Messages in this thread | | | Date | Wed, 8 Jul 2015 20:42:18 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH 4/4] arm: psci: add cpuidle_ops support |
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Dear Russell,
On Wed, 8 Jul 2015 19:38:42 +0800 Jisheng Zhang <jszhang@marvell.com> wrote:
> Dear Russell, > > On Wed, 8 Jul 2015 11:34:29 +0100 > Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > > > On Wed, Jul 08, 2015 at 06:13:37PM +0800, Jisheng Zhang wrote: > > > This patch implements cpuidle_ops using psci. After this patch, we can use > > > cpuidle-arm.c with psci backend for both arm and arm64. > > > > I really don't see the point of most of the patches in this series. > > > > To summarise, what you're doing is: > > > > 1. Renaming arch/arm/kernel/psci_smp.c to arch/arm/kernel/psci.c > > 2. Adding a #ifdef CONFIG_SMP around _all_ the code in psci.c > > 3. Adding cpuidle code with an #ifdef CONFIG_CPU_IDLE around all the > > CPU idle code. > > > > So, we end up with a file which contains: > > > > /* > > header > > */ > > #include statements > > > > /* > > some commentry relevant to SMP code > > */ > > #ifdef CONFIG_CPU_IDLE > > ... cpu idle code ... > > #endif > > #ifdef CONFIG_SMP > > ... smp code ... > > #endif > > > > which (a) is a mess, and (b) is unnecessary. The only relevant bits which > > are shared are the #include statements. > > > > Please try this alternative approach: > > > > 1. Leave psci_smp.c alone. > > 2. Add arch/arm/kernel/psci_cpuidle.c containing the #include statements > > you need, and the CPU idle code.
After more consideration, I have one concern.
Currently, cpuidle_ops is defined as the following,
> struct cpuidle_ops { > int (*suspend)(int cpu, unsigned long arg);
the cpu may not be necessary, because to-be-suspended cpu is always the calling cpu itself.
> int (*init)(struct device_node *, int cpu);
the device_node here may not be necessary either, because we can get the node via. of_get_cpu_node.
So if we refine cpuidle_ops defintion, the code would be as simple as
static struct cpuidle_ops psci_cpuidle_ops __initdata = { .suspend = cpu_psci_cpu_suspend, .init = cpu_psci_cpu_init_idle, }; CPUIDLE_METHOD_OF_DECLARE(psci_idle, "psci", &psci_cpuidle_ops);
I'm not sure a new psci_cpuidle.c only with above 5 lines is acceptable or not.
Thanks, Jisheng
> > > > I think such an approach will reduce your patch series to two patches, > > one moving the ARM64 code, and one adding the cpuidle code. > > > > Good idea! Will refine the patches as you suggested. >
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