Messages in this thread | | | Date | Mon, 4 Jan 2010 16:22:58 -0700 (MST) | From | "Chidambaram, Praveen" <> | Subject | Re: [PATCH] pm_qos: Add QoS param, minimum system bus frequency |
| |
> What happened to the discussion around multiple platforms needing > multiple bus pm_qos_requirements?
> > Is system bus freq too generic? (I'm worried about the name space) Something generic would be nice that each architecture can interpet it for something specific.
> Is this ok? (I'm asking linux-pm for input here.) > On X86 would this be analogous to FSB, Memory, or PCI bus frequencies? I am hoping this would be eqivalent to FSB.
> What will happen when there are two buses each wanting a PM_QOS > parameter? Is that a likely scenario? Possibly. I am not sure how do we solve multiple instances with PM QoS.
> > Also, on your platform you have a throttling driver controlling the > frequency of some bus, that will use this value as a constraint on how > far it will throttle. no? I would be interested in seeing this driver > sometime. (I just want to make sure no one bastardizes pm_qos into an > operating point thing. I'm not sure I can justify why but I want to > avoid that.) The notifier handler and the clock driver limits the bus frequency to the max supported by the hardware.
What is an operating point thing?
> > Lets have a on list discussion around the above. Other than these I > don't see a problem with your patch. I would like to know that other Si > vendors have a need for it other than just yours and the > abstraction/naming is compatible to them as well. In ARM architecture, I hope this parameter would be used for AXI/AHB scaling and could be used by other Si vendors as well.
Thanks, Praveen
> > --mgross > > > > Signed-off-by: Praveen Chidambaram <pchidamb@quicinc.com> > > Signed-off-by: David Brown <davidb@quicinc.com> > > Signed-off-by: Daniel Walker <dwalker@codeaurora.org> > > --- > > include/linux/pm_qos_params.h | 3 ++- > > kernel/pm_qos_params.c | 32 +++++++++++++++++++++++++------- > > 2 files changed, 27 insertions(+), 8 deletions(-) > > > > diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h > > index d74f75e..091c13c 100644 > > --- a/include/linux/pm_qos_params.h > > +++ b/include/linux/pm_qos_params.h > > @@ -10,8 +10,9 @@ > > #define PM_QOS_CPU_DMA_LATENCY 1 > > #define PM_QOS_NETWORK_LATENCY 2 > > #define PM_QOS_NETWORK_THROUGHPUT 3 > > +#define PM_QOS_SYSTEM_BUS_FREQ 4 > > > > -#define PM_QOS_NUM_CLASSES 4 > > +#define PM_QOS_NUM_CLASSES 5 > > #define PM_QOS_DEFAULT_VALUE -1 > > > > int pm_qos_add_requirement(int qos, char *name, s32 value); > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > > index 3db49b9..8576f40 100644 > > --- a/kernel/pm_qos_params.c > > +++ b/kernel/pm_qos_params.c > > @@ -102,12 +102,24 @@ static struct pm_qos_object network_throughput_pm_qos = { > > .comparitor = max_compare > > }; > > > > +static BLOCKING_NOTIFIER_HEAD(system_bus_freq_notifier); > > +static struct pm_qos_object system_bus_freq_pm_qos = { > > + .requirements = > > + {LIST_HEAD_INIT(system_bus_freq_pm_qos.requirements.list)}, > > + .notifiers = &system_bus_freq_notifier, > > + .name = "system_bus_freq", > > + .default_value = 0, > > + .target_value = ATOMIC_INIT(0), > > + .comparitor = max_compare > > +}; > > + > > > > -static struct pm_qos_object *pm_qos_array[] = { > > - &null_pm_qos, > > - &cpu_dma_pm_qos, > > - &network_lat_pm_qos, > > - &network_throughput_pm_qos > > +static struct pm_qos_object *pm_qos_array[PM_QOS_NUM_CLASSES] = { > > + [PM_QOS_RESERVED] = &null_pm_qos, > > + [PM_QOS_CPU_DMA_LATENCY] = &cpu_dma_pm_qos, > > + [PM_QOS_NETWORK_LATENCY] = &network_lat_pm_qos, > > + [PM_QOS_NETWORK_THROUGHPUT] = &network_throughput_pm_qos, > > + [PM_QOS_SYSTEM_BUS_FREQ] = &system_bus_freq_pm_qos, > > I've never used or seen this syntax before. Is it C99? FWIW I like it. > > > }; > > > > static DEFINE_SPINLOCK(pm_qos_lock); > > @@ -313,7 +325,7 @@ EXPORT_SYMBOL_GPL(pm_qos_remove_requirement); > > * will register the notifier into a notification chain that gets called > > * upon changes to the pm_qos_class target value. > > */ > > - int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) > > +int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) > > { > > int retval; > > > > @@ -409,9 +421,15 @@ static int __init pm_qos_power_init(void) > > return ret; > > } > > ret = register_pm_qos_misc(&network_throughput_pm_qos); > > - if (ret < 0) > > + if (ret < 0) { > > printk(KERN_ERR > > "pm_qos_param: network_throughput setup failed\n"); > > + return ret; > > + } > > + ret = register_pm_qos_misc(&system_bus_freq_pm_qos); > > + if (ret < 0) > > + printk(KERN_ERR > > + "pm_qos_param: system_bus_freq setup failed\n"); > > > > return ret; > > } > > -- > > 1.6.3.3 >
| |