高频如何做降频处理？

以6853平台为例，如果需要把最高频4266降低到3200

/vendor/mediatek/proprietary/bootable/bootloader/preloader/platform/mt6853/src/drivers/dramc_pi_main.c
  DRAM_DFS_FREQUENCY_TABLE_T gFreqTbl[DRAM_DFS_SRAM_MAX] =
 {
      {LP4_DDR3200 /*0*/, DIV8_MODE, SRAM_SHU1, DUTY_LAST_K,  VREF_CALI_OFF,  CLOSE_LOOP_MODE},  // highest freq of term group (3733) must k first.
      {LP4_DDR4266 /*1*/, DIV8_MODE, SRAM_SHU0, DUTY_NEED_K,  VREF_CALI_ON,   CLOSE_LOOP_MODE},  // highest freq of term group (3733) must k first.
......

 };

需要修改最高频SRAM_SHU0对应的freq_sel, 默认SRAM_SHU0对应的freq_sel为LP4_DDR4266(4266Mhz)。

如果要把最高频4266降低到3200，需要把LP4_DDR4266改成LP4_DDR3200.

即：LP4_DDR4266 => LP4_3200

DRAM_DFS_FREQUENCY_TABLE_T gFreqTbl[DRAM_DFS_SRAM_MAX] = {
      {LP4_DDR3200 /*0*/, DIV8_MODE, SRAM_SHU1, DUTY_LAST_K,  VREF_CALI_OFF,  CLOSE_LOOP_MODE},  // highest freq of term group (3733) must k first.
      {LP4_DDR3200 /*1*/, DIV8_MODE, SRAM_SHU0, DUTY_NEED_K,  VREF_CALI_ON,   CLOSE_LOOP_MODE},  // highest freq of term group (3733) must k first.
......

}