Messages in this thread | | | Subject | Re: [PATCH] clk: Add support for enabling/disabling clocks from debugfs | From | Stephen Boyd <> | Date | Fri, 24 Jul 2020 02:06:54 -0700 |
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Quoting Mike Tipton (2020-06-29 17:30:24) > For test and debug purposes, it's often necessary to enable or disable > clocks from shell. Add a new debugfs file (clk_prepare_enable) that > calls clk_prepare_enable() when writing "1" and clk_disable_unprepare() > when writing "0". > > This can have security implications, so only support it when the code > has been modified to #define CLOCK_ALLOW_WRITE_DEBUGS.
DEBUGFS
> > Signed-off-by: Mike Tipton <mdtipton@codeaurora.org> > --- > drivers/clk/clk.c | 38 ++++++++++++++++++++++++++++++++++---- > 1 file changed, 34 insertions(+), 4 deletions(-) > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index 236923b25543..3640bbc56870 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -3034,13 +3034,14 @@ static int clk_dump_show(struct seq_file *s, void *data) > } > DEFINE_SHOW_ATTRIBUTE(clk_dump); > > -#undef CLOCK_ALLOW_WRITE_DEBUGFS > -#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
This didn't need to change.
> /* > - * This can be dangerous, therefore don't provide any real compile time > - * configuration option for this feature. > + * These features can be dangerous, therefore don't provide any real compile > + * time configuration option for them. > * People who want to use this will need to modify the source code directly. > */ > +#undef CLOCK_ALLOW_WRITE_DEBUGFS > +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
So I put it back and dropped your rewording.
> + > static int clk_rate_set(void *data, u64 val) > { > struct clk_core *core = data; > @@ -3054,6 +3055,31 @@ static int clk_rate_set(void *data, u64 val) > } > > #define clk_rate_mode 0644 > + > +static int clk_prepare_enable_set(void *data, u64 val) > +{ > + struct clk_core *core = data; > + int ret = 0; > + > + if (val) > + ret = clk_prepare_enable(core->hw->clk); > + else > + clk_disable_unprepare(core->hw->clk); > + > + return ret; > +} > + > +static int clk_prepare_enable_get(void *data, u64 *val) > +{ > + struct clk_core *core = data; > + > + *val = core->enable_count && core->prepare_count; > + return 0; > +} > + > +DEFINE_DEBUGFS_ATTRIBUTE(clk_prepare_enable_fops, clk_prepare_enable_get, > + clk_prepare_enable_set, "%llu\n"); > + > #else > #define clk_rate_set NULL > #define clk_rate_mode 0444 > @@ -3231,6 +3257,10 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry) > debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count); > debugfs_create_file("clk_duty_cycle", 0444, root, core, > &clk_duty_cycle_fops); > +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
This is ugly but I guess we can't do much.
> + debugfs_create_file("clk_prepare_enable", 0644, root, core, > + &clk_prepare_enable_fops); > +#endif >
Applied to clk-next.
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