powerpc/powernv: Move SCOM access code into powernv platform

The powernv platform is the only one that directly accesses SCOMs.
Move the support code to platforms/powernv, and get rid of the
PPC_SCOM Kconfig option, as SCOM support is always selected when
compiling for powernv.

This also means that the Kconfig item for CONFIG_SCOM_DEBUGFS will
show up in menuconfig in the platform menu, rather than at the root,
which is a much better location.
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190509051119.7694-1-ajd@linux.ibm.com

arch/powerpc/platforms/powernv/Kconfig

@@ -12,7 +12,6 @@ config PPC_POWERNV
 	select EPAPR_BOOT
 	select PPC_INDIRECT_PIO
 	select PPC_UDBG_16550
-	select PPC_SCOM
 	select ARCH_RANDOM
 	select CPU_FREQ
 	select PPC_DOORBELL
@@ -47,3 +46,7 @@ config PPC_VAS
 	  VAS adapters are found in POWER9 based systems.
 
 	  If unsure, say N.
+
+config SCOM_DEBUGFS
+	bool "Expose SCOM controllers via debugfs"
+	depends on DEBUG_FS

arch/powerpc/platforms/powernv/Makefile

@@ -4,12 +4,12 @@ obj-y			+= idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
 obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
 obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
+obj-y			+= opal-xscom.o scom.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_PCI)	+= pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o
 obj-$(CONFIG_CXL_BASE)	+= pci-cxl.o
 obj-$(CONFIG_EEH)	+= eeh-powernv.o
-obj-$(CONFIG_PPC_SCOM)	+= opal-xscom.o
 obj-$(CONFIG_MEMORY_FAILURE)	+= opal-memory-errors.o
 obj-$(CONFIG_OPAL_PRD)	+= opal-prd.o
 obj-$(CONFIG_PERF_EVENTS) += opal-imc.o

arch/powerpc/platforms/powernv/opal-xscom.c

@@ -14,7 +14,8 @@
 #include <asm/machdep.h>
 #include <asm/firmware.h>
 #include <asm/opal.h>
-#include <asm/scom.h>
+
+#include "scom.h"
 
 /*
  * We could probably fit that inside the scom_map_t

arch/powerpc/sysdev/scom.c → arch/powerpc/platforms/powernv/scom.c

@@ -10,9 +10,10 @@
 #include <linux/export.h>
 #include <asm/debugfs.h>
 #include <asm/prom.h>
-#include <asm/scom.h>
 #include <linux/uaccess.h>
 
+#include "scom.h"
+
 const struct scom_controller *scom_controller;
 EXPORT_SYMBOL_GPL(scom_controller);
 

arch/powerpc/include/asm/scom.h → arch/powerpc/platforms/powernv/scom.h

@@ -5,12 +5,8 @@
  *     and        David Gibson, IBM Corporation.
  */
 
-#ifndef _ASM_POWERPC_SCOM_H
-#define _ASM_POWERPC_SCOM_H
-
-#ifdef __KERNEL__
-#ifndef __ASSEMBLY__
-#ifdef CONFIG_PPC_SCOM
+#ifndef _SCOM_H
+#define _SCOM_H
 
 /*
  * The SCOM bus is a sideband bus used for accessing various internal
@@ -148,7 +144,4 @@ static inline int scom_write(scom_map_t map, u64 reg, u64 value)
 }
 
 
-#endif /* CONFIG_PPC_SCOM */
-#endif /* __ASSEMBLY__ */
-#endif /* __KERNEL__ */
-#endif /* _ASM_POWERPC_SCOM_H */
+#endif /* _SCOM_H */

arch/powerpc/sysdev/Kconfig

@@ -28,13 +28,6 @@ config PPC_MSI_BITMAP
 source "arch/powerpc/sysdev/xics/Kconfig"
 source "arch/powerpc/sysdev/xive/Kconfig"
 
-config PPC_SCOM
-	bool
-
-config SCOM_DEBUGFS
-	bool "Expose SCOM controllers via debugfs"
-	depends on PPC_SCOM && DEBUG_FS
-
 config GE_FPGA
 	bool
 

arch/powerpc/sysdev/Makefile

@@ -49,8 +49,6 @@ ifdef CONFIG_SUSPEND
 obj-$(CONFIG_PPC_BOOK3S_32)	+= 6xx-suspend.o
 endif
 
-obj-$(CONFIG_PPC_SCOM)		+= scom.o
-
 obj-$(CONFIG_PPC_EARLY_DEBUG_MEMCONS)	+= udbg_memcons.o
 
 obj-$(CONFIG_PPC_XICS)		+= xics/