PolarFire SoC mpfs-mmuart-interrupt 多核通信

e51 ：

　　

/* Clear pending software interrupt in case there was any. */

clear_soft_interrupt();
set_csr(mie, MIP_MSIP);

/* Raise software interrupt to wake hart 1 */
raise_soft_interrupt(1U);

/* Raise software interrupt to wake hart 2 */
raise_soft_interrupt(2U);

__enable_irq();