cpufreq: Add and use cpufreq_for_each_{valid_,}entry_idx()

Pointer subtraction is slow and tedious. Therefore, replace all instances
where cpufreq_for_each_{valid_,}entry loops contained such substractions
with an iteration macro providing an index to the frequency_table entry.

Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Link: http://lkml.kernel.org/r/20180120020237.GM13338@ZenIV.linux.org.uk
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/exynos5440-cpufreq.c b/drivers/cpufreq/exynos5440-cpufreq.c
index b6b369c..932caa3 100644
--- a/drivers/cpufreq/exynos5440-cpufreq.c
+++ b/drivers/cpufreq/exynos5440-cpufreq.c
@@ -115,10 +115,10 @@ static struct cpufreq_freqs freqs;
 static int init_div_table(void)
 {
 	struct cpufreq_frequency_table *pos, *freq_tbl = dvfs_info->freq_table;
-	unsigned int tmp, clk_div, ema_div, freq, volt_id;
+	unsigned int tmp, clk_div, ema_div, freq, volt_id, idx;
 	struct dev_pm_opp *opp;
 
-	cpufreq_for_each_entry(pos, freq_tbl) {
+	cpufreq_for_each_entry_idx(pos, freq_tbl, idx) {
 		opp = dev_pm_opp_find_freq_exact(dvfs_info->dev,
 					pos->frequency * 1000, true);
 		if (IS_ERR(opp)) {
@@ -154,8 +154,7 @@ static int init_div_table(void)
 		tmp = (clk_div | ema_div | (volt_id << P0_7_VDD_SHIFT)
 			| ((freq / FREQ_UNIT) << P0_7_FREQ_SHIFT));
 
-		__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 *
-						(pos - freq_tbl));
+		__raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 * idx);
 		dev_pm_opp_put(opp);
 	}
 
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 3bbbf9e..6d007f8 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -143,10 +143,9 @@ int cpufreq_table_index_unsorted(struct cpufreq_policy *policy,
 		break;
 	}
 
-	cpufreq_for_each_valid_entry(pos, table) {
+	cpufreq_for_each_valid_entry_idx(pos, table, i) {
 		freq = pos->frequency;
 
-		i = pos - table;
 		if ((freq < policy->min) || (freq > policy->max))
 			continue;
 		if (freq == target_freq) {
@@ -211,15 +210,16 @@ int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
 		unsigned int freq)
 {
 	struct cpufreq_frequency_table *pos, *table = policy->freq_table;
+	int idx;
 
 	if (unlikely(!table)) {
 		pr_debug("%s: Unable to find frequency table\n", __func__);
 		return -ENOENT;
 	}
 
-	cpufreq_for_each_valid_entry(pos, table)
+	cpufreq_for_each_valid_entry_idx(pos, table, idx)
 		if (pos->frequency == freq)
-			return pos - table;
+			return idx;
 
 	return -EINVAL;
 }
diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
index 5faa37c..942632a 100644
--- a/drivers/cpufreq/longhaul.c
+++ b/drivers/cpufreq/longhaul.c
@@ -600,7 +600,7 @@ static void longhaul_setup_voltagescaling(void)
 	/* Calculate kHz for one voltage step */
 	kHz_step = (highest_speed - min_vid_speed) / numvscales;
 
-	cpufreq_for_each_entry(freq_pos, longhaul_table) {
+	cpufreq_for_each_entry_idx(freq_pos, longhaul_table, j) {
 		speed = freq_pos->frequency;
 		if (speed > min_vid_speed)
 			pos = (speed - min_vid_speed) / kHz_step + minvid.pos;
@@ -609,7 +609,7 @@ static void longhaul_setup_voltagescaling(void)
 		freq_pos->driver_data |= mV_vrm_table[pos] << 8;
 		vid = vrm_mV_table[mV_vrm_table[pos]];
 		pr_info("f: %d kHz, index: %d, vid: %d mV\n",
-			speed, (int)(freq_pos - longhaul_table), vid.mV);
+			speed, j, vid.mV);
 	}
 
 	can_scale_voltage = 1;
diff --git a/drivers/cpufreq/pasemi-cpufreq.c b/drivers/cpufreq/pasemi-cpufreq.c
index b257fc7..75dfbd2 100644
--- a/drivers/cpufreq/pasemi-cpufreq.c
+++ b/drivers/cpufreq/pasemi-cpufreq.c
@@ -139,7 +139,7 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	struct cpufreq_frequency_table *pos;
 	const u32 *max_freqp;
 	u32 max_freq;
-	int cur_astate;
+	int cur_astate, idx;
 	struct resource res;
 	struct device_node *cpu, *dn;
 	int err = -ENODEV;
@@ -198,9 +198,9 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	pr_debug("initializing frequency table\n");
 
 	/* initialize frequency table */
-	cpufreq_for_each_entry(pos, pas_freqs) {
+	cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
 		pos->frequency = get_astate_freq(pos->driver_data) * 100000;
-		pr_debug("%d: %d\n", (int)(pos - pas_freqs), pos->frequency);
+		pr_debug("%d: %d\n", idx, pos->frequency);
 	}
 
 	cur_astate = get_cur_astate(policy->cpu);