Allow to pass an integer n that results in only keeping n unused clocks
enabled.
This helps to debug the problem if you only know that clk_ignore_unused
helps but you have no clue yet which clock is the culprit.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
Hello,
compared to v2 sent in August 2021 this is a trivial rebase on top of
v6.1-rc1. I pinged that one repeatedly, I'm now trying with resending
and calling the rebased patch v3 to maybe get some feedback. :-\
Best regards
Uwe
Documentation/driver-api/clk.rst | 4 +++-
drivers/clk/clk.c | 33 ++++++++++++++++++++++++--------
2 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/Documentation/driver-api/clk.rst b/Documentation/driver-api/clk.rst
index 3cad45d14187..65ae7c3e2b33 100644
--- a/Documentation/driver-api/clk.rst
+++ b/Documentation/driver-api/clk.rst
@@ -259,7 +259,9 @@ the disabling means that the driver will remain functional while the issues
are sorted out.
To bypass this disabling, include "clk_ignore_unused" in the bootargs to the
-kernel.
+kernel. If you pass "clk_ignore_unused=n" (where n is an integer) the first n
+found clocks are not disabled which can be useful for bisecting over the unused
+clks if you don't know yet which of them is reponsible for your problem.
Locking
=======
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index c3c3f8c07258..356119a7e5fe 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1322,6 +1322,8 @@ static void __init clk_unprepare_unused_subtree(struct clk_core *core)
clk_pm_runtime_put(core);
}
+static unsigned clk_unused_keep_on __initdata;
+
static void __init clk_disable_unused_subtree(struct clk_core *core)
{
struct clk_core *child;
@@ -1352,12 +1354,17 @@ static void __init clk_disable_unused_subtree(struct clk_core *core)
* back to .disable
*/
if (clk_core_is_enabled(core)) {
- trace_clk_disable(core);
- if (core->ops->disable_unused)
- core->ops->disable_unused(core->hw);
- else if (core->ops->disable)
- core->ops->disable(core->hw);
- trace_clk_disable_complete(core);
+ if (clk_unused_keep_on) {
+ pr_warn("Keep unused clk \"%s\" on\n", core->name);
+ clk_unused_keep_on -= 1;
+ } else {
+ trace_clk_disable(core);
+ if (core->ops->disable_unused)
+ core->ops->disable_unused(core->hw);
+ else if (core->ops->disable)
+ core->ops->disable(core->hw);
+ trace_clk_disable_complete(core);
+ }
}
unlock_out:
@@ -1369,9 +1376,17 @@ static void __init clk_disable_unused_subtree(struct clk_core *core)
}
static bool clk_ignore_unused __initdata;
-static int __init clk_ignore_unused_setup(char *__unused)
+static int __init clk_ignore_unused_setup(char *keep)
{
- clk_ignore_unused = true;
+ if (*keep == '=') {
+ int ret;
+
+ ret = kstrtouint(keep + 1, 0, &clk_unused_keep_on);
+ if (ret < 0)
+ pr_err("Warning: failed to parse clk_ignore_unused parameter, ignoring");
+ } else {
+ clk_ignore_unused = true;
+ }
return 1;
}
__setup("clk_ignore_unused", clk_ignore_unused_setup);
@@ -1383,6 +1398,8 @@ static int __init clk_disable_unused(void)
if (clk_ignore_unused) {
pr_warn("clk: Not disabling unused clocks\n");
return 0;
+ } else if (clk_unused_keep_on) {
+ pr_warn("clk: Not disabling %u unused clocks\n", clk_unused_keep_on);
}
clk_prepare_lock();
--
2.37.2
