[ARM] omap: create a proper tree of clocks

Traditionally, we've tracked the parent/child relationships between
clk structures by setting the child's parent member to point at the
upstream clock.  As a result, when decending the tree, we have had
to scan all clocks to find the children.

Avoid this wasteful scanning by keeping a list of the clock's children.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 32 insertions, 19 deletions

diff --git a/arch/arm/plat-omap/clock.c b/arch/arm/plat-omap/clock.c
index 54da27af0bd5..6a1737a74477 100644
--- a/arch/arm/plat-omap/clock.c
+++ b/arch/arm/plat-omap/clock.c
@@ -143,8 +143,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
         if (ret == 0) {
                 if (clk->recalc)
                         clk->recalc(clk);
-                if (clk->flags & RATE_PROPAGATES)
-                        propagate_rate(clk);
+                propagate_rate(clk);
         }
         spin_unlock_irqrestore(&clockfw_lock, flags);
 
@@ -166,8 +165,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
         if (ret == 0) {
                 if (clk->recalc)
                         clk->recalc(clk);
-                if (clk->flags & RATE_PROPAGATES)
-                        propagate_rate(clk);
+                propagate_rate(clk);
         }
         spin_unlock_irqrestore(&clockfw_lock, flags);
 
@@ -214,24 +212,31 @@ void followparent_recalc(struct clk *clk)
         clk->rate = clk->parent->rate;
 }
 
+void clk_reparent(struct clk *child, struct clk *parent)
+{
+        list_del_init(&child->sibling);
+        if (parent)
+                list_add(&child->sibling, &parent->children);
+        child->parent = parent;
+
+        /* now do the debugfs renaming to reattach the child
+           to the proper parent */
+}
+
 /* Propagate rate to children */
 void propagate_rate(struct clk * tclk)
 {
         struct clk *clkp;
 
-        if (tclk == NULL || IS_ERR(tclk))
-                return;
-
-        list_for_each_entry(clkp, &clocks, node) {
-                if (likely(clkp->parent != tclk))
-                        continue;
+        list_for_each_entry(clkp, &tclk->children, sibling) {
                 if (clkp->recalc)
                         clkp->recalc(clkp);
-                if (clkp->flags & RATE_PROPAGATES)
-                        propagate_rate(clkp);
+                propagate_rate(clkp);
         }
 }
 
+static LIST_HEAD(root_clks);
+
 /**
  * recalculate_root_clocks - recalculate and propagate all root clocks
  *
@@ -243,16 +248,18 @@ void recalculate_root_clocks(void)
 {
         struct clk *clkp;
 
-        list_for_each_entry(clkp, &clocks, node) {
-                if (!clkp->parent) {
-                        if (clkp->recalc)
-                                clkp->recalc(clkp);
-                        if (clkp->flags & RATE_PROPAGATES)
-                                propagate_rate(clkp);
-                }
+        list_for_each_entry(clkp, &root_clks, sibling) {
+                if (clkp->recalc)
+                        clkp->recalc(clkp);
+                propagate_rate(clkp);
         }
 }
 
+void clk_init_one(struct clk *clk)
+{
+        INIT_LIST_HEAD(&clk->children);
+}
+
 int clk_register(struct clk *clk)
 {
         if (clk == NULL || IS_ERR(clk))
@@ -265,6 +272,11 @@ int clk_register(struct clk *clk)
                 return 0;
 
         mutex_lock(&clocks_mutex);
+        if (clk->parent)
+                list_add(&clk->sibling, &clk->parent->children);
+        else
+                list_add(&clk->sibling, &root_clks);
+
         list_add(&clk->node, &clocks);
         if (clk->init)
                 clk->init(clk);
@@ -280,6 +292,7 @@ void clk_unregister(struct clk *clk)
                 return;
 
         mutex_lock(&clocks_mutex);
+        list_del(&clk->sibling);
         list_del(&clk->node);
         mutex_unlock(&clocks_mutex);
 }