN_ERR "iseries_init_IRQ: register handler "
-				"failed with rc 0x%x\n", ret);
-}
-
 #define REAL_IRQ_TO_SUBBUS(irq)	(((irq) >> 14) & 0xff)
 #define REAL_IRQ_TO_BUS(irq)	((((irq) >> 6) & 0xff) + 1)
 #define REAL_IRQ_TO_IDSEL(irq)	((((irq) >> 3) & 7) + 1)
@@ -196,7 +175,7 @@ static void iseries_enable_IRQ(unsigned int irq)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
-	unsigned int rirq = virt_irq_to_real_map[irq];
+	unsigned int rirq = (unsigned int)irq_map[irq].hwirq;
 
 	/* The IRQ has already been locked by the caller */
 	bus = REAL_IRQ_TO_BUS(rirq);
@@ -213,7 +192,7 @@ static unsigned int iseries_startup_IRQ(unsigned int irq)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
-	unsigned int rirq = virt_irq_to_real_map[irq];
+	unsigned int rirq = (unsigned int)irq_map[irq].hwirq;
 
 	bus = REAL_IRQ_TO_BUS(rirq);
 	function = REAL_IRQ_TO_FUNC(rirq);
@@ -254,7 +233,7 @@ static void iseries_shutdown_IRQ(unsigned int irq)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
-	unsigned int rirq = virt_irq_to_real_map[irq];
+	unsigned int rirq = (unsigned int)irq_map[irq].hwirq;
 
 	/* irq should be locked by the caller */
 	bus = REAL_IRQ_TO_BUS(rirq);
@@ -277,7 +256,7 @@ static void iseries_disable_IRQ(unsigned int irq)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
-	unsigned int rirq = virt_irq_to_real_map[irq];
+	unsigned int rirq = (unsigned int)irq_map[irq].hwirq;
 
 	/* The IRQ has already been locked by the caller */
 	bus = REAL_IRQ_TO_BUS(rirq);
@@ -291,7 +270,7 @@ static void iseries_disable_IRQ(unsigned int irq)
 
 static void iseries_end_IRQ(unsigned int irq)
 {
-	unsigned int rirq = virt_irq_to_real_map[irq];
+	unsigned int rirq = (unsigned int)irq_map[irq].hwirq;
 
 	HvCallPci_eoi(REAL_IRQ_TO_BUS(rirq), REAL_IRQ_TO_SUBBUS(rirq),
 		(REAL_IRQ_TO_IDSEL(rirq) << 4) + REAL_IRQ_TO_FUNC(rirq));
@@ -314,16 +293,14 @@ static struct irq_chip iseries_pic = {
 int __init iSeries_allocate_IRQ(HvBusNumber bus,
 		HvSubBusNumber sub_bus, u32 bsubbus)
 {
-	int virtirq;
 	unsigned int realirq;
 	u8 idsel = ISERIES_GET_DEVICE_FROM_SUBBUS(bsubbus);
 	u8 function = ISERIES_GET_FUNCTION_FROM_SUBBUS(bsubbus);
 
 	realirq = (((((sub_bus << 8) + (bus - 1)) << 3) + (idsel - 1)) << 3)
 		+ function;
-	virtirq = virt_irq_create_mapping(realirq);
-	set_irq_chip_and_handler(virtirq, &iseries_pic, handle_fasteoi_irq);
-	return virtirq;
+
+	return irq_create_mapping(NULL, realirq, IRQ_TYPE_NONE);
 }
 
 #endif /* CONFIG_PCI */
@@ -331,10 +308,9 @@ int __init iSeries_allocate_IRQ(HvBusNumber bus,
 /*
  * Get the next pending IRQ.
  */
-int iSeries_get_irq(struct pt_regs *regs)
+unsigned int iSeries_get_irq(struct pt_regs *regs)
 {
-	/* -2 means ignore this interrupt */
-	int irq = -2;
+	int irq = NO_IRQ_IGNORE;
 
 #ifdef CONFIG_SMP
 	if (get_lppaca()->int_dword.fields.ipi_cnt) {
@@ -357,9 +333,57 @@ int iSeries_get_irq(struct pt_regs *regs)
 		}
 		spin_unlock(&pending_irqs_lock);
 		if (irq >= NR_IRQS)
-			irq = -2;
+			irq = NO_IRQ_IGNORE;
 	}
 #endif
 
 	return irq;
 }
+
+static int iseries_irq_host_map(struct irq_host *h, unsigned int virq,
+				irq_hw_number_t hw, unsigned int flags)
+{
+	set_irq_chip_and_handler(virq, &iseries_pic, handle_fasteoi_irq);
+
+	return 0;
+}
+
+static struct irq_host_ops iseries_irq_host_ops = {
+	.map = iseries_irq_host_map,
+};
+
+/*
+ * This is called by init_IRQ.  set in ppc_md.init_IRQ by iSeries_setup.c
+ * It must be called before the bus walk.
+ */
+void __init iSeries_init_IRQ(void)
+{
+	/* Register PCI event handler and open an event path */
+	struct irq_host *host;
+	int ret;
+
+	/*
+	 * The Hypervisor only allows us up to 256 interrupt
+	 * sources (the irq number is passed in a u8).
+	 */
+	irq_set_virq_count(256);
+
+	/* Create irq host. No need for a revmap since HV will give us
+	 * back our virtual irq number
+	 */
+	host = irq_alloc_host(IRQ_HOST_MAP_NOMAP, 0, &iseries_irq_host_ops, 0);
+	BUG_ON(host == NULL);
+	irq_set_default_host(host);
+
+	ret = HvLpEvent_registerHandler(HvLpEvent_Type_PciIo,
+			&pci_event_handler);
+	if (ret == 0) {
+		ret = HvLpEvent_openPath(HvLpEvent_Type_PciIo, 0);
+		if (ret != 0)
+			printk(KERN_ERR "iseries_init_IRQ: open event path "
+					"failed with rc 0x%x\n", ret);
+	} else
+		printk(KERN_ERR "iseries_init_IRQ: register handler "
+				"failed with rc 0x%x\n", ret);
+}
+
diff --git a/arch/powerpc/platforms/iseries/irq.h b/arch/powerpc/platforms/iseries/irq.h
index 188aa808abd7..1ee8985140e5 100644
--- a/arch/powerpc/platforms/iseries/irq.h
+++ b/arch/powerpc/platforms/iseries/irq.h
@@ -4,6 +4,6 @@
 extern void iSeries_init_IRQ(void);
 extern int  iSeries_allocate_IRQ(HvBusNumber, HvSubBusNumber, u32);
 extern void iSeries_activate_IRQs(void);
-extern int iSeries_get_irq(struct pt_regs *);
+extern unsigned int iSeries_get_irq(struct pt_regs *);
 
 #endif /* _ISERIES_IRQ_H */
diff --git a/arch/powerpc/platforms/iseries/setup.c b/arch/powerpc/platforms/iseries/setup.c
index c877074745b2..c9605d773a77 100644
--- a/arch/powerpc/platforms/iseries/setup.c
+++ b/arch/powerpc/platforms/iseries/setup.c
@@ -294,8 +294,6 @@ static void __init iSeries_init_early(void)
 {
 	DBG(" -> iSeries_init_early()\n");
 
-	ppc64_interrupt_controller = IC_ISERIES;
-
 #if defined(CONFIG_BLK_DEV_INITRD)
 	/*
 	 * If the init RAM disk has been configured and there is
@@ -659,12 +657,6 @@ static int __init iseries_probe(void)
 	powerpc_firmware_features |= FW_FEATURE_ISERIES;
 	powerpc_firmware_features |= FW_FEATURE_LPAR;
 
-	/*
-	 * The Hypervisor only allows us up to 256 interrupt
-	 * sources (the irq number is passed in a u8).
-	 */
-	virt_irq_max = 255;
-
 	hpte_init_iSeries();
 
 	return 1;