| Message ID | 20130427211018.GA9376@quad.lixom.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Olof Johansson (2013-04-27 14:10:18) > This is primarily useful when there's a driver that doesn't claim clocks > properly, but the bootloader leaves them on. It's not expected to be used > in normal cases, but for bringup and debug it's very useful to have the > option to not gate unclaimed clocks that are still on. > > Signed-off-by: Olof Johansson <olof@lixom.net> Thanks for the respin. I had to fix up a trivial merge issue with Documentation/kernel-parameters.txt, but no big deal. Patch is merged into clk-next. Regards, Mike > --- > Documentation/clk.txt | 11 +++++++++++ > Documentation/kernel-parameters.txt | 8 ++++++++ > drivers/clk/clk.c | 13 +++++++++++++ > 3 files changed, 32 insertions(+) > > diff --git a/Documentation/clk.txt b/Documentation/clk.txt > index 4274a54..b9911c2 100644 > --- a/Documentation/clk.txt > +++ b/Documentation/clk.txt > @@ -231,3 +231,14 @@ To better enforce this policy, always follow this simple rule: any > statically initialized clock data MUST be defined in a separate file > from the logic that implements its ops. Basically separate the logic > from the data and all is well. > + > + Part 6 - Disabling clock gating of unused clocks > + > +Sometimes during development it can be useful to be able to bypass the > +default disabling of unused clocks. For example, if drivers aren't enabling > +clocks properly but rely on them being on from the bootloader, bypassing > +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. > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index c4fa000..c3bfacb 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -44,6 +44,7 @@ parameter is applicable: > AVR32 AVR32 architecture is enabled. > AX25 Appropriate AX.25 support is enabled. > BLACKFIN Blackfin architecture is enabled. > + CLK Common clock infrastructure is enabled. > CMA Contiguous Memory Area support is enabled. > DRM Direct Rendering Management support is enabled. > DYNAMIC_DEBUG Build in debug messages and enable them at runtime > @@ -473,6 +474,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > > cio_ignore= [S390] > See Documentation/s390/CommonIO for details. > + clk_ignore_unused > + [CLK] > + Keep all clocks already enabled by bootloader on, > + even if no driver has claimed them. This is useful > + for debug and development, but should not be > + needed on a platform with proper driver support. > + For more information, see Documentation/clk.txt. > > clock= [BUGS=X86-32, HW] gettimeofday clocksource override. > [Deprecated] > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index 20ce67f..934cfd1 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -499,10 +499,23 @@ out: > return; > } > > +static bool clk_ignore_unused; > +static int __init clk_ignore_unused_setup(char *__unused) > +{ > + clk_ignore_unused = true; > + return 1; > +} > +__setup("clk_ignore_unused", clk_ignore_unused_setup); > + > static int clk_disable_unused(void) > { > struct clk *clk; > > + if (clk_ignore_unused) { > + pr_warn("clk: Not disabling unused clocks\n"); > + return 0; > + } > + > clk_prepare_lock(); > > hlist_for_each_entry(clk, &clk_root_list, child_node) > -- > 1.8.1.192.gc4361b8
diff --git a/Documentation/clk.txt b/Documentation/clk.txt index 4274a54..b9911c2 100644 --- a/Documentation/clk.txt +++ b/Documentation/clk.txt @@ -231,3 +231,14 @@ To better enforce this policy, always follow this simple rule: any statically initialized clock data MUST be defined in a separate file from the logic that implements its ops. Basically separate the logic from the data and all is well. + + Part 6 - Disabling clock gating of unused clocks + +Sometimes during development it can be useful to be able to bypass the +default disabling of unused clocks. For example, if drivers aren't enabling +clocks properly but rely on them being on from the bootloader, bypassing +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. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index c4fa000..c3bfacb 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -44,6 +44,7 @@ parameter is applicable: AVR32 AVR32 architecture is enabled. AX25 Appropriate AX.25 support is enabled. BLACKFIN Blackfin architecture is enabled. + CLK Common clock infrastructure is enabled. CMA Contiguous Memory Area support is enabled. DRM Direct Rendering Management support is enabled. DYNAMIC_DEBUG Build in debug messages and enable them at runtime @@ -473,6 +474,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. cio_ignore= [S390] See Documentation/s390/CommonIO for details. + clk_ignore_unused + [CLK] + Keep all clocks already enabled by bootloader on, + even if no driver has claimed them. This is useful + for debug and development, but should not be + needed on a platform with proper driver support. + For more information, see Documentation/clk.txt. clock= [BUGS=X86-32, HW] gettimeofday clocksource override. [Deprecated] diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 20ce67f..934cfd1 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -499,10 +499,23 @@ out: return; } +static bool clk_ignore_unused; +static int __init clk_ignore_unused_setup(char *__unused) +{ + clk_ignore_unused = true; + return 1; +} +__setup("clk_ignore_unused", clk_ignore_unused_setup); + static int clk_disable_unused(void) { struct clk *clk; + if (clk_ignore_unused) { + pr_warn("clk: Not disabling unused clocks\n"); + return 0; + } + clk_prepare_lock(); hlist_for_each_entry(clk, &clk_root_list, child_node)
This is primarily useful when there's a driver that doesn't claim clocks properly, but the bootloader leaves them on. It's not expected to be used in normal cases, but for bringup and debug it's very useful to have the option to not gate unclaimed clocks that are still on. Signed-off-by: Olof Johansson <olof@lixom.net> --- Documentation/clk.txt | 11 +++++++++++ Documentation/kernel-parameters.txt | 8 ++++++++ drivers/clk/clk.c | 13 +++++++++++++ 3 files changed, 32 insertions(+)