[LinuxBIOS] [PATCH v3] v2, v3: Bug? in CAR setup with CacheSize!={4k, 8k, 16k}

[Carl-Daniel Hailfinger]

Marc?
This has been sitting in my tree for a while now.

On 16.11.2007 16:00, Carl-Daniel Hailfinger wrote:
> Hi,
>
> v2 and v3 have almost identical CAR setup code with identical bugs for
> CAR sizes != {4k,8k,16k}. In v3, the erroneous code paths are not
> triggered and the bug is latent, but we have at a few boards in v2 which
> trigger these bugs, resulting in holes and/or smaller size of the CAR area.
>
> Let's look at the v3 code:
>
>   
>> #ifndef CONFIG_CARSIZE
>> #define CacheSize 4096
>> #else
>> #define CacheSize CONFIG_CARSIZE
>> #endif
>>     
>
> v2 uses DCACHE_RAM_SIZE instead of CONFIG_CARSIZE
> [...]
>   
>> clear_fixed_var_mtrr_out:
>>
>> #if CacheSize == 0x10000 
>>         /* enable caching for 64K using fixed mtrr */
>>         movl    $0x268, %ecx  /* fix4k_c0000*/
>>         movl    $0x06060606, %eax /* WB IO type */
>> 	movl    %eax, %edx
>>         wrmsr
>> 	movl	$0x269, %ecx
>> 	wrmsr
>> #endif
>>     
>
> OK, 64k are working.
>
>   
>> #if CacheSize == 0x8000
>>         /* enable caching for 32K using fixed mtrr */
>>         movl    $0x269, %ecx  /* fix4k_c8000*/
>>         movl    $0x06060606, %eax /* WB IO type */
>> 	movl    %eax, %edx
>> 	wrmsr
>> #endif
>>     
>
> OK, 32k are working.
>   
>>         /* enable caching for 16K/8K/4K using fixed mtrr */
>>         movl    $0x269, %ecx  /* fix4k_cc000*/
>> #if CacheSize == 0x4000
>>         movl    $0x06060606, %edx /* WB IO type */
>> #endif
>> #if CacheSize == 0x2000
>>         movl    $0x06060000, %edx /* WB IO type */
>> #endif
>> #if CacheSize == 0x1000
>>         movl    $0x06000000, %edx /* WB IO type */
>> #endif
>> 	xorl    %eax, %eax
>> 	wrmsr
>>     
>
>
> Disable CAR between 16k and 32k unconditionally. Even if CacheSize is
> 32k or 64k. Not nice. This affects the following boards:
> ./src/mainboard/amd/db800/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/amd/norwich/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/amd/serengeti_cheetah/Options.lb:default
> DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/msi/ms7260/Options.lb:default DCACHE_RAM_SIZE = 0x08000
> ./src/mainboard/asus/a8n_e/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/tyan/s2912/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/artecgroup/dbe61/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/supermicro/h8dmr/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/pcengines/alix1c/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/nvidia/l1_2pvv/Options.lb:default DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/digitallogic/msm800sev/Options.lb:default
> DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/gigabyte/ga_2761gxdk/Options.lb:default
> DCACHE_RAM_SIZE=0x08000
> ./src/mainboard/gigabyte/m57sli/Options.lb:default DCACHE_RAM_SIZE=0x08000
>
> If CacheSize is not one of 4k,8k,16k,32k,64k, we will not set up CAR at
> all. This affects the following board:
> ./src/mainboard/iwill/dk8_htx/Options.lb:default DCACHE_RAM_SIZE=0x0c000
>
> ---------------------------------------------------------------------------------------------
>
> Clean up handling different CAR sizes and round down CAR size to the
> nearest power of two.
> Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
> ---
>
> Index: LinuxBIOSv3-CAR/arch/x86/stage0_i586.S
> ===================================================================
> --- LinuxBIOSv3-CAR/arch/x86/stage0_i586.S	(Revision 510)
> +++ LinuxBIOSv3-CAR/arch/x86/stage0_i586.S	(Arbeitskopie)
> @@ -301,37 +301,36 @@
>          jmp     clear_fixed_var_mtrr
>  clear_fixed_var_mtrr_out:
>  
> -#if CacheSize == 0x10000 
> -        /* enable caching for 64K using fixed mtrr */
> -        movl    $0x268, %ecx  /* fix4k_c0000*/
> -        movl    $0x06060606, %eax /* WB IO type */
> -	movl    %eax, %edx
> -        wrmsr
> -	movl	$0x269, %ecx
> -	wrmsr
> -#endif
> +	/* We round down CAR size to the next power of 2 */
> +        movl    $0x269, %ecx  /* fix4k_c8000*/
>  
> -#if CacheSize == 0x8000
> +#if CacheSize >= 0x8000
>          /* enable caching for 32K using fixed mtrr */
> -        movl    $0x269, %ecx  /* fix4k_c8000*/
>          movl    $0x06060606, %eax /* WB IO type */
>  	movl    %eax, %edx
>  	wrmsr
>  #endif
>  
> +#if CacheSize >= 0x10000 
> +        /* enable caching for 32K-64K using fixed mtrr */
> +        movl    $0x268, %ecx  /* fix4k_c0000*/
> +        wrmsr
> +#endif
> +
> +#if CacheSize < 0x10000
>          /* enable caching for 16K/8K/4K using fixed mtrr */
> -        movl    $0x269, %ecx  /* fix4k_cc000*/
> -#if CacheSize == 0x4000
> +#if CacheSize >= 0x4000
>          movl    $0x06060606, %edx /* WB IO type */
> -#endif
> -#if CacheSize == 0x2000
> +#elif CacheSize >= 0x2000
>          movl    $0x06060000, %edx /* WB IO type */
> -#endif
> -#if CacheSize == 0x1000
> +#elif CacheSize >= 0x1000
>          movl    $0x06000000, %edx /* WB IO type */
> +#else
> +#error Invalid CAR size, must be at least 4k.
>  #endif
>  	xorl    %eax, %eax
>  	wrmsr
> +#endif
>  
>  #if defined(CONFIG_XIP_ROM_SIZE) && defined(CONFIG_XIP_ROM_BASE)
>          /* enable write base caching so we can do execute in place
>