ARM: rmobile: Add recovery SPL for R-Car Gen3

Build an SPL which can be started via SCIF download mode on R-Car Gen3
and allows loading and executing U-Boot uImage with the next stage code.
This is also useful for starting e.g. ATF BL2, which inits the hardware
and returns to the U-Boot SPL, which can then load e.g. U-Boot proper.

The H3, M3-W, M3-N SoCs have plenty of SRAM for storing the U-Boot SPL
while the payload, e.g. ATF BL2, executes, so there is no problem here.

However, E3 and D3 have much less SRAM, hence the loader uses a trick
where it copies itself beyond the area used by BL2 and executes from
there. That area is 32kiB large and not enough to hold U-Boot SPL, BSS,
stack and malloc area, so the later two are placed at +0x4000 offset
from start of SRAM, another area not used by ATF BL2. To make things
even more complicated, the SCIF loader cannot load to the upper 32kiB
of the SRAM directly, hence the copying approach.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

2 files changed, 84 insertions, 0 deletions

diff --git a/arch/arm/mach-rmobile/Kconfig b/arch/arm/mach-rmobile/Kconfig
index a74f16d348..aafeb355ef 100644
--- a/arch/arm/mach-rmobile/Kconfig
+++ b/arch/arm/mach-rmobile/Kconfig
@@ -16,11 +16,22 @@ config RCAR_GEN3
 	select PINCTRL
 	select PINCONF
 	select PINCTRL_PFC
+	select SUPPORT_SPL
 	imply CMD_FS_UUID
 	imply CMD_GPT
 	imply CMD_UUID
 	imply CMD_MMC_SWRITE if MMC
 	imply SUPPORT_EMMC_RPMB if MMC
+	imply SPL
+	imply SPL_BOARD_INIT
+	imply SPL_GZIP
+	imply SPL_LIBCOMMON_SUPPORT
+	imply SPL_LIBGENERIC_SUPPORT
+	imply SPL_SERIAL_SUPPORT
+	imply SPL_SYS_MALLOC_SIMPLE
+	imply SPL_TINY_MEMSET
+	imply SPL_YMODEM_SUPPORT
+	imply USE_TINY_PRINTF
 
 config RZA1
 	prompt "Renesas ARM SoCs RZ/A1 (32bit)"
diff --git a/arch/arm/mach-rmobile/Makefile b/arch/arm/mach-rmobile/Makefile
index 1f26adaca9..a3fdcc3bc0 100644
--- a/arch/arm/mach-rmobile/Makefile
+++ b/arch/arm/mach-rmobile/Makefile
@@ -13,3 +13,76 @@ obj-$(CONFIG_SH73A0) += lowlevel_init.o cpu_info-sh73a0.o pfc-sh73a0.o
 obj-$(CONFIG_R8A7740) += lowlevel_init.o cpu_info-r8a7740.o pfc-r8a7740.o
 obj-$(CONFIG_RCAR_GEN2) += lowlevel_init_ca15.o cpu_info-rcar.o
 obj-$(CONFIG_RCAR_GEN3) += lowlevel_init_gen3.o cpu_info-rcar.o memmap-gen3.o
+
+OBJCOPYFLAGS_u-boot-spl.srec := -O srec
+quiet_cmd_objcopy = OBJCOPY $@
+cmd_objcopy = $(OBJCOPY) --gap-fill=0x00 $(OBJCOPYFLAGS) \
+	$(OBJCOPYFLAGS_$(@F)) $< $@
+
+spl/u-boot-spl.srec: spl/u-boot-spl FORCE
+	$(call if_changed,objcopy)
+
+ifneq ($(CONFIG_R8A77990)$(CONFIG_R8A77995),)
+#
+# The first 6 generate statements generate the R-Car Gen3 SCIF loader header.
+# The subsequent generate statements represent the following chunk of assembler
+# code, which copies the loaded data from 0xe6304030 to 0xe6318000. This is to
+# work around a limitation of the D3/E3 BootROM, which does not permit loading
+# to 0xe6318000 directly.
+#
+#	mov	x0,	#0xe6000000
+#	orr	x0, x0,	#0x00300000
+#	orr	x1, x0,	#0x00004000
+#	orr	x1, x1,	#0x00000030
+#
+#	orr	x2, x0,	#0x00018000
+#	mov	x0, x2
+#	mov	x3,	#0x7000
+#1:	ldp	x4, x5, [x1], #16
+#
+#	stp	x4, x5, [x2], #16
+#	subs	x3, x3, #16
+#	b.ge	1b
+#	br	x0
+#
+quiet_cmd_srec_cat = SRECCAT $@
+      cmd_srec_cat = srec_cat -output $@ -M 8 $< -M 8 \
+			-offset -0x13fd0 \
+			-Output_Block_Size 16 \
+			-generate 0xe6300400 0xe6300404 -l-e-constant 0x0 4 \
+			-generate 0xe630048c 0xe6300490 -l-e-constant 0x0 4 \
+			-generate 0xe63005d4 0xe63005d8 -l-e-constant 0xe6304000 4 \
+			-generate 0xe63006e4 0xe63006e8 -l-e-constant $2 4 \
+			-generate 0xe6301154 0xe6301158 -l-e-constant 0xe6304000 4 \
+			-generate 0xe6301264 0xe6301268 -l-e-constant $2 4 \
+			-generate 0xe6304000 0xe6304004 -l-e-constant 0xd2bcc000 4 \
+			-generate 0xe6304004 0xe6304008 -l-e-constant 0xb26c0400 4 \
+			-generate 0xe6304008 0xe630400c -l-e-constant 0xb2720001 4 \
+			-generate 0xe630400c 0xe6304010 -l-e-constant 0xb27c0421 4 \
+			-generate 0xe6304010 0xe6304014 -l-e-constant 0xb2710402 4 \
+			-generate 0xe6304014 0xe6304018 -l-e-constant 0xaa0203e0 4 \
+			-generate 0xe6304018 0xe630401c -l-e-constant 0xd28e0003 4 \
+			-generate 0xe630401c 0xe6304020 -l-e-constant 0xa8c11424 4 \
+			-generate 0xe6304020 0xe6304024 -l-e-constant 0xa8811444 4 \
+			-generate 0xe6304024 0xe6304028 -l-e-constant 0xf1004063 4 \
+			-generate 0xe6304028 0xe630402c -l-e-constant 0x54ffffaa 4 \
+			-generate 0xe630402c 0xe6304030 -l-e-constant 0xd61f0000 4
+else
+quiet_cmd_srec_cat = SRECCAT $@
+      cmd_srec_cat = srec_cat -output $@ -M 8 $< -M 8 \
+			-Output_Block_Size 16 \
+			-generate 0xe6300400 0xe6300404 -l-e-constant 0x0 4 \
+			-generate 0xe630048c 0xe6300490 -l-e-constant 0x0 4 \
+			-generate 0xe63005d4 0xe63005d8 -l-e-constant $(CONFIG_SPL_TEXT_BASE) 4 \
+			-generate 0xe63006e4 0xe63006e8 -l-e-constant $2 4 \
+			-generate 0xe6301154 0xe6301158 -l-e-constant $(CONFIG_SPL_TEXT_BASE) 4 \
+			-generate 0xe6301264 0xe6301268 -l-e-constant $2 4
+endif
+
+spl/u-boot-spl.scif: spl/u-boot-spl.srec spl/u-boot-spl.bin
+	$(call cmd,srec_cat,$(shell wc -c spl/u-boot-spl.bin | awk '{printf("0x%08x\n",$$1)}'))
+
+# if srec_cat is present build u-boot-spl.scif by default
+has_srec_cat = $(call try-run,srec_cat -VERSion,y,n)
+ALL-$(has_srec_cat) += u-boot-spl.scif
+CLEAN_FILES += u-boot-spl.scif