[Cbe-oss-dev] [PATCH 1/8] powerpc cell: use common smp ipi actions

[Milton Miller]

The cell iic interrupt controller has enough software caused interrupts
to use a unique interrupt for each of the 4 messages powerpc uses.
This means each interrupt gets its own irq action/data combination.

Use the seperate, optimized, arch common ipi action functions
registered via the helper smp_request_message_ipi instead passing the
message as action data to a single action that then demultipexes to
the required acton via a switch statement.

smp_request_message_ipi will register the action as IRQF_PER_CPU
and IRQF_DISABLED, and WARN if the allocation fails for some reason,
so no need to print on that failure.  It will return positive if
the message will not be used by the kernel, in which case we can
free the virq.

In addition to elimiating inefficient code, this also corrects the
error that a kernel built with kexec but without a debugger would
not register the ipi for kdump to notify the other cpus of a crash.

This also restores the debugger action to be static to kernel/smp.c.

Signed-off-by: Milton Miller <miltonm at bga.com>

The merging process for 23d72bfd8f (powerpc: Consolidate ipi message
mux and demux) ended up moving the old smp_message_recv into the cell
code instead of obtaining the prerequisite patch from the patchworks
archive.  My ploy to avoid a duplicate patch in patchworks failed.

Here is the fresh patch.

Index: work.git/arch/powerpc/include/asm/smp.h
===================================================================
--- work.git.orig/arch/powerpc/include/asm/smp.h	2011-05-20 23:47:28.722236978 -0500
+++ work.git/arch/powerpc/include/asm/smp.h	2011-05-20 23:48:30.794220425 -0500
@@ -191,8 +191,6 @@ extern unsigned long __secondary_hold_sp
 extern unsigned long __secondary_hold_acknowledge;
 extern char __secondary_hold;
 
-extern irqreturn_t debug_ipi_action(int irq, void *data);
-
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
Index: work.git/arch/powerpc/kernel/smp.c
===================================================================
--- work.git.orig/arch/powerpc/kernel/smp.c	2011-05-20 23:47:28.750219517 -0500
+++ work.git/arch/powerpc/kernel/smp.c	2011-05-20 23:48:30.794220425 -0500
@@ -129,7 +129,7 @@ static irqreturn_t call_function_single_
 	return IRQ_HANDLED;
 }
 
-irqreturn_t debug_ipi_action(int irq, void *data)
+static irqreturn_t debug_ipi_action(int irq, void *data)
 {
 	if (crash_ipi_function_ptr) {
 		crash_ipi_function_ptr(get_irq_regs());
Index: work.git/arch/powerpc/platforms/cell/interrupt.c
===================================================================
--- work.git.orig/arch/powerpc/platforms/cell/interrupt.c	2011-05-20 23:47:28.738222042 -0500
+++ work.git/arch/powerpc/platforms/cell/interrupt.c	2011-05-20 23:48:30.794220425 -0500
@@ -192,50 +192,31 @@ struct irq_host *iic_get_irq_host(int no
 }
 EXPORT_SYMBOL_GPL(iic_get_irq_host);
 
-static irqreturn_t iic_ipi_action(int irq, void *dev_id)
-{
-	int ipi = (int)(long)dev_id;
-
-	switch(ipi) {
-	case PPC_MSG_CALL_FUNCTION:
-		generic_smp_call_function_interrupt();
-		break;
-	case PPC_MSG_RESCHEDULE:
-		scheduler_ipi();
-		break;
-	case PPC_MSG_CALL_FUNC_SINGLE:
-		generic_smp_call_function_single_interrupt();
-		break;
-	case PPC_MSG_DEBUGGER_BREAK:
-		debug_ipi_action(0, NULL);
-		break;
-	}
-	return IRQ_HANDLED;
-}
-static void iic_request_ipi(int ipi, const char *name)
+static void iic_request_ipi(int ipi)
 {
 	int virq;
 
 	virq = irq_create_mapping(iic_host, iic_ipi_to_irq(ipi));
 	if (virq == NO_IRQ) {
 		printk(KERN_ERR
-		       "iic: failed to map IPI %s\n", name);
+		       "iic: failed to map IPI %s\n", smp_ipi_name[ipi]);
 		return;
 	}
-	if (request_irq(virq, iic_ipi_action, IRQF_DISABLED, name,
-			(void *)(long)ipi))
-		printk(KERN_ERR
-		       "iic: failed to request IPI %s\n", name);
+
+	/*
+	 * If smp_request_message_ipi encounters an error it will notify
+	 * the error.  If a message is not needed it will return non-zero.
+	 */
+	if (smp_request_message_ipi(virq, ipi))
+		irq_dispose_mapping(virq);
 }
 
 void iic_request_IPIs(void)
 {
-	iic_request_ipi(PPC_MSG_CALL_FUNCTION, "IPI-call");
-	iic_request_ipi(PPC_MSG_RESCHEDULE, "IPI-resched");
-	iic_request_ipi(PPC_MSG_CALL_FUNC_SINGLE, "IPI-call-single");
-#ifdef CONFIG_DEBUGGER
-	iic_request_ipi(PPC_MSG_DEBUGGER_BREAK, "IPI-debug");
-#endif /* CONFIG_DEBUGGER */
+	iic_request_ipi(PPC_MSG_CALL_FUNCTION);
+	iic_request_ipi(PPC_MSG_RESCHEDULE);
+	iic_request_ipi(PPC_MSG_CALL_FUNC_SINGLE);
+	iic_request_ipi(PPC_MSG_DEBUGGER_BREAK);
 }
 
 #endif /* CONFIG_SMP */