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authorDave Gerlach <d-gerlach@ti.com>2018-10-03 16:13:15 +0530
committerViresh Kumar <viresh.kumar@linaro.org>2018-10-04 09:21:36 +0530
commitdeac8703da5faafce96be3f91c668dcd5da931a5 (patch)
treedb89ae4539e77676e7791567f06720065a60a1dd /drivers/opp/of.c
parent51c99dd2c06b234575661fa1e0a1dea6c3ef566f (diff)
downloadlinux-deac8703da5faafce96be3f91c668dcd5da931a5.tar.bz2
PM / OPP: _of_add_opp_table_v2(): increment count only if OPP is added
Currently the _of_add_opp_table_v2 call loops through the OPP nodes in the operating-points-v2 table in the device tree and calls _opp_add_static_v2 for each to add them to the table. It counts each iteration through this loop as an added OPP, however there are cases where _opp_add_static_v2() returns 0 but no new OPP is added to the list. This can happen while adding duplicate OPP or if the OPP isn't supported by hardware. Because of this the count variable will contain the number of OPP nodes in the table in device tree but not necessarily the ones that are actually added. As this count value is what is checked to determine if there are any valid OPPs, if a platform has an operating-points-v2 table with all OPP nodes containing opp-supported-hw values that are not currently supported, then _of_add_opp_table_v2 will fail to abort as it should due to an empty table. Additionally, since commit 3ba98324e81a ("PM / OPP: Get performance state using genpd helper"), the same count variable is compared against the number of OPPs containing performance states and requires that either all or none have pstates set, however in the case of any opp table that has any entries that do not get added by _opp_add_static_v2 due to incompatible opp-supported-hw fields, these numbers will not match and _of_add_opp_table_v2 will incorrectly fail. We need to clearly identify all the three cases (success, failure, unsupported/duplicate OPPs) and then increment count only on success case. Change return type of _opp_add_static_v2() to return the pointer to the newly added OPP instead of an integer. This routine now returns a valid pointer if the OPP is really added, NULL for unsupported or duplicate OPPs, and error value cased as a pointer on errors. Ideally the fixes tag in this commit should point back to the commit that introduced OPP v2 initially, as that's where we started incorrectly accounting for duplicate OPPs: commit 274659029c9d ("PM / OPP: Add support to parse "operating-points-v2" bindings") But it wasn't a real problem until recently as the count was only used to check if any OPPs are added or not. And so this commit points to a rather recent commit where we added more code that depends on the value of "count". Fixes: 3ba98324e81a ("PM / OPP: Get performance state using genpd helper") Reported-by: Dave Gerlach <d-gerlach@ti.com> Reported-by: Niklas Cassel <niklas.cassel@linaro.org> Tested-by: Niklas Cassel <niklas.cassel@linaro.org> Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/opp/of.c')
-rw-r--r--drivers/opp/of.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 67a384c8ead2..5a4b47958073 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -297,15 +297,21 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
* removed by dev_pm_opp_remove.
*
* Return:
- * 0 On success OR
+ * Valid OPP pointer:
+ * On success
+ * NULL:
* Duplicate OPPs (both freq and volt are same) and opp->available
- * -EEXIST Freq are same and volt are different OR
+ * OR if the OPP is not supported by hardware.
+ * ERR_PTR(-EEXIST):
+ * Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
- * -ENOMEM Memory allocation failure
- * -EINVAL Failed parsing the OPP node
+ * ERR_PTR(-ENOMEM):
+ * Memory allocation failure
+ * ERR_PTR(-EINVAL):
+ * Failed parsing the OPP node
*/
-static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
- struct device_node *np)
+static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
+ struct device *dev, struct device_node *np)
{
struct dev_pm_opp *new_opp;
u64 rate = 0;
@@ -315,7 +321,7 @@ static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
new_opp = _opp_allocate(opp_table);
if (!new_opp)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
ret = of_property_read_u64(np, "opp-hz", &rate);
if (ret < 0) {
@@ -390,12 +396,12 @@ static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
* frequency/voltage list.
*/
blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
- return 0;
+ return new_opp;
free_opp:
_opp_free(new_opp);
- return ret;
+ return ERR_PTR(ret);
}
/* Initializes OPP tables based on new bindings */
@@ -415,14 +421,15 @@ static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)
/* We have opp-table node now, iterate over it and add OPPs */
for_each_available_child_of_node(opp_table->np, np) {
- count++;
-
- ret = _opp_add_static_v2(opp_table, dev, np);
- if (ret) {
+ opp = _opp_add_static_v2(opp_table, dev, np);
+ if (IS_ERR(opp)) {
+ ret = PTR_ERR(opp);
dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
ret);
of_node_put(np);
goto put_list_kref;
+ } else if (opp) {
+ count++;
}
}