由裸机思维公众号博主开发的专为树莓派Pico提供MDK开发体验的 Pico-Template，为广大单片机爱好者重新拉回了MDK开发的舒适区。
但是，正如博主文章中提到的美中不足之处，需要纯手工下载程序，所以就有了这么一个制作flash下载算法的机会，来实现flash的自动下载功能。
通过MDK创建一批与地址信息无关的函数，实现的功能主要有初始化，擦除，编程，读取，校验等，然后MDK调试下载阶段，会将算法文件加载到芯片的内部RAM里面（加载地址可以通过MDK设置），然后MDK通过与这个算法文件的交互，实现程序下载，调试阶段数据读取等操作。
擦除操作大致流程：
编程操作大致流程：
校验操作大致流程：
mkdir pico-mdk
cd pico-mdk
git clone https://github.com/GorgonMeducer/Pico_Template .
git submodule update --init
从:CMSIS Pack文件夹（通常是C:\Keil\ARM\Pack\ARM\CMSIS\ version \Device_Template_Flash）中的工程复制出FlashDev.c、FlashOS.h、FlashPrg.c三个文件到工程目录中。
修改工程文件如下，只保留如下几个文件：
这个名字是方便用户查看的，由于本次制作的下载算法是针对树莓派pico这款开发板的，所以名字就叫做Raspberry_Pi_Pico
/* -----------------------------------------------------------------------------
* Copyright (c) 2014 ARM Ltd.
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from
* the use of this software. Permission is granted to anyone to use this
* software for any purpose, including commercial applications, and to alter
* it and redistribute it freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software in
* a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any source distribution.
*
*
* $Date: 15. April 2014
* $Revision: V1.00
*
* Project: Flash Programming Functions for ST Microelectronics STM32F10x Flash
* --------------------------------------------------------------------------- */
/* History:
* Version 1.00
* Initial release
*/
#include "FlashOS.H" // FlashOS Structures
#include "hardware/flash.h"
#include "hardware/resets.h"
#include "hardware/structs/sio.h"
#include "hardware/regs/tbman.h"
#define BOOT2_SIZE_BYTES 256
unsigned long base_adr = 0x10000000;
bool running_on_fpga() {
return !!((*(io_ro_32 *)TBMAN_BASE) & TBMAN_PLATFORM_FPGA_BITS);
}
/*
* Initialize Flash Programming Functions
* Parameter: adr: Device Base Address
* clk: Clock Frequency (Hz)
* fnc: Function Code (1 - Erase, 2 - Program, 3 - Verify)
* Return Value: 0 - OK, 1 - Failed
*/
#ifdef FLASH_MEM
__attribute__((used))
int Init (unsigned long adr, unsigned long clk, unsigned long fnc) {
uint32_t count = 1000;
// Reset all peripherals to put system into a known state,
// - except for QSPI pads and the XIP IO bank, as this is fatal if running from flash
// - and the PLLs, as this is fatal if clock muxing has not been reset on this boot
// - and USB, syscfg, as this disturbs USB-to-SWD on core 1
reset_block(~(
RESETS_RESET_IO_QSPI_BITS |
RESETS_RESET_PADS_QSPI_BITS |
RESETS_RESET_PLL_USB_BITS |
RESETS_RESET_USBCTRL_BITS |
RESETS_RESET_SYSCFG_BITS |
RESETS_RESET_PLL_SYS_BITS |
RESETS_RESET_TIMER_BITS
));
// Workaround for behaviour of TXB0108 bidirectional level shifters on
// FPGA platform (JIRA PRJMU-726), not used on ASIC
if (running_on_fpga()) {
*(io_rw_32 *) (IO_QSPI_BASE + 0xc) = 5; // GPIO_FUNC_PROC
sio_hw->gpio_hi_out = 1u << 1; // Level high on CS pin
sio_hw->gpio_hi_oe = 1u << 1; // Output enable
sio_hw->gpio_hi_oe = 0; // Output disable
}
// Check CSn strap: delay for pullups to charge trace, then take a majority vote.
while(count--);
uint32_t sum = 0;
for (int i = 0; i < 9; ++i) {
count = 100;
while(count--);
sum += (sio_hw->gpio_hi_in >> 1) & 1u;
}
return (0);
}
#endif
/*
* De-Initialize Flash Programming Functions
* Parameter: fnc: Function Code (1 - Erase, 2 - Program, 3 - Verify)
* Return Value: 0 - OK, 1 - Failed
*/
#ifdef FLASH_MEM
__attribute__((used))
int UnInit (unsigned long fnc) {
return (0);
}
#endif
/*
* Erase complete Flash Memory
* Return Value: 0 - OK, 1 - Failed
*/
#ifdef FLASH_MEM
__attribute__((used))
int EraseChip (void) {
flash_range_erase(0,0x00200000);
return (0); // Done
}
#endif
/*
* Erase Sector in Flash Memory
* Parameter: adr: Sector Address
* Return Value: 0 - OK, 1 - Failed
*/
#ifdef FLASH_MEM
__attribute__((used))
int EraseSector (unsigned long adr) {
flash_range_erase(adr - base_adr,4096);
return (0); // Done
}
#endif
#ifdef FLASH_MEM
static const uint32_t crc32_table_0x04c11db7[] = {
0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
};
static uint32_t crc32_calculator (uint8_t *pbuf, uint_fast32_t size, uint32_t init)
{
uint32_t crc_result = init;
assert(NULL != pbuf);
assert(size > 0);
do {
crc_result = (crc_result << 8) ^
crc32_table_0x04c11db7[((crc_result >> 24) ^ (*pbuf)) & 0xFF];
pbuf++;
} while(--size);
return crc_result;
}
#endif
/*
* Program Page in Flash Memory
* Parameter: adr: Page Start Address
* sz: Page Size
* buf: Page Data
* Return Value: 0 - OK, 1 - Failed
*/
#ifdef FLASH_MEM
__attribute__((used))
int ProgramPage (unsigned long adr, unsigned long sz, unsigned char *buf) {
if(adr == base_adr){
uint32_t crc = crc32_calculator(buf, BOOT2_SIZE_BYTES - 4, 0xFFFFFFFF);
(*(uint32_t *)&(buf[BOOT2_SIZE_BYTES - 4])) = crc;
}
flash_range_program(adr - base_adr,buf,sz);
return (0); // Done
}
#endif
#ifdef FLASH_MEM
__attribute__((used))
unsigned long Verify (unsigned long adr, unsigned long sz, unsigned char *buf){
if (0 == sz) {
return adr;
}
if(adr == base_adr){
do {
if ( *(char*)adr++ != *((char*)buf++)){
if((adr - base_adr) == (256)){
continue;
}
if((adr - base_adr) == (255)){
continue;
}
if((adr - base_adr) == (254)){
continue;
}
if((adr - base_adr) == (253)){
continue;
}
return (adr-1);
}
} while(--sz);
return adr;
}
do {
if ( *(char*)adr != *((char*)buf++))
return (adr);
adr++;
} while(--sz);
return adr;
}
#endif
注：
/* -----------------------------------------------------------------------------
* Copyright (c) 2014 ARM Ltd.
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from
* the use of this software. Permission is granted to anyone to use this
* software for any purpose, including commercial applications, and to alter
* it and redistribute it freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software in
* a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any source distribution.
*
*
* $Date: 15. April 2014
* $Revision: V1.00
*
* Project: Flash Device Description for ST STM32F10x Flash
* --------------------------------------------------------------------------- */
/* History:
* Version 1.00
* Initial release
*/
#include "FlashOS.H" // FlashOS Structures
__attribute__((used))
struct FlashDevice const FlashDevice = {
FLASH_DRV_VERS, // Driver Version, do not modify!
"Raspberry Pi Pico Flash", // Device Name (2M)
ONCHIP, // Device Type
0x10000000, // Device Start Address
0x00200000, // Device Size in Bytes
0x1000, // Programming Page Size
0, // Reserved, must be 0
0xFF, // Initial Content of Erased Memory
100, // Program Page Timeout 100 mSec
500, // Erase Sector Timeout 500 mSec
// Specify Size and Address of Sectors
0x1000, 0x000000, // Sector Size 4kB
SECTOR_END
};
C和汇编的配置都勾选上：
ROPI地址无关实现
如果程序的所有只读段都与位置无关，则该程序为只读位置无关（ROPI, Read-only position independence）。ROPI段通常是位置无关代码（PIC,position-independent code），但可以是只读数据，也可以是PIC和只读数据的组合。选择“ ROPI”选项，可以避免用户不得不将代码加载到内存中的特定位置。这对于以下例程特别有用：
（1）加载以响应运行事件。
（2）在不同情况下使用其他例程的不同组合加载到内存中。
（3）在执行期间映射到不同的地址。
RWPI数据无关实现
使用Read-Write position independence同理，表示的可读可写数据段。
使用RWPI编译代码，解决RW段即全局变量的加载。首先编译的时候会为每一个全局变量生成一个相对于r9寄存器的偏移量，这个偏移量会在.text段中。
在加载elf阶段，将RW段加载到RAM当中之后，需要将r9寄存器指向此片内存的基地址，然后接下来就可以跳转到加载的elf的代码中去执行，就可以实现全局变量的加载了。这也就是利用MDK的FLM文件生成通用flash驱动中提到的需要在编译选项中添加-ffixed-r9的原因。
axf2uf2.bat是一个将FLM文件自动部署到MDK安装目录的一个脚本文件。
–diag_suppress L6305用于屏蔽没有入口地址的警告信息。
分散加载文件中的内容如下：
; Linker Control File (scatter-loading)
;
PRG 0 PI ; Programming Functions
{
PrgCode +0 ; Code
{
* (+RO)
}
PrgData +0 ; Data
{
* (+RW,+ZI)
}
}
DSCR +0 ; Device Description
{
DevDscr +0
{
FlashDev.o
}
}
最后，奉上此工程的开源链接：https://github.com/Aladdin-Wang/RP2040_Flash_Algorithm.git