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 <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/include/asm/smp.h

···
 
 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

···
 	return err;
 }
 
+#ifdef CONFIG_PPC_SMP_MUXED_IPI
 struct cpu_messages {
 	unsigned long messages;		/* current messages bits */
 	unsigned long data;		/* data for cause ipi */
···
 	}
 	return IRQ_HANDLED;
 }
+#endif /* CONFIG_PPC_SMP_MUXED_IPI */
 
 void smp_send_reschedule(int cpu)
 {

arch/powerpc/platforms/Kconfig

···
 	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

···
 config PPC_BOOK3E_64
 	bool "Embedded processors"
 	select PPC_FPU # Make it a choice ?
+	select PPC_SMP_MUXED_IPI
 
 endchoice
 
···
 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

···
 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

···
 	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

···
 	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 */
···
 		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

···
 static u64 timebase;
 static int tb_req;
 
-#ifdef CONFIG_PPC32
+#ifdef CONFIG_PPC_PMAC32_PSURGE
 
 /*
  * Powersurge (old powermac SMP) support.
···
 	.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
···
 		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
···
 			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

···
 config PPC_XICS
        def_bool n
+       select PPC_SMP_MUXED_IPI
 
 config PPC_ICP_NATIVE
        def_bool n