* Re: [PATCH linux-next tag: next-20210322] ARM: aspeed: Add CPU hotplug callbacks for kexec support
[not found] ` <ddb2757d-36df-8695-ce9b-ab9e26f3d457@linux.vnet.ibm.com>
@ 2021-03-22 18:07 ` Bruce Mitchell
0 siblings, 0 replies; only message in thread
From: Bruce Mitchell @ 2021-03-22 18:07 UTC (permalink / raw)
To: Joel Stanley, openbmc, linux-kernel, linux-arm-kernel
Cc: Andrew Jeffery, Eddie James
On 3/22/2021 09:40, Bruce Mitchell wrote:
> On 3/22/2021 08:57, Bruce Mitchell wrote:
>> These callbacks are required for kexec to function. The AST2600 does not
>> expose any controls for powering down it's CPU cores, so we borrow the
>> approach taken from socfpga and wait in the idle loop.
>>
>> Author: Joel Stanley <joel@jms.id.au>
>>
>> Signed-off-by: Bruce Mitchell <bruce.mitchell@linux.vnet.ibm.com>
>> ---
>> arch/arm/mach-aspeed/platsmp.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/arch/arm/mach-aspeed/platsmp.c
>> b/arch/arm/mach-aspeed/platsmp.c
>> index 2324becf7991..1ae3ff5a9701 100644
>> --- a/arch/arm/mach-aspeed/platsmp.c
>> +++ b/arch/arm/mach-aspeed/platsmp.c
>> @@ -7,6 +7,8 @@
>> #include <linux/of.h>
>> #include <linux/smp.h>
>>
>> +#include <asm/proc-fns.h>
>> +
>> #define BOOT_ADDR 0x00
>> #define BOOT_SIG 0x04
>>
>> @@ -53,9 +55,27 @@ static void __init
>> aspeed_g6_smp_prepare_cpus(unsigned int max_cpus)
>> iounmap(base);
>> }
>>
>> +#ifdef CONFIG_HOTPLUG_CPU
>> +static void aspeed_g6_cpu_die(unsigned int cpu)
>> +{
>> + /* Do WFI. If we wake up early, go back into WFI */
>> + while (1)
>> + cpu_do_idle();
>> +}
>> +
>> +static int aspeed_g6_cpu_kill(unsigned int cpu)
>> +{
>> + return 1;
>> +}
>> +#endif
>> +
>> static const struct smp_operations aspeed_smp_ops __initconst = {
>> .smp_prepare_cpus = aspeed_g6_smp_prepare_cpus,
>> .smp_boot_secondary = aspeed_g6_boot_secondary,
>> +#ifdef CONFIG_HOTPLUG_CPU
>> + .cpu_die = aspeed_g6_cpu_die,
>> + .cpu_kill = aspeed_g6_cpu_kill,
>> +#endif
>> };
>>
>> CPU_METHOD_OF_DECLARE(aspeed_smp, "aspeed,ast2600-smp",
>> &aspeed_smp_ops);
>>
>
> Adding Andrew Jeffery and Eddie James to the CC list.
>
Adding linux-kernel@vger.kernel.org and
linux-arm-kernel@lists.infradead.org based feedback.
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2021-03-22 18:07 ` [PATCH linux-next tag: next-20210322] ARM: aspeed: Add CPU hotplug callbacks for kexec support Bruce Mitchell
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