Subject: [3/4] ARM: EXYNOS: Remove static mapping of SCU SFR

From: [email-masked] (pankaj.dubey)
Date: Mon, 07 Nov 2016 08:05:42 +0530

Hi Alim,

On Friday 04 November 2016 06:56 PM, Alim Akhtar wrote:
> Hi Pankaj,
> 
> On 11/04/2016 09:09 AM, Pankaj Dubey wrote:
>> Lets remove static mapping of SCU SFR mainly used in CORTEX-A9 SoC
>> based boards.
>> Instead use mapping from device tree node of SCU.
>>
>> Signed-off-by: Pankaj Dubey <[email-masked]>
>> ---
>>   arch/arm/mach-exynos/exynos.c                | 22
>> ----------------------
>>   arch/arm/mach-exynos/include/mach/map.h      |  2 --
>>   arch/arm/mach-exynos/platsmp.c               | 18 +++++++++++-------
>>   arch/arm/mach-exynos/pm.c                    | 14 +++++++++++---
>>   arch/arm/mach-exynos/suspend.c               | 15 +++++++++++----
>>   arch/arm/plat-samsung/include/plat/map-s5p.h |  4 ----
>>   6 files changed, 33 insertions(+), 42 deletions(-)
>>
>> diff --git a/arch/arm/mach-exynos/exynos.c
>> b/arch/arm/mach-exynos/exynos.c
>> index 757fc11..fa08ef9 100644
>> --- a/arch/arm/mach-exynos/exynos.c
>> +++ b/arch/arm/mach-exynos/exynos.c
>> @@ -28,15 +28,6 @@
>>
>>   #include "common.h"
>>
>> -static struct map_desc exynos4_iodesc[] __initdata = {
>> -    {
>> -        .virtual    = (unsigned long)S5P_VA_COREPERI_BASE,
>> -        .pfn        = __phys_to_pfn(EXYNOS4_PA_COREPERI),
>> -        .length        = SZ_8K,
>> -        .type        = MT_DEVICE,
>> -    },
>> -};
>> -
>>   static struct platform_device exynos_cpuidle = {
>>       .name              = "exynos_cpuidle",
>>   #ifdef CONFIG_ARM_EXYNOS_CPUIDLE
>> @@ -99,17 +90,6 @@ static int __init exynos_fdt_map_chipid(unsigned
>> long node, const char *uname,
>>       return 1;
>>   }
>>
>> -/*
>> - * exynos_map_io
>> - *
>> - * register the standard cpu IO areas
>> - */
>> -static void __init exynos_map_io(void)
>> -{
>> -    if (soc_is_exynos4())
>> -        iotable_init(exynos4_iodesc, ARRAY_SIZE(exynos4_iodesc));
>> -}
>> -
>>   static void __init exynos_init_io(void)
>>   {
>>       debug_ll_io_init();
>> @@ -118,8 +98,6 @@ static void __init exynos_init_io(void)
>>
>>       /* detect cpu id and rev. */
>>       s5p_init_cpu(S5P_VA_CHIPID);
>> -
>> -    exynos_map_io();
>>   }
>>
>>   /*
>> diff --git a/arch/arm/mach-exynos/include/mach/map.h
>> b/arch/arm/mach-exynos/include/mach/map.h
>> index 5fb0040..0eef407 100644
>> --- a/arch/arm/mach-exynos/include/mach/map.h
>> +++ b/arch/arm/mach-exynos/include/mach/map.h
>> @@ -18,6 +18,4 @@
>>
>>   #define EXYNOS_PA_CHIPID        0x10000000
>>
>> -#define EXYNOS4_PA_COREPERI        0x10500000
>> -
>>   #endif /* __ASM_ARCH_MAP_H */
>> diff --git a/arch/arm/mach-exynos/platsmp.c
>> b/arch/arm/mach-exynos/platsmp.c
>> index a5d6841..553d0d9 100644
>> --- a/arch/arm/mach-exynos/platsmp.c
>> +++ b/arch/arm/mach-exynos/platsmp.c
>> @@ -224,11 +224,6 @@ static void write_pen_release(int val)
>>       sync_cache_w(&pen_release);
>>   }
>>
>> -static void __iomem *scu_base_addr(void)
>> -{
>> -    return (void __iomem *)(S5P_VA_SCU);
>> -}
>> -
>>   static DEFINE_SPINLOCK(boot_lock);
>>
>>   static void exynos_secondary_init(unsigned int cpu)
>> @@ -387,14 +382,23 @@ fail:
>>
>>   static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
>>   {
>> +    struct device_node *np;
>> +    void __iomem *scu_base;
>>       int i;
>>
>>       exynos_sysram_init();
>>
>>       exynos_set_delayed_reset_assertion(true);
>>
>> -    if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9)
>> -        scu_enable(scu_base_addr());
>> +    if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
>> +        np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
> 
> what if of_find_compatible_node() fails? May be add a error check for
> the same?

Thanks for review.

You are right of_find_compatible_node() is bound to fail, but only in
case supplied compatible is missing in DT. In our case this piece of
code will execute only for Cortex-A9 based SoC (which in case of Exynos
SoC is applicable only for Exynos4 series) and we will for sure
providing "arm,cortex-a9-scu" in DT, so there is no chance of failure.
So I feel extra check on "np" for NULL will add no benefit here.

Thanks,
Pankaj Dubey