MIPS: generic: Introduce generic DT-based board support

Introduce a "generic" platform, which aims to be board-agnostic by
making use of device trees passed by the boot protocol defined in the
MIPS UHI (Universal Hosting Interface) specification. Provision is made
for supporting boards which use a legacy boot protocol that can't be
changed, but adding support for such boards or any others is left to
followon patches.

Right now the built kernels expect to be loaded to 0x80100000, ie. in
kseg0. This is fine for the vast majority of MIPS platforms, but
nevertheless it would be good to remove this limitation in the future by
mapping the kernel via the TLB such that it can be loaded anywhere & map
itself appropriately.

Configuration is handled by dynamically generating configs using
scripts/kconfig/merge_config.sh, somewhat similar to the way powerpc
makes use of it. This allows for variations upon the configuration, eg.
differing architecture revisions or subsets of driver support for
differing boards, to be handled without having a large number of
defconfig files.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14353/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 2356439..82b45dc 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -73,6 +73,57 @@ choice
 	prompt "System type"
 	default SGI_IP22
 
+config MIPS_GENERIC
+	bool "Generic board-agnostic MIPS kernel"
+	select BOOT_RAW
+	select BUILTIN_DTB
+	select CEVT_R4K
+	select CLKSRC_MIPS_GIC
+	select COMMON_CLK
+	select CPU_MIPSR2_IRQ_VI
+	select CPU_MIPSR2_IRQ_EI
+	select CSRC_R4K
+	select DMA_PERDEV_COHERENT
+	select HW_HAS_PCI
+	select IRQ_MIPS_CPU
+	select LIBFDT
+	select MIPS_CPU_SCACHE
+	select MIPS_GIC
+	select MIPS_L1_CACHE_SHIFT_7
+	select NO_EXCEPT_FILL
+	select PCI_DRIVERS_GENERIC
+	select PINCTRL
+	select SMP_UP if SMP
+	select SYS_HAS_CPU_MIPS32_R1
+	select SYS_HAS_CPU_MIPS32_R2
+	select SYS_HAS_CPU_MIPS32_R6
+	select SYS_HAS_CPU_MIPS64_R1
+	select SYS_HAS_CPU_MIPS64_R2
+	select SYS_HAS_CPU_MIPS64_R6
+	select SYS_SUPPORTS_32BIT_KERNEL
+	select SYS_SUPPORTS_64BIT_KERNEL
+	select SYS_SUPPORTS_BIG_ENDIAN
+	select SYS_SUPPORTS_HIGHMEM
+	select SYS_SUPPORTS_LITTLE_ENDIAN
+	select SYS_SUPPORTS_MICROMIPS
+	select SYS_SUPPORTS_MIPS_CPS
+	select SYS_SUPPORTS_MIPS16
+	select SYS_SUPPORTS_MULTITHREADING
+	select SYS_SUPPORTS_RELOCATABLE
+	select SYS_SUPPORTS_SMARTMIPS
+	select USB_EHCI_BIG_ENDIAN_DESC if BIG_ENDIAN
+	select USB_EHCI_BIG_ENDIAN_MMIO if BIG_ENDIAN
+	select USB_OHCI_BIG_ENDIAN_DESC if BIG_ENDIAN
+	select USB_OHCI_BIG_ENDIAN_MMIO if BIG_ENDIAN
+	select USB_UHCI_BIG_ENDIAN_DESC if BIG_ENDIAN
+	select USB_UHCI_BIG_ENDIAN_MMIO if BIG_ENDIAN
+	select USE_OF
+	help
+	  Select this to build a kernel which aims to support multiple boards,
+	  generally using a flattened device tree passed from the bootloader
+	  using the boot protocol defined in the UHI (Unified Hosting
+	  Interface) specification.
+
 config MIPS_ALCHEMY
 	bool "Alchemy processor based machines"
 	select ARCH_PHYS_ADDR_T_64BIT
@@ -989,6 +1040,7 @@ source "arch/mips/ath79/Kconfig"
 source "arch/mips/bcm47xx/Kconfig"
 source "arch/mips/bcm63xx/Kconfig"
 source "arch/mips/bmips/Kconfig"
+source "arch/mips/generic/Kconfig"
 source "arch/mips/jazz/Kconfig"
 source "arch/mips/jz4740/Kconfig"
 source "arch/mips/lantiq/Kconfig"