[PATCH v6 06/15] ARM: hisi: enable MCPM implementation

[Haojian Zhuang]

On 13 May 2014 16:28, Dave Martin <Dave.Martin at arm.com> wrote:
> On Sun, May 11, 2014 at 04:06:02PM +0800, Haojian Zhuang wrote:
>> Multiple CPU clusters are used in Hisilicon HiP04 SoC. Now use MCPM
>> framework to manage power on HiP04 SoC.
>>
>> Signed-off-by: Haojian Zhuang <haojian.zhuang at linaro.org>
>> ---
>>  arch/arm/mach-hisi/Makefile   |   1 +
>>  arch/arm/mach-hisi/platmcpm.c | 309 ++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 310 insertions(+)
>>  create mode 100644 arch/arm/mach-hisi/platmcpm.c
>>
>> diff --git a/arch/arm/mach-hisi/Makefile b/arch/arm/mach-hisi/Makefile
>> index 2ae1b59..e7a8640 100644
>> --- a/arch/arm/mach-hisi/Makefile
>> +++ b/arch/arm/mach-hisi/Makefile
>> @@ -3,4 +3,5 @@
>>  #
>>
>>  obj-y        += hisilicon.o
>> +obj-$(CONFIG_MCPM)           += platmcpm.o
>>  obj-$(CONFIG_SMP)            += platsmp.o hotplug.o
>> diff --git a/arch/arm/mach-hisi/platmcpm.c b/arch/arm/mach-hisi/platmcpm.c
>> new file mode 100644
>> index 0000000..6208bc6
>> --- /dev/null
>> +++ b/arch/arm/mach-hisi/platmcpm.c
>> @@ -0,0 +1,309 @@
>
> [...]
>
>> +static int hip04_mcpm_power_up(unsigned int cpu, unsigned int cluster)
>> +{
>> +     unsigned long data, mask;
>> +
>> +     if (!relocation || !sysctrl)
>> +             return -ENODEV;
>> +     if (cluster >= HIP04_MAX_CLUSTERS || cpu >= HIP04_MAX_CPUS_PER_CLUSTER)
>> +             return -EINVAL;
>> +
>> +     spin_lock_irq(&boot_lock);
>> +     writel_relaxed(hip04_boot.bootwrapper_phys, relocation);
>> +     writel_relaxed(hip04_boot.bootwrapper_magic, relocation + 4);
>> +     writel_relaxed(virt_to_phys(mcpm_entry_point), relocation + 8);
>> +     writel_relaxed(0, relocation + 12);
>> +
>> +     if (hip04_cluster_down(cluster)) {
>> +             data = CLUSTER_DEBUG_RESET_BIT;
>> +             writel_relaxed(data, sysctrl + SC_CPU_RESET_DREQ(cluster));
>> +             do {
>> +                     mask = CLUSTER_DEBUG_RESET_STATUS;
>> +                     data = readl_relaxed(sysctrl + \
>> +                                          SC_CPU_RESET_STATUS(cluster));
>> +             } while (data & mask);
>> +             hip04_set_snoop_filter(cluster, 1);
>
> Did you find the answer regarding whether it's safe to enable snoops to
> a powered-down CPU?
>
> Does HiP04 use CCI, or some different interconnect?  As Nico pointed out,
> the above code would definitely not be safe for CCI.
>
First, it's safe.
In the second, HiP04 doesn't use CCI. They designed their own fabric instead.

Regards
Haojian