Messages in this thread | | | Subject | Re: [PATCH v2 2/6] of: Add helper for mapping device node to logical CPU number | From | Suzuki K Poulose <> | Date | Tue, 25 Jul 2017 10:27:31 +0100 |
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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. In fact, I started off with the of_cpu_device_node_get() and switched to the former.
It would be really nice to have your patch, which streamlines the interface and we could switch to that.
Cheers Suzuki
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