rp2040

commit 2775db91ea25347616694020b2429fb76b9ed27a
parent 0e128d270d951765ee0068d2799915c26c6d6d69
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Sat,  8 Apr 2023 10:24:52 +0900

try to copy and exec from sram.
I need to tell assembler or linker to use base address
of sram: 0x20000000, instead of xip base: 0x10000000

Diffstat:
M
Makefile
 | 
4
++--
A
boot2/boot2_sram.s
 | 
49
+++++++++++++++++++++++++++++++++++++++++++++++++
M
mach.s
 | 
11
+++++++++++

3 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
@@ -27,8 +27,8 @@ start.o: start.s
 boot2_crc.o: boot2/boot2_crc.S
 	$(AS) $(ASFLAGS) -o boot2_crc.o boot2/boot2_crc.S
 
-boot2/boot2_crc.S: boot2/boot2_generic.s bincrc
-	$(AS) $(ASFLAGS) -o boot2/boot2.o boot2/boot2_generic.s
+boot2/boot2_crc.S: boot2/boot2_sram.s bincrc
+	$(AS) $(ASFLAGS) -o boot2/boot2.o boot2/boot2_sram.s
 	$(OBJCOPY) -O binary boot2/boot2.o boot2/boot2.bin
 	./bincrc boot2/boot2.bin boot2/boot2_crc.S
 
diff --git a/boot2/boot2_sram.s b/boot2/boot2_sram.s
@@ -0,0 +1,49 @@
+.cpu cortex-m0plus
+.thumb
+
+.equ XIP_BASE,       0x10000000
+.equ XIP_SSI_BASE,   0x18000000
+.equ SRAM_BASE,      0x20000000
+.equ PPB_BASE,       0xe0000000
+
+boot2:
+	ldr r4, =XIP_SSI_BASE
+
+	// set SSI standard SPI
+	mov r1, #0
+	str r1, [r4, #0x8] // SSI: SSIENR
+	mov r1, #4
+	str r1, [r4, #0x14] // SSI: BAUDR
+	mov r1, #1
+	mov r2, #0xf0
+	str r1, [r4, r2] // SSI: RX_SAMPLE_DLY
+	ldr r1, =((31 << 16) | (3 << 8))
+	str r1, [r4, #0x0] // SSI: CTRLR0
+	mov r1, #0 // NDF = 0
+	str r1, [r4, #0x4] // SSI: CTRLR1
+	ldr r1, =((0x03 << 24) | (2 << 8) | (6 << 2))
+	mov r0, #0xf4
+	str r1, [r4, r0] // SSI: SPI_CTRLR0
+	mov r1, #1
+	str r1, [r4, #0x8] // SSI: SSIENR
+
+	// copy program data from flash to sram
+	ldr r2, =(XIP_BASE + 0x100)
+	ldr r3, =SRAM_BASE
+	ldr r0, =0x1000
+sram_cpy:
+	ldr r1, [r2, #0]
+	str r1, [r3, #0]
+	add r2, r2, #0x4
+	add r3, r3, #0x4
+	sub r0, r0, #0x4
+	bne sram_cpy
+
+	// exit from boot2
+	ldr r0, =(XIP_BASE + 0x100)
+	ldr r1, =(PPB_BASE + 0xed08)
+	str r0, [r1, #0] // M0PLUS: VTOR
+	ldr r1, [r0, #4]
+	ldr r0, [r0, #0]
+	mov sp, r0
+	bx r1
diff --git a/mach.s b/mach.s
@@ -119,6 +119,17 @@ pll_lock:
 	lsl r1, r1, #5
 	str r1, [r0, #0x2c] // UART0_UARTLCR_H
 
+	mov r1, #8
+	ldr r2, =0x20000000
+loop:
+	ldr r0, [r2, #0]
+	bl printh
+	mov r0, #0x0A
+	bl putchar
+	add r2, #4
+	sub r1, #1
+	bne loop
+
 	pop {pc}
 
 unreset: