[RESEND PATCH 2/3] clk: Improve errorhandling for clk_set_parent
Ulf Hansson
ulf.hansson at stericsson.com
Tue Mar 12 15:20:49 EDT 2013
From: Ulf Hansson <ulf.hansson at linaro.org>
By verifying all the needed static information before doing the clk
notifications, we minimize number of unwanted rollback notifications
with ABORT_RATE_CHANGE message to occur.
Additionally make sure the parent are valid pointer before using it.
Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
---
drivers/clk/clk.c | 48 +++++++++++++++++++++++++++++-------------------
1 file changed, 29 insertions(+), 19 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 2e10cc1..a61cf6d 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1227,15 +1227,10 @@ static void clk_reparent(struct clk *clk, struct clk *new_parent)
clk->parent = new_parent;
}
-static int __clk_set_parent(struct clk *clk, struct clk *parent)
+static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
{
- struct clk *old_parent;
- unsigned long flags;
- int ret = -EINVAL;
u8 i;
- old_parent = clk->parent;
-
if (!clk->parents)
clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
GFP_KERNEL);
@@ -1255,11 +1250,14 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
}
}
- if (i == clk->num_parents) {
- pr_debug("%s: clock %s is not a possible parent of clock %s\n",
- __func__, parent->name, clk->name);
- goto out;
- }
+ return i;
+}
+
+static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
+{
+ unsigned long flags;
+ int ret;
+ struct clk *old_parent = clk->parent;
/* migrate prepare and enable */
if (clk->prepare_count)
@@ -1272,7 +1270,7 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
spin_unlock_irqrestore(&enable_lock, flags);
/* change clock input source */
- ret = clk->ops->set_parent(clk->hw, i);
+ ret = clk->ops->set_parent(clk->hw, p_index);
/* clean up old prepare and enable */
spin_lock_irqsave(&enable_lock, flags);
@@ -1283,7 +1281,6 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
if (clk->prepare_count)
__clk_unprepare(old_parent);
-out:
return ret;
}
@@ -1302,8 +1299,9 @@ out:
int clk_set_parent(struct clk *clk, struct clk *parent)
{
int ret = 0;
+ u8 p_index;
- if (!clk || !clk->ops)
+ if (!clk || !clk->ops || !parent)
return -EINVAL;
if (!clk->ops->set_parent)
@@ -1315,6 +1313,21 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
if (clk->parent == parent)
goto out;
+ /* check that we are allowed to re-parent if the clock is in use */
+ if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ /* try finding the new parent index */
+ p_index = clk_fetch_parent_index(clk, parent);
+ if (p_index == clk->num_parents) {
+ pr_debug("%s: clock %s is not a possible parent of clock %s\n",
+ __func__, parent->name, clk->name);
+ ret = -EINVAL;
+ goto out;
+ }
+
/* propagate PRE_RATE_CHANGE notifications */
if (clk->notifier_count)
ret = __clk_speculate_rates(clk, parent->rate);
@@ -1323,11 +1336,8 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
if (ret == NOTIFY_STOP)
goto out;
- /* only re-parent if the clock is not in use */
- if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count)
- ret = -EBUSY;
- else
- ret = __clk_set_parent(clk, parent);
+ /* do the re-parent */
+ ret = __clk_set_parent(clk, parent, p_index);
/* propagate ABORT_RATE_CHANGE if .set_parent failed */
if (ret) {
--
1.7.10
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