MIPS: generic: Convert SEAD-3 to a generic board

Convert the MIPS SEAD-3 board support to be a generic board, supported
by generic kernels.

Because the SEAD-3 boot protocol was defined long ago and we don't want
to force a switch to the UHI protocol, SEAD-3 is added as a legacy board
which is detected by reading the REVISION register. This may technically
not be a valid memory read & future work will include attempting to
handle that gracefully. In practice since SEAD-3 is the only legacy
board supported by the generic kernel so far the read will only happen
on SEAD-3 boards, and even once Malta is converted the same REVISION
register exists there too. Other boards such as Boston, Ci20 & Ci40 will
use the UHI boot protocol & thus not run any of the legacy board detect
functions.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14354/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Author: paulburton

arch/mips/Kbuild.platforms

@@ -19,7 +19,6 @@ platforms += lasat
 platforms += loongson32
 platforms += loongson64
 platforms += mti-malta
-platforms += mti-sead3
 platforms += netlogic
 platforms += paravirt
 platforms += pic32

arch/mips/Kconfig

@@ -546,41 +546,6 @@ config MACH_PIC32
 	  Microchip PIC32 is a family of general-purpose 32 bit MIPS core
 	  microcontrollers.
 
-config MIPS_SEAD3
-	bool "MIPS SEAD3 board"
-	select BOOT_ELF32
-	select BOOT_RAW
-	select BUILTIN_DTB
-	select CEVT_R4K
-	select CSRC_R4K
-	select CLKSRC_MIPS_GIC
-	select COMMON_CLK
-	select CPU_MIPSR2_IRQ_VI
-	select CPU_MIPSR2_IRQ_EI
-	select DMA_NONCOHERENT
-	select IRQ_MIPS_CPU
-	select MIPS_GIC
-	select LIBFDT
-	select MIPS_MSC
-	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_SUPPORTS_32BIT_KERNEL
-	select SYS_SUPPORTS_64BIT_KERNEL
-	select SYS_SUPPORTS_BIG_ENDIAN
-	select SYS_SUPPORTS_LITTLE_ENDIAN
-	select SYS_SUPPORTS_SMARTMIPS
-	select SYS_SUPPORTS_MICROMIPS
-	select SYS_SUPPORTS_MIPS16
-	select SYS_SUPPORTS_RELOCATABLE
-	select USB_EHCI_BIG_ENDIAN_DESC
-	select USB_EHCI_BIG_ENDIAN_MMIO
-	select USE_OF
-	help
-	  This enables support for the MIPS Technologies SEAD3 evaluation
-	  board.
-
 config NEC_MARKEINS
 	bool "NEC EMMA2RH Mark-eins board"
 	select SOC_EMMA2RH
@@ -2976,7 +2941,7 @@ endchoice
 choice
 	prompt "Kernel command line type" if !CMDLINE_OVERRIDE
 	default MIPS_CMDLINE_FROM_DTB if USE_OF && !ATH79 && !MACH_INGENIC && \
-					 !MIPS_MALTA && !MIPS_SEAD3 && \
+					 !MIPS_MALTA && \
 					 !CAVIUM_OCTEON_SOC
 	default MIPS_CMDLINE_FROM_BOOTLOADER
 

arch/mips/Makefile

@@ -488,3 +488,16 @@ $(generic_defconfigs):
 # Prevent generic merge_config rules attempting to merge single fragments
 #
 $(generic_config_dir)/%.config: ;
+
+#
+# Legacy defconfig compatibility - these targets used to be real defconfigs but
+# now that the boards have been converted to use the generic kernel they are
+# wrappers around the generic rules above.
+#
+.PHONY: sead3_defconfig
+sead3_defconfig:
+	$(Q)$(MAKE) 32r2el_defconfig BOARDS=sead-3
+
+.PHONY: sead3micro_defconfig
+sead3micro_defconfig:
+	$(Q)$(MAKE) micro32r2el_defconfig BOARDS=sead-3

arch/mips/boot/dts/mti/Makefile

@@ -1,5 +1,5 @@
 dtb-$(CONFIG_MIPS_MALTA)	+= malta.dtb
-dtb-$(CONFIG_MIPS_SEAD3)	+= sead3.dtb
+dtb-$(CONFIG_LEGACY_BOARD_SEAD3)	+= sead3.dtb
 
 obj-y				+= $(patsubst %.dtb, %.dtb.o, $(dtb-y))
 

arch/mips/boot/dts/mti/sead3.dts

@@ -10,6 +10,7 @@
 	#address-cells = <1>;
 	#size-cells = <1>;
 	compatible = "mti,sead-3";
+	model = "MIPS SEAD-3";
 	interrupt-parent = <&gic>;
 
 	chosen {

arch/mips/configs/generic/board-sead-3.config

@@ -0,0 +1,32 @@
+CONFIG_LEGACY_BOARD_SEAD3=y
+
+CONFIG_AUXDISPLAY=y
+CONFIG_IMG_ASCII_LCD=y
+
+CONFIG_NEW_LEDS=y
+CONFIG_LEDS_CLASS=y
+CONFIG_LEDS_SYSCON=y
+
+CONFIG_MMC=y
+CONFIG_MMC_SPI=y
+
+CONFIG_MTD=y
+CONFIG_MTD_BLOCK=y
+CONFIG_MTD_CFI=y
+CONFIG_MTD_CFI_INTELEXT=y
+CONFIG_MTD_OF_PARTS=y
+CONFIG_MTD_PHYSMAP=y
+CONFIG_MTD_PHYSMAP_OF=y
+CONFIG_MTD_UBI=y
+CONFIG_MTD_UBI_GLUEBI=y
+
+CONFIG_NETDEVICES=y
+CONFIG_SMSC911X=y
+CONFIG_SMSC_PHY=y
+
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_OF_PLATFORM=y
+
+CONFIG_USB=y
+CONFIG_USB_EHCI_HCD=y

arch/mips/configs/sead3_defconfig

@@ -9,4 +9,11 @@ config LEGACY_BOARDS
 	  kernel is booted without being provided with an FDT via the UHI
 	  boot protocol.
 
+config LEGACY_BOARD_SEAD3
+	bool "Support MIPS SEAD-3 boards"
+	select LEGACY_BOARDS
+	help
+	  Enable this to include support for booting on MIPS SEAD-3 FPGA-based
+	  development boards, which boot using a legacy boot protocol.
+
 endif

arch/mips/configs/sead3micro_defconfig

@@ -11,3 +11,5 @@
 obj-y += init.o
 obj-y += irq.o
 obj-y += proc.o
+
+obj-$(CONFIG_LEGACY_BOARD_SEAD3)	+= board-sead3.o