Re: [PATCH] arm: exynos: generalize power register address calculation

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Hi Tomasz,

On 18 April 2014 19:42, Tomasz Figa <t.figa@xxxxxxxxxxx> wrote:
> Hi Chander,
>
>
> On 15.04.2014 09:38, Chander Kashyap wrote:
>>
>> Currently status/configuration power register values are hard-coded for
>> cpu1.
>>
>> Make it generic so that it is useful for SoC's with more than two cpus.
>>
>> Signed-off-by: Chander Kashyap <chander.kashyap@xxxxxxxxxx>
>> ---
>> changes in v3:
>>         1. Move cpunr calculation to a macro
>>         2. Changed printk format specifier from unsigned hex to unsigned
>> decimal
>> Changes in v2:
>>         1. Used existing macros for clusterid and cpuid calculation
>>
>>   arch/arm/mach-exynos/hotplug.c  |    7 ++++---
>>   arch/arm/mach-exynos/platsmp.c  |   13 +++++++------
>>   arch/arm/mach-exynos/regs-pmu.h |   15 +++++++++++++--
>>   3 files changed, 24 insertions(+), 11 deletions(-)
>>
>
> Now as I think of it, the code that is touched by this patch is not supposed
> to be used on multi-cluster systems. Instead a separate MCPM driver should.
> As far as I know, somebody is said to be already working on this.
>
> This means that we don't need to consider multi-cluster support in this
> patch and simplify any calculations to just account for core ID. This would
> also eliminate any need to handle non-zero cluster ID on single-cluster
> SoCs.
>
> Please correct me if I'm wrong.

Yes thats true.
As mcpm code is in review process, so i will remove platsmp.c and
hotplug.c changes and respin the patch.
The  patch will add support for cpunr calculation and offset calculation.

>
>
>> diff --git a/arch/arm/mach-exynos/hotplug.c
>> b/arch/arm/mach-exynos/hotplug.c
>> index 5eead53..9f74be2 100644
>> --- a/arch/arm/mach-exynos/hotplug.c
>> +++ b/arch/arm/mach-exynos/hotplug.c
>> @@ -92,11 +92,12 @@ static inline void cpu_leave_lowpower(void)
>>
>>   static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
>>   {
>> +       unsigned int cpunr = ENYNOS_PMU_CPUNR(cpu_logical_map(cpu));
>>         for (;;) {
>>
>> -               /* make cpu1 to be turned off at next WFI command */
>> -               if (cpu == 1)
>> -                       __raw_writel(0, S5P_ARM_CORE1_CONFIGURATION);
>> +               /* make cpu to be turned off at next WFI command */
>> +               if (cpu)
>
>
> As I mentioned in my previous reply, I don't see what could go wrong if this
> check is omitted. What happens if CPU0 is being hot-unplugged?
>
> If hardware doesn't support this (but I don't see any mention about this in
> the documentation), such hotplug attempt should either simply fail on
> .cpu_kill() operation for CPU0 or even have CPU0 marked as non-hotpluggable.

That makes more sense, but i need to cross verify.

>
>
>> +                       __raw_writel(0,
>> S5P_ARM_CORE_CONFIGURATION(cpunr));
>>
>>                 /*
>>                  * here's the WFI
>> diff --git a/arch/arm/mach-exynos/platsmp.c
>> b/arch/arm/mach-exynos/platsmp.c
>> index 03e5e9f..d9c182f 100644
>> --- a/arch/arm/mach-exynos/platsmp.c
>> +++ b/arch/arm/mach-exynos/platsmp.c
>> @@ -90,7 +90,7 @@ static int exynos_boot_secondary(unsigned int cpu,
>> struct task_struct *idle)
>>   {
>>         unsigned long timeout;
>>         unsigned long phys_cpu = cpu_logical_map(cpu);
>> -
>> +       unsigned int cpunr = ENYNOS_PMU_CPUNR(cpu_logical_map(cpu));
>>         /*
>>          * Set synchronisation state between this boot processor
>>          * and the secondary one
>> @@ -107,14 +107,15 @@ static int exynos_boot_secondary(unsigned int cpu,
>> struct task_struct *idle)
>>          */
>>         write_pen_release(phys_cpu);
>>
>> -       if (!(__raw_readl(S5P_ARM_CORE1_STATUS) & S5P_CORE_LOCAL_PWR_EN))
>> {
>> +       if (!(__raw_readl(S5P_ARM_CORE_STATUS(cpunr))
>> +               & S5P_CORE_LOCAL_PWR_EN)) {
>>                 __raw_writel(S5P_CORE_LOCAL_PWR_EN,
>> -                            S5P_ARM_CORE1_CONFIGURATION);
>> +                            S5P_ARM_CORE_CONFIGURATION(cpunr));
>>
>>                 timeout = 10;
>>
>> -               /* wait max 10 ms until cpu1 is on */
>> -               while ((__raw_readl(S5P_ARM_CORE1_STATUS)
>> +               /* wait max 10 ms until secondary cpu is on */
>> +               while ((__raw_readl(S5P_ARM_CORE_STATUS(cpunr))
>>                         & S5P_CORE_LOCAL_PWR_EN) != S5P_CORE_LOCAL_PWR_EN)
>> {
>>                         if (timeout-- == 0)
>>                                 break;
>> @@ -123,7 +124,7 @@ static int exynos_boot_secondary(unsigned int cpu,
>> struct task_struct *idle)
>>                 }
>>
>>                 if (timeout == 0) {
>> -                       printk(KERN_ERR "cpu1 power enable failed");
>> +                       pr_err("cpu%u power enable failed", cpu);
>>                         spin_unlock(&boot_lock);
>>                         return -ETIMEDOUT;
>>                 }
>> diff --git a/arch/arm/mach-exynos/regs-pmu.h
>> b/arch/arm/mach-exynos/regs-pmu.h
>> index 4f6a256..0de6df4 100644
>> --- a/arch/arm/mach-exynos/regs-pmu.h
>> +++ b/arch/arm/mach-exynos/regs-pmu.h
>> @@ -105,8 +105,13 @@
>>   #define S5P_GPS_LOWPWR                                S5P_PMUREG(0x139C)
>>   #define S5P_GPS_ALIVE_LOWPWR                  S5P_PMUREG(0x13A0)
>>
>> -#define S5P_ARM_CORE1_CONFIGURATION            S5P_PMUREG(0x2080)
>> -#define S5P_ARM_CORE1_STATUS                   S5P_PMUREG(0x2084)
>> +#define S5P_ARM_CORE0_CONFIGURATION            S5P_PMUREG(0x2000)
>> +#define S5P_ARM_CORE0_STATUS                   S5P_PMUREG(0x2004)
>> +
>> +#define S5P_ARM_CORE_CONFIGURATION(_cpunr)     \
>> +               (S5P_ARM_CORE0_CONFIGURATION + 0x80 * (_cpunr))
>> +#define S5P_ARM_CORE_STATUS(_cpunr)            \
>> +               (S5P_ARM_CORE0_STATUS + 0x80 * (_cpunr))
>>
>>   #define S5P_PAD_RET_MAUDIO_OPTION             S5P_PMUREG(0x3028)
>>   #define S5P_PAD_RET_GPIO_OPTION                       S5P_PMUREG(0x3108)
>> @@ -313,4 +318,10 @@
>>
>>   #define EXYNOS5_OPTION_USE_RETENTION                          (1 << 4)
>>
>> +#include <asm/cputype.h>
>> +#define MAX_CPUS_IN_CLUSTER    4
>> +#define ENYNOS_PMU_CPUNR(mpidr) \
>> +               ((MPIDR_AFFINITY_LEVEL(mpidr, 1) * MAX_CPUS_IN_CLUSTER) \
>> +                 + MPIDR_AFFINITY_LEVEL(mpidr, 0));
>
>
> Static inline would be preferred and then name in lowercase.

ok

>
> Best regards,
> Tomasz

 Thanks again

-- 
with warm regards,
Chander Kashyap
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