sh: clkfwk: Abstract rate rounding helper.

Presently the only assisted rate rounding is frequency table backed, but there are cases where it's impractical to use a frequency table for certain clocks (such as the FSIDIV case, which supports 65535 divisors), and we wish to reuse the same rate rounding algorithm. This breaks out the core of the rate rounding logic in to its own helper routine and shuffles the frequency table logic around, switching to using an iterator for the generic helper routine. Signed-off-by: Paul Mundt <lethal@linux-sh.org>

sh: clkfwk: Abstract rate rounding helper.
Presently the only assisted rate rounding is frequency table backed, but there are cases where it's impractical to use a frequency table for certain clocks (such as the FSIDIV case, which supports 65535 divisors), and we wish to reuse the same rate rounding algorithm. This breaks out the core of the rate rounding logic in to its own helper routine and shuffles the frequency table logic around, switching to using an iterator for the generic helper routine. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Paul Mundt
1 parent 28085bc5de
Showing 2 changed files with 53 additions and 14 deletions Side-by-side Diff
drivers/sh/clk.c
include/linux/sh_clk.h
@@ -45,6 +45,8 @@
 	unsigned long freq;
 	int i;
  
+	clk->nr_freqs = nr_freqs;
+
 	for (i = 0; i < nr_freqs; i++) {
 		div = 1;
 		mult = 1;
  
  
  
@@ -69,30 +71,39 @@
 	freq_table[i].frequency = CPUFREQ_TABLE_END;
 }
  
-long clk_rate_table_round(struct clk *clk,
-			  struct cpufreq_frequency_table *freq_table,
-			  unsigned long rate)
+struct clk_rate_round_data;
+
+struct clk_rate_round_data {
+	unsigned long rate;
+	unsigned int min, max;
+	long (*func)(unsigned int pos, struct clk_rate_round_data *arg);
+	void *arg;
+};
+
+#define for_each_frequency(pos, r, freq)			\
+	for (pos = r->min, freq = r->func(pos, r->arg);		\
+	     pos < r->max; pos++, freq = r->func(pos, r))	\
+		if (unlikely(freq == 0))			\
+			;					\
+		else
+
+static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
 {
 	unsigned long rate_error, rate_error_prev = ~0UL;
-	unsigned long rate_best_fit = rate;
-	unsigned long highest, lowest;
+	unsigned long rate_best_fit = rounder->rate;
+	unsigned long highest, lowest, freq;
 	int i;
  
 	highest = 0;
 	lowest = ~0UL;
  
-	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
-		unsigned long freq = freq_table[i].frequency;
-
-		if (freq == CPUFREQ_ENTRY_INVALID)
-			continue;
-
+	for_each_frequency(i, rounder, freq) {
 		if (freq > highest)
 			highest = freq;
 		if (freq < lowest)
 			lowest = freq;
  
-		rate_error = abs(freq - rate);
+		rate_error = abs(freq - rounder->rate);
 		if (rate_error < rate_error_prev) {
 			rate_best_fit = freq;
 			rate_error_prev = rate_error;
  
  
@@ -102,12 +113,39 @@
 			break;
 	}
  
-	if (rate >= highest)
+	if (rounder->rate >= highest)
 		rate_best_fit = highest;
-	if (rate <= lowest)
+	if (rounder->rate <= lowest)
 		rate_best_fit = lowest;
  
 	return rate_best_fit;
+}
+
+static long clk_rate_table_iter(unsigned int pos,
+				struct clk_rate_round_data *rounder)
+{
+	struct cpufreq_frequency_table *freq_table = rounder->arg;
+	unsigned long freq = freq_table[pos].frequency;
+
+	if (freq == CPUFREQ_ENTRY_INVALID)
+		freq = 0;
+
+	return freq;
+}
+
+long clk_rate_table_round(struct clk *clk,
+			  struct cpufreq_frequency_table *freq_table,
+			  unsigned long rate)
+{
+	struct clk_rate_round_data table_round = {
+		.min	= 0,
+		.max	= clk->nr_freqs,
+		.func	= clk_rate_table_iter,
+		.arg	= freq_table,
+		.rate	= rate,
+	};
+
+	return clk_rate_round_helper(&table_round);
 }
  
 int clk_rate_table_find(struct clk *clk,
@@ -53,6 +53,7 @@
 	struct dentry		*dentry;
 	struct clk_mapping	*mapping;
 	struct cpufreq_frequency_table *freq_table;
+	unsigned int		nr_freqs;
 };
  
 #define CLK_ENABLE_ON_INIT	(1 << 0)
...	...	@@ -45,6 +45,8 @@
45	45	unsigned long freq;
46	46	int i;
47	47
	48	+ clk->nr_freqs = nr_freqs;
	49	+
48	50	for (i = 0; i < nr_freqs; i++) {
49	51	div = 1;
50	52	mult = 1;
51	53
52	54
53	55
...	...	@@ -69,30 +71,39 @@
69	71	freq_table[i].frequency = CPUFREQ_TABLE_END;
70	72	}
71	73
72		-long clk_rate_table_round(struct clk *clk,
73		- struct cpufreq_frequency_table *freq_table,
74		- unsigned long rate)
	74	+struct clk_rate_round_data;
	75	+
	76	+struct clk_rate_round_data {
	77	+ unsigned long rate;
	78	+ unsigned int min, max;
	79	+ long (func)(unsigned int pos, struct clk_rate_round_data arg);
	80	+ void *arg;
	81	+};
	82	+
	83	+#define for_each_frequency(pos, r, freq) \
	84	+ for (pos = r->min, freq = r->func(pos, r->arg); \
	85	+ pos < r->max; pos++, freq = r->func(pos, r)) \
	86	+ if (unlikely(freq == 0)) \
	87	+ ; \
	88	+ else
	89	+
	90	+static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
75	91	{
76	92	unsigned long rate_error, rate_error_prev = ~0UL;
77		- unsigned long rate_best_fit = rate;
78		- unsigned long highest, lowest;
	93	+ unsigned long rate_best_fit = rounder->rate;
	94	+ unsigned long highest, lowest, freq;
79	95	int i;
80	96
81	97	highest = 0;
82	98	lowest = ~0UL;
83	99
84		- for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
85		- unsigned long freq = freq_table[i].frequency;
86		-
87		- if (freq == CPUFREQ_ENTRY_INVALID)
88		- continue;
89		-
	100	+ for_each_frequency(i, rounder, freq) {
90	101	if (freq > highest)
91	102	highest = freq;
92	103	if (freq < lowest)
93	104	lowest = freq;
94	105
95		- rate_error = abs(freq - rate);
	106	+ rate_error = abs(freq - rounder->rate);
96	107	if (rate_error < rate_error_prev) {
97	108	rate_best_fit = freq;
98	109	rate_error_prev = rate_error;
99	110
100	111
...	...	@@ -102,12 +113,39 @@
102	113	break;
103	114	}
104	115
105		- if (rate >= highest)
	116	+ if (rounder->rate >= highest)
106	117	rate_best_fit = highest;
107		- if (rate <= lowest)
	118	+ if (rounder->rate <= lowest)
108	119	rate_best_fit = lowest;
109	120
110	121	return rate_best_fit;
	122	+}
	123	+
	124	+static long clk_rate_table_iter(unsigned int pos,
	125	+ struct clk_rate_round_data *rounder)
	126	+{
	127	+ struct cpufreq_frequency_table *freq_table = rounder->arg;
	128	+ unsigned long freq = freq_table[pos].frequency;
	129	+
	130	+ if (freq == CPUFREQ_ENTRY_INVALID)
	131	+ freq = 0;
	132	+
	133	+ return freq;
	134	+}
	135	+
	136	+long clk_rate_table_round(struct clk *clk,
	137	+ struct cpufreq_frequency_table *freq_table,
	138	+ unsigned long rate)
	139	+{
	140	+ struct clk_rate_round_data table_round = {
	141	+ .min = 0,
	142	+ .max = clk->nr_freqs,
	143	+ .func = clk_rate_table_iter,
	144	+ .arg = freq_table,
	145	+ .rate = rate,
	146	+ };
	147	+
	148	+ return clk_rate_round_helper(&table_round);
111	149	}
112	150
113	151	int clk_rate_table_find(struct clk *clk,
...	...	@@ -53,6 +53,7 @@
53	53	struct dentry *dentry;
54	54	struct clk_mapping *mapping;
55	55	struct cpufreq_frequency_table *freq_table;
	56	+ unsigned int nr_freqs;
56	57	};
57	58
58	59	#define CLK_ENABLE_ON_INIT (1 << 0)