sequencer.c

		/* precharge all banks ... */
		writel(RW_MGR_PRECHARGE_ALL, grpaddr);

		/* load up MR settings specified by user */

		/*
		 * Use Mirror-ed commands for odd ranks if address
		 * mirrorring is on
		 */
		if ((RW_MGR_MEM_ADDRESS_MIRRORING >> r) & 0x1) {
			set_jump_as_return();
			writel(RW_MGR_MRS2_MIRR, grpaddr);
			delay_for_n_mem_clocks(4);
			set_jump_as_return();
			writel(RW_MGR_MRS3_MIRR, grpaddr);
			delay_for_n_mem_clocks(4);
			set_jump_as_return();
			writel(RW_MGR_MRS1_MIRR, grpaddr);
			delay_for_n_mem_clocks(4);
			set_jump_as_return();
			writel(RW_MGR_MRS0_USER_MIRR, grpaddr);
		} else {
			set_jump_as_return();
			writel(RW_MGR_MRS2, grpaddr);
			delay_for_n_mem_clocks(4);
			set_jump_as_return();
			writel(RW_MGR_MRS3, grpaddr);
			delay_for_n_mem_clocks(4);
			set_jump_as_return();
			writel(RW_MGR_MRS1, grpaddr);
			delay_for_n_mem_clocks(4);
			set_jump_as_return();
			writel(RW_MGR_MRS0_USER, grpaddr);
		}
		/*
		 * USER  need to wait tMOD (12CK or 15ns) time before issuing
		 * other commands, but we will have plenty of NIOS cycles before
		 * actual handoff so its okay.
		 */
	}
}

/*
 * performs a guaranteed read on the patterns we are going to use during a
 * read test to ensure memory works
 */
static uint32_t rw_mgr_mem_calibrate_read_test_patterns(uint32_t rank_bgn,
	uint32_t group, uint32_t num_tries, uint32_t *bit_chk,
	uint32_t all_ranks)
{
	uint32_t r, vg;
	uint32_t correct_mask_vg;
	uint32_t tmp_bit_chk;
	uint32_t rank_end = all_ranks ? RW_MGR_MEM_NUMBER_OF_RANKS :
		(rank_bgn + NUM_RANKS_PER_SHADOW_REG);
	uint32_t addr;
	uint32_t base_rw_mgr;

	*bit_chk = param->read_correct_mask;
	correct_mask_vg = param->read_correct_mask_vg;

	for (r = rank_bgn; r < rank_end; r++) {
		if (param->skip_ranks[r])
			/* request to skip the rank */
			continue;

		/* set rank */
		set_rank_and_odt_mask(r, RW_MGR_ODT_MODE_READ_WRITE);

		/* Load up a constant bursts of read commands */
		writel(0x20, &sdr_rw_load_mgr_regs->load_cntr0);
		writel(RW_MGR_GUARANTEED_READ,
			&sdr_rw_load_jump_mgr_regs->load_jump_add0);

		writel(0x20, &sdr_rw_load_mgr_regs->load_cntr1);
		writel(RW_MGR_GUARANTEED_READ_CONT,
			&sdr_rw_load_jump_mgr_regs->load_jump_add1);

		tmp_bit_chk = 0;
		for (vg = RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS-1; ; vg--) {
			/* reset the fifos to get pointers to known state */

			writel(0, &phy_mgr_cmd->fifo_reset);
			writel(0, SDR_PHYGRP_RWMGRGRP_ADDRESS |
				  RW_MGR_RESET_READ_DATAPATH_OFFSET);

			tmp_bit_chk = tmp_bit_chk << (RW_MGR_MEM_DQ_PER_READ_DQS
				/ RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS);

			addr = SDR_PHYGRP_RWMGRGRP_ADDRESS | RW_MGR_RUN_SINGLE_GROUP_OFFSET;
			writel(RW_MGR_GUARANTEED_READ, addr +
			       ((group * RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS +
				vg) << 2));

			base_rw_mgr = readl(SDR_PHYGRP_RWMGRGRP_ADDRESS);
			tmp_bit_chk = tmp_bit_chk | (correct_mask_vg & (~base_rw_mgr));

			if (vg == 0)
				break;
		}
		*bit_chk &= tmp_bit_chk;
	}

	addr = SDR_PHYGRP_RWMGRGRP_ADDRESS | RW_MGR_RUN_SINGLE_GROUP_OFFSET;
	writel(RW_MGR_CLEAR_DQS_ENABLE, addr + (group << 2));

	set_rank_and_odt_mask(0, RW_MGR_ODT_MODE_OFF);
	debug_cond(DLEVEL == 1, "%s:%d test_load_patterns(%u,ALL) => (%u == %u) =>\
		   %lu\n", __func__, __LINE__, group, *bit_chk, param->read_correct_mask,
		   (long unsigned int)(*bit_chk == param->read_correct_mask));
	return *bit_chk == param->read_correct_mask;
}

static uint32_t rw_mgr_mem_calibrate_read_test_patterns_all_ranks
	(uint32_t group, uint32_t num_tries, uint32_t *bit_chk)
{
	return rw_mgr_mem_calibrate_read_test_patterns(0, group,
		num_tries, bit_chk, 1);
}

/* load up the patterns we are going to use during a read test */
static void rw_mgr_mem_calibrate_read_load_patterns(uint32_t rank_bgn,
	uint32_t all_ranks)
{
	uint32_t r;
	uint32_t rank_end = all_ranks ? RW_MGR_MEM_NUMBER_OF_RANKS :
		(rank_bgn + NUM_RANKS_PER_SHADOW_REG);

	debug("%s:%d\n", __func__, __LINE__);
	for (r = rank_bgn; r < rank_end; r++) {
		if (param->skip_ranks[r])
			/* request to skip the rank */
			continue;

		/* set rank */
		set_rank_and_odt_mask(r, RW_MGR_ODT_MODE_READ_WRITE);

		/* Load up a constant bursts */
		writel(0x20, &sdr_rw_load_mgr_regs->load_cntr0);

		writel(RW_MGR_GUARANTEED_WRITE_WAIT0,
			&sdr_rw_load_jump_mgr_regs->load_jump_add0);

		writel(0x20, &sdr_rw_load_mgr_regs->load_cntr1);

		writel(RW_MGR_GUARANTEED_WRITE_WAIT1,
			&sdr_rw_load_jump_mgr_regs->load_jump_add1);

		writel(0x04, &sdr_rw_load_mgr_regs->load_cntr2);

		writel(RW_MGR_GUARANTEED_WRITE_WAIT2,
			&sdr_rw_load_jump_mgr_regs->load_jump_add2);

		writel(0x04, &sdr_rw_load_mgr_regs->load_cntr3);

		writel(RW_MGR_GUARANTEED_WRITE_WAIT3,
			&sdr_rw_load_jump_mgr_regs->load_jump_add3);

		writel(RW_MGR_GUARANTEED_WRITE, SDR_PHYGRP_RWMGRGRP_ADDRESS |
						RW_MGR_RUN_SINGLE_GROUP_OFFSET);
	}

	set_rank_and_odt_mask(0, RW_MGR_ODT_MODE_OFF);
}

/*
 * try a read and see if it returns correct data back. has dummy reads
 * inserted into the mix used to align dqs enable. has more thorough checks
 * than the regular read test.
 */
static uint32_t rw_mgr_mem_calibrate_read_test(uint32_t rank_bgn, uint32_t group,
	uint32_t num_tries, uint32_t all_correct, uint32_t *bit_chk,
	uint32_t all_groups, uint32_t all_ranks)
{
	uint32_t r, vg;
	uint32_t correct_mask_vg;
	uint32_t tmp_bit_chk;
	uint32_t rank_end = all_ranks ? RW_MGR_MEM_NUMBER_OF_RANKS :
		(rank_bgn + NUM_RANKS_PER_SHADOW_REG);
	uint32_t addr;
	uint32_t base_rw_mgr;

	*bit_chk = param->read_correct_mask;
	correct_mask_vg = param->read_correct_mask_vg;

	uint32_t quick_read_mode = (((STATIC_CALIB_STEPS) &
		CALIB_SKIP_DELAY_SWEEPS) && ENABLE_SUPER_QUICK_CALIBRATION);

	for (r = rank_bgn; r < rank_end; r++) {
		if (param->skip_ranks[r])
			/* request to skip the rank */
			continue;

		/* set rank */
		set_rank_and_odt_mask(r, RW_MGR_ODT_MODE_READ_WRITE);

		writel(0x10, &sdr_rw_load_mgr_regs->load_cntr1);

		writel(RW_MGR_READ_B2B_WAIT1,
			&sdr_rw_load_jump_mgr_regs->load_jump_add1);

		writel(0x10, &sdr_rw_load_mgr_regs->load_cntr2);
		writel(RW_MGR_READ_B2B_WAIT2,
			&sdr_rw_load_jump_mgr_regs->load_jump_add2);

		if (quick_read_mode)
			writel(0x1, &sdr_rw_load_mgr_regs->load_cntr0);
			/* need at least two (1+1) reads to capture failures */
		else if (all_groups)
			writel(0x06, &sdr_rw_load_mgr_regs->load_cntr0);
		else
			writel(0x32, &sdr_rw_load_mgr_regs->load_cntr0);

		writel(RW_MGR_READ_B2B,
			&sdr_rw_load_jump_mgr_regs->load_jump_add0);
		if (all_groups)
			writel(RW_MGR_MEM_IF_READ_DQS_WIDTH *
			       RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS - 1,
			       &sdr_rw_load_mgr_regs->load_cntr3);
		else
			writel(0x0, &sdr_rw_load_mgr_regs->load_cntr3);

		writel(RW_MGR_READ_B2B,
			&sdr_rw_load_jump_mgr_regs->load_jump_add3);

		tmp_bit_chk = 0;
		for (vg = RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS-1; ; vg--) {
			/* reset the fifos to get pointers to known state */
			writel(0, &phy_mgr_cmd->fifo_reset);
			writel(0, SDR_PHYGRP_RWMGRGRP_ADDRESS |
				  RW_MGR_RESET_READ_DATAPATH_OFFSET);

			tmp_bit_chk = tmp_bit_chk << (RW_MGR_MEM_DQ_PER_READ_DQS
				/ RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS);

			if (all_groups)
				addr = SDR_PHYGRP_RWMGRGRP_ADDRESS | RW_MGR_RUN_ALL_GROUPS_OFFSET;
			else
				addr = SDR_PHYGRP_RWMGRGRP_ADDRESS | RW_MGR_RUN_SINGLE_GROUP_OFFSET;

			writel(RW_MGR_READ_B2B, addr +
			       ((group * RW_MGR_MEM_VIRTUAL_GROUPS_PER_READ_DQS +
			       vg) << 2));

			base_rw_mgr = readl(SDR_PHYGRP_RWMGRGRP_ADDRESS);
			tmp_bit_chk = tmp_bit_chk | (correct_mask_vg & ~(base_rw_mgr));

			if (vg == 0)
				break;
		}
		*bit_chk &= tmp_bit_chk;
	}

	addr = SDR_PHYGRP_RWMGRGRP_ADDRESS | RW_MGR_RUN_SINGLE_GROUP_OFFSET;
	writel(RW_MGR_CLEAR_DQS_ENABLE, addr + (group << 2));

	if (all_correct) {
		set_rank_and_odt_mask(0, RW_MGR_ODT_MODE_OFF);
		debug_cond(DLEVEL == 2, "%s:%d read_test(%u,ALL,%u) =>\
			   (%u == %u) => %lu", __func__, __LINE__, group,
			   all_groups, *bit_chk, param->read_correct_mask,
			   (long unsigned int)(*bit_chk ==
			   param->read_correct_mask));
		return *bit_chk == param->read_correct_mask;
	} else	{
		set_rank_and_odt_mask(0, RW_MGR_ODT_MODE_OFF);
		debug_cond(DLEVEL == 2, "%s:%d read_test(%u,ONE,%u) =>\
			   (%u != %lu) => %lu\n", __func__, __LINE__,
			   group, all_groups, *bit_chk, (long unsigned int)0,
			   (long unsigned int)(*bit_chk != 0x00));
		return *bit_chk != 0x00;
	}
}

static uint32_t rw_mgr_mem_calibrate_read_test_all_ranks(uint32_t group,
	uint32_t num_tries, uint32_t all_correct, uint32_t *bit_chk,
	uint32_t all_groups)
{
	return rw_mgr_mem_calibrate_read_test(0, group, num_tries, all_correct,
					      bit_chk, all_groups, 1);
}

static void rw_mgr_incr_vfifo(uint32_t grp, uint32_t *v)
{
	writel(grp, &phy_mgr_cmd->inc_vfifo_hard_phy);
	(*v)++;
}

static void rw_mgr_decr_vfifo(uint32_t grp, uint32_t *v)
{
	uint32_t i;

	for (i = 0; i < VFIFO_SIZE-1; i++)
		rw_mgr_incr_vfifo(grp, v);
}

static int find_vfifo_read(uint32_t grp, uint32_t *bit_chk)
{
	uint32_t  v;
	uint32_t fail_cnt = 0;
	uint32_t test_status;

	for (v = 0; v < VFIFO_SIZE; ) {
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: vfifo %u\n",
			   __func__, __LINE__, v);
		test_status = rw_mgr_mem_calibrate_read_test_all_ranks
			(grp, 1, PASS_ONE_BIT, bit_chk, 0);
		if (!test_status) {
			fail_cnt++;

			if (fail_cnt == 2)
				break;
		}

		/* fiddle with FIFO */
		rw_mgr_incr_vfifo(grp, &v);
	}

	if (v >= VFIFO_SIZE) {
		/* no failing read found!! Something must have gone wrong */
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: vfifo failed\n",
			   __func__, __LINE__);
		return 0;
	} else {
		return v;
	}
}

static int find_working_phase(uint32_t *grp, uint32_t *bit_chk,
			      uint32_t dtaps_per_ptap, uint32_t *work_bgn,
			      uint32_t *v, uint32_t *d, uint32_t *p,
			      uint32_t *i, uint32_t *max_working_cnt)
{
	uint32_t found_begin = 0;
	uint32_t tmp_delay = 0;
	uint32_t test_status;

	for (*d = 0; *d <= dtaps_per_ptap; (*d)++, tmp_delay +=
		IO_DELAY_PER_DQS_EN_DCHAIN_TAP) {
		*work_bgn = tmp_delay;
		scc_mgr_set_dqs_en_delay_all_ranks(*grp, *d);

		for (*i = 0; *i < VFIFO_SIZE; (*i)++) {
			for (*p = 0; *p <= IO_DQS_EN_PHASE_MAX; (*p)++, *work_bgn +=
				IO_DELAY_PER_OPA_TAP) {
				scc_mgr_set_dqs_en_phase_all_ranks(*grp, *p);

				test_status =
				rw_mgr_mem_calibrate_read_test_all_ranks
				(*grp, 1, PASS_ONE_BIT, bit_chk, 0);

				if (test_status) {
					*max_working_cnt = 1;
					found_begin = 1;
					break;
				}
			}

			if (found_begin)
				break;

			if (*p > IO_DQS_EN_PHASE_MAX)
				/* fiddle with FIFO */
				rw_mgr_incr_vfifo(*grp, v);
		}

		if (found_begin)
			break;
	}

	if (*i >= VFIFO_SIZE) {
		/* cannot find working solution */
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: no vfifo/\
			   ptap/dtap\n", __func__, __LINE__);
		return 0;
	} else {
		return 1;
	}
}

static void sdr_backup_phase(uint32_t *grp, uint32_t *bit_chk,
			     uint32_t *work_bgn, uint32_t *v, uint32_t *d,
			     uint32_t *p, uint32_t *max_working_cnt)
{
	uint32_t found_begin = 0;
	uint32_t tmp_delay;

	/* Special case code for backing up a phase */
	if (*p == 0) {
		*p = IO_DQS_EN_PHASE_MAX;
		rw_mgr_decr_vfifo(*grp, v);
	} else {
		(*p)--;
	}
	tmp_delay = *work_bgn - IO_DELAY_PER_OPA_TAP;
	scc_mgr_set_dqs_en_phase_all_ranks(*grp, *p);

	for (*d = 0; *d <= IO_DQS_EN_DELAY_MAX && tmp_delay < *work_bgn;
		(*d)++, tmp_delay += IO_DELAY_PER_DQS_EN_DCHAIN_TAP) {
		scc_mgr_set_dqs_en_delay_all_ranks(*grp, *d);

		if (rw_mgr_mem_calibrate_read_test_all_ranks(*grp, 1,
							     PASS_ONE_BIT,
							     bit_chk, 0)) {
			found_begin = 1;
			*work_bgn = tmp_delay;
			break;
		}
	}

	/* We have found a working dtap before the ptap found above */
	if (found_begin == 1)
		(*max_working_cnt)++;

	/*
	 * Restore VFIFO to old state before we decremented it
	 * (if needed).
	 */
	(*p)++;
	if (*p > IO_DQS_EN_PHASE_MAX) {
		*p = 0;
		rw_mgr_incr_vfifo(*grp, v);
	}

	scc_mgr_set_dqs_en_delay_all_ranks(*grp, 0);
}

static int sdr_nonworking_phase(uint32_t *grp, uint32_t *bit_chk,
			     uint32_t *work_bgn, uint32_t *v, uint32_t *d,
			     uint32_t *p, uint32_t *i, uint32_t *max_working_cnt,
			     uint32_t *work_end)
{
	uint32_t found_end = 0;

	(*p)++;
	*work_end += IO_DELAY_PER_OPA_TAP;
	if (*p > IO_DQS_EN_PHASE_MAX) {
		/* fiddle with FIFO */
		*p = 0;
		rw_mgr_incr_vfifo(*grp, v);
	}

	for (; *i < VFIFO_SIZE + 1; (*i)++) {
		for (; *p <= IO_DQS_EN_PHASE_MAX; (*p)++, *work_end
			+= IO_DELAY_PER_OPA_TAP) {
			scc_mgr_set_dqs_en_phase_all_ranks(*grp, *p);

			if (!rw_mgr_mem_calibrate_read_test_all_ranks
				(*grp, 1, PASS_ONE_BIT, bit_chk, 0)) {
				found_end = 1;
				break;
			} else {
				(*max_working_cnt)++;
			}
		}

		if (found_end)
			break;

		if (*p > IO_DQS_EN_PHASE_MAX) {
			/* fiddle with FIFO */
			rw_mgr_incr_vfifo(*grp, v);
			*p = 0;
		}
	}

	if (*i >= VFIFO_SIZE + 1) {
		/* cannot see edge of failing read */
		debug_cond(DLEVEL == 2, "%s:%d sdr_nonworking_phase: end:\
			   failed\n", __func__, __LINE__);
		return 0;
	} else {
		return 1;
	}
}

static int sdr_find_window_centre(uint32_t *grp, uint32_t *bit_chk,
				  uint32_t *work_bgn, uint32_t *v, uint32_t *d,
				  uint32_t *p, uint32_t *work_mid,
				  uint32_t *work_end)
{
	int i;
	int tmp_delay = 0;

	*work_mid = (*work_bgn + *work_end) / 2;

	debug_cond(DLEVEL == 2, "work_bgn=%d work_end=%d work_mid=%d\n",
		   *work_bgn, *work_end, *work_mid);
	/* Get the middle delay to be less than a VFIFO delay */
	for (*p = 0; *p <= IO_DQS_EN_PHASE_MAX;
		(*p)++, tmp_delay += IO_DELAY_PER_OPA_TAP)
		;
	debug_cond(DLEVEL == 2, "vfifo ptap delay %d\n", tmp_delay);
	while (*work_mid > tmp_delay)
		*work_mid -= tmp_delay;
	debug_cond(DLEVEL == 2, "new work_mid %d\n", *work_mid);

	tmp_delay = 0;
	for (*p = 0; *p <= IO_DQS_EN_PHASE_MAX && tmp_delay < *work_mid;
		(*p)++, tmp_delay += IO_DELAY_PER_OPA_TAP)
		;
	tmp_delay -= IO_DELAY_PER_OPA_TAP;
	debug_cond(DLEVEL == 2, "new p %d, tmp_delay=%d\n", (*p) - 1, tmp_delay);
	for (*d = 0; *d <= IO_DQS_EN_DELAY_MAX && tmp_delay < *work_mid; (*d)++,
		tmp_delay += IO_DELAY_PER_DQS_EN_DCHAIN_TAP)
		;
	debug_cond(DLEVEL == 2, "new d %d, tmp_delay=%d\n", *d, tmp_delay);

	scc_mgr_set_dqs_en_phase_all_ranks(*grp, (*p) - 1);
	scc_mgr_set_dqs_en_delay_all_ranks(*grp, *d);

	/*
	 * push vfifo until we can successfully calibrate. We can do this
	 * because the largest possible margin in 1 VFIFO cycle.
	 */
	for (i = 0; i < VFIFO_SIZE; i++) {
		debug_cond(DLEVEL == 2, "find_dqs_en_phase: center: vfifo=%u\n",
			   *v);
		if (rw_mgr_mem_calibrate_read_test_all_ranks(*grp, 1,
							     PASS_ONE_BIT,
							     bit_chk, 0)) {
			break;
		}

		/* fiddle with FIFO */
		rw_mgr_incr_vfifo(*grp, v);
	}

	if (i >= VFIFO_SIZE) {
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: center: \
			   failed\n", __func__, __LINE__);
		return 0;
	} else {
		return 1;
	}
}

/* find a good dqs enable to use */
static uint32_t rw_mgr_mem_calibrate_vfifo_find_dqs_en_phase(uint32_t grp)
{
	uint32_t v, d, p, i;
	uint32_t max_working_cnt;
	uint32_t bit_chk;
	uint32_t dtaps_per_ptap;
	uint32_t work_bgn, work_mid, work_end;
	uint32_t found_passing_read, found_failing_read, initial_failing_dtap;

	debug("%s:%d %u\n", __func__, __LINE__, grp);

	reg_file_set_sub_stage(CAL_SUBSTAGE_VFIFO_CENTER);

	scc_mgr_set_dqs_en_delay_all_ranks(grp, 0);
	scc_mgr_set_dqs_en_phase_all_ranks(grp, 0);

	/* ************************************************************** */
	/* * Step 0 : Determine number of delay taps for each phase tap * */
	dtaps_per_ptap = IO_DELAY_PER_OPA_TAP/IO_DELAY_PER_DQS_EN_DCHAIN_TAP;

	/* ********************************************************* */
	/* * Step 1 : First push vfifo until we get a failing read * */
	v = find_vfifo_read(grp, &bit_chk);

	max_working_cnt = 0;

	/* ******************************************************** */
	/* * step 2: find first working phase, increment in ptaps * */
	work_bgn = 0;
	if (find_working_phase(&grp, &bit_chk, dtaps_per_ptap, &work_bgn, &v, &d,
				&p, &i, &max_working_cnt) == 0)
		return 0;

	work_end = work_bgn;

	/*
	 * If d is 0 then the working window covers a phase tap and
	 * we can follow the old procedure otherwise, we've found the beginning,
	 * and we need to increment the dtaps until we find the end.
	 */
	if (d == 0) {
		/* ********************************************************* */
		/* * step 3a: if we have room, back off by one and
		increment in dtaps * */

		sdr_backup_phase(&grp, &bit_chk, &work_bgn, &v, &d, &p,
				 &max_working_cnt);

		/* ********************************************************* */
		/* * step 4a: go forward from working phase to non working
		phase, increment in ptaps * */
		if (sdr_nonworking_phase(&grp, &bit_chk, &work_bgn, &v, &d, &p,
					 &i, &max_working_cnt, &work_end) == 0)
			return 0;

		/* ********************************************************* */
		/* * step 5a:  back off one from last, increment in dtaps  * */

		/* Special case code for backing up a phase */
		if (p == 0) {
			p = IO_DQS_EN_PHASE_MAX;
			rw_mgr_decr_vfifo(grp, &v);
		} else {
			p = p - 1;
		}

		work_end -= IO_DELAY_PER_OPA_TAP;
		scc_mgr_set_dqs_en_phase_all_ranks(grp, p);

		/* * The actual increment of dtaps is done outside of
		the if/else loop to share code */
		d = 0;

		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: v/p: \
			   vfifo=%u ptap=%u\n", __func__, __LINE__,
			   v, p);
	} else {
		/* ******************************************************* */
		/* * step 3-5b:  Find the right edge of the window using
		delay taps   * */
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase:vfifo=%u \
			   ptap=%u dtap=%u bgn=%u\n", __func__, __LINE__,
			   v, p, d, work_bgn);

		work_end = work_bgn;

		/* * The actual increment of dtaps is done outside of the
		if/else loop to share code */

		/* Only here to counterbalance a subtract later on which is
		not needed if this branch of the algorithm is taken */
		max_working_cnt++;
	}

	/* The dtap increment to find the failing edge is done here */
	for (; d <= IO_DQS_EN_DELAY_MAX; d++, work_end +=
		IO_DELAY_PER_DQS_EN_DCHAIN_TAP) {
			debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: \
				   end-2: dtap=%u\n", __func__, __LINE__, d);
			scc_mgr_set_dqs_en_delay_all_ranks(grp, d);

			if (!rw_mgr_mem_calibrate_read_test_all_ranks(grp, 1,
								      PASS_ONE_BIT,
								      &bit_chk, 0)) {
				break;
			}
	}

	/* Go back to working dtap */
	if (d != 0)
		work_end -= IO_DELAY_PER_DQS_EN_DCHAIN_TAP;

	debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: v/p/d: vfifo=%u \
		   ptap=%u dtap=%u end=%u\n", __func__, __LINE__,
		   v, p, d-1, work_end);

	if (work_end < work_bgn) {
		/* nil range */
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: end-2: \
			   failed\n", __func__, __LINE__);
		return 0;
	}

	debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: found range [%u,%u]\n",
		   __func__, __LINE__, work_bgn, work_end);

	/* *************************************************************** */
	/*
	 * * We need to calculate the number of dtaps that equal a ptap
	 * * To do that we'll back up a ptap and re-find the edge of the
	 * * window using dtaps
	 */

	debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: calculate dtaps_per_ptap \
		   for tracking\n", __func__, __LINE__);

	/* Special case code for backing up a phase */
	if (p == 0) {
		p = IO_DQS_EN_PHASE_MAX;
		rw_mgr_decr_vfifo(grp, &v);
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: backedup \
			   cycle/phase: v=%u p=%u\n", __func__, __LINE__,
			   v, p);
	} else {
		p = p - 1;
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: backedup \
			   phase only: v=%u p=%u", __func__, __LINE__,
			   v, p);
	}

	scc_mgr_set_dqs_en_phase_all_ranks(grp, p);

	/*
	 * Increase dtap until we first see a passing read (in case the
	 * window is smaller than a ptap),
	 * and then a failing read to mark the edge of the window again
	 */

	/* Find a passing read */
	debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: find passing read\n",
		   __func__, __LINE__);
	found_passing_read = 0;
	found_failing_read = 0;
	initial_failing_dtap = d;
	for (; d <= IO_DQS_EN_DELAY_MAX; d++) {
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: testing \
			   read d=%u\n", __func__, __LINE__, d);
		scc_mgr_set_dqs_en_delay_all_ranks(grp, d);

		if (rw_mgr_mem_calibrate_read_test_all_ranks(grp, 1,
							     PASS_ONE_BIT,
							     &bit_chk, 0)) {
			found_passing_read = 1;
			break;
		}
	}

	if (found_passing_read) {
		/* Find a failing read */
		debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: find failing \
			   read\n", __func__, __LINE__);
		for (d = d + 1; d <= IO_DQS_EN_DELAY_MAX; d++) {
			debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: \
				   testing read d=%u\n", __func__, __LINE__, d);
			scc_mgr_set_dqs_en_delay_all_ranks(grp, d);

			if (!rw_mgr_mem_calibrate_read_test_all_ranks
				(grp, 1, PASS_ONE_BIT, &bit_chk, 0)) {
				found_failing_read = 1;
				break;
			}
		}
	} else {
		debug_cond(DLEVEL == 1, "%s:%d find_dqs_en_phase: failed to \
			   calculate dtaps", __func__, __LINE__);
		debug_cond(DLEVEL == 1, "per ptap. Fall back on static value\n");
	}

	/*
	 * The dynamically calculated dtaps_per_ptap is only valid if we
	 * found a passing/failing read. If we didn't, it means d hit the max
	 * (IO_DQS_EN_DELAY_MAX). Otherwise, dtaps_per_ptap retains its
	 * statically calculated value.
	 */
	if (found_passing_read && found_failing_read)
		dtaps_per_ptap = d - initial_failing_dtap;

	writel(dtaps_per_ptap, &sdr_reg_file->dtaps_per_ptap);
	debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: dtaps_per_ptap=%u \
		   - %u = %u",  __func__, __LINE__, d,
		   initial_failing_dtap, dtaps_per_ptap);

	/* ******************************************** */
	/* * step 6:  Find the centre of the window   * */
	if (sdr_find_window_centre(&grp, &bit_chk, &work_bgn, &v, &d, &p,
				   &work_mid, &work_end) == 0)
		return 0;

	debug_cond(DLEVEL == 2, "%s:%d find_dqs_en_phase: center found: \
		   vfifo=%u ptap=%u dtap=%u\n", __func__, __LINE__,
		   v, p-1, d);
	return 1;
}

/*
 * Try rw_mgr_mem_calibrate_vfifo_find_dqs_en_phase across different
 * dq_in_delay values
 */
static uint32_t
rw_mgr_mem_calibrate_vfifo_find_dqs_en_phase_sweep_dq_in_delay
(uint32_t write_group, uint32_t read_group, uint32_t test_bgn)
{
	uint32_t found;
	uint32_t i;
	uint32_t p;
	uint32_t d;
	uint32_t r;

	const uint32_t delay_step = IO_IO_IN_DELAY_MAX /
		(RW_MGR_MEM_DQ_PER_READ_DQS-1);
		/* we start at zero, so have one less dq to devide among */

	debug("%s:%d (%u,%u,%u)", __func__, __LINE__, write_group, read_group,
	      test_bgn);

	/* try different dq_in_delays since the dq path is shorter than dqs */

	for (r = 0; r < RW_MGR_MEM_NUMBER_OF_RANKS;
	     r += NUM_RANKS_PER_SHADOW_REG) {
		for (i = 0, p = test_bgn, d = 0; i < RW_MGR_MEM_DQ_PER_READ_DQS; i++, p++, d += delay_step) {
			debug_cond(DLEVEL == 1, "%s:%d rw_mgr_mem_calibrate_\
				   vfifo_find_dqs_", __func__, __LINE__);
			debug_cond(DLEVEL == 1, "en_phase_sweep_dq_in_delay: g=%u/%u ",
			       write_group, read_group);
			debug_cond(DLEVEL == 1, "r=%u, i=%u p=%u d=%u\n", r, i , p, d);
			scc_mgr_set_dq_in_delay(p, d);
			scc_mgr_load_dq(p);
		}
		writel(0, &sdr_scc_mgr->update);
	}

	found = rw_mgr_mem_calibrate_vfifo_find_dqs_en_phase(read_group);

	debug_cond(DLEVEL == 1, "%s:%d rw_mgr_mem_calibrate_vfifo_find_dqs_\
		   en_phase_sweep_dq", __func__, __LINE__);
	debug_cond(DLEVEL == 1, "_in_delay: g=%u/%u found=%u; Reseting delay \
		   chain to zero\n", write_group, read_group, found);

	for (r = 0; r < RW_MGR_MEM_NUMBER_OF_RANKS;
	     r += NUM_RANKS_PER_SHADOW_REG) {
		for (i = 0, p = test_bgn; i < RW_MGR_MEM_DQ_PER_READ_DQS;
			i++, p++) {
			scc_mgr_set_dq_in_delay(p, 0);
			scc_mgr_load_dq(p);
		}
		writel(0, &sdr_scc_mgr->update);
	}

	return found;
}

/* per-bit deskew DQ and center */
static uint32_t rw_mgr_mem_calibrate_vfifo_center(uint32_t rank_bgn,
	uint32_t write_group, uint32_t read_group, uint32_t test_bgn,
	uint32_t use_read_test, uint32_t update_fom)
{
	uint32_t i, p, d, min_index;
	/*
	 * Store these as signed since there are comparisons with
	 * signed numbers.
	 */
	uint32_t bit_chk;
	uint32_t sticky_bit_chk;
	int32_t left_edge[RW_MGR_MEM_DQ_PER_READ_DQS];
	int32_t right_edge[RW_MGR_MEM_DQ_PER_READ_DQS];
	int32_t final_dq[RW_MGR_MEM_DQ_PER_READ_DQS];
	int32_t mid;
	int32_t orig_mid_min, mid_min;
	int32_t new_dqs, start_dqs, start_dqs_en, shift_dq, final_dqs,
		final_dqs_en;
	int32_t dq_margin, dqs_margin;
	uint32_t stop;
	uint32_t temp_dq_in_delay1, temp_dq_in_delay2;
	uint32_t addr;

	debug("%s:%d: %u %u", __func__, __LINE__, read_group, test_bgn);

	addr = SDR_PHYGRP_SCCGRP_ADDRESS | SCC_MGR_DQS_IN_DELAY_OFFSET;
	start_dqs = readl(addr + (read_group << 2));
	if (IO_SHIFT_DQS_EN_WHEN_SHIFT_DQS)
		start_dqs_en = readl(addr + ((read_group << 2)
				     - IO_DQS_EN_DELAY_OFFSET));

	/* set the left and right edge of each bit to an illegal value */
	/* use (IO_IO_IN_DELAY_MAX + 1) as an illegal value */
	sticky_bit_chk = 0;
	for (i = 0; i < RW_MGR_MEM_DQ_PER_READ_DQS; i++) {
		left_edge[i]  = IO_IO_IN_DELAY_MAX + 1;
		right_edge[i] = IO_IO_IN_DELAY_MAX + 1;
	}

	/* Search for the left edge of the window for each bit */
	for (d = 0; d <= IO_IO_IN_DELAY_MAX; d++) {
		scc_mgr_apply_group_dq_in_delay(write_group, test_bgn, d);

		writel(0, &sdr_scc_mgr->update);

		/*
		 * Stop searching when the read test doesn't pass AND when
		 * we've seen a passing read on every bit.
		 */
		if (use_read_test) {
			stop = !rw_mgr_mem_calibrate_read_test(rank_bgn,
				read_group, NUM_READ_PB_TESTS, PASS_ONE_BIT,
				&bit_chk, 0, 0);
		} else {
			rw_mgr_mem_calibrate_write_test(rank_bgn, write_group,
							0, PASS_ONE_BIT,
							&bit_chk, 0);
			bit_chk = bit_chk >> (RW_MGR_MEM_DQ_PER_READ_DQS *
				(read_group - (write_group *
					RW_MGR_MEM_IF_READ_DQS_WIDTH /
					RW_MGR_MEM_IF_WRITE_DQS_WIDTH)));
			stop = (bit_chk == 0);
		}
		sticky_bit_chk = sticky_bit_chk | bit_chk;
		stop = stop && (sticky_bit_chk == param->read_correct_mask);
		debug_cond(DLEVEL == 2, "%s:%d vfifo_center(left): dtap=%u => %u == %u \
			   && %u", __func__, __LINE__, d,
			   sticky_bit_chk,
			param->read_correct_mask, stop);

		if (stop == 1) {
			break;
		} else {
			for (i = 0; i < RW_MGR_MEM_DQ_PER_READ_DQS; i++) {
				if (bit_chk & 1) {
					/* Remember a passing test as the
					left_edge */
					left_edge[i] = d;
				} else {
					/* If a left edge has not been seen yet,
					then a future passing test will mark
					this edge as the right edge */
					if (left_edge[i] ==
						IO_IO_IN_DELAY_MAX + 1) {
						right_edge[i] = -(d + 1);
					}
				}
				bit_chk = bit_chk >> 1;
			}
		}
	}

	/* Reset DQ delay chains to 0 */
	scc_mgr_apply_group_dq_in_delay(test_bgn, 0);
	sticky_bit_chk = 0;
	for (i = RW_MGR_MEM_DQ_PER_READ_DQS - 1;; i--) {
		debug_cond(DLEVEL == 2, "%s:%d vfifo_center: left_edge[%u]: \
			   %d right_edge[%u]: %d\n", __func__, __LINE__,
			   i, left_edge[i], i, right_edge[i]);

		/*
		 * Check for cases where we haven't found the left edge,
		 * which makes our assignment of the the right edge invalid.
		 * Reset it to the illegal value.
		 */
		if ((left_edge[i] == IO_IO_IN_DELAY_MAX + 1) && (
			right_edge[i] != IO_IO_IN_DELAY_MAX + 1)) {
			right_edge[i] = IO_IO_IN_DELAY_MAX + 1;
			debug_cond(DLEVEL == 2, "%s:%d vfifo_center: reset \
				   right_edge[%u]: %d\n", __func__, __LINE__,
				   i, right_edge[i]);
		}

		/*
		 * Reset sticky bit (except for bits where we have seen
		 * both the left and right edge).
		 */
		sticky_bit_chk = sticky_bit_chk << 1;
		if ((left_edge[i] != IO_IO_IN_DELAY_MAX + 1) &&
		    (right_edge[i] != IO_IO_IN_DELAY_MAX + 1)) {
			sticky_bit_chk = sticky_bit_chk | 1;
		}

		if (i == 0)
			break;
	}

	/* Search for the right edge of the window for each bit */
	for (d = 0; d <= IO_DQS_IN_DELAY_MAX - start_dqs; d++) {
		scc_mgr_set_dqs_bus_in_delay(read_group, d + start_dqs);
		if (IO_SHIFT_DQS_EN_WHEN_SHIFT_DQS) {
			uint32_t delay = d + start_dqs_en;
			if (delay > IO_DQS_EN_DELAY_MAX)
				delay = IO_DQS_EN_DELAY_MAX;
			scc_mgr_set_dqs_en_delay(read_group, delay);
		}
		scc_mgr_load_dqs(read_group);

		writel(0, &sdr_scc_mgr->update);

		/*
		 * Stop searching when the read test doesn't pass AND when
		 * we've seen a passing read on every bit.
		 */
		if (use_read_test) {
			stop = !rw_mgr_mem_calibrate_read_test(rank_bgn,
				read_group, NUM_READ_PB_TESTS, PASS_ONE_BIT,
				&bit_chk, 0, 0);
		} else {
			rw_mgr_mem_calibrate_write_test(rank_bgn, write_group,
							0, PASS_ONE_BIT,
							&bit_chk, 0);
			bit_chk = bit_chk >> (RW_MGR_MEM_DQ_PER_READ_DQS *
				(read_group - (write_group *
					RW_MGR_MEM_IF_READ_DQS_WIDTH /
					RW_MGR_MEM_IF_WRITE_DQS_WIDTH)));
			stop = (bit_chk == 0);
		}
		sticky_bit_chk = sticky_bit_chk | bit_chk;
		stop = stop && (sticky_bit_chk == param->read_correct_mask);

		debug_cond(DLEVEL == 2, "%s:%d vfifo_center(right): dtap=%u => %u == \
			   %u && %u", __func__, __LINE__, d,
			   sticky_bit_chk, param->read_correct_mask, stop);

		if (stop == 1) {
			break;
		} else {
			for (i = 0; i < RW_MGR_MEM_DQ_PER_READ_DQS; i++) {
				if (bit_chk & 1) {
					/* Remember a passing test as
					the right_edge */
					right_edge[i] = d;
				} else {
					if (d != 0) {
						/* If a right edge has not been
						seen yet, then a future passing
						test will mark this edge as the
						left edge */