Messages in this thread | | | Subject | Re: [PATCH v2 2/6] of: Add helper for mapping device node to logical CPU number | From | Sudeep Holla <> | Date | Tue, 25 Jul 2017 10:49:24 +0100 |
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On 25/07/17 10:27, Suzuki K Poulose wrote: > On 24/07/17 17:42, Sudeep Holla wrote: >> >> >> On 24/07/17 11:29, Suzuki K Poulose wrote: >>> Add a helper to map a device node to a logical CPU number to avoid >>> duplication. Currently this is open coded in different places (e.g >>> gic-v3, coresight). The helper tries to map device node to a "possible" >>> logical CPU id, which may not be online yet. It is the responsibility >>> of the user to make sure that the CPU is online. The helper uses >>> of_get_cpu_node() which uses arch specific backends to match the >>> phyiscal >>> ids. >>> >>> Cc: Rob Herring <robh+dt@kernel.org> >>> Cc: Mark Rutland <mark.rutland@arm.com> >>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >>> --- >>> drivers/of/base.c | 26 ++++++++++++++++++++++++++ >>> include/linux/of_device.h | 7 +++++++ >>> 2 files changed, 33 insertions(+) >>> >>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>> index 686628d..639af23 100644 >>> --- a/drivers/of/base.c >>> +++ b/drivers/of/base.c >>> @@ -420,6 +420,32 @@ struct device_node *of_get_cpu_node(int cpu, >>> unsigned int *thread) >>> EXPORT_SYMBOL(of_get_cpu_node); >>> >>> /** >>> + * of_device_node_get_cpu: Get the logical CPU number for a given >>> device_node >>> + * >>> + * @cpu_node: Pointer to the device_node for CPU. >>> + * >>> + * Returns the logical CPU number of the given CPU device_node. >>> + * Returns >= nr_cpu_ids if CPU is not found. >>> + */ >>> +int of_device_node_get_cpu(struct device_node *cpu_node) >>> +{ >>> + int cpu, thread; >>> + bool found = false; >>> + struct device_node *np; >>> + >>> + for_each_possible_cpu(cpu) { >>> + np = of_get_cpu_node(cpu, &thread); >> >> Ideally, we should be able to use of_cpu_device_node_get instead of >> of_get_cpu_node which parses the device tree. Not sure if that's the >> case here too. >> >> Sorry for following up on this so late. I had a patch in my tree >> for-a-while to address that. Just posted it[1] now seeing this patch now. >> >> You can move to of_cpu_device_node_get if all users of this function are >> called after CPU's are registered. Otherwise, you can keep it as is for >> now and it can be changed once [1] lands. > > As you mentioned offline, since GIC uses this, we need to stick to > of_get_cpu_node.
Agreed.
> In fact, I started off with the of_cpu_device_node_get() and switched > to the former. >
Ah OK.
> It would be really nice to have your patch, which streamlines the > interface and we could switch to that. >
Yes, I will wait for that patch to land in the mainline, I can follow up and remove the use of of_get_cpu_node wherever required. -- Regards, Sudeep
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