feat(imx8m): add the ddr frequency change support for imx8m family

Add the DDR frequency change support.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: If1167785796b8678c351569b83d2922c66f6e530
diff --git a/plat/imx/imx8m/ddr/lpddr4_dvfs.c b/plat/imx/imx8m/ddr/lpddr4_dvfs.c
new file mode 100644
index 0000000..2b4f300
--- /dev/null
+++ b/plat/imx/imx8m/ddr/lpddr4_dvfs.c
@@ -0,0 +1,292 @@
+/*
+ * Copyright 2018-2022 NXP
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <lib/mmio.h>
+
+#include <dram.h>
+
+static void lpddr4_mr_write(uint32_t mr_rank, uint32_t mr_addr, uint32_t mr_data)
+{
+	/*
+	 * 1. Poll MRSTAT.mr_wr_busy until it is 0. This checks that there
+	 * is no outstanding MR transaction. No
+	 * writes should be performed to MRCTRL0 and MRCTRL1 if MRSTAT.mr_wr_busy = 1.
+	 */
+	while (mmio_read_32(DDRC_MRSTAT(0)) & 0x1)
+		;
+
+	/*
+	 * 2. Write the MRCTRL0.mr_type, MRCTRL0.mr_addr,
+	 * MRCTRL0.mr_rank and (for MRWs)
+	 * MRCTRL1.mr_data to define the MR transaction.
+	 */
+	mmio_write_32(DDRC_MRCTRL0(0), (mr_rank << 4));
+	mmio_write_32(DDRC_MRCTRL1(0), (mr_addr << 8) | mr_data);
+	mmio_setbits_32(DDRC_MRCTRL0(0), BIT(31));
+}
+
+void lpddr4_swffc(struct dram_info *info, unsigned int init_fsp,
+	 unsigned int fsp_index)
+
+{
+	uint32_t mr, emr, emr2, emr3;
+	uint32_t mr11, mr12, mr22, mr14;
+	uint32_t val;
+	uint32_t derate_backup[3];
+	uint32_t (*mr_data)[8];
+
+	/* 1. program targetd UMCTL2_REGS_FREQ1/2/3,already done, skip it. */
+
+	/* 2. MR13.FSP-WR=1, MRW to update MR registers */
+	mr_data = info->mr_table;
+	mr = mr_data[fsp_index][0];
+	emr  = mr_data[fsp_index][1];
+	emr2 = mr_data[fsp_index][2];
+	emr3 = mr_data[fsp_index][3];
+	mr11 = mr_data[fsp_index][4];
+	mr12 = mr_data[fsp_index][5];
+	mr22 = mr_data[fsp_index][6];
+	mr14 = mr_data[fsp_index][7];
+
+	val = (init_fsp == 1) ? 0x2 << 6 : 0x1 << 6;
+	emr3 = (emr3 & 0x003f) | val | 0x0d00;
+
+	/* 12. set PWRCTL.selfref_en=0 */
+	mmio_clrbits_32(DDRC_PWRCTL(0), 0xf);
+
+	/* It is more safe to config it here */
+	mmio_clrbits_32(DDRC_DFIPHYMSTR(0), 0x1);
+
+	lpddr4_mr_write(3, 13, emr3);
+	lpddr4_mr_write(3, 1, mr);
+	lpddr4_mr_write(3, 2, emr);
+	lpddr4_mr_write(3, 3, emr2);
+	lpddr4_mr_write(3, 11, mr11);
+	lpddr4_mr_write(3, 12, mr12);
+	lpddr4_mr_write(3, 14, mr14);
+	lpddr4_mr_write(3, 22, mr22);
+
+	do {
+		val = mmio_read_32(DDRC_MRSTAT(0));
+	} while (val & 0x1);
+
+	/* 3. disable AXI ports */
+	mmio_write_32(DDRC_PCTRL_0(0), 0x0);
+
+	/* 4.Poll PSTAT.rd_port_busy_n=0 and PSTAT.wr_port_busy_n=0. */
+	do {
+		val = mmio_read_32(DDRC_PSTAT(0));
+	} while (val != 0);
+
+	/* 6.disable SBRCTL.scrub_en, skip if never enable it */
+	/* 7.poll SBRSTAT.scrub_busy  Q2: should skip phy master if never enable it */
+	/* Disable phy master */
+#ifdef DFILP_SPT
+	/* 8. disable DFI LP */
+	/* DFILPCFG0.dfi_lp_en_sr */
+	val = mmio_read_32(DDRC_DFILPCFG0(0));
+	if (val & 0x100) {
+		mmio_write_32(DDRC_DFILPCFG0(0), 0x0);
+		do {
+			val = mmio_read_32(DDRC_DFISTAT(0)); // dfi_lp_ack
+			val2 = mmio_read_32(DDRC_STAT(0)); // operating_mode
+		} while (((val & 0x2) == 0x2) && ((val2 & 0x7) == 3));
+	}
+#endif
+	/* 9. wait until in normal or power down states */
+	do {
+		/* operating_mode */
+		val = mmio_read_32(DDRC_STAT(0));
+	} while (((val & 0x7) != 1) && ((val & 0x7) != 2));
+
+	/* 10. Disable automatic derating: derate_enable */
+	val = mmio_read_32(DDRC_DERATEEN(0));
+	derate_backup[0] = val;
+	mmio_clrbits_32(DDRC_DERATEEN(0), 0x1);
+
+	val = mmio_read_32(DDRC_FREQ1_DERATEEN(0));
+	derate_backup[1] = val;
+	mmio_clrbits_32(DDRC_FREQ1_DERATEEN(0), 0x1);
+
+	val = mmio_read_32(DDRC_FREQ2_DERATEEN(0));
+	derate_backup[2] = val;
+	mmio_clrbits_32(DDRC_FREQ2_DERATEEN(0), 0x1);
+
+	/* 11. disable automatic ZQ calibration */
+	mmio_setbits_32(DDRC_ZQCTL0(0), BIT(31));
+	mmio_setbits_32(DDRC_FREQ1_ZQCTL0(0), BIT(31));
+	mmio_setbits_32(DDRC_FREQ2_ZQCTL0(0), BIT(31));
+
+	/* 12. set PWRCTL.selfref_en=0 */
+	mmio_clrbits_32(DDRC_PWRCTL(0), 0x1);
+
+	/* 13.Poll STAT.operating_mode is in "Normal" (001) or "Power-down" (010) */
+	do {
+		val = mmio_read_32(DDRC_STAT(0));
+	} while (((val & 0x7) != 1) && ((val & 0x7) != 2));
+
+	/* 14-15. trigger SW SR */
+	/* bit 5: selfref_sw, bit 6: stay_in_selfref */
+	mmio_setbits_32(DDRC_PWRCTL(0), 0x60);
+
+	/* 16. Poll STAT.selfref_state in "Self Refresh 1" */
+	do {
+		val = mmio_read_32(DDRC_STAT(0));
+	} while ((val & 0x300) != 0x100);
+
+	/* 17. disable dq */
+	mmio_setbits_32(DDRC_DBG1(0), 0x1);
+
+	/* 18. Poll DBGCAM.wr_data_pipeline_empty and DBGCAM.rd_data_pipeline_empty */
+	do {
+		val = mmio_read_32(DDRC_DBGCAM(0));
+		val &= 0x30000000;
+	} while (val != 0x30000000);
+
+	/* 19. change MR13.FSP-OP to new FSP and MR13.VRCG to high current */
+	emr3 = (((~init_fsp) & 0x1) << 7) | (0x1 << 3) | (emr3 & 0x0077) | 0x0d00;
+	lpddr4_mr_write(3, 13, emr3);
+
+	/* 20. enter SR Power Down */
+	mmio_clrsetbits_32(DDRC_PWRCTL(0), 0x60, 0x20);
+
+	/* 21. Poll STAT.selfref_state is in "SR Power down" */
+	do {
+		val = mmio_read_32(DDRC_STAT(0));
+	} while ((val & 0x300) != 0x200);
+
+	/* 22. set dfi_init_complete_en = 0 */
+
+	/* 23. switch clock */
+	/* set SWCTL.dw_done to 0 */
+	mmio_write_32(DDRC_SWCTL(0), 0x0000);
+
+	/* 24. program frequency mode=1(bit 29), target_frequency=target_freq (bit 29) */
+	mmio_write_32(DDRC_MSTR2(0), fsp_index);
+
+	/* 25. DBICTL for FSP-OP[1], skip it if never enable it */
+
+	/* 26.trigger initialization in the PHY */
+
+	/* Q3: if refresh level is updated, then should program */
+	/* as updating refresh, need to toggle refresh_update_level signal */
+	val = mmio_read_32(DDRC_RFSHCTL3(0));
+	val = val ^ 0x2;
+	mmio_write_32(DDRC_RFSHCTL3(0), val);
+
+	/* Q4: only for legacy PHY, so here can skipped */
+
+	/* dfi_frequency -> 0x1x */
+	val = mmio_read_32(DDRC_DFIMISC(0));
+	val &= 0xFE;
+	val |= (fsp_index << 8);
+	mmio_write_32(DDRC_DFIMISC(0), val);
+	/* dfi_init_start */
+	val |= 0x20;
+	mmio_write_32(DDRC_DFIMISC(0), val);
+
+	/* polling dfi_init_complete de-assert */
+	do {
+		val = mmio_read_32(DDRC_DFISTAT(0));
+	} while ((val & 0x1) == 0x1);
+
+	/* change the clock frequency */
+	dram_clock_switch(info->timing_info->fsp_table[fsp_index], info->bypass_mode);
+
+	/* dfi_init_start de-assert */
+	mmio_clrbits_32(DDRC_DFIMISC(0), 0x20);
+
+	/* polling dfi_init_complete re-assert */
+	do {
+		val = mmio_read_32(DDRC_DFISTAT(0));
+	} while ((val & 0x1) == 0x0);
+
+	/* 27. set ZQCTL0.dis_srx_zqcl = 1 */
+	if (fsp_index == 0) {
+		mmio_setbits_32(DDRC_ZQCTL0(0), BIT(30));
+	} else  if (fsp_index == 1) {
+		mmio_setbits_32(DDRC_FREQ1_ZQCTL0(0), BIT(30));
+	} else {
+		mmio_setbits_32(DDRC_FREQ2_ZQCTL0(0), BIT(30));
+	}
+
+	/* 28,29. exit "self refresh power down" to stay "self refresh 2" */
+	/* exit SR power down */
+	mmio_clrsetbits_32(DDRC_PWRCTL(0), 0x60, 0x40);
+	/* 30. Poll STAT.selfref_state in "Self refresh 2" */
+	do {
+		val = mmio_read_32(DDRC_STAT(0));
+	} while ((val & 0x300) != 0x300);
+
+	/* 31. change MR13.VRCG to normal */
+	emr3 = (emr3 & 0x00f7) | 0x0d00;
+	lpddr4_mr_write(3, 13, emr3);
+
+	/* enable PHY master */
+	mmio_write_32(DDRC_DFIPHYMSTR(0), 0x1);
+
+	/* 32. issue ZQ if required: zq_calib_short, bit 4 */
+	/* polling zq_calib_short_busy */
+	mmio_setbits_32(DDRC_DBGCMD(0), 0x10);
+
+	do {
+		val = mmio_read_32(DDRC_DBGSTAT(0));
+	} while ((val & 0x10) != 0x0);
+
+	/* 33. Reset ZQCTL0.dis_srx_zqcl=0 */
+	if (fsp_index == 1)
+		mmio_clrbits_32(DDRC_FREQ1_ZQCTL0(0), BIT(30));
+	else if (fsp_index == 2)
+		mmio_clrbits_32(DDRC_FREQ2_ZQCTL0(0), BIT(30));
+	else
+		mmio_clrbits_32(DDRC_ZQCTL0(0), BIT(30));
+
+	/* set SWCTL.dw_done to 1 and poll SWSTAT.sw_done_ack=1 */
+	mmio_write_32(DDRC_SWCTL(0), 0x1);
+
+	/* wait SWSTAT.sw_done_ack to 1 */
+	do {
+		val = mmio_read_32(DDRC_SWSTAT(0));
+	} while ((val & 0x1) == 0x0);
+
+	/* 34. set PWRCTL.stay_in_selfreh=0, exit SR */
+	mmio_clrbits_32(DDRC_PWRCTL(0), 0x40);
+	/* wait tXSR */
+
+	/* 35. Poll STAT.selfref_state in "Idle" */
+	do {
+		val = mmio_read_32(DDRC_STAT(0));
+	} while ((val & 0x300) != 0x0);
+
+#ifdef DFILP_SPT
+	/* 36. restore dfi_lp.dfi_lp_en_sr */
+	mmio_setbits_32(DDRC_DFILPCFG0(0), BIT(8));
+#endif
+
+	/* 37. re-enable CAM: dis_dq */
+	mmio_clrbits_32(DDRC_DBG1(0), 0x1);
+
+	/* 38. re-enable automatic SR: selfref_en */
+	mmio_setbits_32(DDRC_PWRCTL(0), 0x1);
+
+	/* 39. re-enable automatic ZQ: dis_auto_zq=0 */
+	/* disable automatic ZQ calibration */
+	if (fsp_index == 1)
+		mmio_clrbits_32(DDRC_FREQ1_ZQCTL0(0), BIT(31));
+	else if (fsp_index == 2)
+		mmio_clrbits_32(DDRC_FREQ2_ZQCTL0(0), BIT(31));
+	else
+		mmio_clrbits_32(DDRC_ZQCTL0(0), BIT(31));
+	/* 40. re-emable automatic derating: derate_enable */
+	mmio_write_32(DDRC_DERATEEN(0), derate_backup[0]);
+	mmio_write_32(DDRC_FREQ1_DERATEEN(0), derate_backup[1]);
+	mmio_write_32(DDRC_FREQ2_DERATEEN(0), derate_backup[2]);
+
+	/* 41. write 1 to PCTRL.port_en */
+	mmio_write_32(DDRC_PCTRL_0(0), 0x1);
+
+	/* 42. enable SBRCTL.scrub_en, skip if never enable it */
+}