[PATCH v5 2/5] clk: move some parent related functions upwards

James Hogan
2013-06-13T16:05:59Z

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@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel at lists.infradead.org
---
Changes in v5:

* Rebased on latest clk-next ("clk: tegra: Use common of_clk_init
function")

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 | 208 +++++++++++++++++++++++++++---------------------------
1 file changed, 104 insertions(+), 104 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index ce74e91..06d2b5e 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1027,6 +1027,110 @@ 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.
+ *
+ * See also: Comment for clk_set_parent() below.
+ */
+ 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 +1438,6 @@ 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);
@@ -1353,98 +1445,6 @@ 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.
- *
- * See also: Comment for clk_set_parent() below.
- */
- 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