From cc96eace48fdf0f8925a74c6c1f7ffa512e458d2 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Wed, 13 May 2009 20:28:15 +0900 Subject: 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: Paul Mundt --- arch/sh/kernel/cpu/clock.c | 3 + arch/sh/kernel/cpu/sh4a/clock-sh7785.c | 109 +++++++++++++++++++++++++++++---- 2 files changed, 99 insertions(+), 13 deletions(-) (limited to 'arch/sh/kernel') diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c index 033f4662b59..56c6e11fa83 100644 --- a/arch/sh/kernel/cpu/clock.c +++ b/arch/sh/kernel/cpu/clock.c @@ -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); } } diff --git a/arch/sh/kernel/cpu/sh4a/clock-sh7785.c b/arch/sh/kernel/cpu/sh4a/clock-sh7785.c index 87584dc8192..b7a32dd1b2d 100644 --- a/arch/sh/kernel/cpu/sh4a/clock-sh7785.c +++ b/arch/sh/kernel/cpu/sh4a/clock-sh7785.c @@ -13,28 +13,43 @@ #include #include #include +#include #include #include static unsigned int div2[] = { 1, 2, 4, 6, 8, 12, 16, 18, 24, 32, 36, 48 }; struct clk_priv { - unsigned int shift; + 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, }; /* -- cgit v1.2.3