CLK_PLL_PWR_REQ_N0
rc = amd_smn_read(0, CLK_PLL_PWR_REQ_N0, &data);
rc = amd_smn_write(0, CLK_PLL_PWR_REQ_N0, data | PLL_AUTO_STOP_REQ);
rc = amd_smn_read(0, CLK_PLL_PWR_REQ_N0, &data);
rc = amd_smn_write(0, CLK_PLL_PWR_REQ_N0, data | PLL_AUTO_START_REQ);