[OpenBIOS] [PATCH v2] ppc: Set up SLBs for ppc64

[Andreas Färber]

Am 21.11.2010 um 20:14 schrieb Alexander Graf:

> On 21.11.2010, at 19:53, Andreas Färber wrote:
>
>> Set up SLBs with slbmte instead of mtsrin, suggested by Alex.
>>
>> v2:
>> * Don't initialize 64 SLBs, then invalidate them, as in IBM's  
>> application note
>> for the 970. Use slbia instead, recommended by Alex.
>> * Conditionalize when to use SLB or SR.
>>
>> Cc: Alexander Graf <agraf at suse.de>
>> Signed-off-by: Andreas Färber <andreas.faerber at web.de>
>> ---
>> arch/ppc/qemu/ofmem.c |   25 ++++++++++++++++++++++---
>> 1 files changed, 22 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/ppc/qemu/ofmem.c b/arch/ppc/qemu/ofmem.c
>> index 72694b3..24f3a25 100644
>> --- a/arch/ppc/qemu/ofmem.c
>> +++ b/arch/ppc/qemu/ofmem.c
>> @@ -387,7 +387,7 @@ void
>> setup_mmu( unsigned long ramsize )
>> {
>> 	ofmem_t *ofmem;
>> -	unsigned long sdr1, sr_base;
>> +	unsigned long sdr1;
>> 	unsigned long hash_base;
>> 	unsigned long hash_mask = 0xfff00000; /* alignment for ppc64 */
>> 	int i;
>> @@ -399,13 +399,32 @@ setup_mmu( unsigned long ramsize )
>> 	sdr1 = hash_base | ((HASH_SIZE-1) >> 16);
>> 	asm volatile("mtsdr1 %0" :: "r" (sdr1) );
>>
>> +#if defined(__powerpc64__) || defined(CONFIG_PPC_64BITSUPPORT)
>> +#ifdef CONFIG_PPC_64BITSUPPORT
>
> Phew - too much ifdef for my taste. How about the idea I mentioned  
> in the mail before to just make is_ppc64 return always 0 on ppc32  
> hosts without compat config option? Then you could also protect the  
> slbia and slbmte and whatever ppc64 specific pieces with #ifdefs but  
> not care about the rest :). Would hopefully make this code a lot  
> more readable!
>
>> +	if (is_ppc64()) {
>> +#endif
>> +	/* Segment Lookaside Buffer */
>> +	asm volatile("slbia" ::: "memory");
>
> Inline function please :)
>
>> +	for (i = 0; i < 16; i++) {
>> +		unsigned long rs = ((0x400 + i) << 12) | (0x10 << 7);
>> +		unsigned long rb = ((unsigned long)i << 28) | (1 << 27) | i;
>> +		asm volatile("slbmte %0,%1" :: "r" (rs), "r" (rb) : "memory");
>
> Inline function again

Don't see the advantage here, these two are used nowhere else. But  
I'll do.

>> +	}
>> +	asm volatile("isync" ::: "memory");
>
> And this would be awesome to get as inline function too! :)

Is this one necessary at all?

Andreas