On 19/08/13 14:11, Rob Herring wrote: > On 08/16/2013 12:39 PM, Sudeep KarkadaNagesha wrote: >> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@xxxxxxx> >> >> This patch moves the generalized implementation of of_get_cpu_node from >> PowerPC to DT core library, thereby adding support for retrieving cpu >> node for a given logical cpu index on any architecture. >> >> The CPU subsystem can now use this function to assign of_node in the >> cpu device while registering CPUs. >> >> It is recommended to use these helper function only in pre-SMP/early >> initialisation stages to retrieve CPU device node pointers in logical >> ordering. Once the cpu devices are registered, it can be retrieved easily >> from cpu device of_node which avoids unnecessary parsing and matching. >> >> Cc: Rob Herring <rob.herring@xxxxxxxxxxx> >> Cc: Grant Likely <grant.likely@xxxxxxxxxx> >> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> >> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@xxxxxxx> > > [snip] > >> +/** >> + * of_get_cpu_node - Get device node associated with the given logical CPU >> + * >> + * @cpu: CPU number(logical index) for which device node is required >> + * @thread: if not NULL, local thread number within the physical core is >> + * returned >> + * >> + * The main purpose of this function is to retrieve the device node for the >> + * given logical CPU index. It should be used to initialize the of_node in >> + * cpu device. Once of_node in cpu device is populated, all the further >> + * references can use that instead. >> + * >> + * CPU logical to physical index mapping is architecture specific and is built >> + * before booting secondary cores. This function uses arch_match_cpu_phys_id >> + * which can be overridden by architecture specific implementation. >> + * >> + * Returns a node pointer for the logical cpu if found, else NULL. >> + */ >> +struct device_node *of_get_cpu_node(int cpu, unsigned int *thread) >> +{ >> + struct device_node *cpun, *cpus; >> + >> + cpus = of_find_node_by_path("/cpus"); >> + if (!cpus) { >> + pr_warn("Missing cpus node, bailing out\n"); >> + return NULL; >> + } >> + >> + for_each_child_of_node(cpus, cpun) { >> + if (of_node_cmp(cpun->type, "cpu")) >> + continue; >> +#ifdef CONFIG_PPC > > You don't really need this ifdef as this function should never succeed > on other arches. Alternatively, you can use "IS_ENABLED(CONFIG_PPC)" > instead. > Agreed, I can remove it as long as no other architecture use that property. It's just to avoid checking for it on other architectures. I will use IS_ENABLED as you suggested. > Otherwise, > > Acked-by: Rob Herring <rob.herring@xxxxxxxxxxx> > Thanks. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html