Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cc96eace authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: clkfwk: rate table construction and rounding for SH7785. 



This adds support for constructing a rate table by looking at potential
divisors for a specified clock. Each FQRMR clock is given its own table.
Presently each table is rebuilt when the parent propagates down a new
rate, so some more logic needs to be added to do this more intelligently.

Additionally, a fairly generic round_rate() implementation is then
layered on top of it, which subsequently provides us with cpufreq support.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent a77b5ac0

arch/sh/include/asm/clock.h

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ struct clk_ops { 
	int (*set_rate)(struct clk *clk, unsigned long rate, int algo_id);

	int (*set_parent)(struct clk *clk, struct clk *parent);

	long (*round_rate)(struct clk *clk, unsigned long rate);

	void (*build_rate_table)(struct clk *clk);

};



struct clk {

arch/sh/kernel/cpu/clock.c

+3 −0
Original line number Diff line number Diff line
@@ -63,6 +63,9 @@ void propagate_rate(struct clk *tclk) 
	list_for_each_entry(clkp, &tclk->children, sibling) {

		if (clkp->ops && clkp->ops->recalc)

			clkp->rate = clkp->ops->recalc(clkp);

		if (clkp->ops && clkp->ops->build_rate_table)

			clkp->ops->build_rate_table(clkp);



		propagate_rate(clkp);

	}

}

arch/sh/kernel/cpu/sh4a/clock-sh7785.c

+96 −13
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/kernel.h>

#include <linux/clk.h>

#include <linux/io.h>

#include <linux/cpufreq.h>

#include <asm/clock.h>

#include <asm/freq.h>
@@ -20,21 +21,35 @@ static unsigned int div2[] = { 1, 2, 4, 6, 8, 12, 16, 18, 
			       24, 32, 36, 48 };

struct clk_priv {

	unsigned int			shift;



	/* allowable divisor bitmap */

	unsigned long			div_bitmap;



	/* Supportable frequencies + termination entry */

	struct cpufreq_frequency_table	freq_table[ARRAY_SIZE(div2)+1];

};



#define FRQMR_CLK_DATA(_name, _shift)	\

static struct clk_priv _name##_data = {	.shift = _shift, }

#define FRQMR_CLK_DATA(_name, _shift, _div_bitmap)	\

static struct clk_priv _name##_data = {			\

	.shift		= _shift,			\

	.div_bitmap	= _div_bitmap,			\

							\

	.freq_table[0]	= {				\

		.index = 0,				\

		.frequency = CPUFREQ_TABLE_END,		\

	},						\

}



FRQMR_CLK_DATA(pfc,  0);

FRQMR_CLK_DATA(s3fc, 4);

FRQMR_CLK_DATA(s2fc, 8);

FRQMR_CLK_DATA(mfc, 12);

FRQMR_CLK_DATA(bfc, 16);

FRQMR_CLK_DATA(sfc, 20);

FRQMR_CLK_DATA(ufc, 24);

FRQMR_CLK_DATA(ifc, 28);

FRQMR_CLK_DATA(pfc,  0, 0x0f80);

FRQMR_CLK_DATA(s3fc, 4, 0x0ff0);

FRQMR_CLK_DATA(s2fc, 8, 0x0030);

FRQMR_CLK_DATA(mfc, 12, 0x000c);

FRQMR_CLK_DATA(bfc, 16, 0x0fe0);

FRQMR_CLK_DATA(sfc, 20, 0x000c);

FRQMR_CLK_DATA(ufc, 24, 0x000c);

FRQMR_CLK_DATA(ifc, 28, 0x000e);



static unsigned long frqmr_clk_recalc(struct clk *clk)

static unsigned long frqmr_recalc(struct clk *clk)

{

	struct clk_priv *data = clk->priv;

	unsigned int idx;
@@ -49,8 +64,76 @@ static unsigned long frqmr_clk_recalc(struct clk *clk) 
	return clk->parent->rate * 36 / div2[idx];

}



static void frqmr_build_rate_table(struct clk *clk)

{

	struct clk_priv *data = clk->priv;

	int i, entry;



	for (i = entry = 0; i < ARRAY_SIZE(div2); i++) {

		if ((data->div_bitmap & (1 << i)) == 0)

			continue;



		data->freq_table[entry].index = entry;

		data->freq_table[entry].frequency =

			clk->parent->rate * 36 / div2[i];



		entry++;

	}



	if (entry == 0) {

		pr_warning("clkfwk: failed to build frequency table "

			   "for \"%s\" clk!\n", clk->name);

		return;

	}



	/* Termination entry */

	data->freq_table[entry].index = entry;

	data->freq_table[entry].frequency = CPUFREQ_TABLE_END;

}



static long frqmr_round_rate(struct clk *clk, unsigned long rate)

{

	struct clk_priv *data = clk->priv;

	unsigned long rate_error, rate_error_prev = ~0UL;

	unsigned long rate_best_fit = rate;

	unsigned long highest, lowest;

	int i;



	highest = lowest = 0;



	for (i = 0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {

		unsigned long freq = data->freq_table[i].frequency;



		if (freq == CPUFREQ_ENTRY_INVALID)

			continue;



		if (freq > highest)

			highest = freq;

		if (freq < lowest)

			lowest = freq;



		rate_error = abs(freq - rate);

		if (rate_error < rate_error_prev) {

			rate_best_fit = freq;

			rate_error_prev = rate_error;

		}



		if (rate_error == 0)

			break;

	}



	if (rate >= highest)

		rate_best_fit = highest;

	if (rate <= lowest)

		rate_best_fit = lowest;



	return rate_best_fit;

}



static struct clk_ops frqmr_clk_ops = {

	.recalc		= frqmr_clk_recalc,

	.recalc			= frqmr_recalc,

	.build_rate_table	= frqmr_build_rate_table,

	.round_rate		= frqmr_round_rate,

};



/*