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Message-ID: <1369056507-32521-3-git-send-email-james.hogan@imgtec.com>
Date: Mon, 20 May 2013 14:28:24 +0100
From: James Hogan <james.hogan@...tec.com>
To: Mike Turquette <mturquette@...aro.org>,
<linux-arm-kernel@...ts.infradead.org>
CC: Stephen Boyd <sboyd@...eaurora.org>,
<linux-kernel@...r.kernel.org>,
Saravana Kannan <skannan@...eaurora.org>,
James Hogan <james.hogan@...tec.com>
Subject: [PATCH v4 2/5] clk: move some parent related functions upwards
Move some parent related functions up in clk.c so they can be used by
the modifications in the following patch which enables clock reparenting
during set_rate. No other changes are made so this patch makes no
functional difference in isolation. This is separate from the following
patch primarily to ease readability of that patch.
Signed-off-by: James Hogan <james.hogan@...tec.com>
Cc: Mike Turquette <mturquette@...aro.org>
Cc: linux-arm-kernel@...ts.infradead.org
---
Changes in v4:
* new patch (patch 2) split out of patch 3 to avoid having to declare
static __clk_set_parent() at the top of clk.c, and to ease readability
of patch 3.
drivers/clk/clk.c | 220 +++++++++++++++++++++++++++---------------------------
1 file changed, 110 insertions(+), 110 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f0ebada..a4cd6bc 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1027,6 +1027,108 @@ unsigned long clk_get_rate(struct clk *clk)
}
EXPORT_SYMBOL_GPL(clk_get_rate);
+static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
+{
+ u8 i;
+
+ if (!clk->parents)
+ clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
+ GFP_KERNEL);
+
+ /*
+ * find index of new parent clock using cached parent ptrs,
+ * or if not yet cached, use string name comparison and cache
+ * them now to avoid future calls to __clk_lookup.
+ */
+ for (i = 0; i < clk->num_parents; i++) {
+ if (clk->parents && clk->parents[i] == parent)
+ break;
+ else if (!strcmp(clk->parent_names[i], parent->name)) {
+ if (clk->parents)
+ clk->parents[i] = __clk_lookup(parent->name);
+ break;
+ }
+ }
+
+ return i;
+}
+
+static void clk_reparent(struct clk *clk, struct clk *new_parent)
+{
+ hlist_del(&clk->child_node);
+
+ if (new_parent)
+ hlist_add_head(&clk->child_node, &new_parent->children);
+ else
+ hlist_add_head(&clk->child_node, &clk_orphan_list);
+
+ clk->parent = new_parent;
+}
+
+static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
+{
+ unsigned long flags;
+ int ret = 0;
+ struct clk *old_parent = clk->parent;
+
+ /*
+ * Migrate prepare state between parents and prevent race with
+ * clk_enable().
+ *
+ * If the clock is not prepared, then a race with
+ * clk_enable/disable() is impossible since we already have the
+ * prepare lock (future calls to clk_enable() need to be preceded by
+ * a clk_prepare()).
+ *
+ * If the clock is prepared, migrate the prepared state to the new
+ * parent and also protect against a race with clk_enable() by
+ * forcing the clock and the new parent on. This ensures that all
+ * future calls to clk_enable() are practically NOPs with respect to
+ * hardware and software states.
+ */
+ if (clk->prepare_count) {
+ __clk_prepare(parent);
+ clk_enable(parent);
+ clk_enable(clk);
+ }
+
+ /* update the clk tree topology */
+ flags = clk_enable_lock();
+ clk_reparent(clk, parent);
+ clk_enable_unlock(flags);
+
+ /* change clock input source */
+ if (parent && clk->ops->set_parent)
+ ret = clk->ops->set_parent(clk->hw, p_index);
+
+ if (ret) {
+ flags = clk_enable_lock();
+ clk_reparent(clk, old_parent);
+ clk_enable_unlock(flags);
+
+ if (clk->prepare_count) {
+ clk_disable(clk);
+ clk_disable(parent);
+ __clk_unprepare(parent);
+ }
+ return ret;
+ }
+
+ /*
+ * Finish the migration of prepare state and undo the changes done
+ * for preventing a race with clk_enable().
+ */
+ if (clk->prepare_count) {
+ clk_disable(clk);
+ clk_disable(old_parent);
+ __clk_unprepare(old_parent);
+ }
+
+ /* update debugfs with new clk tree topology */
+ clk_debug_reparent(clk, parent);
+ return 0;
+}
+
/**
* __clk_speculate_rates
* @clk: first clk in the subtree
@@ -1334,18 +1436,6 @@ out:
return ret;
}
-static void clk_reparent(struct clk *clk, struct clk *new_parent)
-{
- hlist_del(&clk->child_node);
-
- if (new_parent)
- hlist_add_head(&clk->child_node, &new_parent->children);
- else
- hlist_add_head(&clk->child_node, &clk_orphan_list);
-
- clk->parent = new_parent;
-}
-
void __clk_reparent(struct clk *clk, struct clk *new_parent)
{
clk_reparent(clk, new_parent);
@@ -1353,96 +1443,6 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent)
__clk_recalc_rates(clk, POST_RATE_CHANGE);
}
-static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
-{
- u8 i;
-
- if (!clk->parents)
- clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
- GFP_KERNEL);
-
- /*
- * find index of new parent clock using cached parent ptrs,
- * or if not yet cached, use string name comparison and cache
- * them now to avoid future calls to __clk_lookup.
- */
- for (i = 0; i < clk->num_parents; i++) {
- if (clk->parents && clk->parents[i] == parent)
- break;
- else if (!strcmp(clk->parent_names[i], parent->name)) {
- if (clk->parents)
- clk->parents[i] = __clk_lookup(parent->name);
- break;
- }
- }
-
- return i;
-}
-
-static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
-{
- unsigned long flags;
- int ret = 0;
- struct clk *old_parent = clk->parent;
-
- /*
- * Migrate prepare state between parents and prevent race with
- * clk_enable().
- *
- * If the clock is not prepared, then a race with
- * clk_enable/disable() is impossible since we already have the
- * prepare lock (future calls to clk_enable() need to be preceded by
- * a clk_prepare()).
- *
- * If the clock is prepared, migrate the prepared state to the new
- * parent and also protect against a race with clk_enable() by
- * forcing the clock and the new parent on. This ensures that all
- * future calls to clk_enable() are practically NOPs with respect to
- * hardware and software states.
- */
- if (clk->prepare_count) {
- __clk_prepare(parent);
- clk_enable(parent);
- clk_enable(clk);
- }
-
- /* update the clk tree topology */
- flags = clk_enable_lock();
- clk_reparent(clk, parent);
- clk_enable_unlock(flags);
-
- /* change clock input source */
- if (parent && clk->ops->set_parent)
- ret = clk->ops->set_parent(clk->hw, p_index);
-
- if (ret) {
- flags = clk_enable_lock();
- clk_reparent(clk, old_parent);
- clk_enable_unlock(flags);
-
- if (clk->prepare_count) {
- clk_disable(clk);
- clk_disable(parent);
- __clk_unprepare(parent);
- }
- return ret;
- }
-
- /*
- * Finish the migration of prepare state and undo the changes done
- * for preventing a race with clk_enable().
- */
- if (clk->prepare_count) {
- clk_disable(clk);
- clk_disable(old_parent);
- __clk_unprepare(old_parent);
- }
-
- /* update debugfs with new clk tree topology */
- clk_debug_reparent(clk, parent);
- return 0;
-}
-
/**
* clk_set_parent - switch the parent of a mux clk
* @clk: the mux clk whose input we are switching
--
1.8.1.2
--
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