plat/imx/imx8m/ddr/dram.c - trusted-firmware-a - Git at Google

 /*
  * Copyright 2019-2023 NXP
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */

 #include <bl31/interrupt_mgmt.h>
 #include <common/runtime_svc.h>
 #include <lib/mmio.h>
 #include <lib/spinlock.h>
 #include <plat/common/platform.h>

 #include <dram.h>
 #include <gpc.h>

 #define IMX_SIP_DDR_DVFS_GET_FREQ_COUNT		0x10
 #define IMX_SIP_DDR_DVFS_GET_FREQ_INFO		0x11

 struct dram_info dram_info;

 /* lock used for DDR DVFS */
 spinlock_t dfs_lock;

 #if defined(PLAT_imx8mq)
 /* ocram used to dram timing */
 static uint8_t dram_timing_saved[13 * 1024] __aligned(8);
 #endif

 static volatile uint32_t wfe_done;
 static volatile bool wait_ddrc_hwffc_done = true;
 static unsigned int dev_fsp = 0x1;

 static uint32_t fsp_init_reg[3][4] = {
 	{ DDRC_INIT3(0), DDRC_INIT4(0), DDRC_INIT6(0), DDRC_INIT7(0) },
 	{ DDRC_FREQ1_INIT3(0), DDRC_FREQ1_INIT4(0), DDRC_FREQ1_INIT6(0), DDRC_FREQ1_INIT7(0) },
 	{ DDRC_FREQ2_INIT3(0), DDRC_FREQ2_INIT4(0), DDRC_FREQ2_INIT6(0), DDRC_FREQ2_INIT7(0) },
 };

 #if defined(PLAT_imx8mq)
 static inline struct dram_cfg_param *get_cfg_ptr(void *ptr,
 		void *old_base, void *new_base)
 {
 	uintptr_t offset = (uintptr_t)ptr & ~((uintptr_t)old_base);

 	return (struct dram_cfg_param *)(offset + new_base);
 }

 /* copy the dram timing info from DRAM to OCRAM */
 void imx8mq_dram_timing_copy(struct dram_timing_info *from)
 {
 	struct dram_timing_info *info = (struct dram_timing_info *)dram_timing_saved;

 	/* copy the whole 13KB content used for dram timing info */
 	memcpy(dram_timing_saved, from, sizeof(dram_timing_saved));

 	/* correct the header after copied into ocram */
 	info->ddrc_cfg = get_cfg_ptr(info->ddrc_cfg, from, dram_timing_saved);
 	info->ddrphy_cfg = get_cfg_ptr(info->ddrphy_cfg, from, dram_timing_saved);
 	info->ddrphy_trained_csr = get_cfg_ptr(info->ddrphy_trained_csr, from, dram_timing_saved);
 	info->ddrphy_pie = get_cfg_ptr(info->ddrphy_pie, from, dram_timing_saved);
 }
 #endif

 #if defined(PLAT_imx8mp)
 static uint32_t lpddr4_mr_read(unsigned int mr_rank, unsigned int mr_addr)
 {
 	unsigned int tmp, drate_byte;

 	tmp = mmio_read_32(DRC_PERF_MON_MRR0_DAT(0));
 	mmio_write_32(DRC_PERF_MON_MRR0_DAT(0), tmp | 0x1);
 	do {
 		tmp = mmio_read_32(DDRC_MRSTAT(0));
 	} while (tmp & 0x1);

 	mmio_write_32(DDRC_MRCTRL0(0), (mr_rank << 4) | 0x1);
 	mmio_write_32(DDRC_MRCTRL1(0), (mr_addr << 8));
 	mmio_write_32(DDRC_MRCTRL0(0), (mr_rank << 4) | BIT(31) | 0x1);

 	/* Workaround for SNPS STAR 9001549457 */
 	do {
 		tmp = mmio_read_32(DDRC_MRSTAT(0));
 	} while (tmp & 0x1);

 	do {
 		tmp = mmio_read_32(DRC_PERF_MON_MRR0_DAT(0));
 	} while (!(tmp & 0x8));
 	tmp = mmio_read_32(DRC_PERF_MON_MRR1_DAT(0));

 	drate_byte = (mmio_read_32(DDRC_DERATEEN(0)) >> 4) & 0xff;
 	tmp = (tmp >> (drate_byte * 8)) & 0xff;
 	mmio_write_32(DRC_PERF_MON_MRR0_DAT(0), 0x4);

 	return tmp;
 }
 #endif

 static void get_mr_values(uint32_t (*mr_value)[8])
 {
 	uint32_t init_val;
 	unsigned int i, fsp_index;

 	for (fsp_index = 0U; fsp_index < 3U; fsp_index++) {
 		for (i = 0U; i < 4U; i++) {
 			init_val = mmio_read_32(fsp_init_reg[fsp_index][i]);
 			mr_value[fsp_index][2*i] = init_val >> 16;
 			mr_value[fsp_index][2*i + 1] = init_val & 0xFFFF;
 		}

 #if defined(PLAT_imx8mp)
 		if (dram_info.dram_type == DDRC_LPDDR4) {
 			mr_value[fsp_index][5] = lpddr4_mr_read(1, MR12); /* read MR12 from DRAM */
 			mr_value[fsp_index][7] = lpddr4_mr_read(1, MR14); /* read MR14 from DRAM */
 		}
 #endif
 	}
 }

 static void save_rank_setting(void)
 {
 	uint32_t i, offset;
 	uint32_t pstate_num = dram_info.num_fsp;

 	/* only support maximum 3 setpoints */
 	pstate_num = (pstate_num > MAX_FSP_NUM) ? MAX_FSP_NUM : pstate_num;

 	for (i = 0U; i < pstate_num; i++) {
 		offset = i ? (i + 1) * 0x1000 : 0U;
 		dram_info.rank_setting[i][0] = mmio_read_32(DDRC_DRAMTMG2(0) + offset);
 		if (dram_info.dram_type != DDRC_LPDDR4) {
 			dram_info.rank_setting[i][1] = mmio_read_32(DDRC_DRAMTMG9(0) + offset);
 		}
 #if !defined(PLAT_imx8mq)
 		dram_info.rank_setting[i][2] = mmio_read_32(DDRC_RANKCTL(0) + offset);
 #endif
 	}
 #if defined(PLAT_imx8mq)
 	dram_info.rank_setting[0][2] = mmio_read_32(DDRC_RANKCTL(0));
 #endif
 }
 /* Restore the ddrc configs */
 void dram_umctl2_init(struct dram_timing_info *timing)
 {
 	struct dram_cfg_param *ddrc_cfg = timing->ddrc_cfg;
 	unsigned int i;

 	for (i = 0U; i < timing->ddrc_cfg_num; i++) {
 		mmio_write_32(ddrc_cfg->reg, ddrc_cfg->val);
 		ddrc_cfg++;
 	}

 	/* set the default fsp to P0 */
 	mmio_write_32(DDRC_MSTR2(0), 0x0);
 }

 /* Restore the dram PHY config */
 void dram_phy_init(struct dram_timing_info *timing)
 {
 	struct dram_cfg_param *cfg = timing->ddrphy_cfg;
 	unsigned int i;

 	/* Restore the PHY init config */
 	cfg = timing->ddrphy_cfg;
 	for (i = 0U; i < timing->ddrphy_cfg_num; i++) {
 		dwc_ddrphy_apb_wr(cfg->reg, cfg->val);
 		cfg++;
 	}

 	/* Restore the DDR PHY CSRs */
 	cfg = timing->ddrphy_trained_csr;
 	for (i = 0U; i < timing->ddrphy_trained_csr_num; i++) {
 		dwc_ddrphy_apb_wr(cfg->reg, cfg->val);
 		cfg++;
 	}

 	/* Load the PIE image */
 	cfg = timing->ddrphy_pie;
 	for (i = 0U; i < timing->ddrphy_pie_num; i++) {
 		dwc_ddrphy_apb_wr(cfg->reg, cfg->val);
 		cfg++;
 	}
 }

 /* EL3 SGI-8 IPI handler for DDR Dynamic frequency scaling */
 static uint64_t waiting_dvfs(uint32_t id, uint32_t flags,
 				void *handle, void *cookie)
 {
 	uint64_t mpidr = read_mpidr_el1();
 	unsigned int cpu_id = MPIDR_AFFLVL0_VAL(mpidr);
 	uint32_t irq;

 	irq = plat_ic_acknowledge_interrupt();
 	if (irq < 1022U) {
 		plat_ic_end_of_interrupt(irq);
 	}

 	/* set the WFE done status */
 	spin_lock(&dfs_lock);
 	wfe_done |= (1 << cpu_id * 8);
 	dsb();
 	spin_unlock(&dfs_lock);

 	while (1) {
 		/* ddr frequency change done */
 		if (!wait_ddrc_hwffc_done)
 			break;

 		wfe();
 	}

 	return 0;
 }

 void dram_info_init(unsigned long dram_timing_base)
 {
 	uint32_t ddrc_mstr, current_fsp;
 	unsigned int idx = 0;
 	uint32_t flags = 0;
 	uint32_t rc;
 	unsigned int i;

 	/* Get the dram type & rank */
 	ddrc_mstr = mmio_read_32(DDRC_MSTR(0));

 	dram_info.dram_type = ddrc_mstr & DDR_TYPE_MASK;
 	dram_info.num_rank = ((ddrc_mstr >> 24) & ACTIVE_RANK_MASK) == 0x3 ?
 		DDRC_ACTIVE_TWO_RANK : DDRC_ACTIVE_ONE_RANK;

 	/* Get current fsp info */
 	current_fsp = mmio_read_32(DDRC_DFIMISC(0));
 	current_fsp = (current_fsp >> 8) & 0xf;
 	dram_info.boot_fsp = current_fsp;
 	dram_info.current_fsp = current_fsp;

 #if defined(PLAT_imx8mq)
 	imx8mq_dram_timing_copy((struct dram_timing_info *)dram_timing_base);
 	dram_timing_base = (unsigned long) dram_timing_saved;
 #endif
 	get_mr_values(dram_info.mr_table);

 	dram_info.timing_info = (struct dram_timing_info *)dram_timing_base;

 	/* get the num of supported fsp */
 	for (i = 0U; i < 4U; ++i) {
 		if (!dram_info.timing_info->fsp_table[i]) {
 			break;
 		}
 		idx = i;
 	}

 	/* only support maximum 3 setpoints */
 	dram_info.num_fsp = (i > MAX_FSP_NUM) ? MAX_FSP_NUM : i;

 	/* no valid fsp table, return directly */
 	if (i == 0U) {
 		return;
 	}

 	/* save the DRAMTMG2/9 for rank to rank workaround */
 	save_rank_setting();

 	/* check if has bypass mode support */
 	if (dram_info.timing_info->fsp_table[idx] < 666) {
 		dram_info.bypass_mode = true;
 	} else {
 		dram_info.bypass_mode = false;
 	}

 	/* Register the EL3 handler for DDR DVFS */
 	set_interrupt_rm_flag(flags, NON_SECURE);
 	rc = register_interrupt_type_handler(INTR_TYPE_EL3, waiting_dvfs, flags);
 	if (rc != 0) {
 		panic();
 	}

 	if (dram_info.dram_type == DDRC_LPDDR4 && current_fsp != 0x0) {
 		/* flush the L1/L2 cache */
 		dcsw_op_all(DCCSW);
 		lpddr4_swffc(&dram_info, dev_fsp, 0x0);
 		dev_fsp = (~dev_fsp) & 0x1;
 	} else if (current_fsp != 0x0) {
 		/* flush the L1/L2 cache */
 		dcsw_op_all(DCCSW);
 		ddr4_swffc(&dram_info, 0x0);
 	}
 }

 /*
  * For each freq return the following info:
  *
  * r1: data rate
  * r2: 1 + dram_core parent
  * r3: 1 + dram_alt parent index
  * r4: 1 + dram_apb parent index
  *
  * The parent indices can be used by an OS who manages source clocks to enabled
  * them ahead of the switch.
  *
  * A parent value of "0" means "don't care".
  *
  * Current implementation of freq switch is hardcoded in
  * plat/imx/common/imx8m/clock.c but in theory this can be enhanced to support
  * a wide variety of rates.
  */
 int dram_dvfs_get_freq_info(void *handle, u_register_t index)
 {
 	switch (index) {
 	case 0:
 		 SMC_RET4(handle, dram_info.timing_info->fsp_table[0],
 			1, 0, 5);
 	case 1:
 		if (!dram_info.bypass_mode) {
 			SMC_RET4(handle, dram_info.timing_info->fsp_table[1],
 				1, 0, 0);
 		}
 		SMC_RET4(handle, dram_info.timing_info->fsp_table[1],
 			2, 2, 4);
 	case 2:
 		if (!dram_info.bypass_mode) {
 			SMC_RET4(handle, dram_info.timing_info->fsp_table[2],
 				1, 0, 0);
 		}
 		SMC_RET4(handle, dram_info.timing_info->fsp_table[2],
 			2, 3, 3);
 	case 3:
 		 SMC_RET4(handle, dram_info.timing_info->fsp_table[3],
 			1, 0, 0);
 	default:
 		SMC_RET1(handle, -3);
 	}
 }

 int dram_dvfs_handler(uint32_t smc_fid, void *handle,
 	u_register_t x1, u_register_t x2, u_register_t x3)
 {
 	uint64_t mpidr = read_mpidr_el1();
 	unsigned int cpu_id = MPIDR_AFFLVL0_VAL(mpidr);
 	unsigned int fsp_index = x1;
 	uint32_t online_cores = x2;

 	if (x1 == IMX_SIP_DDR_DVFS_GET_FREQ_COUNT) {
 		SMC_RET1(handle, dram_info.num_fsp);
 	} else if (x1 == IMX_SIP_DDR_DVFS_GET_FREQ_INFO) {
 		return dram_dvfs_get_freq_info(handle, x2);
 	} else if (x1 < 3U) {
 		wait_ddrc_hwffc_done = true;
 		dsb();

 		/* trigger the SGI IPI to info other cores */
 		for (int i = 0; i < PLATFORM_CORE_COUNT; i++) {
 			if (cpu_id != i && (online_cores & (0x1 << (i * 8)))) {
 				plat_ic_raise_el3_sgi(0x8, i);
 			}
 		}
 #if defined(PLAT_imx8mq)
 		for (unsigned int i = 0; i < PLATFORM_CORE_COUNT; i++) {
 			if (i != cpu_id && online_cores & (1 << (i * 8))) {
 				imx_gpc_core_wake(1 << i);
 			}
 		}
 #endif
 		/* make sure all the core in WFE */
 		online_cores &= ~(0x1 << (cpu_id * 8));
 		while (1) {
 			if (online_cores == wfe_done) {
 				break;
 			}
 		}

 		/* flush the L1/L2 cache */
 		dcsw_op_all(DCCSW);

 		if (dram_info.dram_type == DDRC_LPDDR4) {
 			lpddr4_swffc(&dram_info, dev_fsp, fsp_index);
 			dev_fsp = (~dev_fsp) & 0x1;
 		} else {
 			ddr4_swffc(&dram_info, fsp_index);
 		}

 		dram_info.current_fsp = fsp_index;
 		wait_ddrc_hwffc_done = false;
 		wfe_done = 0;
 		dsb();
 		sev();
 		isb();
 	}

 	SMC_RET1(handle, 0);
 }
	/*
	* Copyright 2019-2023 NXP
	*
	* SPDX-License-Identifier: BSD-3-Clause
	*/

	#include <bl31/interrupt_mgmt.h>
	#include <common/runtime_svc.h>
	#include <lib/mmio.h>
	#include <lib/spinlock.h>
	#include <plat/common/platform.h>

	#include <dram.h>
	#include <gpc.h>

	#define IMX_SIP_DDR_DVFS_GET_FREQ_COUNT 0x10
	#define IMX_SIP_DDR_DVFS_GET_FREQ_INFO 0x11

	struct dram_info dram_info;

	/* lock used for DDR DVFS */
	spinlock_t dfs_lock;

	#if defined(PLAT_imx8mq)
	/* ocram used to dram timing */
	static uint8_t dram_timing_saved[13 * 1024] __aligned(8);
	#endif

	static volatile uint32_t wfe_done;
	static volatile bool wait_ddrc_hwffc_done = true;
	static unsigned int dev_fsp = 0x1;

	static uint32_t fsp_init_reg[3][4] = {
	{ DDRC_INIT3(0), DDRC_INIT4(0), DDRC_INIT6(0), DDRC_INIT7(0) },
	{ DDRC_FREQ1_INIT3(0), DDRC_FREQ1_INIT4(0), DDRC_FREQ1_INIT6(0), DDRC_FREQ1_INIT7(0) },
	{ DDRC_FREQ2_INIT3(0), DDRC_FREQ2_INIT4(0), DDRC_FREQ2_INIT6(0), DDRC_FREQ2_INIT7(0) },
	};

	#if defined(PLAT_imx8mq)
	static inline struct dram_cfg_param get_cfg_ptr(void ptr,
	void old_base, void new_base)
	{
	uintptr_t offset = (uintptr_t)ptr & ~((uintptr_t)old_base);

	return (struct dram_cfg_param *)(offset + new_base);
	}

	/* copy the dram timing info from DRAM to OCRAM */
	void imx8mq_dram_timing_copy(struct dram_timing_info *from)
	{
	struct dram_timing_info info = (struct dram_timing_info )dram_timing_saved;

	/* copy the whole 13KB content used for dram timing info */
	memcpy(dram_timing_saved, from, sizeof(dram_timing_saved));

	/* correct the header after copied into ocram */
	info->ddrc_cfg = get_cfg_ptr(info->ddrc_cfg, from, dram_timing_saved);
	info->ddrphy_cfg = get_cfg_ptr(info->ddrphy_cfg, from, dram_timing_saved);
	info->ddrphy_trained_csr = get_cfg_ptr(info->ddrphy_trained_csr, from, dram_timing_saved);
	info->ddrphy_pie = get_cfg_ptr(info->ddrphy_pie, from, dram_timing_saved);
	}
	#endif

	#if defined(PLAT_imx8mp)
	static uint32_t lpddr4_mr_read(unsigned int mr_rank, unsigned int mr_addr)
	{
	unsigned int tmp, drate_byte;

	tmp = mmio_read_32(DRC_PERF_MON_MRR0_DAT(0));
	mmio_write_32(DRC_PERF_MON_MRR0_DAT(0), tmp \| 0x1);
	do {
	tmp = mmio_read_32(DDRC_MRSTAT(0));
	} while (tmp & 0x1);

	mmio_write_32(DDRC_MRCTRL0(0), (mr_rank << 4) \| 0x1);
	mmio_write_32(DDRC_MRCTRL1(0), (mr_addr << 8));
	mmio_write_32(DDRC_MRCTRL0(0), (mr_rank << 4) \| BIT(31) \| 0x1);

	/* Workaround for SNPS STAR 9001549457 */
	do {
	tmp = mmio_read_32(DDRC_MRSTAT(0));
	} while (tmp & 0x1);

	do {
	tmp = mmio_read_32(DRC_PERF_MON_MRR0_DAT(0));
	} while (!(tmp & 0x8));
	tmp = mmio_read_32(DRC_PERF_MON_MRR1_DAT(0));

	drate_byte = (mmio_read_32(DDRC_DERATEEN(0)) >> 4) & 0xff;
	tmp = (tmp >> (drate_byte * 8)) & 0xff;
	mmio_write_32(DRC_PERF_MON_MRR0_DAT(0), 0x4);

	return tmp;
	}
	#endif

	static void get_mr_values(uint32_t (*mr_value)[8])
	{
	uint32_t init_val;
	unsigned int i, fsp_index;

	for (fsp_index = 0U; fsp_index < 3U; fsp_index++) {
	for (i = 0U; i < 4U; i++) {
	init_val = mmio_read_32(fsp_init_reg[fsp_index][i]);
	mr_value[fsp_index][2*i] = init_val >> 16;
	mr_value[fsp_index][2*i + 1] = init_val & 0xFFFF;
	}

	#if defined(PLAT_imx8mp)
	if (dram_info.dram_type == DDRC_LPDDR4) {
	mr_value[fsp_index][5] = lpddr4_mr_read(1, MR12); /* read MR12 from DRAM */
	mr_value[fsp_index][7] = lpddr4_mr_read(1, MR14); /* read MR14 from DRAM */
	}
	#endif
	}
	}

	static void save_rank_setting(void)
	{
	uint32_t i, offset;
	uint32_t pstate_num = dram_info.num_fsp;

	/* only support maximum 3 setpoints */
	pstate_num = (pstate_num > MAX_FSP_NUM) ? MAX_FSP_NUM : pstate_num;

	for (i = 0U; i < pstate_num; i++) {
	offset = i ? (i + 1) * 0x1000 : 0U;
	dram_info.rank_setting[i][0] = mmio_read_32(DDRC_DRAMTMG2(0) + offset);
	if (dram_info.dram_type != DDRC_LPDDR4) {
	dram_info.rank_setting[i][1] = mmio_read_32(DDRC_DRAMTMG9(0) + offset);
	}
	#if !defined(PLAT_imx8mq)
	dram_info.rank_setting[i][2] = mmio_read_32(DDRC_RANKCTL(0) + offset);
	#endif
	}
	#if defined(PLAT_imx8mq)
	dram_info.rank_setting[0][2] = mmio_read_32(DDRC_RANKCTL(0));
	#endif
	}
	/* Restore the ddrc configs */
	void dram_umctl2_init(struct dram_timing_info *timing)
	{
	struct dram_cfg_param *ddrc_cfg = timing->ddrc_cfg;
	unsigned int i;

	for (i = 0U; i < timing->ddrc_cfg_num; i++) {
	mmio_write_32(ddrc_cfg->reg, ddrc_cfg->val);
	ddrc_cfg++;
	}

	/* set the default fsp to P0 */
	mmio_write_32(DDRC_MSTR2(0), 0x0);
	}

	/* Restore the dram PHY config */
	void dram_phy_init(struct dram_timing_info *timing)
	{
	struct dram_cfg_param *cfg = timing->ddrphy_cfg;
	unsigned int i;

	/* Restore the PHY init config */
	cfg = timing->ddrphy_cfg;
	for (i = 0U; i < timing->ddrphy_cfg_num; i++) {
	dwc_ddrphy_apb_wr(cfg->reg, cfg->val);
	cfg++;
	}

	/* Restore the DDR PHY CSRs */
	cfg = timing->ddrphy_trained_csr;
	for (i = 0U; i < timing->ddrphy_trained_csr_num; i++) {
	dwc_ddrphy_apb_wr(cfg->reg, cfg->val);
	cfg++;
	}

	/* Load the PIE image */
	cfg = timing->ddrphy_pie;
	for (i = 0U; i < timing->ddrphy_pie_num; i++) {
	dwc_ddrphy_apb_wr(cfg->reg, cfg->val);
	cfg++;
	}
	}

	/* EL3 SGI-8 IPI handler for DDR Dynamic frequency scaling */
	static uint64_t waiting_dvfs(uint32_t id, uint32_t flags,
	void handle, void cookie)
	{
	uint64_t mpidr = read_mpidr_el1();
	unsigned int cpu_id = MPIDR_AFFLVL0_VAL(mpidr);
	uint32_t irq;

	irq = plat_ic_acknowledge_interrupt();
	if (irq < 1022U) {
	plat_ic_end_of_interrupt(irq);
	}

	/* set the WFE done status */
	spin_lock(&dfs_lock);
	wfe_done \|= (1 << cpu_id * 8);
	dsb();
	spin_unlock(&dfs_lock);

	while (1) {
	/* ddr frequency change done */
	if (!wait_ddrc_hwffc_done)
	break;

	wfe();
	}

	return 0;
	}

	void dram_info_init(unsigned long dram_timing_base)
	{
	uint32_t ddrc_mstr, current_fsp;
	unsigned int idx = 0;
	uint32_t flags = 0;
	uint32_t rc;
	unsigned int i;

	/* Get the dram type & rank */
	ddrc_mstr = mmio_read_32(DDRC_MSTR(0));

	dram_info.dram_type = ddrc_mstr & DDR_TYPE_MASK;
	dram_info.num_rank = ((ddrc_mstr >> 24) & ACTIVE_RANK_MASK) == 0x3 ?
	DDRC_ACTIVE_TWO_RANK : DDRC_ACTIVE_ONE_RANK;

	/* Get current fsp info */
	current_fsp = mmio_read_32(DDRC_DFIMISC(0));
	current_fsp = (current_fsp >> 8) & 0xf;
	dram_info.boot_fsp = current_fsp;
	dram_info.current_fsp = current_fsp;

	#if defined(PLAT_imx8mq)
	imx8mq_dram_timing_copy((struct dram_timing_info *)dram_timing_base);
	dram_timing_base = (unsigned long) dram_timing_saved;
	#endif
	get_mr_values(dram_info.mr_table);

	dram_info.timing_info = (struct dram_timing_info *)dram_timing_base;

	/* get the num of supported fsp */
	for (i = 0U; i < 4U; ++i) {
	if (!dram_info.timing_info->fsp_table[i]) {
	break;
	}
	idx = i;
	}

	/* only support maximum 3 setpoints */
	dram_info.num_fsp = (i > MAX_FSP_NUM) ? MAX_FSP_NUM : i;

	/* no valid fsp table, return directly */
	if (i == 0U) {
	return;
	}

	/* save the DRAMTMG2/9 for rank to rank workaround */
	save_rank_setting();

	/* check if has bypass mode support */
	if (dram_info.timing_info->fsp_table[idx] < 666) {
	dram_info.bypass_mode = true;
	} else {
	dram_info.bypass_mode = false;
	}

	/* Register the EL3 handler for DDR DVFS */
	set_interrupt_rm_flag(flags, NON_SECURE);
	rc = register_interrupt_type_handler(INTR_TYPE_EL3, waiting_dvfs, flags);
	if (rc != 0) {
	panic();
	}

	if (dram_info.dram_type == DDRC_LPDDR4 && current_fsp != 0x0) {
	/* flush the L1/L2 cache */
	dcsw_op_all(DCCSW);
	lpddr4_swffc(&dram_info, dev_fsp, 0x0);
	dev_fsp = (~dev_fsp) & 0x1;
	} else if (current_fsp != 0x0) {
	/* flush the L1/L2 cache */
	dcsw_op_all(DCCSW);
	ddr4_swffc(&dram_info, 0x0);
	}
	}

	/*
	* For each freq return the following info:
	*
	* r1: data rate
	* r2: 1 + dram_core parent
	* r3: 1 + dram_alt parent index
	* r4: 1 + dram_apb parent index
	*
	* The parent indices can be used by an OS who manages source clocks to enabled
	* them ahead of the switch.
	*
	* A parent value of "0" means "don't care".
	*
	* Current implementation of freq switch is hardcoded in
	* plat/imx/common/imx8m/clock.c but in theory this can be enhanced to support
	* a wide variety of rates.
	*/
	int dram_dvfs_get_freq_info(void *handle, u_register_t index)
	{
	switch (index) {
	case 0:
	SMC_RET4(handle, dram_info.timing_info->fsp_table[0],
	1, 0, 5);
	case 1:
	if (!dram_info.bypass_mode) {
	SMC_RET4(handle, dram_info.timing_info->fsp_table[1],
	1, 0, 0);
	}
	SMC_RET4(handle, dram_info.timing_info->fsp_table[1],
	2, 2, 4);
	case 2:
	if (!dram_info.bypass_mode) {
	SMC_RET4(handle, dram_info.timing_info->fsp_table[2],
	1, 0, 0);
	}
	SMC_RET4(handle, dram_info.timing_info->fsp_table[2],
	2, 3, 3);
	case 3:
	SMC_RET4(handle, dram_info.timing_info->fsp_table[3],
	1, 0, 0);
	default:
	SMC_RET1(handle, -3);
	}
	}

	int dram_dvfs_handler(uint32_t smc_fid, void *handle,
	u_register_t x1, u_register_t x2, u_register_t x3)
	{
	uint64_t mpidr = read_mpidr_el1();
	unsigned int cpu_id = MPIDR_AFFLVL0_VAL(mpidr);
	unsigned int fsp_index = x1;
	uint32_t online_cores = x2;

	if (x1 == IMX_SIP_DDR_DVFS_GET_FREQ_COUNT) {
	SMC_RET1(handle, dram_info.num_fsp);
	} else if (x1 == IMX_SIP_DDR_DVFS_GET_FREQ_INFO) {
	return dram_dvfs_get_freq_info(handle, x2);
	} else if (x1 < 3U) {
	wait_ddrc_hwffc_done = true;
	dsb();

	/* trigger the SGI IPI to info other cores */
	for (int i = 0; i < PLATFORM_CORE_COUNT; i++) {
	if (cpu_id != i && (online_cores & (0x1 << (i * 8)))) {
	plat_ic_raise_el3_sgi(0x8, i);
	}
	}
	#if defined(PLAT_imx8mq)
	for (unsigned int i = 0; i < PLATFORM_CORE_COUNT; i++) {
	if (i != cpu_id && online_cores & (1 << (i * 8))) {
	imx_gpc_core_wake(1 << i);
	}
	}
	#endif
	/* make sure all the core in WFE */
	online_cores &= ~(0x1 << (cpu_id * 8));
	while (1) {
	if (online_cores == wfe_done) {
	break;
	}
	}

	/* flush the L1/L2 cache */
	dcsw_op_all(DCCSW);

	if (dram_info.dram_type == DDRC_LPDDR4) {
	lpddr4_swffc(&dram_info, dev_fsp, fsp_index);
	dev_fsp = (~dev_fsp) & 0x1;
	} else {
	ddr4_swffc(&dram_info, fsp_index);
	}

	dram_info.current_fsp = fsp_index;
	wait_ddrc_hwffc_done = false;
	wfe_done = 0;
	dsb();
	sev();
	isb();
	}

	SMC_RET1(handle, 0);
	}