From: Ingo Molnar <mingo@elte.hu>

This patch converts all the i386 PIC controllers (except VisWS and Voyager,
which I could not test - but which should still work as old-style IRQ layers)
to the new and simpler irq-chip interrupt handling layer.

[akpm@osdl.org: build fix]
[mingo@elte.hu: enable fasteoi handler for i386 level-triggered IO-APIC irqs]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 arch/i386/kernel/i8259.c   |   45 +++------
 arch/i386/kernel/io_apic.c |  160 ++++++++++++-----------------------
 arch/i386/kernel/irq.c     |   19 ++--
 include/asm-i386/hw_irq.h  |    2 
 4 files changed, 81 insertions(+), 145 deletions(-)

diff -puN arch/i386/kernel/i8259.c~genirq-convert-the-i386-architecture-to-irq-chips arch/i386/kernel/i8259.c
--- a/arch/i386/kernel/i8259.c~genirq-convert-the-i386-architecture-to-irq-chips
+++ a/arch/i386/kernel/i8259.c
@@ -34,39 +34,21 @@
  * moves to arch independent land
  */
 
-DEFINE_SPINLOCK(i8259A_lock);
-
-static void end_8259A_irq (unsigned int irq)
-{
-	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)) &&
-							irq_desc[irq].action)
-		enable_8259A_irq(irq);
-}
-
-#define shutdown_8259A_irq	disable_8259A_irq
-
 static void mask_and_ack_8259A(unsigned int);
 
-unsigned int startup_8259A_irq(unsigned int irq)
-{ 
-	enable_8259A_irq(irq);
-	return 0; /* never anything pending */
-}
-
-static struct hw_interrupt_type i8259A_irq_type = {
-	.typename = "XT-PIC",
-	.startup = startup_8259A_irq,
-	.shutdown = shutdown_8259A_irq,
-	.enable = enable_8259A_irq,
-	.disable = disable_8259A_irq,
-	.ack = mask_and_ack_8259A,
-	.end = end_8259A_irq,
+static struct irq_chip i8259A_chip = {
+	.name		= "XT-PIC",
+	.mask		= disable_8259A_irq,
+	.unmask		= enable_8259A_irq,
+	.mask_ack	= mask_and_ack_8259A,
 };
 
 /*
  * 8259A PIC functions to handle ISA devices:
  */
 
+DEFINE_SPINLOCK(i8259A_lock);
+
 /*
  * This contains the irq mask for both 8259A irq controllers,
  */
@@ -131,7 +113,7 @@ void make_8259A_irq(unsigned int irq)
 {
 	disable_irq_nosync(irq);
 	io_apic_irqs &= ~(1<<irq);
-	irq_desc[irq].chip = &i8259A_irq_type;
+	set_irq_chip_and_handler(irq, &i8259A_chip, handle_level_irq);
 	enable_irq(irq);
 }
 
@@ -323,12 +305,12 @@ void init_8259A(int auto_eoi)
 	outb_p(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR); /* (slave's support for AEOI in flat mode is to be investigated) */
 	if (auto_eoi)
 		/*
-		 * in AEOI mode we just have to mask the interrupt
+		 * In AEOI mode we just have to mask the interrupt
 		 * when acking.
 		 */
-		i8259A_irq_type.ack = disable_8259A_irq;
+		i8259A_chip.mask_ack = disable_8259A_irq;
 	else
-		i8259A_irq_type.ack = mask_and_ack_8259A;
+		i8259A_chip.mask_ack = mask_and_ack_8259A;
 
 	udelay(100);		/* wait for 8259A to initialize */
 
@@ -385,12 +367,13 @@ void __init init_ISA_irqs (void)
 			/*
 			 * 16 old-style INTA-cycle interrupts:
 			 */
-			irq_desc[i].chip = &i8259A_irq_type;
+			set_irq_chip_and_handler(i, &i8259A_chip,
+						 handle_level_irq);
 		} else {
 			/*
 			 * 'high' PCI IRQs filled in on demand
 			 */
-			irq_desc[i].chip = &no_irq_type;
+			irq_desc[i].chip = &no_irq_chip;
 		}
 	}
 }
diff -puN arch/i386/kernel/io_apic.c~genirq-convert-the-i386-architecture-to-irq-chips arch/i386/kernel/io_apic.c
--- a/arch/i386/kernel/io_apic.c~genirq-convert-the-i386-architecture-to-irq-chips
+++ a/arch/i386/kernel/io_apic.c
@@ -1198,8 +1198,7 @@ next:
 	return vector;
 }
 
-static struct hw_interrupt_type ioapic_level_type;
-static struct hw_interrupt_type ioapic_edge_type;
+static struct irq_chip ioapic_chip;
 
 #define IOAPIC_AUTO	-1
 #define IOAPIC_EDGE	0
@@ -1213,9 +1212,11 @@ static void ioapic_register_intr(int irq
 
 	if ((trigger == IOAPIC_AUTO && IO_APIC_irq_trigger(irq)) ||
 			trigger == IOAPIC_LEVEL)
-		irq_desc[idx].chip = &ioapic_level_type;
+		set_irq_chip_and_handler(idx, &ioapic_chip,
+					 handle_fasteoi_irq);
 	else
-		irq_desc[idx].chip = &ioapic_edge_type;
+		set_irq_chip_and_handler(idx, &ioapic_chip,
+					 handle_edge_irq);
 	set_intr_gate(vector, interrupt[idx]);
 }
 
@@ -1327,7 +1328,8 @@ static void __init setup_ExtINT_IRQ0_pin
 	 * The timer IRQ doesn't have to know that behind the
 	 * scene we have a 8259A-master in AEOI mode ...
 	 */
-	irq_desc[0].chip = &ioapic_edge_type;
+	irq_desc[0].chip = &ioapic_chip;
+	set_irq_handler(0, handle_edge_irq);
 
 	/*
 	 * Add it to the IO-APIC irq-routing table:
@@ -1914,6 +1916,8 @@ static int __init timer_irq_works(void)
  */
 
 /*
+ * Startup quirk:
+ *
  * Starting up a edge-triggered IO-APIC interrupt is
  * nasty - we need to make sure that we get the edge.
  * If it is already asserted for some reason, we need
@@ -1921,8 +1925,10 @@ static int __init timer_irq_works(void)
  *
  * This is not complete - we should be able to fake
  * an edge even if it isn't on the 8259A...
+ *
+ * (We do this for level-triggered IRQs too - it cannot hurt.)
  */
-static unsigned int startup_edge_ioapic_irq(unsigned int irq)
+static unsigned int startup_ioapic_irq(unsigned int irq)
 {
 	int was_pending = 0;
 	unsigned long flags;
@@ -1939,42 +1945,13 @@ static unsigned int startup_edge_ioapic_
 	return was_pending;
 }
 
-/*
- * Once we have recorded IRQ_PENDING already, we can mask the
- * interrupt for real. This prevents IRQ storms from unhandled
- * devices.
- */
-static void ack_edge_ioapic_irq(unsigned int irq)
+static void ack_ioapic_irq(unsigned int irq)
 {
 	move_irq(irq);
-	if ((irq_desc[irq].status & (IRQ_PENDING | IRQ_DISABLED))
-					== (IRQ_PENDING | IRQ_DISABLED))
-		mask_IO_APIC_irq(irq);
 	ack_APIC_irq();
 }
 
-/*
- * Level triggered interrupts can just be masked,
- * and shutting down and starting up the interrupt
- * is the same as enabling and disabling them -- except
- * with a startup need to return a "was pending" value.
- *
- * Level triggered interrupts are special because we
- * do not touch any IO-APIC register while handling
- * them. We ack the APIC in the end-IRQ handler, not
- * in the start-IRQ-handler. Protection against reentrance
- * from the same interrupt is still provided, both by the
- * generic IRQ layer and by the fact that an unacked local
- * APIC does not accept IRQs.
- */
-static unsigned int startup_level_ioapic_irq (unsigned int irq)
-{
-	unmask_IO_APIC_irq(irq);
-
-	return 0; /* don't check for pending */
-}
-
-static void end_level_ioapic_irq (unsigned int irq)
+static void ack_ioapic_quirk_irq(unsigned int irq)
 {
 	unsigned long v;
 	int i;
@@ -2014,35 +1991,27 @@ static void end_level_ioapic_irq (unsign
 	}
 }
 
-#ifdef CONFIG_PCI_MSI
-static unsigned int startup_edge_ioapic_vector(unsigned int vector)
+static unsigned int startup_ioapic_vector(unsigned int vector)
 {
 	int irq = vector_to_irq(vector);
 
-	return startup_edge_ioapic_irq(irq);
+	return startup_ioapic_irq(irq);
 }
 
-static void ack_edge_ioapic_vector(unsigned int vector)
+static void ack_ioapic_vector(unsigned int vector)
 {
 	int irq = vector_to_irq(vector);
 
 	move_native_irq(vector);
-	ack_edge_ioapic_irq(irq);
-}
-
-static unsigned int startup_level_ioapic_vector (unsigned int vector)
-{
-	int irq = vector_to_irq(vector);
-
-	return startup_level_ioapic_irq (irq);
+	ack_ioapic_irq(irq);
 }
 
-static void end_level_ioapic_vector (unsigned int vector)
+static void ack_ioapic_quirk_vector(unsigned int vector)
 {
 	int irq = vector_to_irq(vector);
 
 	move_native_irq(vector);
-	end_level_ioapic_irq(irq);
+	ack_ioapic_quirk_irq(irq);
 }
 
 static void mask_IO_APIC_vector (unsigned int vector)
@@ -2059,7 +2028,12 @@ static void unmask_IO_APIC_vector (unsig
 	unmask_IO_APIC_irq(irq);
 }
 
-#ifdef CONFIG_SMP
+/*
+ * Oh just glorious.  If CONFIG_PCI_MSI we've done
+ * #define set_ioapic_affinity set_ioapic_affinity_vector
+ */
+#if defined (CONFIG_SMP) && defined(CONFIG_X86_IO_APIC) && \
+		defined(CONFIG_PCI_MSI)
 static void set_ioapic_affinity_vector (unsigned int vector,
 					cpumask_t cpu_mask)
 {
@@ -2069,50 +2043,29 @@ static void set_ioapic_affinity_vector (
 	set_ioapic_affinity_irq(irq, cpu_mask);
 }
 #endif
-#endif
 
-static int ioapic_retrigger(unsigned int irq)
+static int ioapic_retrigger_vector(unsigned int vector)
 {
+	int irq = vector_to_irq(vector);
+
 	send_IPI_self(IO_APIC_VECTOR(irq));
 
 	return 1;
 }
 
-/*
- * Level and edge triggered IO-APIC interrupts need different handling,
- * so we use two separate IRQ descriptors. Edge triggered IRQs can be
- * handled with the level-triggered descriptor, but that one has slightly
- * more overhead. Level-triggered interrupts cannot be handled with the
- * edge-triggered handler, without risking IRQ storms and other ugly
- * races.
- */
-static struct hw_interrupt_type ioapic_edge_type __read_mostly = {
-	.typename 	= "IO-APIC-edge",
-	.startup 	= startup_edge_ioapic,
-	.shutdown 	= shutdown_edge_ioapic,
-	.enable 	= enable_edge_ioapic,
-	.disable 	= disable_edge_ioapic,
-	.ack 		= ack_edge_ioapic,
-	.end 		= end_edge_ioapic,
+static struct irq_chip ioapic_chip __read_mostly = {
+	.name 		= "IO-APIC",
+	.startup 	= startup_ioapic_vector,
+	.mask	 	= mask_IO_APIC_vector,
+	.unmask	 	= unmask_IO_APIC_vector,
+	.ack 		= ack_ioapic_vector,
+	.eoi 		= ack_ioapic_quirk_vector,
 #ifdef CONFIG_SMP
 	.set_affinity 	= set_ioapic_affinity,
 #endif
-	.retrigger	= ioapic_retrigger,
+	.retrigger	= ioapic_retrigger_vector,
 };
 
-static struct hw_interrupt_type ioapic_level_type __read_mostly = {
-	.typename 	= "IO-APIC-level",
-	.startup 	= startup_level_ioapic,
-	.shutdown 	= shutdown_level_ioapic,
-	.enable 	= enable_level_ioapic,
-	.disable 	= disable_level_ioapic,
-	.ack 		= mask_and_ack_level_ioapic,
-	.end 		= end_level_ioapic,
-#ifdef CONFIG_SMP
-	.set_affinity 	= set_ioapic_affinity,
-#endif
-	.retrigger	= ioapic_retrigger,
-};
 
 static inline void init_IO_APIC_traps(void)
 {
@@ -2146,20 +2099,21 @@ static inline void init_IO_APIC_traps(vo
 				make_8259A_irq(irq);
 			else
 				/* Strange. Oh, well.. */
-				irq_desc[irq].chip = &no_irq_type;
+				irq_desc[irq].chip = &no_irq_chip;
 		}
 	}
 }
 
-static void enable_lapic_irq (unsigned int irq)
-{
-	unsigned long v;
+/*
+ * The local APIC irq-chip implementation:
+ */
 
-	v = apic_read(APIC_LVT0);
-	apic_write_around(APIC_LVT0, v & ~APIC_LVT_MASKED);
+static void ack_apic(unsigned int irq)
+{
+	ack_APIC_irq();
 }
 
-static void disable_lapic_irq (unsigned int irq)
+static void mask_lapic_irq (unsigned int irq)
 {
 	unsigned long v;
 
@@ -2167,21 +2121,19 @@ static void disable_lapic_irq (unsigned 
 	apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
 }
 
-static void ack_lapic_irq (unsigned int irq)
+static void unmask_lapic_irq (unsigned int irq)
 {
-	ack_APIC_irq();
-}
+	unsigned long v;
 
-static void end_lapic_irq (unsigned int i) { /* nothing */ }
+	v = apic_read(APIC_LVT0);
+	apic_write_around(APIC_LVT0, v & ~APIC_LVT_MASKED);
+}
 
-static struct hw_interrupt_type lapic_irq_type __read_mostly = {
-	.typename 	= "local-APIC-edge",
-	.startup 	= NULL, /* startup_irq() not used for IRQ0 */
-	.shutdown 	= NULL, /* shutdown_irq() not used for IRQ0 */
-	.enable 	= enable_lapic_irq,
-	.disable 	= disable_lapic_irq,
-	.ack 		= ack_lapic_irq,
-	.end 		= end_lapic_irq
+static struct irq_chip lapic_chip __read_mostly = {
+	.name		= "local-APIC-edge",
+	.mask		= mask_lapic_irq,
+	.unmask		= unmask_lapic_irq,
+	.eoi		= ack_apic,
 };
 
 static void setup_nmi (void)
@@ -2362,7 +2314,7 @@ static inline void check_timer(void)
 	printk(KERN_INFO "...trying to set up timer as Virtual Wire IRQ...");
 
 	disable_8259A_irq(0);
-	irq_desc[0].chip = &lapic_irq_type;
+	set_irq_chip_and_handler(0, &lapic_chip, handle_fasteoi_irq);
 	apic_write_around(APIC_LVT0, APIC_DM_FIXED | vector);	/* Fixed mode */
 	enable_8259A_irq(0);
 
diff -puN arch/i386/kernel/irq.c~genirq-convert-the-i386-architecture-to-irq-chips arch/i386/kernel/irq.c
--- a/arch/i386/kernel/irq.c~genirq-convert-the-i386-architecture-to-irq-chips
+++ a/arch/i386/kernel/irq.c
@@ -55,6 +55,7 @@ fastcall unsigned int do_IRQ(struct pt_r
 {	
 	/* high bit used in ret_from_ code */
 	int irq = ~regs->orig_eax;
+	struct irq_desc *desc = irq_desc + irq;
 #ifdef CONFIG_4KSTACKS
 	union irq_ctx *curctx, *irqctx;
 	u32 *isp;
@@ -98,7 +99,7 @@ fastcall unsigned int do_IRQ(struct pt_r
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (curctx != irqctx) {
-		int arg1, arg2, ebx;
+		int arg1, arg2, arg3, ebx;
 
 		/* build the stack frame on the IRQ stack */
 		isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
@@ -114,16 +115,17 @@ fastcall unsigned int do_IRQ(struct pt_r
 			(curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 
 		asm volatile(
-			"       xchgl   %%ebx,%%esp      \n"
-			"       call    __do_IRQ         \n"
+			"       xchgl  %%ebx,%%esp      \n"
+			"       call   *%%edi           \n"
 			"       movl   %%ebx,%%esp      \n"
-			: "=a" (arg1), "=d" (arg2), "=b" (ebx)
-			:  "0" (irq),   "1" (regs),  "2" (isp)
-			: "memory", "cc", "ecx"
+			: "=a" (arg1), "=d" (arg2), "=c" (arg3), "=b" (ebx)
+			:  "0" (irq),   "1" (desc),  "2" (regs),  "3" (isp),
+			   "D" (desc->handle_irq)
+			: "memory", "cc"
 		);
 	} else
 #endif
-		__do_IRQ(irq, regs);
+		desc->handle_irq(irq, desc, regs);
 
 out_exit:
 	irq_exit();
@@ -258,7 +260,8 @@ int show_interrupts(struct seq_file *p, 
 		for_each_online_cpu(j)
 			seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 #endif
-		seq_printf(p, " %14s", irq_desc[i].chip->typename);
+		seq_printf(p, " %8s", irq_desc[i].chip->name);
+		seq_printf(p, "-%s", handle_irq_name(irq_desc[i].handle_irq));
 		seq_printf(p, "  %s", action->name);
 
 		for (action=action->next; action; action = action->next)
diff -puN include/asm-i386/hw_irq.h~genirq-convert-the-i386-architecture-to-irq-chips include/asm-i386/hw_irq.h
--- a/include/asm-i386/hw_irq.h~genirq-convert-the-i386-architecture-to-irq-chips
+++ a/include/asm-i386/hw_irq.h
@@ -17,8 +17,6 @@
 #include <asm/irq.h>
 #include <asm/sections.h>
 
-struct hw_interrupt_type;
-
 #define NMI_VECTOR		0x02
 
 /*
_