powerpc: Add kconfig for muxed smp ipi support

Compile the new smp ipi mux and demux code only if a platform
will make use of it.  The new config is selected as required.

The new cause_ipi smp op is only available conditionally to point out
configs where the select is required; this makes setting the op an
immediate fail instead of a deferred unresolved symbol at link.

This also creates a new config for power surge powermac upgrade support
that can be disabled in expert mode but is default on.

I also removed the depends / default y on CONFIG_XICS since it is selected
by PSERIES.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/smp.h

@@ -38,7 +38,9 @@ extern void cpu_die(void);
 
 struct smp_ops_t {
 	void  (*message_pass)(int cpu, int msg);
+#ifdef CONFIG_PPC_SMP_MUXED_IPI
 	void  (*cause_ipi)(int cpu, unsigned long data);
+#endif
 	int   (*probe)(void);
 	int   (*kick_cpu)(int nr);
 	void  (*setup_cpu)(int nr);

arch/powerpc/kernel/smp.c

@@ -178,6 +178,7 @@ int smp_request_message_ipi(int virq, int msg)
 	return err;
 }
 
+#ifdef CONFIG_PPC_SMP_MUXED_IPI
 struct cpu_messages {
 	unsigned long messages;		/* current messages bits */
 	unsigned long data;		/* data for cause ipi */
@@ -230,6 +231,7 @@ irqreturn_t smp_ipi_demux(void)
 	}
 	return IRQ_HANDLED;
 }
+#endif /* CONFIG_PPC_SMP_MUXED_IPI */
 
 void smp_send_reschedule(int cpu)
 {

arch/powerpc/platforms/Kconfig

@@ -57,6 +57,14 @@ config UDBG_RTAS_CONSOLE
 	depends on PPC_RTAS
 	default n
 
+config PPC_SMP_MUXED_IPI
+	bool
+	help
+	  Select this opton if your platform supports SMP and your
+	  interrupt controller provides less than 4 interrupts to each
+	  cpu.	This will enable the generic code to multiplex the 4
+	  messages on to one ipi.
+
 config PPC_UDBG_BEAT
 	bool "BEAT based debug console"
 	depends on PPC_CELLEB

arch/powerpc/platforms/Kconfig.cputype

@@ -73,6 +73,7 @@ config PPC_BOOK3S_64
 config PPC_BOOK3E_64
 	bool "Embedded processors"
 	select PPC_FPU # Make it a choice ?
+	select PPC_SMP_MUXED_IPI
 
 endchoice
 
@@ -178,6 +179,7 @@ config FSL_BOOKE
 config PPC_FSL_BOOK3E
 	bool
 	select FSL_EMB_PERFMON
+	select PPC_SMP_MUXED_IPI
 	default y if FSL_BOOKE
 
 config PTE_64BIT

arch/powerpc/platforms/iseries/Kconfig

@@ -1,6 +1,7 @@
 config PPC_ISERIES
 	bool "IBM Legacy iSeries"
 	depends on PPC64 && PPC_BOOK3S
+	select PPC_SMP_MUXED_IPI
 	select PPC_INDIRECT_PIO
 	select PPC_INDIRECT_MMIO
 	select PPC_PCI_CHOICE if EXPERT

arch/powerpc/platforms/powermac/Kconfig

@@ -18,4 +18,13 @@ config PPC_PMAC64
 	select PPC_970_NAP
 	default y
 
-
+config PPC_PMAC32_PSURGE
+	bool "Support for powersurge upgrade cards" if EXPERT
+	depends on SMP && PPC32 && PPC_PMAC
+	select PPC_SMP_MUXED_IPI
+	default y
+	help
+	  The powersurge cpu boards can be used in the generation
+	  of powermacs that have a socket for an upgradeable cpu card,
+	  including the 7500, 8500, 9500, 9600.  Support exists for
+	  both dual and quad socket upgrade cards.

arch/powerpc/platforms/powermac/pic.c

@@ -239,7 +239,7 @@ static unsigned int pmac_pic_get_irq(void)
 	unsigned long bits = 0;
 	unsigned long flags;
 
-#ifdef CONFIG_SMP
+#ifdef CONFIG_PPC_PMAC32_PSURGE
 	void psurge_smp_message_recv(void);
 
        	/* IPI's are a hack on the powersurge -- Cort */
@@ -247,7 +247,7 @@ static unsigned int pmac_pic_get_irq(void)
 		psurge_smp_message_recv();
 		return NO_IRQ_IGNORE;	/* ignore, already handled */
         }
-#endif /* CONFIG_SMP */
+#endif /* CONFIG_PPC_PMAC32_PSURGE */
 	raw_spin_lock_irqsave(&pmac_pic_lock, flags);
 	for (irq = max_real_irqs; (irq -= 32) >= 0; ) {
 		int i = irq >> 5;

arch/powerpc/platforms/powermac/smp.c

@@ -70,7 +70,7 @@ static void (*pmac_tb_freeze)(int freeze);
 static u64 timebase;
 static int tb_req;
 
-#ifdef CONFIG_PPC32
+#ifdef CONFIG_PPC_PMAC32_PSURGE
 
 /*
  * Powersurge (old powermac SMP) support.
@@ -420,7 +420,7 @@ struct smp_ops_t psurge_smp_ops = {
 	.give_timebase	= smp_psurge_give_timebase,
 	.take_timebase	= smp_psurge_take_timebase,
 };
-#endif /* CONFIG_PPC32 - actually powersurge support */
+#endif /* CONFIG_PPC_PMAC32_PSURGE */
 
 /*
  * Core 99 and later support
@@ -980,7 +980,7 @@ void __init pmac_setup_smp(void)
 		of_node_put(np);
 		smp_ops = &core99_smp_ops;
 	}
-#ifdef CONFIG_PPC32
+#ifdef CONFIG_PPC_PMAC32_PSURGE
 	else {
 		/* We have to set bits in cpu_possible_mask here since the
 		 * secondary CPU(s) aren't in the device tree. Various
@@ -993,7 +993,7 @@ void __init pmac_setup_smp(void)
 			set_cpu_possible(cpu, true);
 		smp_ops = &psurge_smp_ops;
 	}
-#endif /* CONFIG_PPC32 */
+#endif /* CONFIG_PPC_PMAC32_PSURGE */
 
 #ifdef CONFIG_HOTPLUG_CPU
 	ppc_md.cpu_die = pmac_cpu_die;

arch/powerpc/sysdev/xics/Kconfig

@@ -1,5 +1,6 @@
 config PPC_XICS
        def_bool n
+       select PPC_SMP_MUXED_IPI
 
 config PPC_ICP_NATIVE
        def_bool n