user/sven/linux.git/include/linux/cpufreq.h, branch v3.18.104

cpufreq: allow driver-specific data

2014-10-20T22:51:01Z

This commit extends the cpufreq_driver structure with an additional 'void *driver_data' field that can be filled by the ->probe() function of a cpufreq driver to pass additional custom information to the driver itself. A new function called cpufreq_get_driver_data() is added to allow a cpufreq driver to retrieve those driver data, since they are typically needed from a cpufreq_policy->init() callback, which does not have access to the cpufreq_driver structure. This function call is similar to the existing cpufreq_get_current_driver() function call. Signed-off-by: Thomas Petazzoni Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Add support for per-policy driver data

2014-09-08T23:44:40Z

Drivers supporting multiple clusters or multiple 'struct cpufreq_policy' instances may need to keep per-policy data. If the core doesn't provide support for that, they might do it in the most unoptimized way: 'per-cpu' data. This patch adds another field in struct cpufreq_policy: 'driver_data'. It isn't accessed by core and is for driver's internal use only. Tested-by: Stephen Boyd Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Introduce new relation for freq selection

2014-07-21T11:43:19Z

Introduce CPUFREQ_RELATION_C for frequency selection. It selects the frequency with the minimum euclidean distance to target. In case of equal distance between 2 frequencies, it will select the greater frequency. Signed-off-by: Stratos Karafotis Signed-off-by: Rafael J. Wysocki

cpufreq: make table sentinel macros unsigned to match use

2014-07-18T00:56:38Z

Commit 5eeaf1f18973 (cpufreq: Fix build error on some platforms that use cpufreq_for_each_*) moved function cpufreq_next_valid() to a public header. Warnings are now generated when objects including that header are built with -Wsign-compare (as an out-of-tree module might be): .../include/linux/cpufreq.h: In function ‘cpufreq_next_valid’: .../include/linux/cpufreq.h:519:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while ((*pos)->frequency != CPUFREQ_TABLE_END) ^ .../include/linux/cpufreq.h:520:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((*pos)->frequency != CPUFREQ_ENTRY_INVALID) ^ Constants CPUFREQ_ENTRY_INVALID and CPUFREQ_TABLE_END are signed, but are used with unsigned member 'frequency' of cpufreq_frequency_table. Update the macro definitions to be explicitly unsigned to match their use. This also corrects potentially wrong behavior of clk_rate_table_iter() if unsigned long is wider than usigned int. Fixes: 5eeaf1f18973 (cpufreq: Fix build error on some platforms that use cpufreq_for_each_*) Signed-off-by: Brian W Hart Reviewed-by: Simon Horman Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: add support for intermediate (stable) frequencies

2014-06-05T21:32:29Z

Douglas Anderson, recently pointed out an interesting problem due to which udelay() was expiring earlier than it should. While transitioning between frequencies few platforms may temporarily switch to a stable frequency, waiting for the main PLL to stabilize. For example: When we transition between very low frequencies on exynos, like between 200MHz and 300MHz, we may temporarily switch to a PLL running at 800MHz. No CPUFREQ notification is sent for that. That means there's a period of time when we're running at 800MHz but loops_per_jiffy is calibrated at between 200MHz and 300MHz. And so udelay behaves badly. To get this fixed in a generic way, introduce another set of callbacks get_intermediate() and target_intermediate(), only for drivers with target_index() and CPUFREQ_ASYNC_NOTIFICATION unset. get_intermediate() should return a stable intermediate frequency platform wants to switch to, and target_intermediate() should set CPU to that frequency, before jumping to the frequency corresponding to 'index'. Core will take care of sending notifications and driver doesn't have to handle them in target_intermediate() or target_index(). NOTE: ->target_index() should restore to policy->restore_freq in case of failures as core would send notifications for that. Tested-by: Stephen Warren Signed-off-by: Viresh Kumar Reviewed-by: Doug Anderson Signed-off-by: Rafael J. Wysocki

cpufreq: Fix build error on some platforms that use cpufreq_for_each_*

2014-05-08T11:10:56Z

On platforms that use cpufreq_for_each_* macros, build fails if CONFIG_CPU_FREQ=n, e.g. ARM/shmobile/koelsch/non-multiplatform: drivers/built-in.o: In function `clk_round_parent': clkdev.c:(.text+0xcf168): undefined reference to `cpufreq_next_valid' drivers/built-in.o: In function `clk_rate_table_find': clkdev.c:(.text+0xcf820): undefined reference to `cpufreq_next_valid' make[3]: *** [vmlinux] Error 1 Fix this making cpufreq_next_valid function inline and move it to cpufreq.h. Fixes: 27e289dce297 (cpufreq: Introduce macros for cpufreq_frequency_table iteration) Reported-and-tested-by: Geert Uytterhoeven Signed-off-by: Stratos Karafotis Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

PM / OPP: Move cpufreq specific OPP functions out of generic OPP library

2014-05-06T22:39:03Z

CPUFreq specific helper functions for OPP (Operating Performance Points) now use generic OPP functions that allow CPUFreq to be be moved back into CPUFreq framework. This allows for independent modifications or future enhancements as needed isolated to just CPUFreq framework alone. Here, we just move relevant code and documentation to make this part of CPUFreq infrastructure. Cc: Kevin Hilman Signed-off-by: Nishanth Menon Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Catch double invocations of cpufreq_freq_transition_begin/end

2014-05-06T22:32:39Z

Some cpufreq drivers were redundantly invoking the _begin() and _end() APIs around frequency transitions, and this double invocation (one from the cpufreq core and the other from the cpufreq driver) used to result in a self-deadlock, leading to system hangs during boot. (The _begin() API makes contending callers wait until the previous invocation is complete. Hence, the cpufreq driver would end up waiting on itself!). Now all such drivers have been fixed, but debugging this issue was not very straight-forward (even lockdep didn't catch this). So let us add a debug infrastructure to the cpufreq core to catch such issues more easily in the future. We add a new field called 'transition_task' to the policy structure, to keep track of the task which is performing the frequency transition. Using this field, we make note of this task during _begin() and print a warning if we find a case where the same task is calling _begin() again, before completing the previous frequency transition using the corresponding _end(). We have left out ASYNC_NOTIFICATION drivers from this debug infrastructure for 2 reasons: 1. At the moment, we have no way to avoid a particular scenario where this debug infrastructure can emit false-positive warnings for such drivers. The scenario is depicted below: Task A Task B /* 1st freq transition */ Invoke _begin() { ... ... } Change the frequency /* 2nd freq transition */ Invoke _begin() { ... //waiting for B to ... //finish _end() for ... //the 1st transition ... | Got interrupt for successful ... | change of frequency (1st one). ... | ... | /* 1st freq transition */ ... | Invoke _end() { ... | ... ... V } ... ... } This scenario is actually deadlock-free because, once Task A changes the frequency, it is Task B's responsibility to invoke the corresponding _end() for the 1st frequency transition. Hence it is perfectly legal for Task A to go ahead and attempt another frequency transition in the meantime. (Of course it won't be able to proceed until Task B finishes the 1st _end(), but this doesn't cause a deadlock or a hang). The debug infrastructure cannot handle this scenario and will treat it as a deadlock and print a warning. To avoid this, we exclude such drivers from the purview of this code. 2. Luckily, we don't _need_ this infrastructure for ASYNC_NOTIFICATION drivers at all! The cpufreq core does not automatically invoke the _begin() and _end() APIs during frequency transitions in such drivers. Thus, the driver alone is responsible for invoking _begin()/_end() and hence there shouldn't be any conflicts which lead to double invocations. So, we can skip these drivers, since the probability that such drivers will hit this problem is extremely low, as outlined above. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Introduce macros for cpufreq_frequency_table iteration

2014-04-29T22:05:31Z

Many cpufreq drivers need to iterate over the cpufreq_frequency_table for various tasks. This patch introduces two macros which can be used for iteration over cpufreq_frequency_table keeping a common coding style across drivers: - cpufreq_for_each_entry: iterate over each entry of the table - cpufreq_for_each_valid_entry: iterate over each entry that contains a valid frequency. It should have no functional changes. Signed-off-by: Stratos Karafotis Acked-by: Lad, Prabhakar Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: create another field .flags in cpufreq_frequency_table

2014-04-07T12:43:50Z

Currently cpufreq frequency table has two fields: frequency and driver_data. driver_data is only for drivers' internal use and cpufreq core shouldn't use it at all. But with the introduction of BOOST frequencies, this assumption was broken and we started using it as a flag instead. There are two problems due to this: - It is against the description of this field, as driver's data is used by the core now. - if drivers fill it with -3 for any frequency, then those frequencies are never considered by cpufreq core as it is exactly same as value of CPUFREQ_BOOST_FREQ, i.e. ~2. The best way to get this fixed is by creating another field flags which will be used for such flags. This patch does that. Along with that various drivers need modifications due to the change of struct cpufreq_frequency_table. Reviewed-by: Gautham R Shenoy Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki