sh: clkfwk: Consolidate the ALWAYS_ENABLED / NEEDS_INIT mess.

There is no real distinction here in behaviour, either a clock needs to
be enabled on initialiation or not. The ALWAYS_ENABLED flag was always
intended to only apply to clocks that were physically always on and could
simply not be disabled at all from software. Unfortunately over time this
was abused and the meaning became a bit blurry.

So, we kill off both of all of those paths now, as well as the newer
NEEDS_INIT flag, and consolidate on a CLK_ENABLE_ON_INIT. Clocks that
need to be enabled on initialization can set this, and it will purposely
enable them and bump the refcount up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/clock.h

@@ -37,8 +37,7 @@ struct clk {
 	unsigned long		arch_flags;
 };
 
-#define CLK_ALWAYS_ENABLED	(1 << 0)
-#define CLK_NEEDS_INIT		(1 << 2)
+#define CLK_ENABLE_ON_INIT	(1 << 0)
 
 /* Should be defined by processor-specific code */
 void arch_init_clk_ops(struct clk_ops **, int type);

arch/sh/kernel/cpu/clock.c

@@ -43,26 +43,26 @@ static DEFINE_MUTEX(clock_list_sem);
  */
 static struct clk master_clk = {
 	.name		= "master_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.rate		= CONFIG_SH_PCLK_FREQ,
 };
 
 static struct clk module_clk = {
 	.name		= "module_clk",
 	.parent		= &master_clk,
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 };
 
 static struct clk bus_clk = {
 	.name		= "bus_clk",
 	.parent		= &master_clk,
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 };
 
 static struct clk cpu_clk = {
 	.name		= "cpu_clk",
 	.parent		= &master_clk,
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 };
 
 /*
@@ -93,39 +93,11 @@ void propagate_rate(struct clk *tclk)
 	}
 }
 
-static void __clk_init(struct clk *clk)
-{
-	/*
-	 * See if this is the first time we're enabling the clock, some
-	 * clocks that are always enabled still require "special"
-	 * initialization. This is especially true if the clock mode
-	 * changes and the clock needs to hunt for the proper set of
-	 * divisors to use before it can effectively recalc.
-	 */
-
-	if (clk->flags & CLK_NEEDS_INIT) {
-		if (clk->ops && clk->ops->init)
-			clk->ops->init(clk);
-
-		clk->flags &= ~CLK_NEEDS_INIT;
-	}
-}
-
 static int __clk_enable(struct clk *clk)
 {
-	if (!clk)
-		return -EINVAL;
-
-	clk->usecount++;
-
-	/* nothing to do if always enabled */
-	if (clk->flags & CLK_ALWAYS_ENABLED)
-		return 0;
-
-	if (clk->usecount == 1) {
-		__clk_init(clk);
-
-		__clk_enable(clk->parent);
+	if (clk->usecount++ == 0) {
+		if (clk->parent)
+			__clk_enable(clk->parent);
 
 		if (clk->ops && clk->ops->enable)
 			clk->ops->enable(clk);
@@ -139,6 +111,9 @@ int clk_enable(struct clk *clk)
 	unsigned long flags;
 	int ret;
 
+	if (!clk)
+		return -EINVAL;
+
 	spin_lock_irqsave(&clock_lock, flags);
 	ret = __clk_enable(clk);
 	spin_unlock_irqrestore(&clock_lock, flags);
@@ -149,21 +124,11 @@ EXPORT_SYMBOL_GPL(clk_enable);
 
 static void __clk_disable(struct clk *clk)
 {
-	if (!clk)
-		return;
-
-	clk->usecount--;
-
-	WARN_ON(clk->usecount < 0);
-
-	if (clk->flags & CLK_ALWAYS_ENABLED)
-		return;
-
-	if (clk->usecount == 0) {
+	if (clk->usecount > 0 && !(--clk->usecount)) {
 		if (likely(clk->ops && clk->ops->disable))
 			clk->ops->disable(clk);
-
-		__clk_disable(clk->parent);
+		if (likely(clk->parent))
+			__clk_disable(clk->parent);
 	}
 }
 
@@ -171,6 +136,9 @@ void clk_disable(struct clk *clk)
 {
 	unsigned long flags;
 
+	if (!clk)
+		return;
+
 	spin_lock_irqsave(&clock_lock, flags);
 	__clk_disable(clk);
 	spin_unlock_irqrestore(&clock_lock, flags);
@@ -211,6 +179,7 @@ int clk_register(struct clk *clk)
 	mutex_lock(&clock_list_sem);
 
 	INIT_LIST_HEAD(&clk->children);
+	clk->usecount = 0;
 
 	if (clk->parent)
 		list_add(&clk->sibling, &clk->parent->children);
@@ -218,19 +187,10 @@ int clk_register(struct clk *clk)
 		list_add(&clk->sibling, &root_clks);
 
 	list_add(&clk->node, &clock_list);
-	clk->usecount = 0;
-	clk->flags |= CLK_NEEDS_INIT;
-
+	if (clk->ops->init)
+		clk->ops->init(clk);
 	mutex_unlock(&clock_list_sem);
 
-	if (clk->flags & CLK_ALWAYS_ENABLED) {
-		__clk_init(clk);
-		pr_debug( "Clock '%s' is ALWAYS_ENABLED\n", clk->name);
-		if (clk->ops && clk->ops->enable)
-			clk->ops->enable(clk);
-		pr_debug( "Enabled.");
-	}
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(clk_register);
@@ -244,6 +204,15 @@ void clk_unregister(struct clk *clk)
 }
 EXPORT_SYMBOL_GPL(clk_unregister);
 
+static void clk_enable_init_clocks(void)
+{
+	struct clk *clkp;
+
+	list_for_each_entry(clkp, &clock_list, node)
+		if (clkp->flags & CLK_ENABLE_ON_INIT)
+			clk_enable(clkp);
+}
+
 unsigned long clk_get_rate(struct clk *clk)
 {
 	return clk->rate;
@@ -404,9 +373,7 @@ static int show_clocks(char *buf, char **start, off_t off,
 
 		p += sprintf(p, "%-12s\t: %ld.%02ldMHz\t%s\n", clk->name,
 			     rate / 1000000, (rate % 1000000) / 10000,
-			     ((clk->flags & CLK_ALWAYS_ENABLED) ||
-			      clk->usecount > 0) ?
-			     "enabled" : "disabled");
+			      (clk->usecount > 0) ?  "enabled" : "disabled");
 	}
 
 	return p - buf;
@@ -496,6 +463,9 @@ int __init clk_init(void)
 	/* Kick the child clocks.. */
 	recalculate_root_clocks();
 
+	/* Enable the necessary init clocks */
+	clk_enable_init_clocks();
+
 	return ret;
 }
 

arch/sh/kernel/cpu/sh4/clock-sh4-202.c

@@ -46,7 +46,7 @@ static struct clk_ops sh4202_emi_clk_ops = {
 
 static struct clk sh4202_emi_clk = {
 	.name		= "emi_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh4202_emi_clk_ops,
 };
 
@@ -62,7 +62,7 @@ static struct clk_ops sh4202_femi_clk_ops = {
 
 static struct clk sh4202_femi_clk = {
 	.name		= "femi_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh4202_femi_clk_ops,
 };
 
@@ -140,7 +140,7 @@ static struct clk_ops sh4202_shoc_clk_ops = {
 
 static struct clk sh4202_shoc_clk = {
 	.name		= "shoc_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh4202_shoc_clk_ops,
 };
 

arch/sh/kernel/cpu/sh4a/clock-sh7763.c

@@ -78,7 +78,7 @@ static struct clk_ops sh7763_shyway_clk_ops = {
 
 static struct clk sh7763_shyway_clk = {
 	.name		= "shyway_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7763_shyway_clk_ops,
 };
 

arch/sh/kernel/cpu/sh4a/clock-sh7780.c

@@ -84,7 +84,7 @@ static struct clk_ops sh7780_shyway_clk_ops = {
 
 static struct clk sh7780_shyway_clk = {
 	.name		= "shyway_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7780_shyway_clk_ops,
 };
 

arch/sh/kernel/cpu/sh4a/clock-sh7785.c

@@ -88,7 +88,7 @@ static struct clk_ops sh7785_shyway_clk_ops = {
 
 static struct clk sh7785_shyway_clk = {
 	.name		= "shyway_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7785_shyway_clk_ops,
 };
 
@@ -104,7 +104,7 @@ static struct clk_ops sh7785_ddr_clk_ops = {
 
 static struct clk sh7785_ddr_clk = {
 	.name		= "ddr_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7785_ddr_clk_ops,
 };
 
@@ -120,7 +120,7 @@ static struct clk_ops sh7785_ram_clk_ops = {
 
 static struct clk sh7785_ram_clk = {
 	.name		= "ram_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7785_ram_clk_ops,
 };
 

arch/sh/kernel/cpu/sh4a/clock-sh7786.c

@@ -91,7 +91,7 @@ static struct clk_ops sh7786_shyway_clk_ops = {
 
 static struct clk sh7786_shyway_clk = {
 	.name		= "shyway_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7786_shyway_clk_ops,
 };
 
@@ -107,7 +107,7 @@ static struct clk_ops sh7786_ddr_clk_ops = {
 
 static struct clk sh7786_ddr_clk = {
 	.name		= "ddr_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &sh7786_ddr_clk_ops,
 };
 

arch/sh/kernel/cpu/sh4a/clock-shx3.c

@@ -95,7 +95,7 @@ static struct clk_ops shx3_shyway_clk_ops = {
 
 static struct clk shx3_shyway_clk = {
 	.name		= "shyway_clk",
-	.flags		= CLK_ALWAYS_ENABLED,
+	.flags		= CLK_ENABLE_ON_INIT,
 	.ops		= &shx3_shyway_clk_ops,
 };