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ddr: altera: Clean up sdr_find_window_centre() part 2

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This function is a treasure trove of ad-hoc iterative
implementations of mathematical functions. Replace all
of those with their non-iterative counterpart.

Signed-off-by: Marek Vasut <marex@denx.de>
This commit is contained in:
Marek Vasut 2015-07-19 04:04:33 +02:00
parent 28fd242a18
commit cbb0b7e036
1 changed files with 15 additions and 16 deletions
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31
drivers/ddr/altera/sequencer.c
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@ -1492,28 +1492,27 @@ static int sdr_find_window_centre(const u32 grp, const u32 work_bgn,
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)
;
tmp_delay = (IO_DQS_EN_PHASE_MAX + 1) * 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;
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);
tmp_delay = rounddown(work_mid, IO_DELAY_PER_OPA_TAP);
if (tmp_delay > IO_DQS_EN_PHASE_MAX * IO_DELAY_PER_OPA_TAP)
tmp_delay = IO_DQS_EN_PHASE_MAX * IO_DELAY_PER_OPA_TAP;
p = tmp_delay / IO_DELAY_PER_OPA_TAP;
debug_cond(DLEVEL == 2, "new p %d, tmp_delay=%d\n", p, tmp_delay);
d = DIV_ROUND_UP(work_mid - tmp_delay, IO_DELAY_PER_DQS_EN_DCHAIN_TAP);
if (d > IO_DQS_EN_DELAY_MAX)
d = IO_DQS_EN_DELAY_MAX;
tmp_delay += d * IO_DELAY_PER_DQS_EN_DCHAIN_TAP;
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_phase_all_ranks(grp, p);
scc_mgr_set_dqs_en_delay_all_ranks(grp, d);
/*
@ -1540,7 +1539,7 @@ static int sdr_find_window_centre(const u32 grp, const u32 work_bgn,
} else {
debug_cond(DLEVEL == 2,
"%s:%d center: found: vfifo=%u ptap=%u dtap=%u\n",
__func__, __LINE__, v, p - 1, d);
__func__, __LINE__, v, p, d);
return 1;
}
}