sh: clkfwk: refactor rate propagation.
This resyncs the rate propagation strategy with the scheme used by the
OMAP clock framework. Child clocks are tracked on a list under each
parent and propagation happens there specifically rather than constantly
iterating over the global clock list.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c
index 17f6c07..0a06df8 100644
--- a/arch/sh/kernel/cpu/clock.c
+++ b/arch/sh/kernel/cpu/clock.c
@@ -1,11 +1,11 @@
/*
* arch/sh/kernel/cpu/clock.c - SuperH clock framework
*
- * Copyright (C) 2005, 2006, 2007 Paul Mundt
+ * Copyright (C) 2005 - 2009 Paul Mundt
*
* This clock framework is derived from the OMAP version by:
*
- * Copyright (C) 2004 - 2005 Nokia Corporation
+ * Copyright (C) 2004 - 2008 Nokia Corporation
* Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
*
* Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
@@ -43,20 +43,20 @@
*/
static struct clk master_clk = {
.name = "master_clk",
- .flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
+ .flags = CLK_ALWAYS_ENABLED,
.rate = CONFIG_SH_PCLK_FREQ,
};
static struct clk module_clk = {
.name = "module_clk",
.parent = &master_clk,
- .flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
+ .flags = CLK_ALWAYS_ENABLED,
};
static struct clk bus_clk = {
.name = "bus_clk",
.parent = &master_clk,
- .flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
+ .flags = CLK_ALWAYS_ENABLED,
};
static struct clk cpu_clk = {
@@ -75,27 +75,24 @@
&cpu_clk,
};
-/* Propagate rate to children */
-static void propagate_rate(struct clk *clk)
-{
- struct clk *clkp;
-
- list_for_each_entry(clkp, &clock_list, node) {
- if (likely(clkp->parent != clk))
- continue;
- if (likely(clkp->ops && clkp->ops->recalc))
- clkp->rate = clkp->ops->recalc(clkp);
- if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
- propagate_rate(clkp);
- }
-}
-
/* Used for clocks that always have same value as the parent clock */
unsigned long followparent_recalc(struct clk *clk)
{
return clk->parent->rate;
}
+/* Propagate rate to children */
+void propagate_rate(struct clk *tclk)
+{
+ struct clk *clkp;
+
+ list_for_each_entry(clkp, &tclk->children, sibling) {
+ if (clkp->ops->recalc)
+ clkp->rate = clkp->ops->recalc(clkp);
+ propagate_rate(clkp);
+ }
+}
+
static void __clk_init(struct clk *clk)
{
/*
@@ -180,10 +177,46 @@
}
EXPORT_SYMBOL_GPL(clk_disable);
+static LIST_HEAD(root_clks);
+
+/**
+ * recalculate_root_clocks - recalculate and propagate all root clocks
+ *
+ * Recalculates all root clocks (clocks with no parent), which if the
+ * clock's .recalc is set correctly, should also propagate their rates.
+ * Called at init.
+ */
+void recalculate_root_clocks(void)
+{
+ struct clk *clkp;
+
+ list_for_each_entry(clkp, &root_clks, sibling) {
+ if (clkp->ops->recalc)
+ clkp->rate = clkp->ops->recalc(clkp);
+ propagate_rate(clkp);
+ }
+}
+
int clk_register(struct clk *clk)
{
+ if (clk == NULL || IS_ERR(clk))
+ return -EINVAL;
+
+ /*
+ * trap out already registered clocks
+ */
+ if (clk->node.next || clk->node.prev)
+ return 0;
+
mutex_lock(&clock_list_sem);
+ INIT_LIST_HEAD(&clk->children);
+
+ if (clk->parent)
+ list_add(&clk->sibling, &clk->parent->children);
+ else
+ list_add(&clk->sibling, &root_clks);
+
list_add(&clk->node, &clock_list);
clk->usecount = 0;
clk->flags |= CLK_NEEDS_INIT;
@@ -205,6 +238,7 @@
void clk_unregister(struct clk *clk)
{
mutex_lock(&clock_list_sem);
+ list_del(&clk->sibling);
list_del(&clk->node);
mutex_unlock(&clock_list_sem);
}
@@ -231,50 +265,53 @@
spin_lock_irqsave(&clock_lock, flags);
ret = clk->ops->set_rate(clk, rate, algo_id);
+ if (ret == 0) {
+ if (clk->ops->recalc)
+ clk->rate = clk->ops->recalc(clk);
+ propagate_rate(clk);
+ }
spin_unlock_irqrestore(&clock_lock, flags);
}
- if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
- propagate_rate(clk);
-
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate_ex);
void clk_recalc_rate(struct clk *clk)
{
- if (likely(clk->ops && clk->ops->recalc)) {
- unsigned long flags;
+ unsigned long flags;
- spin_lock_irqsave(&clock_lock, flags);
- clk->rate = clk->ops->recalc(clk);
- spin_unlock_irqrestore(&clock_lock, flags);
- }
+ if (!clk->ops->recalc)
+ return;
- if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
- propagate_rate(clk);
+ spin_lock_irqsave(&clock_lock, flags);
+ clk->rate = clk->ops->recalc(clk);
+ propagate_rate(clk);
+ spin_unlock_irqrestore(&clock_lock, flags);
}
EXPORT_SYMBOL_GPL(clk_recalc_rate);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
+ unsigned long flags;
int ret = -EINVAL;
- struct clk *old;
if (!parent || !clk)
return ret;
- old = clk->parent;
- if (likely(clk->ops && clk->ops->set_parent)) {
- unsigned long flags;
- spin_lock_irqsave(&clock_lock, flags);
- ret = clk->ops->set_parent(clk, parent);
- spin_unlock_irqrestore(&clock_lock, flags);
- clk->parent = (ret ? old : parent);
- }
+ spin_lock_irqsave(&clock_lock, flags);
+ if (clk->usecount == 0) {
+ if (clk->ops->set_parent)
+ ret = clk->ops->set_parent(clk, parent);
+ if (ret == 0) {
+ if (clk->ops->recalc)
+ clk->rate = clk->ops->recalc(clk);
+ propagate_rate(clk);
+ }
+ } else
+ ret = -EBUSY;
+ spin_unlock_irqrestore(&clock_lock, flags);
- if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
- propagate_rate(clk);
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_parent);
@@ -457,8 +494,7 @@
ret |= arch_clk_init();
/* Kick the child clocks.. */
- propagate_rate(&master_clk);
- propagate_rate(&bus_clk);
+ recalculate_root_clocks();
return ret;
}