• Daniel Lezcano's avatar
    cpuidle: make a single register function for all · 4c637b21
    Daniel Lezcano authored
    
    
    The usual scheme to initialize a cpuidle driver on a SMP is:
    
    	cpuidle_register_driver(drv);
    	for_each_possible_cpu(cpu) {
    		device = &per_cpu(cpuidle_dev, cpu);
    		cpuidle_register_device(device);
    	}
    
    This code is duplicated in each cpuidle driver.
    
    On UP systems, it is done this way:
    
    	cpuidle_register_driver(drv);
    	device = &per_cpu(cpuidle_dev, cpu);
    	cpuidle_register_device(device);
    
    On UP, the macro 'for_each_cpu' does one iteration:
    
    #define for_each_cpu(cpu, mask)                 \
            for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
    
    Hence, the initialization loop is the same for UP than SMP.
    
    Beside, we saw different bugs / mis-initialization / return code unchecked in
    the different drivers, the code is duplicated including bugs. After fixing all
    these ones, it appears the initialization pattern is the same for everyone.
    
    Please note, some drivers are doing dev->state_count = drv->state_count. This is
    not necessary because it is done by the cpuidle_enable_device function in the
    cpuidle framework. This is true, until you have the same states for all your
    devices. Otherwise, the 'low level' API should be used instead with the specific
    initialization for the driver.
    
    Let's add a wrapper function doing this initialization with a cpumask parameter
    for the coupled idle states and use it for all the drivers.
    
    That will save a lot of LOC, consolidate the code, and the modifications in the
    future could be done in a single place. Another benefit is the consolidation of
    the cpuidle_device variable which is now in the cpuidle framework and no longer
    spread accross the different arch specific drivers.
    
    Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    4c637b21