153 lines
11 KiB
C
153 lines
11 KiB
C
/* Copyright (c) 2013 Nordic Semiconductor. All Rights Reserved.
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*
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* The information contained herein is property of Nordic Semiconductor ASA.
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* Terms and conditions of usage are described in detail in NORDIC
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* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
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*
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* Licensees are granted free, non-transferable use of the information. NO
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* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
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* the file.
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*
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*/
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#include "bootloader_util.h"
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#include <stdint.h>
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#include <string.h>
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/**
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* @brief Function for aborting current application/bootloader jump to to other app/bootloader.
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*
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* @details This functions will use the address provide to swap the stack pointer and then load
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* the address of the reset handler to be executed. It will check current system mode
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* (thread/handler) and if in thread mode it will reset into other application.
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* If in handler mode \ref isr_abort will be executed to ensure correct exit of handler
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* mode and jump into reset handler of other application.
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*
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* @param[in] start_addr Start address of other application. This address must point to the
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initial stack pointer of the application.
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*
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* @note This function will never return but issue a reset into provided application.
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*/
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#if defined ( __CC_ARM )
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__asm static void bootloader_util_reset(uint32_t start_addr)
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{
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LDR R5, [R0] ; Get App initial MSP for bootloader.
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MSR MSP, R5 ; Set the main stack pointer to the applications MSP.
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LDR R0, [R0, #0x04] ; Load Reset handler into R0. This will be first argument to branch instruction (BX).
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MOVS R4, #0xFF ; Load ones to R4.
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SXTB R4, R4 ; Sign extend R4 to obtain 0xFFFFFFFF instead of 0xFF.
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MRS R5, IPSR ; Load IPSR to R5 to check for handler or thread mode.
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CMP R5, #0x00 ; Compare, if 0 then we are in thread mode and can continue to reset handler of bootloader.
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BNE isr_abort ; If not zero we need to exit current ISR and jump to reset handler of bootloader.
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MOV LR, R4 ; Clear the link register and set to ones to ensure no return, R4 = 0xFFFFFFFF.
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BX R0 ; Branch to reset handler of bootloader.
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isr_abort
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; R4 contains ones from line above. Will be popped as R12 when exiting ISR (Cleaning up the registers).
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MOV R5, R4 ; Fill with ones before jumping to reset handling. We be popped as LR when exiting ISR. Ensures no return to application.
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MOV R6, R0 ; Move address of reset handler to R6. Will be popped as PC when exiting ISR. Ensures the reset handler will be executed when exist ISR.
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MOVS r7, #0x21 ; Move MSB reset value of xPSR to R7. Will be popped as xPSR when exiting ISR. xPSR is 0x21000000 thus MSB is 0x21.
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REV r7, r7 ; Reverse byte order to put 0x21 as MSB.
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PUSH {r4-r7} ; Push everything to new stack to allow interrupt handler to fetch it on exiting the ISR.
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MOVS R4, #0x00 ; Fill with zeros before jumping to reset handling. We be popped as R0 when exiting ISR (Cleaning up of the registers).
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MOVS R5, #0x00 ; Fill with zeros before jumping to reset handling. We be popped as R1 when exiting ISR (Cleaning up of the registers).
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MOVS R6, #0x00 ; Fill with zeros before jumping to reset handling. We be popped as R2 when exiting ISR (Cleaning up of the registers).
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MOVS R7, #0x00 ; Fill with zeros before jumping to reset handling. We be popped as R3 when exiting ISR (Cleaning up of the registers).
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PUSH {r4-r7} ; Push zeros (R4-R7) to stack to prepare for exiting the interrupt routine.
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MOVS R0, #0xF9 ; Move the execution return command into register, 0xFFFFFFF9.
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SXTB R0, R0 ; Sign extend R0 to obtain 0xFFFFFFF9 instead of 0xF9.
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BX R0 ; No return - Handler mode will be exited. Stack will be popped and execution will continue in reset handler initializing other application.
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ALIGN
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}
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#elif defined ( __GNUC__ )
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static inline void bootloader_util_reset(uint32_t start_addr)
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{
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__asm volatile(
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"ldr r0, [%0]\t\n" // Get App initial MSP for bootloader.
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"msr msp, r0\t\n" // Set the main stack pointer to the applications MSP.
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"ldr r0, [%0, #0x04]\t\n" // Load Reset handler into R0.
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"movs r4, #0xFF\t\n" // Move ones to R4.
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"sxtb r4, r4\t\n" // Sign extend R4 to obtain 0xFFFFFFFF instead of 0xFF.
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"mrs r5, IPSR\t\n" // Load IPSR to R5 to check for handler or thread mode.
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"cmp r5, #0x00\t\n" // Compare, if 0 then we are in thread mode and can continue to reset handler of bootloader.
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"bne isr_abort\t\n" // If not zero we need to exit current ISR and jump to reset handler of bootloader.
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"mov lr, r4\t\n" // Clear the link register and set to ones to ensure no return.
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"bx r0\t\n" // Branch to reset handler of bootloader.
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"isr_abort: \t\n"
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"mov r5, r4\t\n" // Fill with ones before jumping to reset handling. Will be popped as LR when exiting ISR. Ensures no return to application.
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"mov r6, r0\t\n" // Move address of reset handler to R6. Will be popped as PC when exiting ISR. Ensures the reset handler will be executed when exist ISR.
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"movs r7, #0x21\t\n" // Move MSB reset value of xPSR to R7. Will be popped as xPSR when exiting ISR. xPSR is 0x21000000 thus MSB is 0x21.
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"rev r7, r7\t\n" // Reverse byte order to put 0x21 as MSB.
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"push {r4-r7}\t\n" // Push everything to new stack to allow interrupt handler to fetch it on exiting the ISR.
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"movs r4, #0x00\t\n" // Fill with zeros before jumping to reset handling. We be popped as R0 when exiting ISR (Cleaning up of the registers).
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"movs r5, #0x00\t\n" // Fill with zeros before jumping to reset handling. We be popped as R1 when exiting ISR (Cleaning up of the registers).
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"movs r6, #0x00\t\n" // Fill with zeros before jumping to reset handling. We be popped as R2 when exiting ISR (Cleaning up of the registers).
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"movs r7, #0x00\t\n" // Fill with zeros before jumping to reset handling. We be popped as R3 when exiting ISR (Cleaning up of the registers).
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"push {r4-r7}\t\n" // Push zeros (R4-R7) to stack to prepare for exiting the interrupt routine.
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"movs r0, #0xF9\t\n" // Move the execution return command into register, 0xFFFFFFF9.
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"sxtb r0, r0\t\n" // Sign extend R0 to obtain 0xFFFFFFF9 instead of 0xF9.
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"bx r0\t\n" // No return - Handler mode will be exited. Stack will be popped and execution will continue in reset handler initializing other application.
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".align\t\n"
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:: "r" (start_addr) // Argument list for the gcc assembly. start_addr is %0.
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: "r0", "r4", "r5", "r6", "r7" // List of register maintained manually.
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);
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}
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#elif defined ( __ICCARM__ )
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static inline void bootloader_util_reset(uint32_t start_addr)
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{
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asm("ldr r5, [%0]\n" // Get App initial MSP for bootloader.
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"msr msp, r5\n" // Set the main stack pointer to the applications MSP.
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"ldr r0, [%0, #0x04]\n" // Load Reset handler into R0.
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"movs r4, #0x00\n" // Load zero into R4.
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"mvns r4, r4\n" // Invert R4 to ensure it contain ones.
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"mrs r5, IPSR\n" // Load IPSR to R5 to check for handler or thread mode
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"cmp r5, #0x00\n" // Compare, if 0 then we are in thread mode and can continue to reset handler of bootloader.
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"bne.n isr_abort\n" // If not zero we need to exit current ISR and jump to reset handler of bootloader.
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"mov lr, r4\n" // Clear the link register and set to ones to ensure no return.
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"bx r0\n" // Branch to reset handler of bootloader.
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"isr_abort: \n"
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// R4 contains ones from line above. We be popped as R12 when exiting ISR (Cleaning up the registers).
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"mov r5, r4\n" // Fill with ones before jumping to reset handling. Will be popped as LR when exiting ISR. Ensures no return to application.
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"mov r6, r0\n" // Move address of reset handler to R6. Will be popped as PC when exiting ISR. Ensures the reset handler will be executed when exist ISR.
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"movs r7, #0x21\n" // Move MSB reset value of xPSR to R7. Will be popped as xPSR when exiting ISR. xPSR is 0x21000000 thus MSB is 0x21.
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"rev r7, r7\n" // Reverse byte order to put 0x21 as MSB.
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"push {r4-r7}\n" // Push everything to new stack to allow interrupt handler to fetch it on exiting the ISR.
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"movs r4, #0x00\n" // Fill with zeros before jumping to reset handling. We be popped as R0 when exiting ISR (Cleaning up of the registers).
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"movs r5, #0x00\n" // Fill with zeros before jumping to reset handling. We be popped as R1 when exiting ISR (Cleaning up of the registers).
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"movs r6, #0x00\n" // Fill with zeros before jumping to reset handling. We be popped as R2 when exiting ISR (Cleaning up of the registers).
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"movs r7, #0x00\n" // Fill with zeros before jumping to reset handling. We be popped as R3 when exiting ISR (Cleaning up of the registers).
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"push {r4-r7}\n" // Push zeros (R4-R7) to stack to prepare for exiting the interrupt routine.
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"movs r0, #0x06\n" // Load 0x06 into R6 to prepare for exec return command.
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"mvns r0, r0\n" // Invert 0x06 to obtain EXEC_RETURN, 0xFFFFFFF9.
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"bx r0\n" // No return - Handler mode will be exited. Stack will be popped and execution will continue in reset handler initializing other application.
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:: "r" (start_addr) // Argument list for the IAR assembly. start_addr is %0.
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: "r0", "r4", "r5", "r6", "r7"); // List of register maintained manually.
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}
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#else
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#error Compiler not supported.
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#endif
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void bootloader_util_app_start(uint32_t start_addr)
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{
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bootloader_util_reset(start_addr);
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}
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