On Thu, Jan 10, 2013 at 04:43:03PM +0000, Rob Herring wrote: > > > On 01/10/2013 05:48 AM, Lorenzo Pieralisi wrote: > > Since the introduction of /cpu nodes bindings for ARM and the > > corresponding parse function arm_dt_init_cpu_maps(), the cpu_logical_map > > and the number of possible CPUs are set according to the DT /cpu > > nodes entries. Currently most of the existing ARM SMP platforms detect the > > number of cores through HW probing in their .smp_init_cpus functions and set > > the possible CPU mask accordingly. > > This method should be upgraded so that the CPU counting mechanism will be > > based on DT, keeping legacy HW probing mechanism as a fall back solution. > > > > In order to implement this fall back solution mechanism, the ARM DT code > > should provide a helper function to platforms to check if the cpu map > > has been properly initialized through DT. If the check fails the > > platform will resort to legacy HW based cores counting mechanism. > > > > This patch implements a trivial flag and a helper function that platform > > can call to check whether DT based cpu map initialization and cores count > > were completed successfully. > > > > Signed-off-by: Lorenzo Pieralisi <[email protected]> > > --- > > arch/arm/include/asm/prom.h | 10 ++++++++++ > > arch/arm/kernel/devtree.c | 5 +++++ > > 2 files changed, 15 insertions(+) > > > > diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h > > index a219227..487614a 100644 > > --- a/arch/arm/include/asm/prom.h > > +++ b/arch/arm/include/asm/prom.h > > @@ -18,6 +18,15 @@ > > extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys); > > extern void arm_dt_memblock_reserve(void); > > extern void __init arm_dt_init_cpu_maps(void); > > +/* > > + * Return true if cpu map initialization has been > > + * carried out correctly from DT > > + */ > > +static inline bool __init arm_dt_cpu_map_valid(void) > > +{ > > + extern bool valid_dt_cpu_map; > > + return valid_dt_cpu_map; > > +} > > > > #else /* CONFIG_OF */ > > > > @@ -28,6 +37,7 @@ static inline struct machine_desc > > *setup_machine_fdt(unsigned int dt_phys) > > > > static inline void arm_dt_memblock_reserve(void) { } > > static inline void arm_dt_init_cpu_maps(void) { } > > +static inline bool __init arm_dt_cpu_map_valid(void) { return false; } > > > > #endif /* CONFIG_OF */ > > #endif /* ASMARM_PROM_H */ > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > > index 70f1bde..c82af3b 100644 > > --- a/arch/arm/kernel/devtree.c > > +++ b/arch/arm/kernel/devtree.c > > @@ -62,6 +62,10 @@ void __init arm_dt_memblock_reserve(void) > > memblock_reserve(base, size); > > } > > } > > +/* > > + * Export DT cpu map validity flag to platforms > > + */ > > +bool valid_dt_cpu_map __initdata; > > > > /* > > * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree > > @@ -158,6 +162,7 @@ void __init arm_dt_init_cpu_maps(void) > > * a reg property, the DT CPU list can be considered valid and the > > * logical map created in smp_setup_processor_id() can be overridden > > */ > > + valid_dt_cpu_map = true; > > for (i = 0; i < cpuidx; i++) { > > set_cpu_possible(i, true); > > I don't see why we need another variable. Doesn't cpu_possible mask > being set here imply that the DT map is valid.
Yes, that's correct I can use cpu_possible mask to check that, but I still want to do it through a function/macro, I do not want platform code to check possible mask explicitly, they have to do it through a helper function. I will remove the variable. > We should start requiring valid /cpus nodes and the legacy fall-back > should be temporary. I could not agree more. Thanks, Lorenzo _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
