raspberrypi: allow directly specifying the original boot .S file

.. all the necessary steps to transform it into a padded, checksummed
file are now done by the build system.

Since it is assigned by "?=", it _should_ be the case that individual
builds can override it.

I did not "test" this per se, but it gives the same content and checksum
(except for the identifying comment with a path) as #4302.

2 files changed, 19 insertions, 25 deletions

diff --git a/ports/raspberrypi/Makefile b/ports/raspberrypi/Makefile
index f5e65f256..9d66338c7 100644
--- a/ports/raspberrypi/Makefile
+++ b/ports/raspberrypi/Makefile
@@ -231,8 +231,9 @@ SRC_SHARED_MODULE_EXPANDED = $(addprefix shared-bindings/, $(SRC_SHARED_MODULE))
 SRC_COMMON_HAL_SHARED_MODULE_EXPANDED = $(sort $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED))
 
 SRC_S = supervisor/$(CHIP_FAMILY)_cpu.s
-SRC_S_UPPER = bs2_default_padded_checksummed.S \
-              sdk/src/rp2_common/hardware_divider/divider.S \
+BOOT2_S_UPPER ?= sdk/src/rp2_common/boot_stage2/boot2_generic_03h.S
+BOOT2_S_CFLAGS ?= -DPICO_FLASH_SPI_CLKDIV=2
+SRC_S_UPPER = sdk/src/rp2_common/hardware_divider/divider.S \
               sdk/src/rp2_common/hardware_irq/irq_handler_chain.S \
               sdk/src/rp2_common/pico_bit_ops/bit_ops_aeabi.S \
               sdk/src/rp2_common/pico_double/double_aeabi.S \
@@ -253,7 +254,23 @@ endif
 OBJ += $(addprefix $(BUILD)/, $(SRC_S:.s=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_S_UPPER:.S=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_MOD:.c=.o))
+OBJ += $(BUILD)/boot2_padded_checksummed.o
 
+$(BUILD)/boot2_padded_checksummed.o: $(BUILD)/boot2_padded_checksummed.S
+	$(STEPECHO) "CC $<"
+	$(Q)$(CC) $(CFLAGS) -c -o $@ $<
+
+$(BUILD)/boot2_padded_checksummed.S: $(BUILD)/boot2.bin
+	$(STEPECHO) "PAD_CHECKSUM $<"
+	$(Q)$(PYTHON3) sdk/src/rp2_common/boot_stage2/pad_checksum -s 0xffffffff $< $@
+
+$(BUILD)/boot2.bin: $(BUILD)/boot2.elf
+	$(STEPECHO) "OBJCOPY $<"
+	$(Q)$(OBJCOPY) -O binary $< $@
+
+$(BUILD)/boot2.elf: $(BOOT2_S_UPPER) | $(BUILD)/
+	$(STEPECHO) "BOOT $<"
+	$(Q)$(CC) $(CFLAGS) $(BOOT2_S_CFLAGS) -Isdk/src/rp2_common/boot_stage2/asminclude --specs=nosys.specs -nostartfiles -Wl,-T,sdk/src/rp2_common/boot_stage2/boot_stage2.ld -o $@ $<
 
 SRC_QSTR += $(SRC_C) $(SRC_SUPERVISOR) $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED)
 
diff --git a/ports/raspberrypi/bs2_default_padded_checksummed.S b/ports/raspberrypi/bs2_default_padded_checksummed.S
deleted file mode 100644
index 6b7074e3b..000000000
--- a/ports/raspberrypi/bs2_default_padded_checksummed.S
+++ /dev/null
@@ -1,23 +0,0 @@
-// Padded and checksummed version of: /home/pi/pico/pico-examples/build/pico-sdk/src/rp2_common/boot_stage2/bs2_default.bin
-
-.cpu cortex-m0plus
-.thumb
-
-.section .boot2, "ax"
-
-.byte 0x00, 0xb5, 0x32, 0x4b, 0x21, 0x20, 0x58, 0x60, 0x98, 0x68, 0x02, 0x21, 0x88, 0x43, 0x98, 0x60
-.byte 0xd8, 0x60, 0x18, 0x61, 0x58, 0x61, 0x2e, 0x4b, 0x00, 0x21, 0x99, 0x60, 0x02, 0x21, 0x59, 0x61
-.byte 0x01, 0x21, 0xf0, 0x22, 0x99, 0x50, 0x2b, 0x49, 0x19, 0x60, 0x01, 0x21, 0x99, 0x60, 0x35, 0x20
-.byte 0x00, 0xf0, 0x44, 0xf8, 0x02, 0x22, 0x90, 0x42, 0x14, 0xd0, 0x06, 0x21, 0x19, 0x66, 0x00, 0xf0
-.byte 0x34, 0xf8, 0x19, 0x6e, 0x01, 0x21, 0x19, 0x66, 0x00, 0x20, 0x18, 0x66, 0x1a, 0x66, 0x00, 0xf0
-.byte 0x2c, 0xf8, 0x19, 0x6e, 0x19, 0x6e, 0x19, 0x6e, 0x05, 0x20, 0x00, 0xf0, 0x2f, 0xf8, 0x01, 0x21
-.byte 0x08, 0x42, 0xf9, 0xd1, 0x00, 0x21, 0x99, 0x60, 0x1b, 0x49, 0x19, 0x60, 0x00, 0x21, 0x59, 0x60
-.byte 0x1a, 0x49, 0x1b, 0x48, 0x01, 0x60, 0x01, 0x21, 0x99, 0x60, 0xeb, 0x21, 0x19, 0x66, 0xa0, 0x21
-.byte 0x19, 0x66, 0x00, 0xf0, 0x12, 0xf8, 0x00, 0x21, 0x99, 0x60, 0x16, 0x49, 0x14, 0x48, 0x01, 0x60
-.byte 0x01, 0x21, 0x99, 0x60, 0x01, 0xbc, 0x00, 0x28, 0x00, 0xd0, 0x00, 0x47, 0x12, 0x48, 0x13, 0x49
-.byte 0x08, 0x60, 0x03, 0xc8, 0x80, 0xf3, 0x08, 0x88, 0x08, 0x47, 0x03, 0xb5, 0x99, 0x6a, 0x04, 0x20
-.byte 0x01, 0x42, 0xfb, 0xd0, 0x01, 0x20, 0x01, 0x42, 0xf8, 0xd1, 0x03, 0xbd, 0x02, 0xb5, 0x18, 0x66
-.byte 0x18, 0x66, 0xff, 0xf7, 0xf2, 0xff, 0x18, 0x6e, 0x18, 0x6e, 0x02, 0xbd, 0x00, 0x00, 0x02, 0x40
-.byte 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x07, 0x00, 0x00, 0x03, 0x5f, 0x00, 0x21, 0x22, 0x00, 0x00
-.byte 0xf4, 0x00, 0x00, 0x18, 0x22, 0x20, 0x00, 0xa0, 0x00, 0x01, 0x00, 0x10, 0x08, 0xed, 0x00, 0xe0
-.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0xb2, 0x4e, 0x7a