TRIMUI SMART
如何使用MicroSD製作多重開機模式
參考資訊：
1. Allwinner-V3s-BROM
BROM
;; Vector table ffff0000: ea000008 b reset ; reset ffff0004: ea000006 b unimplemented ; _undefined_instruction ffff0008: ea000005 b unimplemented ; _software_interrupt ffff000c: ea000004 b unimplemented ; _prefetch_abort ffff0010: ea000003 b unimplemented ; _data_abort ffff0014: ea000002 b unimplemented ; _not_used ffff0018: ea000011 b irq ; _irq ffff001c: ea000000 b unimplemented ; _fiq ffff0020: ea000013 b fel_setup ; FEL unimplemented: ffff0024: eafffffe b unimplemented ; loop forever
P.S. fel = 0xffff0020
BROM
boot: ffff2e34: eb000cce bl check_uboot ; check if uboot button is pressed, return value in r0 ffff2e38: e1a04000 mov r4, r0 ; r4 = check_uboot(); ffff2e3c: e3540000 cmp r4, #0 ; see if check_uboot returned 0 ffff2e40: 0a000000 beq .try_boot_MMC0 ; if check_uboot was 0, try to boot from MMC0 ffff2e44: ea000026 b .boot_fel ; else boot FEL mode .try_boot_MMC0: ffff2e48: e3a00000 mov r0, #0 ffff2e4c: ebffffed bl 0xffff2e08 ffff2e50: e3a00000 mov r0, #0 ; r0 = 0x0; (which card_no to boot, 0 = mmc0) ffff2e54: eb000190 bl load_boot0_from_mmc ; load SPL from mmc0 ffff2e58: e1a04000 mov r4, r0 ; r4 = load_from_mmc(); ffff2e5c: e3540000 cmp r4, #0 ; see if load_from_mmc returned 0 ffff2e60: 1a000000 bne .try_boot_eMMC ; if load_from_mmc returned 0 try to boot from eMMc on MMC2 ffff2e64: ea000021 b .boot_spl ; else skip to .boot_spl .try_boot_eMMC: ffff2e68: e3a00001 mov r0, #1 ffff2e6c: ebffffe5 bl 0xffff2e08 ffff2e70: e3a00002 mov r0, #2 ; r0 = 0x2; (which card_no to boot, 2 = mmc2) ffff2e74: eb0001b0 bl 0xffff353c ; load SPL from eMMC ffff2e78: e1a04000 mov r4, r0 ; r4 = load_from_emmc(); ffff2e7c: e3540000 cmp r4, #0 ; see if load_from_emmc returned 0 ffff2e80: 1a000000 bne .try_boot_MMC2 ; if load_from_emmc returned 0 try to boot from MMC2 ffff2e84: ea000019 b .boot_spl ; else skip to .boot_spl .try_boot_MMC2: ffff2e88: e3a00002 mov r0, #2 ; r0 = 0x2; (which card_no to boot, 2 = mmc2) ffff2e8c: eb000182 bl load_boot0_from_mmc ; load SPL from mmc2 ffff2e90: e1a04000 mov r4, r0 ; r4 = load_from_mmc(); ffff2e94: e3540000 cmp r4, #0 ; see if load_from_mmc returned 0 ffff2e98: 1a000000 bne .try_boot_SPINOR; if load_from_mmc returned 0 try to boot from SPI NAND-flash ffff2e9c: ea000013 b .boot_spl .try_boot_SPINOR: ffff2ea0: e3a00002 mov r0, #2 ffff2ea4: ebffffd7 bl 0xffff2e08 ffff2ea8: eb000c2b bl load_boot0_from_spinor ; load SPL from SPI NOR-flash ffff2eac: e1a04000 mov r4, r0 ; r4 = load_from_spinor(); ffff2eb0: e3540000 cmp r4, #0 ; see if load_from_spinor returned 0 ffff2eb4: 1a000000 bne .try_boot_from_SPINAND ; if load_from_spinor returned 0 try to boot from SPI NOR-flash ffff2eb8: ea00000c b .boot_spl ; else skip to .boot_spl .try_boot_SPINAND: ffff2ebc: e3a00003 mov r0, #3 ffff2ec0: ebffffd0 bl 0xffff2e08 ffff2ec4: eb0000d7 bl load_boot0_from_spinand ; load SPL from SPI NAND-flash ffff2ec8: e1a04000 mov r4, r0 ; r4 = load_from_spinand(); ffff2ecc: e3540000 cmp r4, #0 ; see if load_from_spinand returned 0 ffff2ed0: 1a000000 bne .none_found ; if load_from_spinand returned 0 boot from FEL mode (via .none_found) ffff2ed4: ea000005 b .boot_spl ; else skip to .boot_spl
P.S. mmc2 = 0xffff2e88
main.s
.global _start
.equ GPIO_BASE, 0x01c20800
.equ PE_CFG1, (GPIO_BASE + (0x24 * 4) + 0x04)
.equ PE_PULL0, (GPIO_BASE + (0x24 * 4) + 0x1c)
.equ PE_DATA, (GPIO_BASE + (0x24 * 4) + 0x10)
.arm
.text
_start:
.long 0xea000016
.byte 'e', 'G', 'O', 'N', '.', 'B', 'T', '0'
.long 0, __spl_size
.byte 'S', 'P', 'L', 2
.long 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
.long 0, 0, 0, 0, 0, 0, 0, 0
_vector:
b reset
b .
b .
b .
b .
b .
b .
b .
reset:
ldr r0, =PE_CFG1
ldr r1, =0x00000000
str r1, [r0]
ldr r0, =PE_PULL0
ldr r1, =0x55555555
str r1, [r0]
0:
ldr r0, =PE_DATA
ldr r1, [r0]
tst r1, #(1 << 12)
beq fel
b 0xffff2e88
fel:
b 0xffff0020
.end
編譯並燒錄到MicroSD後，插入開機，預設從eMMC2(官方系統)執行，如果按下SELECT按鍵開機，則進入fel模式