PM: EM: Change debugfs configuration to use runtime EM table data

Dump the runtime EM table values which can be modified in time. In order
to do that allocate chunk of debug memory which can be later freed
automatically thanks to devm_kcalloc().

This design can handle the fact that the EM table memory can change
after EM update, so debug code cannot use the pointer from initialization
phase.

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/energy_model.c

@@ -37,20 +37,65 @@ static bool _is_cpu_device(struct device *dev)
 #ifdef CONFIG_DEBUG_FS
 static struct dentry *rootdir;
 
-static void em_debug_create_ps(struct em_perf_state *ps, struct dentry *pd)
+struct em_dbg_info {
+	struct em_perf_domain *pd;
+	int ps_id;
+};
+
+#define DEFINE_EM_DBG_SHOW(name, fname)					\
+static int em_debug_##fname##_show(struct seq_file *s, void *unused)	\
+{									\
+	struct em_dbg_info *em_dbg = s->private;			\
+	struct em_perf_state *table;					\
+	unsigned long val;						\
+									\
+	rcu_read_lock();						\
+	table = em_perf_state_from_pd(em_dbg->pd);			\
+	val = table[em_dbg->ps_id].name;				\
+	rcu_read_unlock();						\
+									\
+	seq_printf(s, "%lu\n", val);					\
+	return 0;							\
+}									\
+DEFINE_SHOW_ATTRIBUTE(em_debug_##fname)
+
+DEFINE_EM_DBG_SHOW(frequency, frequency);
+DEFINE_EM_DBG_SHOW(power, power);
+DEFINE_EM_DBG_SHOW(cost, cost);
+DEFINE_EM_DBG_SHOW(performance, performance);
+DEFINE_EM_DBG_SHOW(flags, inefficiency);
+
+static void em_debug_create_ps(struct em_perf_domain *em_pd,
+			       struct em_dbg_info *em_dbg, int i,
+			       struct dentry *pd)
 {
+	struct em_perf_state *table;
+	unsigned long freq;
 	struct dentry *d;
 	char name[24];
 
-	snprintf(name, sizeof(name), "ps:%lu", ps->frequency);
+	em_dbg[i].pd = em_pd;
+	em_dbg[i].ps_id = i;
+
+	rcu_read_lock();
+	table = em_perf_state_from_pd(em_pd);
+	freq = table[i].frequency;
+	rcu_read_unlock();
+
+	snprintf(name, sizeof(name), "ps:%lu", freq);
 
 	/* Create per-ps directory */
 	d = debugfs_create_dir(name, pd);
-	debugfs_create_ulong("frequency", 0444, d, &ps->frequency);
-	debugfs_create_ulong("power", 0444, d, &ps->power);
-	debugfs_create_ulong("cost", 0444, d, &ps->cost);
-	debugfs_create_ulong("performance", 0444, d, &ps->performance);
-	debugfs_create_ulong("inefficient", 0444, d, &ps->flags);
+	debugfs_create_file("frequency", 0444, d, &em_dbg[i],
+			    &em_debug_frequency_fops);
+	debugfs_create_file("power", 0444, d, &em_dbg[i],
+			    &em_debug_power_fops);
+	debugfs_create_file("cost", 0444, d, &em_dbg[i],
+			    &em_debug_cost_fops);
+	debugfs_create_file("performance", 0444, d, &em_dbg[i],
+			    &em_debug_performance_fops);
+	debugfs_create_file("inefficient", 0444, d, &em_dbg[i],
+			    &em_debug_inefficiency_fops);
 }
 
 static int em_debug_cpus_show(struct seq_file *s, void *unused)
@@ -73,6 +118,7 @@ DEFINE_SHOW_ATTRIBUTE(em_debug_flags);
 
 static void em_debug_create_pd(struct device *dev)
 {
+	struct em_dbg_info *em_dbg;
 	struct dentry *d;
 	int i;
 
@@ -86,9 +132,14 @@ static void em_debug_create_pd(struct device *dev)
 	debugfs_create_file("flags", 0444, d, dev->em_pd,
 			    &em_debug_flags_fops);
 
+	em_dbg = devm_kcalloc(dev, dev->em_pd->nr_perf_states,
+			      sizeof(*em_dbg), GFP_KERNEL);
+	if (!em_dbg)
+		return;
+
 	/* Create a sub-directory for each performance state */
 	for (i = 0; i < dev->em_pd->nr_perf_states; i++)
-		em_debug_create_ps(&dev->em_pd->table[i], d);
+		em_debug_create_ps(dev->em_pd, em_dbg, i, d);
 
 }