| /* |
| * Copyright (c) 2020 Raspberry Pi (Trading) Ltd. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| #include "pico/asm_helper.S" |
| |
| // Stub second stage which calls into USB bootcode, with parameters. |
| // USB boot takes two parameters: |
| // - A GPIO mask for activity LED -- if mask is 0, don't touch GPIOs at all |
| // - A mask of interfaces to disable. Bit 0 disables MSC, bit 1 disables PICOBoot |
| // The bootrom passes 0 for both of these parameters, but user code (or this |
| // second stage) can pass anything. |
| |
| #define USB_BOOT_MSD_AND_PICOBOOT 0x0 |
| #define USB_BOOT_MSD_ONLY 0x2 |
| #define USB_BOOT_PICOBOOT_ONLY 0x1 |
| |
| // Config |
| #define ACTIVITY_LED 0 |
| #define BOOT_MODE USB_BOOT_MSD_AND_PICOBOOT |
| |
| pico_default_asm_setup |
| |
| .section .text |
| |
| // On RP2350 boot stage2 is always called as a regular function, and should return normally |
| regular_func _stage2_boot |
| movs r7, #0x14 // Pointer to _well_known pointer table in ROM |
| ldrh r0, [r7, #0] // Offset 0 is 16 bit pointer to function table |
| ldrh r7, [r7, #4] // Offset 4 is 16 bit pointer to table lookup routine |
| ldr r1, =('U' | ('B' << 8)) // Symbol for USB Boot |
| blx r7 |
| cmp r0, #0 |
| beq dead |
| |
| mov r7, r0 |
| ldr r0, =(1u << ACTIVITY_LED) // Mask of which GPIO (or GPIOs) to use |
| movs r1, #BOOT_MODE |
| blx r7 |
| |
| dead: |
| wfi |
| b dead |
| |
| .global literals |
| literals: |
| .ltorg |
| |
| .end |
