[PATCH 1/6] ARM: make cpu architecture detection available as static inline function

[Alexander Aring]

Hi,

On Mon, Mar 04, 2013 at 09:03:04PM +0100, Sascha Hauer wrote:
> When we have multi cpu support compiled in we need the cpu architecture
> early so that we can pick the correct cacheflush function. Make it available
> as static inline function and add a comment above it that this function
> normally should not be used.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  arch/arm/cpu/cpu.c                 | 34 +-----------------------------
>  arch/arm/include/asm/system_info.h | 43 ++++++++++++++++++++++++++++++++++++++
>  2 files changed, 44 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/arm/cpu/cpu.c b/arch/arm/cpu/cpu.c
> index 5f697d7..f2e698d 100644
> --- a/arch/arm/cpu/cpu.c
> +++ b/arch/arm/cpu/cpu.c
> @@ -148,45 +148,13 @@ postcore_initcall(execute_init);
>  #endif
>  
>  #ifdef ARM_MULTIARCH
> -static int __get_cpu_architecture(void)
> -{
> -	int cpu_arch;
> -
> -	if ((read_cpuid_id() & 0x0008f000) == 0) {
> -		cpu_arch = CPU_ARCH_UNKNOWN;
> -	} else if ((read_cpuid_id() & 0x0008f000) == 0x00007000) {
> -		cpu_arch = (read_cpuid_id() & (1 << 23)) ? CPU_ARCH_ARMv4T : CPU_ARCH_ARMv3;
> -	} else if ((read_cpuid_id() & 0x00080000) == 0x00000000) {
> -		cpu_arch = (read_cpuid_id() >> 16) & 7;
> -		if (cpu_arch)
> -			cpu_arch += CPU_ARCH_ARMv3;
> -	} else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
> -		unsigned int mmfr0;
> -
> -		/* Revised CPUID format. Read the Memory Model Feature
> -		 * Register 0 and check for VMSAv7 or PMSAv7 */
> -		asm("mrc	p15, 0, %0, c0, c1, 4"
> -		    : "=r" (mmfr0));
> -		if ((mmfr0 & 0x0000000f) >= 0x00000003 ||
> -		    (mmfr0 & 0x000000f0) >= 0x00000030)
> -			cpu_arch = CPU_ARCH_ARMv7;
> -		else if ((mmfr0 & 0x0000000f) == 0x00000002 ||
> -			 (mmfr0 & 0x000000f0) == 0x00000020)
> -			cpu_arch = CPU_ARCH_ARMv6;
> -		else
> -			cpu_arch = CPU_ARCH_UNKNOWN;
> -	} else
> -		cpu_arch = CPU_ARCH_UNKNOWN;
> -
> -	return cpu_arch;
> -}
>  
>  int __cpu_architecture;
>  
>  int __pure cpu_architecture(void)
>  {
>  	if(__cpu_architecture == CPU_ARCH_UNKNOWN)
> -		__cpu_architecture = __get_cpu_architecture();
> +		__cpu_architecture = arm_early_get_cpu_architecture();
>  
>  	return __cpu_architecture;
>  }
> diff --git a/arch/arm/include/asm/system_info.h b/arch/arm/include/asm/system_info.h
> index 56ebb11..50769ec 100644
> --- a/arch/arm/include/asm/system_info.h
> +++ b/arch/arm/include/asm/system_info.h
> @@ -110,8 +110,51 @@
>  #ifndef __ASSEMBLY__
>  
>  #ifdef ARM_MULTIARCH
> +/*
> + * Early version to get the ARM cpu architecture. Only needed during
> + * early startup when the C environment is not yet fully initialized.
> + * Normally you should use cpu_architecture() instead.
> + */
> +static inline int arm_early_get_cpu_architecture(void)
> +{
> +	int cpu_arch;
> +
> +	if ((read_cpuid_id() & 0x0008f000) == 0) {
> +		cpu_arch = CPU_ARCH_UNKNOWN;
> +	} else if ((read_cpuid_id() & 0x0008f000) == 0x00007000) {
> +		cpu_arch = (read_cpuid_id() & (1 << 23)) ? CPU_ARCH_ARMv4T : CPU_ARCH_ARMv3;
> +	} else if ((read_cpuid_id() & 0x00080000) == 0x00000000) {
> +		cpu_arch = (read_cpuid_id() >> 16) & 7;
> +		if (cpu_arch)
> +			cpu_arch += CPU_ARCH_ARMv3;

I know... it's only a movement, but is cpu += CPU_ARCH_ARMv3 correct
here? All other has only a assignment.

> +	} else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
> +		unsigned int mmfr0;
> +
> +		/* Revised CPUID format. Read the Memory Model Feature
> +		 * Register 0 and check for VMSAv7 or PMSAv7 */
> +		asm("mrc	p15, 0, %0, c0, c1, 4"
> +		    : "=r" (mmfr0));
> +		if ((mmfr0 & 0x0000000f) >= 0x00000003 ||
> +		    (mmfr0 & 0x000000f0) >= 0x00000030)
> +			cpu_arch = CPU_ARCH_ARMv7;
> +		else if ((mmfr0 & 0x0000000f) == 0x00000002 ||
> +			 (mmfr0 & 0x000000f0) == 0x00000020)
> +			cpu_arch = CPU_ARCH_ARMv6;
> +		else
> +			cpu_arch = CPU_ARCH_UNKNOWN;
> +	} else
> +		cpu_arch = CPU_ARCH_UNKNOWN;
> +
> +	return cpu_arch;
> +}
> +
>  extern int __pure cpu_architecture(void);
>  #else
> +static inline int __pure arm_early_get_cpu_architecture(void)
> +{
> +	return ARM_ARCH;
> +}
> +
>  static inline int __pure cpu_architecture(void)
>  {
>  	return ARM_ARCH;
> -- 
> 1.8.2.rc2
> 
> 
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