简介
在上一篇帖子（[IAR] Flash Loader 下载过程解析）中已经介绍了IAR flash 程序下载的过程，其中flah 上内容的跟新是通过C-SPY，将flash 下载算法加载到RAM 中调用flashloader 的下载算法完成，flash 的编程。
上述流程为flashloader 下载算法的主要工作流程，flashloader 下载算法中主要依赖如下flash 写入和擦除的函数。
以下是flashloader 中其他接口功能说明
IAR 针对 flashloader 的制作，也提供了标准的实现模板，我们使用标准模板的基础上实现对应的flash 下载算法就可以实现一个基本功能的flash 下载算法了。IAR 的\arm\src\flashloader安装路径下包含部分flash loader 的示例工程，我们可以基于此模板进行修改，默认的flash loader 程序是不能进行串口打印输出的，我们再次gd32 的flash loader 工程上进行修改，添加串口打印功能方便我们理解flashloader 的工作过程，从以上的函数接口功能描述可知，FlashInit函数是第一个被调用的函数，我们可以在这个函数里添加串口的初始话配置处理。
FlashInit 接口功能描述如下
#if USE_ARGC_ARGV
uint32_t FlashInit(void *base_of_flash, uint32_t image_size,
uint32_t link_address, uint32_t flags,
int argc, char const *argv[])
#else
uint32_t FlashInit(void *base_of_flash, uint32_t image_size,
uint32_t link_address, uint32_t flags)
#endif
{
uint32_t temp = 0;
parallelism = 1;
/* enable GPIO clock */
RCU_AHB1EN |= 0x01u << 1;
/* enable USART clock */
RCU_APB2EN |= 0x01u <<4;
GPIO_CTL(GPIOB) &= ~(0x03u << (2*6));
GPIO_CTL(GPIOB) |= (2 << (2*6));
GPIO_PUD(GPIOB) &= ~(0x03u << (2*6));
GPIO_PUD(GPIOB) |= (1u << (2*6));
GPIO_OMODE(GPIOB) &= ~(0x01u << 6);
GPIO_OSPD(GPIOB) &= ~(0x03u << (2*6));
GPIO_OSPD(GPIOB) |= (0x01u << (2*6));
GPIO_AFSEL0(GPIOB) &= ~(0xf << (4*6));
GPIO_AFSEL0(GPIOB) |= (0x7 << (4*6));
/* config uart0 */
uint32_t uclk = 0U, intdiv = 0U, fradiv = 0U, udiv = 0U;
uclk = rcu_clock_freq_get(CK_APB2);
if(USART_CTL0(USART0) & USART_CTL0_OVSMOD) {
/* when oversampling by 8, configure the value of USART_BAUD */
udiv = ((2U * uclk) + 115200 / 2U) / 115200;
intdiv = udiv & 0xfff0U;
fradiv = (udiv >> 1U) & 0x7U;
USART_BAUD(USART0) = ((USART_BAUD_FRADIV | USART_BAUD_INTDIV) & (intdiv | fradiv));
} else {
/* when oversampling by 16, configure the value of USART_BAUD */
udiv = (uclk + 115200 / 2U) / 115200;
intdiv = udiv & 0xfff0U;
fradiv = udiv & 0xfU;
USART_BAUD(USART0) = ((USART_BAUD_FRADIV | USART_BAUD_INTDIV) & (intdiv | fradiv));
}
USART_CTL0(USART0) &= ~(0x01u << 10);
USART_CTL0(USART0) &= ~(0x01u << 12);
USART_CTL1(USART0) &= ~(0x03u << 12);
USART_CTL0(USART0) |= (0x01u << 3);
USART_CTL0(USART0) |= (0x01u << 13);
FMC_WS = 0x00000000;
temp = FMC_CTL;
temp &= ~(0x3u << 8);
temp |= (parallelism << 8);
FMC_CTL = temp;
return 0;
}参考GD32F4 的flash 编程接口实现flashwrite/flasherase 接口。对应实现如下
FlashWrite 接口功能描述如下
uint32_t FlashWrite(void *block_start,
uint32_t offset_into_block,
uint32_t count,
char const *buffer)
{
uint8_t * dst = (uint8_t *)((unsigned char *)block_start + offset_into_block);
uint8_t * src = (uint8_t *)buffer;
mini_printf("flash write dst %p %d %d.\r\n",dst,offset_into_block,count);
FMC_CTL |= 0x01u;
FMC_STAT = 0x1d2;
for ( ; count; count -= 8)
{
while (FMC_STAT & (0x01u<<16));
*((uint64_t *)dst) = *((uint64_t *)src);
src += 8;
dst += 8;
}
}
while (FMC_STAT & (0x01u<<16));
FMC_CTL &= ~0x01;
if(FMC_STAT & 0x1d2)
return 1;
return 0;
}FlashErase 接口功能描述如下
uint32_t FlashErase(void *block_start,
uint32_t block_size)
{
uint32_t offset = (uint32_t)block_start;
uint32_t sector_num = 0;
mini_printf("flash erase %x.\r\n",offset);
if(offset >= 0x08000000 && offset <= 0x08003fff)
{
//sector_num = 0;
sector_num = 0x00u << 3;
}
else if(offset >= 0x08004000 && offset <= 0x08007fff)
{
//sector_num = 1;
sector_num = 0x01u << 3;
}
else if(offset >= 0x08008000 && offset <= 0x0800bfff)
{
//sector_num = 2;
sector_num = 0x02u << 3;
}
else if(offset >= 0x0800c000 && offset <= 0x0800ffff)
{
//sector_num = 3;
sector_num = 0x03u << 3;
}
else if(offset >= 0x08010000 && offset <= 0x0801ffff)
{
//sector_num = 4;
sector_num = 0x04u << 3;
}
else if(offset >= 0x08020000 && offset <= 0x0803ffff)
{
//sector_num = 5;
sector_num = 0x05u << 3;
}
else if(offset >= 0x08040000 && offset <= 0x0805ffff)
{
//sector_num = 6;
sector_num = 0x06u << 3;
}
else if(offset >= 0x08060000 && offset <= 0x0807ffff)
{
//sector_num = 7;
sector_num = 0x07u << 3;
}
else if(offset >= 0x08080000 && offset <= 0x0809ffff)
{
//sector_num = 8;
sector_num = 0x08u << 3;
}
else if(offset >= 0x080a0000 && offset <= 0x080bffff)
{
//sector_num = 9;
sector_num = 0x09u << 3;
}
else if(offset >= 0x080c0000 && offset <= 0x080dffff)
{
//sector_num = 10;
sector_num = 10u << 3;
}
else if(offset >= 0x080e0000 && offset <= 0x080fffff)
{
//sector_num = 11;
sector_num = 11u << 3;
}
else if(offset >= 0x08100000 && offset <= 0x08103fff)
{
//sector_num = 12;
sector_num = 0x10u << 3;
}
else if(offset >= 0x08104000 && offset <= 0x08107fff)
{
//sector_num = 13;
sector_num = 0x11u << 3;
}
else if(offset >= 0x08108000 && offset <= 0x0810Bfff)
{
//sector_num = 14;
sector_num = 0x12u << 3;
}
else if(offset >= 0x0810C000 && offset <= 0x0810Ffff)
{
//sector_num = 15;
sector_num = 0x13u << 3;
}
else if(offset >= 0x08110000 && offset <= 0x0811Ffff)
{
//sector_num = 16;
sector_num = 0x14u << 3;
}
else if(offset >= 0x08120000 && offset <= 0x0813Ffff)
{
//sector_num = 17;
sector_num = 0x15u << 3;
}
else if(offset >= 0x08140000 && offset <= 0x0815Ffff)
{
//sector_num = 18;
sector_num = 0x16u << 3;
}
else if(offset >= 0x08160000 && offset <= 0x0817Ffff)
{
//sector_num = 19;
sector_num = 0x17u << 3;
}
else if(offset >= 0x08180000 && offset <= 0x0819Ffff)
{
//sector_num = 20;
sector_num = 0x18u << 3;
}
else if(offset >= 0x081A0000 && offset <= 0x081BFfff)
{
//sector_num = 21;
sector_num = 0x19u << 3;
}
else if(offset >= 0x081C0000 && offset <= 0x081DFfff)
{
//sector_num = 22;
sector_num = 0x1au << 3;
}
else if(offset >= 0x081E0000 && offset <= 0x081FFfff)
{
//sector_num = 23;
sector_num = 0x1bu << 3;
}
else if(offset >= 0x08200000 && offset <= 0x0823Ffff)
{
//sector_num = 24;
sector_num = 0xcu << 3;
}
else if(offset >= 0x08240000 && offset <= 0x0827Ffff)
{
//sector_num = 25;
sector_num = 0xdu << 3;
}
else if(offset >= 0x08280000 && offset <= 0x082BFfff)
{
//sector_num = 26;
sector_num = 0xeu << 3;
}
else if(offset >= 0x082C0000 && offset <= 0x082FFfff)
{
//sector_num = 27;
sector_num = 0xfu << 3;
}
else
{
return 1;
}
while (FMC_STAT & (0x01u<<16));
FMC_CTL |= ((sector_num) | (0x01<<1));
FMC_CTL |= (0x01u<<16);
while (FMC_STAT & (0x01u<<16));
FMC_CTL &= ~(0x1f<<3 | 0x01<<1);
if(FMC_STAT & 0x1d2)
return 1;
return 0;
}因为在FlashInit 函数中已经完成了flash 的初始化处理，在flash 的write 和 erase 函数里添加了打印处理，我们使用本地编译的flashloader 程序，下载过程中对应的log 也按照预期的打印输出了。
只要添加以上三个函数即可完成基本的flashloader 功能,至此已经完成flashloader 下载算法的编写并可以在IAR环境下使用。
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