#define IO_BASE 0x3f000000
#define UART0_BASE (IO_BASE + 0x201000)
#define UART0_DR (*(volatile unsigned *)(UART0_BASE + 0x0))
#define UART0_FR (*(volatile unsigned *)(UART0_BASE + 0x18))

extern unsigned long int __ld_kernel_begin;

static __attribute__((section("static_tools"))) char uart_recv(void)
{
	while (UART0_FR & (1 << 4)) {
	}
	return UART0_DR & 0xFF;
}

static int __attribute__((section("static_tools"))) uart_read_int() {
    int num = 0;
    for (int i = 0; i < 4; i++) {
        char c = uart_recv();
        num = num << 8;
        num += (int)c;
    }
    return num;
}

int __attribute__((section("static_tools"))) copy_kernel()
{
        unsigned int kernel_size = uart_read_int();
        int expected_checksum    = uart_read_int();
        int debug                = uart_read_int();
        char *kernel             = (char *)&__ld_kernel_begin;
        int checksum             = 0;
	(void)debug;

        for (unsigned int i = 0; i < kernel_size; i++) {
                char c = uart_recv();
                checksum += c;
                kernel[i] = c;
        }

	if(checksum != expected_checksum)
		return -1;

	return 0;
}