vfio/platform: Cleanup Kconfig

Like vfio-pci, there's also a base module here where vfio-amba depends on
vfio-platform, when really it only needs vfio-platform-base.  Create a
sub-menu for platform drivers and a nested menu for reset drivers.  Cleanup
Makefile to make use of new CONFIG_VFIO_PLATFORM_BASE for building the
shared modules and traversing reset modules.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20230614193948.477036-3-alex.williamson@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/Makefile

@@ -11,6 +11,6 @@ vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
 obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_PCI_CORE) += pci/
-obj-$(CONFIG_VFIO_PLATFORM) += platform/
+obj-$(CONFIG_VFIO_PLATFORM_BASE) += platform/
 obj-$(CONFIG_VFIO_MDEV) += mdev/
 obj-$(CONFIG_VFIO_FSL_MC) += fsl-mc/

drivers/vfio/platform/Kconfig

@@ -1,25 +1,35 @@
 # SPDX-License-Identifier: GPL-2.0-only
-config VFIO_PLATFORM
-	tristate "VFIO support for platform devices"
+menu "VFIO support for platform devices"
 	depends on ARM || ARM64 || COMPILE_TEST
+
+config VFIO_PLATFORM_BASE
+	tristate
 	select VFIO_VIRQFD
+
+config VFIO_PLATFORM
+	tristate "Generic VFIO support for any platform device"
+	select VFIO_PLATFORM_BASE
 	help
 	  Support for platform devices with VFIO. This is required to make
 	  use of platform devices present on the system using the VFIO
 	  framework.
 
 	  If you don't know what to do here, say N.
 
-if VFIO_PLATFORM
 config VFIO_AMBA
 	tristate "VFIO support for AMBA devices"
 	depends on ARM_AMBA || COMPILE_TEST
+	select VFIO_PLATFORM_BASE
 	help
 	  Support for ARM AMBA devices with VFIO. This is required to make
 	  use of ARM AMBA devices present on the system using the VFIO
 	  framework.
 
 	  If you don't know what to do here, say N.
 
+menu "VFIO platform reset drivers"
+	depends on VFIO_PLATFORM_BASE
+
 source "drivers/vfio/platform/reset/Kconfig"
-endif
+endmenu
+endmenu

drivers/vfio/platform/Makefile

@@ -1,13 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0
 vfio-platform-base-y := vfio_platform_common.o vfio_platform_irq.o
-vfio-platform-y := vfio_platform.o
+obj-$(CONFIG_VFIO_PLATFORM_BASE) += vfio-platform-base.o
+obj-$(CONFIG_VFIO_PLATFORM_BASE) += reset/
 
+vfio-platform-y := vfio_platform.o
 obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
-obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform-base.o
-obj-$(CONFIG_VFIO_PLATFORM) += reset/
 
 vfio-amba-y := vfio_amba.o
-
 obj-$(CONFIG_VFIO_AMBA) += vfio-amba.o
-obj-$(CONFIG_VFIO_AMBA) += vfio-platform-base.o
-obj-$(CONFIG_VFIO_AMBA) += reset/

drivers/vfio/platform/reset/Kconfig

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
+if VFIO_PLATFORM
 config VFIO_PLATFORM_CALXEDAXGMAC_RESET
 	tristate "VFIO support for calxeda xgmac reset"
 	help
@@ -21,3 +22,4 @@ config VFIO_PLATFORM_BCMFLEXRM_RESET
 	  Enables the VFIO platform driver to handle reset for Broadcom FlexRM
 
 	  If you don't know what to do here, say N.
+endif