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 <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/clock.h b/arch/sh/include/asm/clock.h
index 40cf3c0..da681de 100644
--- a/arch/sh/include/asm/clock.h
+++ b/arch/sh/include/asm/clock.h
@@ -16,6 +16,7 @@
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 {
diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c
index 033f466..56c6e11 100644
--- a/arch/sh/kernel/cpu/clock.c
+++ b/arch/sh/kernel/cpu/clock.c
@@ -63,6 +63,9 @@
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 87584dc..b7a32dd 100644
--- a/arch/sh/kernel/cpu/sh4a/clock-sh7785.c
+++ b/arch/sh/kernel/cpu/sh4a/clock-sh7785.c
@@ -13,28 +13,43 @@
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/io.h>
+#include <linux/cpufreq.h>
#include <asm/clock.h>
#include <asm/freq.h>
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 @@
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,
};
/*