/**
* omap2_dpll_round_rate - round a target rate for an OMAP DPLL
* @clk: struct clk * for a DPLL
* @target_rate: desired DPLL clock rate
*
* Given a DPLL and a desired target rate, round the target rate to a
* possible, programmable rate for this DPLL. Attempts to select the
* minimum possible n. Stores the computed (m, n) in the DPLL's
* dpll_data structure so set_rate() will not need to call this
* (expensive) function again. Returns ~0 if the target rate cannot
* be rounded, or the rounded rate upon success.
*/
long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
{
int m, n, r, scaled_max_m;
unsigned long scaled_rt_rp;
unsigned long new_rate = 0;
struct dpll_data *dd;
if (!clk || !clk->dpll_data)
return ~0;
dd = clk->dpll_data;
pr_debug("clock: %s: starting DPLL round_rate, target rate %ld\n",
clk->name, target_rate);
scaled_rt_rp = DIV_ROUND_CLOSEST(target_rate,
dd->clk_ref->rate / DPLL_SCALE_FACTOR);
scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
dd->last_rounded_rate = 0;
for (n = dd->min_divider; n <= dd->max_divider; n++) {
if (cpu_is_omap34xx()) {
/* Is the (input clk, divider)pair valid for the DPLL?*/
r = _dpll_test_fint(clk, n);
if (r == DPLL_FINT_UNDERFLOW)
break;
else if (r == DPLL_FINT_INVALID)
continue;
}
/* Compute the scaled DPLL multiplier, based on the divider */
m = scaled_rt_rp * n;
/*
* Since we're counting n up, a m overflow means we
* can bail out completely (since as n increases in
* the next iteration, there's no way that m can
* increase beyond the current m)
*/
if (m > scaled_max_m)
break;
r = _dpll_test_mult(&m, n, &new_rate, target_rate,
dd->clk_ref->rate);
/* m can't be set low enough for this n - try with a larger n */
if (r == DPLL_MULT_UNDERFLOW)
continue;
pr_debug("clock: %s: m = %d: n = %d: new_rate = %ld\n",
clk->name, m, n, new_rate);
if (target_rate == new_rate) {
dd->last_rounded_m = m;
dd->last_rounded_n = n;
dd->last_rounded_rate = target_rate;
break;
}
}
if (target_rate != new_rate) {
pr_debug("clock: %s: cannot round to rate %ld\n", clk->name,
target_rate);
return ~0;
}
return target_rate;
}
long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
{
int m, n, r, scaled_max_m;
unsigned long scaled_rt_rp;
unsigned long new_rate = 0;
struct dpll_data *dd;
if (!clk || !clk->dpll_data)
return ~0;
dd = clk->dpll_data;
pr_debug("clock: %s: starting DPLL round_rate, target rate %ld\n",
clk->name, target_rate);
scaled_rt_rp = target_rate / (dd->clk_ref->rate / DPLL_SCALE_FACTOR);
scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
dd->last_rounded_rate = 0;
for (n = dd->min_divider; n <= dd->max_divider; n++) {
r = _dpll_test_fint(clk, n);
if (r == DPLL_FINT_UNDERFLOW)
break;
else if (r == DPLL_FINT_INVALID)
continue;
m = scaled_rt_rp * n;
if (m > scaled_max_m)
break;
r = _dpll_test_mult(&m, n, &new_rate, target_rate,
dd->clk_ref->rate);
if (r == DPLL_MULT_UNDERFLOW)
continue;
pr_debug("clock: %s: m = %d: n = %d: new_rate = %ld\n",
clk->name, m, n, new_rate);
if (target_rate == new_rate) {
dd->last_rounded_m = m;
dd->last_rounded_n = n;
dd->last_rounded_rate = target_rate;
break;
}
}
if (target_rate != new_rate) {
pr_debug("clock: %s: cannot round to rate %ld\n", clk->name,
target_rate);
return ~0;
}
return target_rate;
}
/**
* omap2_dpll_round_rate - round a target rate for an OMAP DPLL
* @clk: struct clk * for a DPLL
* @target_rate: desired DPLL clock rate
*
* Given a DPLL, a desired target rate, and a rate tolerance, round
* the target rate to a possible, programmable rate for this DPLL.
* Rate tolerance is assumed to be set by the caller before this
* function is called. Attempts to select the minimum possible n
* within the tolerance to reduce power consumption. Stores the
* computed (m, n) in the DPLL's dpll_data structure so set_rate()
* will not need to call this (expensive) function again. Returns ~0
* if the target rate cannot be rounded, either because the rate is
* too low or because the rate tolerance is set too tightly; or the
* rounded rate upon success.
*/
long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
{
int m, n, r, e, scaled_max_m;
unsigned long scaled_rt_rp, new_rate;
int min_e = -1, min_e_m = -1, min_e_n = -1;
struct dpll_data *dd;
if (!clk || !clk->dpll_data)
return ~0;
dd = clk->dpll_data;
pr_debug("clock: starting DPLL round_rate for clock %s, target rate "
"%ld\n", clk->name, target_rate);
scaled_rt_rp = target_rate / (dd->clk_ref->rate / DPLL_SCALE_FACTOR);
scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
dd->last_rounded_rate = 0;
for (n = dd->min_divider; n <= dd->max_divider; n++) {
/* Is the (input clk, divider) pair valid for the DPLL? */
r = _dpll_test_fint(clk, n);
if (r == DPLL_FINT_UNDERFLOW)
break;
else if (r == DPLL_FINT_INVALID)
continue;
/* Compute the scaled DPLL multiplier, based on the divider */
m = scaled_rt_rp * n;
/*
* Since we're counting n up, a m overflow means we
* can bail out completely (since as n increases in
* the next iteration, there's no way that m can
* increase beyond the current m)
*/
if (m > scaled_max_m)
break;
r = _dpll_test_mult(&m, n, &new_rate, target_rate,
dd->clk_ref->rate);
/* m can't be set low enough for this n - try with a larger n */
if (r == DPLL_MULT_UNDERFLOW)
continue;
e = target_rate - new_rate;
pr_debug("clock: n = %d: m = %d: rate error is %d "
"(new_rate = %ld)\n", n, m, e, new_rate);
if (min_e == -1 ||
min_e >= (int)(abs(e) - dd->rate_tolerance)) {
min_e = e;
min_e_m = m;
min_e_n = n;
pr_debug("clock: found new least error %d\n", min_e);
/* We found good settings -- bail out now */
if (min_e <= dd->rate_tolerance)
break;
}
}
if (min_e < 0) {
pr_debug("clock: error: target rate or tolerance too low\n");
return ~0;
}
dd->last_rounded_m = min_e_m;
dd->last_rounded_n = min_e_n;
dd->last_rounded_rate = _dpll_compute_new_rate(dd->clk_ref->rate,
min_e_m, min_e_n);
pr_debug("clock: final least error: e = %d, m = %d, n = %d\n",
min_e, min_e_m, min_e_n);
pr_debug("clock: final rate: %ld (target rate: %ld)\n",
dd->last_rounded_rate, target_rate);
return dd->last_rounded_rate;
}
/**
* omap2_dpll_round_rate - round a target rate for an OMAP DPLL
* @clk: struct clk * for a DPLL
* @target_rate: desired DPLL clock rate
*
* Given a DPLL and a desired target rate, round the target rate to a
* possible, programmable rate for this DPLL. Attempts to select the
* minimum possible n. Stores the computed (m, n) in the DPLL's
* dpll_data structure so set_rate() will not need to call this
* (expensive) function again. Returns ~0 if the target rate cannot
* be rounded, or the rounded rate upon success.
*/
long omap2_dpll_round_rate(struct clk_hw *hw, unsigned long target_rate,
unsigned long *parent_rate)
{
struct clk_hw_omap *clk = to_clk_hw_omap(hw);
int m, n, r, scaled_max_m;
int min_delta_m = INT_MAX, min_delta_n = INT_MAX;
unsigned long scaled_rt_rp;
unsigned long new_rate = 0;
struct dpll_data *dd;
unsigned long ref_rate;
long delta;
long prev_min_delta = LONG_MAX;
const char *clk_name;
if (!clk || !clk->dpll_data)
return ~0;
dd = clk->dpll_data;
if (dd->max_rate && target_rate > dd->max_rate)
target_rate = dd->max_rate;
ref_rate = __clk_get_rate(dd->clk_ref);
clk_name = __clk_get_name(hw->clk);
pr_debug("clock: %s: starting DPLL round_rate, target rate %lu\n",
clk_name, target_rate);
scaled_rt_rp = target_rate / (ref_rate / DPLL_SCALE_FACTOR);
scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
dd->last_rounded_rate = 0;
for (n = dd->min_divider; n <= dd->max_divider; n++) {
/* Is the (input clk, divider) pair valid for the DPLL? */
r = _dpll_test_fint(clk, n);
if (r == DPLL_FINT_UNDERFLOW)
break;
else if (r == DPLL_FINT_INVALID)
continue;
/* Compute the scaled DPLL multiplier, based on the divider */
m = scaled_rt_rp * n;
/*
* Since we're counting n up, a m overflow means we
* can bail out completely (since as n increases in
* the next iteration, there's no way that m can
* increase beyond the current m)
*/
if (m > scaled_max_m)
break;
r = _dpll_test_mult(&m, n, &new_rate, target_rate,
ref_rate);
/* m can't be set low enough for this n - try with a larger n */
if (r == DPLL_MULT_UNDERFLOW)
continue;
/* skip rates above our target rate */
delta = target_rate - new_rate;
if (delta < 0)
continue;
if (delta < prev_min_delta) {
prev_min_delta = delta;
min_delta_m = m;
min_delta_n = n;
}
pr_debug("clock: %s: m = %d: n = %d: new_rate = %lu\n",
clk_name, m, n, new_rate);
if (delta == 0)
break;
}
if (prev_min_delta == LONG_MAX) {
pr_debug("clock: %s: cannot round to rate %lu\n",
clk_name, target_rate);
return ~0;
}
dd->last_rounded_m = min_delta_m;
dd->last_rounded_n = min_delta_n;
dd->last_rounded_rate = target_rate - prev_min_delta;
return dd->last_rounded_rate;
}
long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
{
int m, n, r, e, scaled_max_m;
unsigned long scaled_rt_rp, new_rate;
int min_e = -1, min_e_m = -1, min_e_n = -1;
struct dpll_data *dd;
if (!clk || !clk->dpll_data)
return ~0;
dd = clk->dpll_data;
pr_debug("clock: starting DPLL round_rate for clock %s, target rate "
"%ld\n", clk->name, target_rate);
scaled_rt_rp = target_rate / (dd->clk_ref->rate / DPLL_SCALE_FACTOR);
scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
dd->last_rounded_rate = 0;
for (n = dd->min_divider; n <= dd->max_divider; n++) {
r = _dpll_test_fint(clk, n);
if (r == DPLL_FINT_UNDERFLOW)
break;
else if (r == DPLL_FINT_INVALID)
continue;
m = scaled_rt_rp * n;
if (m > scaled_max_m)
break;
r = _dpll_test_mult(&m, n, &new_rate, target_rate,
dd->clk_ref->rate);
if (r == DPLL_MULT_UNDERFLOW)
continue;
e = target_rate - new_rate;
pr_debug("clock: n = %d: m = %d: rate error is %d "
"(new_rate = %ld)\n", n, m, e, new_rate);
if (min_e == -1 ||
min_e >= (int)(abs(e) - dd->rate_tolerance)) {
min_e = e;
min_e_m = m;
min_e_n = n;
pr_debug("clock: found new least error %d\n", min_e);
if (min_e <= dd->rate_tolerance)
break;
}
}
if (min_e < 0) {
pr_debug("clock: error: target rate or tolerance too low\n");
return ~0;
}
dd->last_rounded_m = min_e_m;
dd->last_rounded_n = min_e_n;
dd->last_rounded_rate = _dpll_compute_new_rate(dd->clk_ref->rate,
min_e_m, min_e_n);
pr_debug("clock: final least error: e = %d, m = %d, n = %d\n",
min_e, min_e_m, min_e_n);
pr_debug("clock: final rate: %ld (target rate: %ld)\n",
dd->last_rounded_rate, target_rate);
return dd->last_rounded_rate;
}
/**
* omap2_dpll_round_rate - round a target rate for an OMAP DPLL
* @clk: struct clk * for a DPLL
* @target_rate: desired DPLL clock rate
*
* Given a DPLL and a desired target rate, round the target rate to a
* possible, programmable rate for this DPLL. Attempts to select the
* minimum possible n. Stores the computed (m, n) in the DPLL's
* dpll_data structure so set_rate() will not need to call this
* (expensive) function again. Returns ~0 if the target rate cannot
* be rounded, or the rounded rate upon success.
*/
long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
{
int m, n, r, scaled_max_m;
unsigned long scaled_rt_rp;
unsigned long new_rate = 0;
struct dpll_data *dd;
unsigned long bestrate = 0, diff, bestdiff = ULONG_MAX;
int bestm = 0, bestn = 0;
struct dpll_rate_list *rs, *rate_cache;
if (!clk || !clk->dpll_data)
return ~0;
dd = clk->dpll_data;
rate_cache = dd->rate_cache;
for (rs = rate_cache; rs; rs = rs->next)
if (rs->target_rate == target_rate) {
dd->last_rounded_m = rs->m;
dd->last_rounded_n = rs->n;
dd->last_rounded_rate = rs->actual_rate;
return rs->actual_rate;
}
pr_debug("clock: %s: starting DPLL round_rate, target rate %ld\n",
clk->name, target_rate);
scaled_rt_rp = target_rate / (dd->clk_ref->rate / DPLL_SCALE_FACTOR);
scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
dd->last_rounded_rate = 0;
for (n = dd->min_divider; n <= dd->max_divider; n++) {
/* Is the (input clk, divider) pair valid for the DPLL? */
r = _dpll_test_fint(clk, n);
if (r == DPLL_FINT_UNDERFLOW)
break;
else if (r == DPLL_FINT_INVALID)
continue;
/* Compute the scaled DPLL multiplier, based on the divider */
m = scaled_rt_rp * n;
/*
* Since we're counting n up, a m overflow means we
* can bail out completely (since as n increases in
* the next iteration, there's no way that m can
* increase beyond the current m)
*/
if (m > scaled_max_m)
break;
r = _dpll_test_mult(&m, n, &new_rate, target_rate,
dd->clk_ref->rate);
/* m can't be set low enough for this n - try with a larger n */
if (r == DPLL_MULT_UNDERFLOW)
continue;
#ifdef DEBUG
pr_err("clock: target=%ld %s: m = %d: n = %d: new_rate = %ld\n",
target_rate, clk->name, m, n, new_rate);
#endif
if (target_rate > new_rate)
diff = target_rate - new_rate;
else
diff = new_rate - target_rate;
if (diff < bestdiff) {
bestm = m;
bestn = n;
bestrate = new_rate;
bestdiff = diff;
}
if (new_rate == target_rate)
break;
}
/*
* The following if verifies that the new frequency is within 0.01% of
* the target frequency.
*/
if (bestdiff < (ULONG_MAX / 10000) &&
((bestdiff * 10000) / target_rate) < 1) {
dd->last_rounded_m = bestm;
dd->last_rounded_n = bestn;
dd->last_rounded_rate = bestrate;
rs = kzalloc(sizeof (struct dpll_rate_list), GFP_ATOMIC);
if (rs) {
rs->m = bestm;
rs->n = bestn;
rs->target_rate = target_rate;
rs->actual_rate = bestrate;
if (rate_cache == dd->rate_cache) {
rs->next = dd->rate_cache;
dd->rate_cache = rs;
} else
kzfree(rs);
}
return bestrate;
} else
return 0;
}
