stm32mp1: ram: add tuning in DDR interactive mode

Add command tuning for DDR interactive mode, used during
board bring-up or with CubeMX DDR tools to execute software
tuning for the DDR configuration:
- software read DQS Gating (replace the built-in one)
- Bit de-skew
- Eye Training or DQS training

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>

6 files changed, 1414 insertions, 1 deletions

diff --git a/drivers/ram/stm32mp1/Kconfig b/drivers/ram/stm32mp1/Kconfig
index 4e682b4edf..2fd8c7b7e3 100644
--- a/drivers/ram/stm32mp1/Kconfig
+++ b/drivers/ram/stm32mp1/Kconfig
@@ -37,3 +37,13 @@ config STM32MP1_DDR_TESTS
 	help
 		activate test support for interactive support in
 		STM32MP1 DDR controller driver: command test
+
+config STM32MP1_DDR_TUNING
+	bool "STM32MP1 DDR driver : support of tuning"
+	depends on STM32MP1_DDR_INTERACTIVE
+	default y
+	help
+		activate tuning command in STM32MP1 DDR interactive mode
+		used for DDR tuning tools
+		- DQ Deskew algorithm
+		- DQS Trimming
diff --git a/drivers/ram/stm32mp1/Makefile b/drivers/ram/stm32mp1/Makefile
index 71ded6bed4..e1e9135603 100644
--- a/drivers/ram/stm32mp1/Makefile
+++ b/drivers/ram/stm32mp1/Makefile
@@ -8,6 +8,7 @@ obj-y += stm32mp1_ddr.o
 
 obj-$(CONFIG_STM32MP1_DDR_INTERACTIVE) += stm32mp1_interactive.o
 obj-$(CONFIG_STM32MP1_DDR_TESTS) += stm32mp1_tests.o
+obj-$(CONFIG_STM32MP1_DDR_TUNING) += stm32mp1_tuning.o
 
 ifneq ($(DDR_INTERACTIVE),)
 CFLAGS_stm32mp1_interactive.o += -DCONFIG_STM32MP1_DDR_INTERACTIVE_FORCE=y
diff --git a/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h b/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h
index 97f268e66d..9d33186b3a 100644
--- a/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h
+++ b/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h
@@ -332,6 +332,7 @@ struct stm32mp1_ddrphy {
 
 #define DDRPHYC_DXNGCR_DXEN			BIT(0)
 
+#define DDRPHYC_DXNDLLCR_DLLSRST		BIT(30)
 #define DDRPHYC_DXNDLLCR_DLLDIS			BIT(31)
 #define DDRPHYC_DXNDLLCR_SDPHASE_MASK		GENMASK(17, 14)
 #define DDRPHYC_DXNDLLCR_SDPHASE_SHIFT		14
diff --git a/drivers/ram/stm32mp1/stm32mp1_interactive.c b/drivers/ram/stm32mp1/stm32mp1_interactive.c
index 62d61ac869..cc9b2e7c96 100644
--- a/drivers/ram/stm32mp1/stm32mp1_interactive.c
+++ b/drivers/ram/stm32mp1/stm32mp1_interactive.c
@@ -55,6 +55,9 @@ enum ddr_command stm32mp1_get_command(char *cmd, int argc)
 #ifdef CONFIG_STM32MP1_DDR_TESTS
 		[DDR_CMD_TEST] = "test",
 #endif
+#ifdef CONFIG_STM32MP1_DDR_TUNING
+		[DDR_CMD_TUNING] = "tuning",
+#endif
 	};
 	/* min and max number of argument */
 	const char cmd_arg[DDR_CMD_UNKNOWN][2] = {
@@ -71,6 +74,9 @@ enum ddr_command stm32mp1_get_command(char *cmd, int argc)
 #ifdef CONFIG_STM32MP1_DDR_TESTS
 		[DDR_CMD_TEST] = { 0, 255 },
 #endif
+#ifdef CONFIG_STM32MP1_DDR_TUNING
+		[DDR_CMD_TUNING] = { 0, 255 },
+#endif
 	};
 	int i;
 
@@ -115,6 +121,9 @@ static void stm32mp1_do_usage(void)
 #ifdef CONFIG_STM32MP1_DDR_TESTS
 		"test [help] | <n> [...]    lists (with help) or executes test <n>\n"
 #endif
+#ifdef CONFIG_STM32MP1_DDR_TUNING
+		"tuning [help] | <n> [...]  lists (with help) or execute tuning <n>\n"
+#endif
 		"\nwith for [type|reg]:\n"
 		"  all registers if absent\n"
 		"  <type> = ctl, phy\n"
@@ -297,7 +306,7 @@ end:
 	return step;
 }
 
-#if defined(CONFIG_STM32MP1_DDR_TESTS)
+#if defined(CONFIG_STM32MP1_DDR_TESTS) || defined(CONFIG_STM32MP1_DDR_TUNING)
 static const char * const s_result[] = {
 		[TEST_PASSED] = "Pass",
 		[TEST_FAILED] = "Failed",
@@ -457,6 +466,15 @@ bool stm32mp1_ddr_interactive(void *priv,
 			break;
 #endif
 
+#ifdef CONFIG_STM32MP1_DDR_TUNING
+		case DDR_CMD_TUNING:
+			if (!stm32mp1_check_step(step, STEP_DDR_READY))
+				continue;
+			stm32mp1_ddr_subcmd(priv, argc, argv,
+					    tuning, tuning_nb);
+			break;
+#endif
+
 		default:
 			break;
 		}
diff --git a/drivers/ram/stm32mp1/stm32mp1_tests.h b/drivers/ram/stm32mp1/stm32mp1_tests.h
index 8436780790..55f5d6d93b 100644
--- a/drivers/ram/stm32mp1/stm32mp1_tests.h
+++ b/drivers/ram/stm32mp1/stm32mp1_tests.h
@@ -28,4 +28,7 @@ struct test_desc {
 extern const struct test_desc test[];
 extern const int test_nb;
 
+extern const struct test_desc tuning[];
+extern const int tuning_nb;
+
 #endif
diff --git a/drivers/ram/stm32mp1/stm32mp1_tuning.c b/drivers/ram/stm32mp1/stm32mp1_tuning.c
new file mode 100644
index 0000000000..4e1c1fab54
--- /dev/null
+++ b/drivers/ram/stm32mp1/stm32mp1_tuning.c
@@ -0,0 +1,1380 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ */
+#include <common.h>
+#include <console.h>
+#include <clk.h>
+#include <ram.h>
+#include <reset.h>
+#include <asm/io.h>
+
+#include "stm32mp1_ddr_regs.h"
+#include "stm32mp1_ddr.h"
+#include "stm32mp1_tests.h"
+
+#define MAX_DQS_PHASE_IDX _144deg
+#define MAX_DQS_UNIT_IDX 7
+#define MAX_GSL_IDX 5
+#define MAX_GPS_IDX 3
+
+/* Number of bytes used in this SW. ( min 1--> max 4). */
+#define NUM_BYTES 4
+
+enum dqs_phase_enum {
+	_36deg = 0,
+	_54deg = 1,
+	_72deg = 2,
+	_90deg = 3,
+	_108deg = 4,
+	_126deg = 5,
+	_144deg = 6
+};
+
+/* BIST Result struct */
+struct BIST_result {
+	/* Overall test result:
+	 * 0 Fail (any bit failed) ,
+	 * 1 Success (All bits success)
+	 */
+	bool test_result;
+	/* 1: true, all fail /  0: False, not all bits fail */
+	bool all_bits_fail;
+	bool bit_i_test_result[8];  /* 0 fail / 1 success */
+};
+
+/* a struct that defines tuning parameters of a byte. */
+struct tuning_position {
+	u8 phase; /* DQS phase */
+	u8 unit; /* DQS unit delay */
+	u32 bits_delay; /* Bits deskew in this byte */
+};
+
+/* 36deg, 54deg, 72deg, 90deg, 108deg, 126deg, 144deg */
+const u8 dx_dll_phase[7] = {3, 2, 1, 0, 14, 13, 12};
+
+static u8 BIST_error_max = 1;
+static u32 BIST_seed = 0x1234ABCD;
+
+static u8 get_nb_bytes(struct stm32mp1_ddrctl *ctl)
+{
+	u32 data_bus = readl(&ctl->mstr) & DDRCTRL_MSTR_DATA_BUS_WIDTH_MASK;
+	u8 nb_bytes = NUM_BYTES;
+
+	switch (data_bus) {
+	case DDRCTRL_MSTR_DATA_BUS_WIDTH_HALF:
+		nb_bytes /= 2;
+		break;
+	case DDRCTRL_MSTR_DATA_BUS_WIDTH_QUARTER:
+		nb_bytes /= 4;
+		break;
+	default:
+		break;
+	}
+
+	return nb_bytes;
+}
+
+static void itm_soft_reset(struct stm32mp1_ddrphy *phy)
+{
+	stm32mp1_ddrphy_init(phy, DDRPHYC_PIR_ITMSRST);
+}
+
+/* Read DQ unit delay register and provides the retrieved value for DQS
+ * We are assuming that we have the same delay when clocking
+ * by DQS and when clocking by DQSN
+ */
+static u8 DQ_unit_index(struct stm32mp1_ddrphy *phy, u8 byte, u8 bit)
+{
+	u32 index;
+	u32 addr = DXNDQTR(phy, byte);
+
+	/* We are assuming that we have the same delay when clocking by DQS
+	 * and when clocking by DQSN : use only the low bits
+	 */
+	index = (readl(addr) >> DDRPHYC_DXNDQTR_DQDLY_SHIFT(bit))
+		& DDRPHYC_DXNDQTR_DQDLY_LOW_MASK;
+
+	pr_debug("%s: [%x]: %x => DQ unit index = %x\n",
+		 __func__, addr, readl(addr), index);
+
+	return index;
+}
+
+/* Sets the DQS phase delay for a byte lane.
+ *phase delay is specified by giving the index of the desired delay
+ * in the dx_dll_phase array.
+ */
+static void DQS_phase_delay(struct stm32mp1_ddrphy *phy, u8 byte, u8 phase_idx)
+{
+	u8 sdphase_val = 0;
+
+	/*	Write DXNDLLCR.SDPHASE = dx_dll_phase(phase_index); */
+	sdphase_val = dx_dll_phase[phase_idx];
+	clrsetbits_le32(DXNDLLCR(phy, byte),
+			DDRPHYC_DXNDLLCR_SDPHASE_MASK,
+			sdphase_val << DDRPHYC_DXNDLLCR_SDPHASE_SHIFT);
+}
+
+/* Sets the DQS unit delay for a byte lane.
+ * unit delay is specified by giving the index of the desired delay
+ * for dgsdly and dqsndly (same value).
+ */
+static void DQS_unit_delay(struct stm32mp1_ddrphy *phy,
+			   u8 byte, u8 unit_dly_idx)
+{
+	/* Write the same value in DXNDQSTR.DQSDLY and DXNDQSTR.DQSNDLY */
+	clrsetbits_le32(DXNDQSTR(phy, byte),
+			DDRPHYC_DXNDQSTR_DQSDLY_MASK |
+			DDRPHYC_DXNDQSTR_DQSNDLY_MASK,
+			(unit_dly_idx << DDRPHYC_DXNDQSTR_DQSDLY_SHIFT) |
+			(unit_dly_idx << DDRPHYC_DXNDQSTR_DQSNDLY_SHIFT));
+
+	/* After changing this value, an ITM soft reset (PIR.ITMSRST=1,
+	 * plus PIR.INIT=1) must be issued.
+	 */
+	stm32mp1_ddrphy_init(phy, DDRPHYC_PIR_ITMSRST);
+}
+
+/* Sets the DQ unit delay for a bit line in particular byte lane.
+ * unit delay is specified by giving the desired delay
+ */
+static void set_DQ_unit_delay(struct stm32mp1_ddrphy *phy,
+			      u8 byte, u8 bit,
+			      u8 dq_delay_index)
+{
+	u8 dq_bit_delay_val = dq_delay_index | (dq_delay_index << 2);
+
+	/* same value on delay for clock DQ an DQS_b */
+	clrsetbits_le32(DXNDQTR(phy, byte),
+			DDRPHYC_DXNDQTR_DQDLY_MASK
+			<< DDRPHYC_DXNDQTR_DQDLY_SHIFT(bit),
+			dq_bit_delay_val << DDRPHYC_DXNDQTR_DQDLY_SHIFT(bit));
+}
+
+static void set_r0dgsl_delay(struct stm32mp1_ddrphy *phy,
+			     u8 byte, u8 r0dgsl_idx)
+{
+	clrsetbits_le32(DXNDQSTR(phy, byte),
+			DDRPHYC_DXNDQSTR_R0DGSL_MASK,
+			r0dgsl_idx << DDRPHYC_DXNDQSTR_R0DGSL_SHIFT);
+}
+
+static void set_r0dgps_delay(struct stm32mp1_ddrphy *phy,
+			     u8 byte, u8 r0dgps_idx)
+{
+	clrsetbits_le32(DXNDQSTR(phy, byte),
+			DDRPHYC_DXNDQSTR_R0DGPS_MASK,
+			r0dgps_idx << DDRPHYC_DXNDQSTR_R0DGPS_SHIFT);
+}
+
+/* Basic BIST configuration for data lane tests. */
+static void config_BIST(struct stm32mp1_ddrphy *phy)
+{
+	/* Selects the SDRAM bank address to be used during BIST. */
+	u32 bbank = 0;
+	/* Selects the SDRAM row address to be used during BIST. */
+	u32 brow = 0;
+	/* Selects the SDRAM column address to be used during BIST. */
+	u32 bcol = 0;
+	/* Selects the value by which the SDRAM address is incremented
+	 * for each write/read access.
+	 */
+	u32 bainc = 0x00000008;
+	/* Specifies the maximum SDRAM rank to be used during BIST.
+	 * The default value is set to maximum ranks minus 1.
+	 * must be 0 with single rank
+	 */
+	u32 bmrank = 0;
+	/* Selects the SDRAM rank to be used during BIST.
+	 * must be 0 with single rank
+	 */
+	u32 brank = 0;
+	/* Specifies the maximum SDRAM bank address to be used during
+	 * BIST before the address & increments to the next rank.
+	 */
+	u32 bmbank = 1;
+	/* Specifies the maximum SDRAM row address to be used during
+	 * BIST before the address & increments to the next bank.
+	 */
+	u32 bmrow = 0x7FFF; /* To check */
+	/* Specifies the maximum SDRAM column address to be used during
+	 * BIST before the address & increments to the next row.
+	 */
+	u32 bmcol = 0x3FF;  /* To check */
+	u32 bmode_conf = 0x00000001;  /* DRam mode */
+	u32 bdxen_conf = 0x00000001;  /* BIST on Data byte */
+	u32 bdpat_conf = 0x00000002;  /* Select LFSR pattern */
+
+	/*Setup BIST for DRAM mode,  and LFSR-random data pattern.*/
+	/*Write BISTRR.BMODE = 1?b1;*/
+	/*Write BISTRR.BDXEN = 1?b1;*/
+	/*Write BISTRR.BDPAT = 2?b10;*/
+
+	/* reset BIST */
+	writel(0x3, &phy->bistrr);
+
+	writel((bmode_conf << 3) | (bdxen_conf << 14) | (bdpat_conf << 17),
+	       &phy->bistrr);
+
+	/*Setup BIST Word Count*/
+	/*Write BISTWCR.BWCNT = 16?b0008;*/
+	writel(0x00000200, &phy->bistwcr); /* A multiple of BL/2 */
+
+	writel(bcol | (brow << 12) | (bbank << 28), &phy->bistar0);
+	writel(brank | (bmrank << 2) | (bainc << 4), &phy->bistar1);
+
+	/* To check this line : */
+	writel(bmcol | (bmrow << 12) | (bmbank << 28), &phy->bistar2);
+}
+
+/* Select the Byte lane to be tested by BIST. */
+static void BIST_datx8_sel(struct stm32mp1_ddrphy *phy, u8 datx8)
+{
+	clrsetbits_le32(&phy->bistrr,
+			DDRPHYC_BISTRR_BDXSEL_MASK,
+			datx8 << DDRPHYC_BISTRR_BDXSEL_SHIFT);
+
+	/*(For example, selecting Byte Lane 3, BISTRR.BDXSEL = 4?b0011)*/
+	/* Write BISTRR.BDXSEL = datx8; */
+}
+
+/* Perform BIST Write_Read test on a byte lane and return test result. */
+static void BIST_test(struct stm32mp1_ddrphy *phy, u8 byte,
+		      struct BIST_result *bist)
+{
+	bool result = true; /* BIST_SUCCESS */
+	u32 cnt = 0;
+	u32 error = 0;
+
+	bist->test_result = true;
+
+run:
+	itm_soft_reset(phy);
+
+	/*Perform BIST Reset*/
+	/* Write BISTRR.BINST = 3?b011; */
+	clrsetbits_le32(&phy->bistrr,
+			0x00000007,
+			0x00000003);
+
+	/*Re-seed LFSR*/
+	/* Write BISTLSR.SEED = 32'h1234ABCD; */
+	if (BIST_seed)
+		writel(BIST_seed, &phy->bistlsr);
+	else
+		writel(rand(), &phy->bistlsr);
+
+	/* some delay to reset BIST */
+	mdelay(1);
+
+	/*Perform BIST Run*/
+	clrsetbits_le32(&phy->bistrr,
+			0x00000007,
+			0x00000001);
+	/* Write BISTRR.BINST = 3?b001; */
+
+	/* Wait for a number of CTL clocks before reading BIST register*/
+	/* Wait 300 ctl_clk cycles;  ... IS it really needed?? */
+	/* Perform BIST Instruction Stop*/
+	/* Write BISTRR.BINST = 3?b010;*/
+
+	/* poll on BISTGSR.BDONE. If 0, wait.  ++TODO Add timeout */
+	while (!(readl(&phy->bistgsr) & DDRPHYC_BISTGSR_BDDONE))
+		;
+
+	/*Check if received correct number of words*/
+	/* if (Read BISTWCSR.DXWCNT = Read BISTWCR.BWCNT) */
+	if (((readl(&phy->bistwcsr)) >> DDRPHYC_BISTWCSR_DXWCNT_SHIFT) ==
+	    readl(&phy->bistwcr)) {
+		/*Determine if there is a data comparison error*/
+		/* if (Read BISTGSR.BDXERR = 1?b0) */
+		if (readl(&phy->bistgsr) & DDRPHYC_BISTGSR_BDXERR)
+			result = false; /* BIST_FAIL; */
+		else
+			result = true; /* BIST_SUCCESS; */
+	} else {
+		result = false; /* BIST_FAIL; */
+	}
+
+	/* loop while success */
+	cnt++;
+	if (result && cnt != 1000)
+		goto run;
+
+	if (!result)
+		error++;
+
+	if (error < BIST_error_max) {
+		if (cnt != 1000)
+			goto run;
+		bist->test_result = true;
+	} else {
+		bist->test_result = false;
+	}
+}
+
+/* After running the deskew algo, this function applies the new DQ delays
+ * by reading them from the array "deskew_delay"and writing in PHY registers.
+ * The bits that are not deskewed parfectly (too much skew on them,
+ * or data eye very wide) are marked in the array deskew_non_converge.
+ */
+static void apply_deskew_results(struct stm32mp1_ddrphy *phy, u8 byte,
+				 u8 deskew_delay[NUM_BYTES][8],
+				 u8 deskew_non_converge[NUM_BYTES][8])
+{
+	u8  bit_i;
+	u8  index;
+
+	for (bit_i = 0; bit_i < 8; bit_i++) {
+		set_DQ_unit_delay(phy, byte, bit_i, deskew_delay[byte][bit_i]);
+		index = DQ_unit_index(phy, byte, bit_i);
+		pr_debug("Byte %d ; bit %d : The new DQ delay (%d) index=%d [delta=%d, 3 is the default]",
+			 byte, bit_i, deskew_delay[byte][bit_i],
+			 index, index - 3);
+		printf("Byte %d, bit %d, DQ delay = %d",
+		       byte, bit_i, deskew_delay[byte][bit_i]);
+		if (deskew_non_converge[byte][bit_i] == 1)
+			pr_debug(" - not converged : still more skew");
+		printf("\n");
+	}
+}
+
+/* DQ Bit de-skew algorithm.
+ * Deskews data lines as much as possible.
+ * 1. Add delay to DQS line until finding the failure
+ *    (normally a hold time violation)
+ * 2. Reduce DQS line by small steps until finding the very first time
+ *    we go back to "Pass" condition.
+ * 3. For each DQ line, Reduce DQ delay until finding the very first failure
+ *    (normally a hold time fail)
+ * 4. When all bits are at their first failure delay, we can consider them
+ *    aligned.
+ * Handle conrer situation (Can't find Pass-fail, or fail-pass transitions
+ * at any step)
+ * TODO Provide a return Status. Improve doc
+ */
+static enum test_result bit_deskew(struct stm32mp1_ddrctl *ctl,
+				   struct stm32mp1_ddrphy *phy, char *string)
+{
+	/* New DQ delay value (index), set during Deskew algo */
+	u8 deskew_delay[NUM_BYTES][8];
+	/*If there is still skew on a bit, mark this bit. */
+	u8 deskew_non_converge[NUM_BYTES][8];
+	struct BIST_result result;
+	s8 dqs_unit_delay_index = 0;
+	u8 datx8 = 0;
+	u8 bit_i = 0;
+	s8 phase_idx = 0;
+	s8 bit_i_delay_index = 0;
+	u8 success = 0;
+	struct tuning_position last_right_ok;
+	u8 force_stop = 0;
+	u8 fail_found;
+	u8 error = 0;
+	u8 nb_bytes = get_nb_bytes(ctl);
+	/* u8 last_pass_dqs_unit = 0; */
+
+	memset(deskew_delay, 0, sizeof(deskew_delay));
+	memset(deskew_non_converge, 0, sizeof(deskew_non_converge));
+
+	/*Disable DQS Drift Compensation*/
+	clrbits_le32(&phy->pgcr, DDRPHYC_PGCR_DFTCMP);
+	/*Disable all bytes*/
+	/* Disable automatic power down of DLL and IOs when disabling
+	 * a byte (To avoid having to add programming and  delay
+	 * for a DLL re-lock when later re-enabling a disabled Byte Lane)
+	 */
+	clrbits_le32(&phy->pgcr, DDRPHYC_PGCR_PDDISDX);
+
+	/* Disable all data bytes */
+	clrbits_le32(&phy->dx0gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx1gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx2gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx3gcr, DDRPHYC_DXNGCR_DXEN);
+
+	/* Config the BIST block */
+	config_BIST(phy);
+	pr_debug("BIST Config done.\n");
+
+	/* Train each byte */
+	for (datx8 = 0; datx8 < nb_bytes; datx8++) {
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				datx8 + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		pr_debug("\n======================\n");
+		pr_debug("Start deskew byte %d .\n", datx8);
+		pr_debug("======================\n");
+		/* Enable Byte (DXNGCR, bit DXEN) */
+		setbits_le32(DXNGCR(phy, datx8), DDRPHYC_DXNGCR_DXEN);
+
+		/* Select the byte lane for comparison of read data */
+		BIST_datx8_sel(phy, datx8);
+
+		/* Set all DQDLYn to maximum value. All bits within the byte
+		 * will be delayed with DQSTR = 2 instead of max = 3
+		 * to avoid inter bits fail influence
+		 */
+		writel(0xAAAAAAAA, DXNDQTR(phy, datx8));
+
+		/* Set the DQS phase delay to 90 DEG (default).
+		 * What is defined here is the index of the desired config
+		 * in the PHASE array.
+		 */
+		phase_idx = _90deg;
+
+		/* Set DQS unit delay to the max value. */
+		dqs_unit_delay_index = MAX_DQS_UNIT_IDX;
+		DQS_unit_delay(phy, datx8, dqs_unit_delay_index);
+		DQS_phase_delay(phy, datx8, phase_idx);
+
+		/* Issue a DLL soft reset */
+		clrbits_le32(DXNDLLCR(phy, datx8), DDRPHYC_DXNDLLCR_DLLSRST);
+		setbits_le32(DXNDLLCR(phy, datx8), DDRPHYC_DXNDLLCR_DLLSRST);
+
+		/* Test this typical init condition */
+		BIST_test(phy, datx8, &result);
+		success = result.test_result;
+
+		/* If the test pass in this typical condition,
+		 * start the algo with it.
+		 * Else, look for Pass init condition
+		 */
+		if (!success) {
+			pr_debug("Fail at init condtion. Let's look for a good init condition.\n");
+			success = 0; /* init */
+			/* Make sure we start with a PASS condition before
+			 * looking for a fail condition.
+			 * Find the first PASS PHASE condition
+			 */
+
+			/* escape if we find a PASS */
+			pr_debug("increase Phase idx\n");
+			while (!success && (phase_idx <= MAX_DQS_PHASE_IDX)) {
+				DQS_phase_delay(phy, datx8, phase_idx);
+				BIST_test(phy, datx8, &result);
+				success = result.test_result;
+				phase_idx++;
+			}
+			/* if ended with success
+			 * ==>> Restore the fist success condition
+			 */
+			if (success)
+				phase_idx--; /* because it ended with ++ */
+		}
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				datx8 + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		/* We couldn't find a successful condition, its seems
+		 * we have hold violation, lets try reduce DQS_unit Delay
+		 */
+		if (!success) {
+			/* We couldn't find a successful condition, its seems
+			 * we have hold violation, lets try reduce DQS_unit
+			 * Delay
+			 */
+			pr_debug("Still fail. Try decrease DQS Unit delay\n");
+
+			phase_idx = 0;
+			dqs_unit_delay_index = 0;
+			DQS_phase_delay(phy, datx8, phase_idx);
+
+			/* escape if we find a PASS */
+			while (!success &&
+			       (dqs_unit_delay_index <=
+				MAX_DQS_UNIT_IDX)) {
+				DQS_unit_delay(phy, datx8,
+					       dqs_unit_delay_index);
+				BIST_test(phy, datx8, &result);
+				success = result.test_result;
+				dqs_unit_delay_index++;
+			}
+			if (success) {
+				/* Restore the first success condition*/
+				dqs_unit_delay_index--;
+				/* last_pass_dqs_unit = dqs_unit_delay_index;*/
+				DQS_unit_delay(phy, datx8,
+					       dqs_unit_delay_index);
+			} else {
+				/* No need to continue,
+				 * there is no pass region.
+				 */
+				force_stop = 1;
+			}
+		}
+
+		/* There is an initial PASS condition
+		 * Look for the first failing condition by PHASE stepping.
+		 * This part of the algo can finish without converging.
+		 */
+		if (force_stop) {
+			printf("Result: Failed ");
+			printf("[Cannot Deskew lines, ");
+			printf("there is no PASS region]\n");
+			error++;
+			continue;
+		}
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				datx8 + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+
+		pr_debug("there is a pass region for phase idx %d\n",
+			 phase_idx);
+		pr_debug("Step1: Find the first failing condition\n");
+		/* Look for the first failing condition by PHASE stepping.
+		 * This part of the algo can finish without converging.
+		 */
+
+		/* escape if we find a fail (hold time violation)
+		 * condition at any bit or if out of delay range.
+		 */
+		while (success && (phase_idx <= MAX_DQS_PHASE_IDX)) {
+			DQS_phase_delay(phy, datx8, phase_idx);
+			BIST_test(phy, datx8, &result);
+			success = result.test_result;
+			phase_idx++;
+		}
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				datx8 + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+
+		/* if the loop ended with a failing condition at any bit,
+		 * lets look for the first previous success condition by unit
+		 * stepping (minimal delay)
+		 */
+		if (!success) {
+			pr_debug("Fail region (PHASE) found phase idx %d\n",
+				 phase_idx);
+			pr_debug("Let's look for first success by DQS Unit steps\n");
+			/* This part, the algo always converge */
+			phase_idx--;
+
+			/* escape if we find a success condition
+			 * or if out of delay range.
+			 */
+			while (!success && dqs_unit_delay_index >= 0) {
+				DQS_unit_delay(phy, datx8,
+					       dqs_unit_delay_index);
+				BIST_test(phy, datx8, &result);
+				success = result.test_result;
+				dqs_unit_delay_index--;
+			}
+			/* if the loop ended with a success condition,
+			 * the last delay Right OK (before hold violation)
+			 *  condition is then defined as following:
+			 */
+			if (success) {
+				/* Hold the dely parameters of the the last
+				 * delay Right OK condition.
+				 * -1 to get back to current condition
+				 */
+				last_right_ok.phase = phase_idx;
+				/*+1 to get back to current condition */
+				last_right_ok.unit = dqs_unit_delay_index + 1;
+				last_right_ok.bits_delay = 0xFFFFFFFF;
+				pr_debug("Found %d\n", dqs_unit_delay_index);
+			} else {
+				/* the last OK condition is then with the
+				 * previous phase_idx.
+				 * -2 instead of -1 because at the last
+				 * iteration of the while(),
+				 * we incremented phase_idx
+				 */
+				last_right_ok.phase = phase_idx - 1;
+				/* Nominal+1. Because we want the previous
+				 * delay after reducing the phase delay.
+				 */
+				last_right_ok.unit = 1;
+				last_right_ok.bits_delay = 0xFFFFFFFF;
+				pr_debug("Not Found : try previous phase %d\n",
+					 phase_idx - 1);
+
+				DQS_phase_delay(phy, datx8, phase_idx - 1);
+				dqs_unit_delay_index = 0;
+				success = true;
+				while (success &&
+				       (dqs_unit_delay_index <
+					MAX_DQS_UNIT_IDX)) {
+					DQS_unit_delay(phy, datx8,
+						       dqs_unit_delay_index);
+					BIST_test(phy, datx8, &result);
+					success = result.test_result;
+					dqs_unit_delay_index++;
+					pr_debug("dqs_unit_delay_index = %d, result = %d\n",
+						 dqs_unit_delay_index, success);
+				}
+
+				if (!success) {
+					last_right_ok.unit =
+						 dqs_unit_delay_index - 1;
+				} else {
+					last_right_ok.unit = 0;
+					pr_debug("ERROR: failed region not FOUND");
+				}
+			}
+		} else {
+			/* we can't find a failing  condition at all bits
+			 * ==> Just hold the last test condition
+			 * (the max DQS delay)
+			 * which is the most likely,
+			 * the closest to a hold violation
+			 * If we can't find a Fail condition after
+			 * the Pass region, stick at this position
+			 * In order to have max chances to find a fail
+			 * when reducing DQ delays.
+			 */
+			last_right_ok.phase = MAX_DQS_PHASE_IDX;
+			last_right_ok.unit = MAX_DQS_UNIT_IDX;
+			last_right_ok.bits_delay = 0xFFFFFFFF;
+			pr_debug("Can't find the a fail condition\n");
+		}
+
+		/* step 2:
+		 * if we arrive at this stage, it means that we found the last
+		 * Right OK condition (by tweeking the DQS delay). Or we simply
+		 * pushed DQS delay to the max
+		 * This means that by reducing the delay on some DQ bits,
+		 * we should find a failing condition.
+		 */
+		printf("Byte %d, DQS unit = %d, phase = %d\n",
+		       datx8, last_right_ok.unit, last_right_ok.phase);
+		pr_debug("Step2, unit = %d, phase = %d, bits delay=%x\n",
+			 last_right_ok.unit, last_right_ok.phase,
+			 last_right_ok.bits_delay);
+
+		/* Restore the last_right_ok condtion. */
+		DQS_unit_delay(phy, datx8, last_right_ok.unit);
+		DQS_phase_delay(phy, datx8, last_right_ok.phase);
+		writel(last_right_ok.bits_delay, DXNDQTR(phy, datx8));
+
+		/* train each bit
+		 * reduce delay on each bit, and perform a write/read test
+		 * and stop at the very first time it fails.
+		 * the goal is the find the first failing condition
+		 * for each bit.
+		 * When we achieve this condition<  for all the bits,
+		 * we are sure they are aligned (+/- step resolution)
+		 */
+		fail_found = 0;
+		for (bit_i = 0; bit_i < 8; bit_i++) {
+			if (ctrlc()) {
+				sprintf(string,
+					"interrupted at byte %d/%d, error=%d",
+					datx8 + 1, nb_bytes, error);
+				return error;
+			}
+			pr_debug("deskewing bit %d:\n", bit_i);
+			success = 1; /* init */
+			/* Set all DQDLYn to maximum value.
+			 * Only bit_i will be down-delayed
+			 * ==> if we have a fail, it will be definitely
+			 *     from bit_i
+			 */
+			writel(0xFFFFFFFF, DXNDQTR(phy, datx8));
+			/* Arriving at this stage,
+			 * we have a success condition with delay = 3;
+			 */
+			bit_i_delay_index = 3;
+
+			/* escape if bit delay is out of range or
+			 * if a fatil occurs
+			 */
+			while ((bit_i_delay_index >= 0) && success) {
+				set_DQ_unit_delay(phy, datx8,
+						  bit_i,
+						  bit_i_delay_index);
+				BIST_test(phy, datx8, &result);
+				success = result.test_result;
+				bit_i_delay_index--;
+			}
+
+			/* if escape with a fail condition
+			 * ==> save this position for bit_i
+			 */
+			if (!success) {
+				/* save the delay position.
+				 * Add 1 because the while loop ended with a --,
+				 * and that we need to hold the last success
+				 *  delay
+				 */
+				deskew_delay[datx8][bit_i] =
+					bit_i_delay_index + 2;
+				if (deskew_delay[datx8][bit_i] > 3)
+					deskew_delay[datx8][bit_i] = 3;
+
+				/* A flag that states we found at least a fail
+				 * at one bit.
+				 */
+				fail_found = 1;
+				pr_debug("Fail found on bit %d, for delay = %d => deskew[%d][%d] = %d\n",
+					 bit_i, bit_i_delay_index + 1,
+					 datx8, bit_i,
+					 deskew_delay[datx8][bit_i]);
+			} else {
+				/* if we can find a success condition by
+				 * back-delaying this bit, just set the delay
+				 * to 0 (the best deskew
+				 * possible) and mark the bit.
+				 */
+				deskew_delay[datx8][bit_i] = 0;
+				/* set a flag that will be used later
+				 * in the report.
+				 */
+				deskew_non_converge[datx8][bit_i] = 1;
+				pr_debug("Fail not found on bit %d => deskew[%d][%d] = %d\n",
+					 bit_i, datx8, bit_i,
+					 deskew_delay[datx8][bit_i]);
+			}
+		}
+		pr_debug("**********byte %d tuning complete************\n",
+			 datx8);
+		/* If we can't find any failure by back delaying DQ lines,
+		 * hold the default values
+		 */
+		if (!fail_found) {
+			for (bit_i = 0; bit_i < 8; bit_i++)
+				deskew_delay[datx8][bit_i] = 0;
+			pr_debug("The Deskew algorithm can't converge, there is too much margin in your design. Good job!\n");
+		}
+
+		apply_deskew_results(phy, datx8, deskew_delay,
+				     deskew_non_converge);
+		/* Restore nominal value for DQS delay */
+		DQS_phase_delay(phy, datx8, 3);
+		DQS_unit_delay(phy, datx8, 3);
+		/* disable byte after byte bits deskew */
+		clrbits_le32(DXNGCR(phy, datx8), DDRPHYC_DXNGCR_DXEN);
+	}  /* end of byte deskew */
+
+	/* re-enable all data bytes */
+	setbits_le32(&phy->dx0gcr, DDRPHYC_DXNGCR_DXEN);
+	setbits_le32(&phy->dx1gcr, DDRPHYC_DXNGCR_DXEN);
+	setbits_le32(&phy->dx2gcr, DDRPHYC_DXNGCR_DXEN);
+	setbits_le32(&phy->dx3gcr, DDRPHYC_DXNGCR_DXEN);
+
+	if (error) {
+		sprintf(string, "error = %d", error);
+		return TEST_FAILED;
+	}
+
+	return TEST_PASSED;
+} /* end function */
+
+/* Trim DQS timings and set it in the centre of data eye.
+ * Look for a PPPPF region, then look for a FPPP region and finally select
+ * the mid of the FPPPPPF region
+ */
+static enum test_result eye_training(struct stm32mp1_ddrctl *ctl,
+				     struct stm32mp1_ddrphy *phy, char *string)
+{
+	/*Stores the DQS trim values (PHASE index, unit index) */
+	u8 eye_training_val[NUM_BYTES][2];
+	u8 byte = 0;
+	struct BIST_result result;
+	s8 dqs_unit_delay_index = 0;
+	s8 phase_idx = 0;
+	s8 dqs_unit_delay_index_pass = 0;
+	s8 phase_idx_pass = 0;
+	u8 success = 0;
+	u8 left_phase_bound_found, right_phase_bound_found;
+	u8 left_unit_bound_found, right_unit_bound_found;
+	u8 left_bound_found, right_bound_found;
+	struct tuning_position left_bound, right_bound;
+	u8 error = 0;
+	u8 nb_bytes = get_nb_bytes(ctl);
+
+	/*Disable DQS Drift Compensation*/
+	clrbits_le32(&phy->pgcr, DDRPHYC_PGCR_DFTCMP);
+	/*Disable all bytes*/
+	/* Disable automatic power down of DLL and IOs when disabling a byte
+	 * (To avoid having to add programming and  delay
+	 * for a DLL re-lock when later re-enabling a disabled Byte Lane)
+	 */
+	clrbits_le32(&phy->pgcr, DDRPHYC_PGCR_PDDISDX);
+
+	/*Disable all data bytes */
+	clrbits_le32(&phy->dx0gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx1gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx2gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx3gcr, DDRPHYC_DXNGCR_DXEN);
+
+	/* Config the BIST block */
+	config_BIST(phy);
+
+	for (byte = 0; byte < nb_bytes; byte++) {
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				byte + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		right_bound.phase = 0;
+		right_bound.unit = 0;
+
+		left_bound.phase = 0;
+		left_bound.unit = 0;
+
+		left_phase_bound_found = 0;
+		right_phase_bound_found = 0;
+
+		left_unit_bound_found = 0;
+		right_unit_bound_found = 0;
+
+		left_bound_found = 0;
+		right_bound_found = 0;
+
+		/* Enable Byte (DXNGCR, bit DXEN) */
+		setbits_le32(DXNGCR(phy, byte), DDRPHYC_DXNGCR_DXEN);
+
+		/* Select the byte lane for comparison of read data */
+		BIST_datx8_sel(phy, byte);
+
+		/* Set DQS phase delay to the nominal value. */
+		phase_idx = _90deg;
+		phase_idx_pass = phase_idx;
+
+		/* Set DQS unit delay to the nominal value. */
+		dqs_unit_delay_index = 3;
+		dqs_unit_delay_index_pass = dqs_unit_delay_index;
+		success = 0;
+
+		pr_debug("STEP0: Find Init delay\n");
+		/* STEP0: Find Init delay: a delay that put the system
+		 * in a "Pass" condition then (TODO) update
+		 * dqs_unit_delay_index_pass & phase_idx_pass
+		 */
+		DQS_unit_delay(phy, byte, dqs_unit_delay_index);
+		DQS_phase_delay(phy, byte, phase_idx);
+		BIST_test(phy, byte, &result);
+		success = result.test_result;
+		/* If we have a fail in the nominal condition */
+		if (!success) {
+			/* Look at the left */
+			while (phase_idx >= 0 && !success) {
+				phase_idx--;
+				DQS_phase_delay(phy, byte, phase_idx);
+				BIST_test(phy, byte, &result);
+				success = result.test_result;
+			}
+		}
+		if (!success) {
+			/* if we can't find pass condition,
+			 * then look at the right
+			 */
+			phase_idx = _90deg;
+			while (phase_idx <= MAX_DQS_PHASE_IDX &&
+			       !success) {
+				phase_idx++;
+				DQS_phase_delay(phy, byte,
+						phase_idx);
+				BIST_test(phy, byte, &result);
+				success = result.test_result;
+			}
+		}
+		/* save the pass condition */
+		if (success) {
+			phase_idx_pass = phase_idx;
+		} else {
+			printf("Result: Failed ");
+			printf("[Cannot DQS timings, ");
+			printf("there is no PASS region]\n");
+			error++;
+			continue;
+		}
+
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				byte + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		pr_debug("STEP1: Find LEFT PHASE DQS Bound\n");
+		/* STEP1: Find LEFT PHASE DQS Bound */
+		while ((phase_idx >= 0) &&
+		       (phase_idx <= MAX_DQS_PHASE_IDX) &&
+		       !left_phase_bound_found) {
+			DQS_unit_delay(phy, byte,
+				       dqs_unit_delay_index);
+			DQS_phase_delay(phy, byte,
+					phase_idx);
+			BIST_test(phy, byte, &result);
+			success = result.test_result;
+
+			/*TODO: Manage the case were at the beginning
+			 * there is already a fail
+			 */
+			if (!success) {
+				/* the last pass condition */
+				left_bound.phase = ++phase_idx;
+				left_phase_bound_found = 1;
+			} else if (success) {
+				phase_idx--;
+			}
+		}
+		if (!left_phase_bound_found) {
+			left_bound.phase = 0;
+			phase_idx = 0;
+		}
+		/* If not found, lets take 0 */
+
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				byte + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		pr_debug("STEP2: Find UNIT left bound\n");
+		/* STEP2: Find UNIT left bound */
+		while ((dqs_unit_delay_index >= 0) &&
+		       !left_unit_bound_found) {
+			DQS_unit_delay(phy, byte,
+				       dqs_unit_delay_index);
+			DQS_phase_delay(phy, byte, phase_idx);
+			BIST_test(phy, byte, &result);
+			success = result.test_result;
+			if (!success) {
+				left_bound.unit =
+					++dqs_unit_delay_index;
+				left_unit_bound_found = 1;
+				left_bound_found = 1;
+			} else if (success) {
+				dqs_unit_delay_index--;
+			}
+		}
+
+		/* If not found, lets take 0 */
+		if (!left_unit_bound_found)
+			left_bound.unit = 0;
+
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				byte + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		pr_debug("STEP3: Find PHase right bound\n");
+		/* STEP3: Find PHase right bound, start with "pass"
+		 * condition
+		 */
+
+		/* Set DQS phase delay to the pass value. */
+		phase_idx = phase_idx_pass;
+
+		/* Set DQS unit delay to the pass value. */
+		dqs_unit_delay_index = dqs_unit_delay_index_pass;
+
+		while ((phase_idx <= MAX_DQS_PHASE_IDX) &&
+		       !right_phase_bound_found) {
+			DQS_unit_delay(phy, byte,
+				       dqs_unit_delay_index);
+			DQS_phase_delay(phy, byte, phase_idx);
+			BIST_test(phy, byte, &result);
+			success = result.test_result;
+			if (!success) {
+				/* the last pass condition */
+				right_bound.phase = --phase_idx;
+				right_phase_bound_found = 1;
+			} else if (success) {
+				phase_idx++;
+			}
+		}
+
+		/* If not found, lets take the max value */
+		if (!right_phase_bound_found) {
+			right_bound.phase = MAX_DQS_PHASE_IDX;
+			phase_idx = MAX_DQS_PHASE_IDX;
+		}
+
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d, error=%d",
+				byte + 1, nb_bytes, error);
+			return TEST_FAILED;
+		}
+		pr_debug("STEP4: Find UNIT right bound\n");
+		/* STEP4: Find UNIT right bound */
+		while ((dqs_unit_delay_index <= MAX_DQS_UNIT_IDX) &&
+		       !right_unit_bound_found) {
+			DQS_unit_delay(phy, byte,
+				       dqs_unit_delay_index);
+			DQS_phase_delay(phy, byte, phase_idx);
+			BIST_test(phy, byte, &result);
+			success = result.test_result;
+			if (!success) {
+				right_bound.unit =
+					--dqs_unit_delay_index;
+				right_unit_bound_found = 1;
+				right_bound_found = 1;
+			} else if (success) {
+				dqs_unit_delay_index++;
+			}
+		}
+		/* If not found, lets take the max value */
+		if (!right_unit_bound_found)
+			right_bound.unit = MAX_DQS_UNIT_IDX;
+
+		/* If we found a regular FAil Pass FAil pattern
+		 * FFPPPPPPFF
+		 * OR PPPPPFF  Or FFPPPPP
+		 */
+
+		if (left_bound_found || right_bound_found) {
+			eye_training_val[byte][0] = (right_bound.phase +
+						 left_bound.phase) / 2;
+			eye_training_val[byte][1] = (right_bound.unit +
+						 left_bound.unit) / 2;
+
+			/* If we already lost 1/2PHASE Tuning,
+			 * let's try to recover by ++ on unit
+			 */
+			if (((right_bound.phase + left_bound.phase) % 2 == 1) &&
+			    eye_training_val[byte][1] != MAX_DQS_UNIT_IDX)
+				eye_training_val[byte][1]++;
+			pr_debug("** found phase : %d -  %d & unit %d - %d\n",
+				 right_bound.phase, left_bound.phase,
+				 right_bound.unit, left_bound.unit);
+			pr_debug("** calculating mid region: phase: %d  unit: %d (nominal is 3)\n",
+				 eye_training_val[byte][0],
+				 eye_training_val[byte][1]);
+		} else {
+			/* PPPPPPPPPP, we're already good.
+			 * Set nominal values.
+			 */
+			eye_training_val[byte][0] = 3;
+			eye_training_val[byte][1] = 3;
+		}
+		DQS_phase_delay(phy, byte, eye_training_val[byte][0]);
+		DQS_unit_delay(phy, byte, eye_training_val[byte][1]);
+
+		printf("Byte %d, DQS unit = %d, phase = %d\n",
+		       byte,
+		       eye_training_val[byte][1],
+		       eye_training_val[byte][0]);
+	}
+
+	if (error) {
+		sprintf(string, "error = %d", error);
+		return TEST_FAILED;
+	}
+
+	return TEST_PASSED;
+}
+
+static void display_reg_results(struct stm32mp1_ddrphy *phy, u8 byte)
+{
+	u8 i = 0;
+
+	printf("Byte %d Dekew result, bit0 delay, bit1 delay...bit8 delay\n  ",
+	       byte);
+
+	for (i = 0; i < 8; i++)
+		printf("%d ", DQ_unit_index(phy, byte, i));
+	printf("\n");
+
+	printf("dxndllcr: [%08x] val:%08x\n",
+	       DXNDLLCR(phy, byte),
+	       readl(DXNDLLCR(phy, byte)));
+	printf("dxnqdstr: [%08x] val:%08x\n",
+	       DXNDQSTR(phy, byte),
+	       readl(DXNDQSTR(phy, byte)));
+	printf("dxndqtr: [%08x] val:%08x\n",
+	       DXNDQTR(phy, byte),
+	       readl(DXNDQTR(phy, byte)));
+}
+
+/* analyse the dgs gating log table, and determine the midpoint.*/
+static u8 set_midpoint_read_dqs_gating(struct stm32mp1_ddrphy *phy, u8 byte,
+				       u8 dqs_gating[NUM_BYTES]
+						    [MAX_GSL_IDX + 1]
+						    [MAX_GPS_IDX + 1])
+{
+	/* stores the dqs gate values (gsl index, gps index) */
+	u8 dqs_gate_values[NUM_BYTES][2];
+	u8 gsl_idx, gps_idx = 0;
+	u8 left_bound_idx[2] = {0, 0};
+	u8 right_bound_idx[2] = {0, 0};
+	u8 left_bound_found = 0;
+	u8 right_bound_found = 0;
+	u8 intermittent = 0;
+	u8 value;
+
+	for (gsl_idx = 0; gsl_idx <= MAX_GSL_IDX; gsl_idx++) {
+		for (gps_idx = 0; gps_idx <= MAX_GPS_IDX; gps_idx++) {
+			value = dqs_gating[byte][gsl_idx][gps_idx];
+			if (value == 1 && left_bound_found == 0) {
+				left_bound_idx[0] = gsl_idx;
+				left_bound_idx[1] = gps_idx;
+				left_bound_found = 1;
+			} else if (value == 0 &&
+				   left_bound_found == 1 &&
+				   !right_bound_found) {
+				if (gps_idx == 0) {
+					right_bound_idx[0] = gsl_idx - 1;
+					right_bound_idx[1] = MAX_GPS_IDX;
+				} else {
+					right_bound_idx[0] = gsl_idx;
+					right_bound_idx[1] = gps_idx - 1;
+				}
+				right_bound_found = 1;
+			} else if (value == 1 &&
+				   right_bound_found == 1) {
+				intermittent = 1;
+			}
+		}
+	}
+
+	/* if only ppppppp is found, there is no mid region. */
+	if (left_bound_idx[0] == 0 && left_bound_idx[1] == 0 &&
+	    right_bound_idx[0] == 0 && right_bound_idx[1] == 0)
+		intermittent = 1;
+
+	/*if we found a regular fail pass fail pattern ffppppppff
+	 * or pppppff  or ffppppp
+	 */
+	if (!intermittent) {
+		/*if we found a regular fail pass fail pattern ffppppppff
+		 * or pppppff  or ffppppp
+		 */
+		if (left_bound_found || right_bound_found) {
+			pr_debug("idx0(%d): %d %d      idx1(%d) : %d %d\n",
+				 left_bound_found,
+				 right_bound_idx[0], left_bound_idx[0],
+				 right_bound_found,
+				 right_bound_idx[1], left_bound_idx[1]);
+			dqs_gate_values[byte][0] =
+				(right_bound_idx[0] + left_bound_idx[0]) / 2;
+			dqs_gate_values[byte][1] =
+				(right_bound_idx[1] + left_bound_idx[1]) / 2;
+			/* if we already lost 1/2gsl tuning,
+			 * let's try to recover by ++ on gps
+			 */
+			if (((right_bound_idx[0] +
+			      left_bound_idx[0]) % 2 == 1) &&
+			    dqs_gate_values[byte][1] != MAX_GPS_IDX)
+				dqs_gate_values[byte][1]++;
+			/* if we already lost 1/2gsl tuning and gps is on max*/
+			else if (((right_bound_idx[0] +
+				   left_bound_idx[0]) % 2 == 1) &&
+				 dqs_gate_values[byte][1] == MAX_GPS_IDX) {
+				dqs_gate_values[byte][1] = 0;
+				dqs_gate_values[byte][0]++;
+			}
+			/* if we have gsl left and write limit too close
+			 * (difference=1)
+			 */
+			if (((right_bound_idx[0] - left_bound_idx[0]) == 1)) {
+				dqs_gate_values[byte][1] = (left_bound_idx[1] +
+							    right_bound_idx[1] +
+							    4) / 2;
+				if (dqs_gate_values[byte][1] >= 4) {
+					dqs_gate_values[byte][0] =
+						right_bound_idx[0];
+					dqs_gate_values[byte][1] -= 4;
+				} else {
+					dqs_gate_values[byte][0] =
+						left_bound_idx[0];
+				}
+			}
+			pr_debug("*******calculating mid region: system latency: %d  phase: %d********\n",
+				 dqs_gate_values[byte][0],
+				 dqs_gate_values[byte][1]);
+			pr_debug("*******the nominal values were system latency: 0  phase: 2*******\n");
+			set_r0dgsl_delay(phy, byte, dqs_gate_values[byte][0]);
+			set_r0dgps_delay(phy, byte, dqs_gate_values[byte][1]);
+		}
+	} else {
+		/* if intermitant, restore defaut values */
+		pr_debug("dqs gating:no regular fail/pass/fail found. defaults values restored.\n");
+		set_r0dgsl_delay(phy, byte, 0);
+		set_r0dgps_delay(phy, byte, 2);
+	}
+
+	/* return 0 if intermittent or if both left_bound
+	 * and right_bound are not found
+	 */
+	return !(intermittent || (left_bound_found && right_bound_found));
+}
+
+static enum test_result read_dqs_gating(struct stm32mp1_ddrctl *ctl,
+					struct stm32mp1_ddrphy *phy,
+					char *string)
+{
+	/* stores the log of pass/fail */
+	u8 dqs_gating[NUM_BYTES][MAX_GSL_IDX + 1][MAX_GPS_IDX + 1];
+	u8 byte, gsl_idx, gps_idx = 0;
+	struct BIST_result result;
+	u8 success = 0;
+	u8 nb_bytes = get_nb_bytes(ctl);
+
+	memset(dqs_gating, 0x0, sizeof(dqs_gating));
+
+	/*disable dqs drift compensation*/
+	clrbits_le32(&phy->pgcr, DDRPHYC_PGCR_DFTCMP);
+	/*disable all bytes*/
+	/* disable automatic power down of dll and ios when disabling a byte
+	 * (to avoid having to add programming and  delay
+	 * for a dll re-lock when later re-enabling a disabled byte lane)
+	 */
+	clrbits_le32(&phy->pgcr, DDRPHYC_PGCR_PDDISDX);
+
+	/* disable all data bytes */
+	clrbits_le32(&phy->dx0gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx1gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx2gcr, DDRPHYC_DXNGCR_DXEN);
+	clrbits_le32(&phy->dx3gcr, DDRPHYC_DXNGCR_DXEN);
+
+	/* config the bist block */
+	config_BIST(phy);
+
+	for (byte = 0; byte < nb_bytes; byte++) {
+		if (ctrlc()) {
+			sprintf(string, "interrupted at byte %d/%d",
+				byte + 1, nb_bytes);
+			return TEST_FAILED;
+		}
+		/* enable byte x (dxngcr, bit dxen) */
+		setbits_le32(DXNGCR(phy, byte), DDRPHYC_DXNGCR_DXEN);
+
+		/* select the byte lane for comparison of read data */
+		BIST_datx8_sel(phy, byte);
+		for (gsl_idx = 0; gsl_idx <= MAX_GSL_IDX; gsl_idx++) {
+			for (gps_idx = 0; gps_idx <= MAX_GPS_IDX; gps_idx++) {
+				if (ctrlc()) {
+					sprintf(string,
+						"interrupted at byte %d/%d",
+						byte + 1, nb_bytes);
+					return TEST_FAILED;
+				}
+				/* write cfg to dxndqstr */
+				set_r0dgsl_delay(phy, byte, gsl_idx);
+				set_r0dgps_delay(phy, byte, gps_idx);
+
+				BIST_test(phy, byte, &result);
+				success = result.test_result;
+				if (success)
+					dqs_gating[byte][gsl_idx][gps_idx] = 1;
+				itm_soft_reset(phy);
+			}
+		}
+		set_midpoint_read_dqs_gating(phy, byte, dqs_gating);
+		/* dummy reads */
+		readl(0xc0000000);
+		readl(0xc0000000);
+	}
+
+	/* re-enable drift compensation */
+	/* setbits_le32(&phy->pgcr, DDRPHYC_PGCR_DFTCMP); */
+	return TEST_PASSED;
+}
+
+/****************************************************************
+ * TEST
+ ****************************************************************
+ */
+static enum test_result do_read_dqs_gating(struct stm32mp1_ddrctl *ctl,
+					   struct stm32mp1_ddrphy *phy,
+					   char *string, int argc,
+					   char *argv[])
+{
+	u32 rfshctl3 = readl(&ctl->rfshctl3);
+	u32 pwrctl = readl(&ctl->pwrctl);
+	enum test_result res;
+
+	stm32mp1_refresh_disable(ctl);
+	res = read_dqs_gating(ctl, phy, string);
+	stm32mp1_refresh_restore(ctl, rfshctl3, pwrctl);
+
+	return res;
+}
+
+static enum test_result do_bit_deskew(struct stm32mp1_ddrctl *ctl,
+				      struct stm32mp1_ddrphy *phy,
+				      char *string, int argc, char *argv[])
+{
+	u32 rfshctl3 = readl(&ctl->rfshctl3);
+	u32 pwrctl = readl(&ctl->pwrctl);
+	enum test_result res;
+
+	stm32mp1_refresh_disable(ctl);
+	res = bit_deskew(ctl, phy, string);
+	stm32mp1_refresh_restore(ctl, rfshctl3, pwrctl);
+
+	return res;
+}
+
+static enum test_result do_eye_training(struct stm32mp1_ddrctl *ctl,
+					struct stm32mp1_ddrphy *phy,
+					char *string, int argc, char *argv[])
+{
+	u32 rfshctl3 = readl(&ctl->rfshctl3);
+	u32 pwrctl = readl(&ctl->pwrctl);
+	enum test_result res;
+
+	stm32mp1_refresh_disable(ctl);
+	res = eye_training(ctl, phy, string);
+	stm32mp1_refresh_restore(ctl, rfshctl3, pwrctl);
+
+	return res;
+}
+
+static enum test_result do_display(struct stm32mp1_ddrctl *ctl,
+				   struct stm32mp1_ddrphy *phy,
+				   char *string, int argc, char *argv[])
+{
+	int byte;
+	u8 nb_bytes = get_nb_bytes(ctl);
+
+	for (byte = 0; byte < nb_bytes; byte++)
+		display_reg_results(phy, byte);
+
+	return TEST_PASSED;
+}
+
+static enum test_result do_bist_config(struct stm32mp1_ddrctl *ctl,
+				       struct stm32mp1_ddrphy *phy,
+				       char *string, int argc, char *argv[])
+{
+	unsigned long value;
+
+	if (argc > 0) {
+		if (strict_strtoul(argv[0], 0, &value) < 0) {
+			sprintf(string, "invalid nbErr %s", argv[0]);
+			return TEST_FAILED;
+		}
+		BIST_error_max = value;
+	}
+	if (argc > 1) {
+		if (strict_strtoul(argv[1], 0, &value) < 0) {
+			sprintf(string, "invalid Seed %s", argv[1]);
+			return TEST_FAILED;
+		}
+		BIST_seed = value;
+	}
+	printf("Bist.nbErr = %d\n", BIST_error_max);
+	if (BIST_seed)
+		printf("Bist.Seed = 0x%x\n", BIST_seed);
+	else
+		printf("Bist.Seed = random\n");
+
+	return TEST_PASSED;
+}
+
+/****************************************************************
+ * TEST Description
+ ****************************************************************
+ */
+
+const struct test_desc tuning[] = {
+	{do_read_dqs_gating, "Read DQS gating",
+		"software read DQS Gating", "", 0 },
+	{do_bit_deskew, "Bit de-skew", "", "", 0 },
+	{do_eye_training, "Eye Training", "or DQS training", "", 0 },
+	{do_display, "Display registers", "", "", 0 },
+	{do_bist_config, "Bist config", "[nbErr] [seed]",
+	 "configure Bist test", 2},
+};
+
+const int tuning_nb = ARRAY_SIZE(tuning);