Re: [PATCH 09/28] ARM: mmu: Specify size in bytes in create_sections()

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, May 08, 2018 at 02:29:32PM -0700, Andrey Smirnov wrote:
> Seeing
> 
>         create_sections(ttb, 0, PAGE_SIZE, ...);
> 
> as the code the creates initial flat 4 GiB mapping is a bit less
> intuitive then
> 
>         create_sections(ttb, 0, SZ_4G, ...);
> 
> so, for the sake of clarification, convert create_sections() to accept
> size in bytes and do bytes -> MiB converstion as a part of the
> function.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> ---
>  arch/arm/cpu/mmu-early.c | 4 ++--
>  arch/arm/cpu/mmu.c       | 4 ++--
>  arch/arm/cpu/mmu.h       | 4 ++--
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/cpu/mmu-early.c b/arch/arm/cpu/mmu-early.c
> index 70ece0d2f..136b33c3a 100644
> --- a/arch/arm/cpu/mmu-early.c
> +++ b/arch/arm/cpu/mmu-early.c
> @@ -16,7 +16,7 @@ static void map_cachable(unsigned long start, unsigned long size)
>  	start = ALIGN_DOWN(start, SZ_1M);
>  	size  = ALIGN(size, SZ_1M);
>  
> -	create_sections(ttb, start, size >> 20, PMD_SECT_AP_WRITE |
> +	create_sections(ttb, start, size, PMD_SECT_AP_WRITE |
>  			PMD_SECT_AP_READ | PMD_TYPE_SECT | PMD_SECT_WB);
>  }
>  
> @@ -30,7 +30,7 @@ void mmu_early_enable(unsigned long membase, unsigned long memsize,
>  	set_ttbr(ttb);
>  	set_domain(DOMAIN_MANAGER);
>  
> -	create_sections(ttb, 0, 4096, PMD_SECT_AP_WRITE |
> +	create_sections(ttb, 0, SZ_4G, PMD_SECT_AP_WRITE |
>  			PMD_SECT_AP_READ | PMD_TYPE_SECT);
>  
>  	map_cachable(membase, memsize);
> diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
> index 0c367e47c..f02c99f65 100644
> --- a/arch/arm/cpu/mmu.c
> +++ b/arch/arm/cpu/mmu.c
> @@ -460,7 +460,7 @@ static int mmu_init(void)
>  	set_domain(DOMAIN_MANAGER);
>  
>  	/* create a flat mapping using 1MiB sections */
> -	create_sections(ttb, 0, PAGE_SIZE, PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
> +	create_sections(ttb, 0, SZ_4G, PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
>  			PMD_TYPE_SECT);
>  	__mmu_cache_flush();
>  
> @@ -472,7 +472,7 @@ static int mmu_init(void)
>  	 * below
>  	 */
>  	for_each_memory_bank(bank) {
> -		create_sections(ttb, bank->start, bank->size >> 20,
> +		create_sections(ttb, bank->start, bank->size,
>  				PMD_SECT_DEF_CACHED);
>  		__mmu_cache_flush();
>  	}
> diff --git a/arch/arm/cpu/mmu.h b/arch/arm/cpu/mmu.h
> index 8b51e3f9f..d87d82c1c 100644
> --- a/arch/arm/cpu/mmu.h
> +++ b/arch/arm/cpu/mmu.h
> @@ -26,10 +26,10 @@ static inline void set_domain(unsigned val)
>  
>  static inline void
>  create_sections(uint32_t *ttb, unsigned long addr,
> -		int size_m, unsigned int flags)
> +		unsigned long long size, unsigned int flags)
>  {
>  	unsigned long ttb_start = add >> 20;
> -	unsigned long ttb_end   = ttb_start + size_m;
> +	unsigned long ttb_end   = ttb_start + size >> 20;
>  	unsigned int i;

I agree reading size_m is not very intuitive. I don't like this
unnecessary introduction of 64bit variables though. Can we instead pass
start/end instead of start/size?

Sascha

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