On 09/02/16 13:19, Maciej W. Rozycki wrote:
> On Tue, 9 Feb 2016, Florian Fainelli wrote:
>
>> +static void bmips5000_pref30_quirk(void)
>> +{
>> + __asm__ __volatile__(
>> + " .word 0x4008b008\n" /* mfc0 $8, $22, 8 */
>> + " lui $9, 0x0100\n"
>> + " or $8, $9\n"
>> + /* disable "pref 30" on buggy CPUs */
>> + " lui $9, 0x0800\n"
>> + " or $8, $9\n"
>> + " .word 0x4088b008\n" /* mtc0 $8, $22, 8 */
>> + : : : "$8", "$9");
>> +}
>
> Ouch, why not using our standard accessors and avoid magic numbers, e.g.:
Are you positive the assembler will not barf on these custom cp0 reg 22
selectors?
>
> #define read_c0_brcm_whateverthisiscalled() \
> __read_32bit_c0_register($22, 8)
> #define write_c0_brcm_whateverthisiscalled(val) \
> __write_32bit_c0_register($22, 8, val)
>
> #define BMIPS5000_WHATEVERTHISISCALLED_BIT_X 0x0100
> #define BMIPS5000_WHATEVERTHISISCALLED_BIT_Y 0x0800
>
> static void bmips5000_pref30_quirk(void)
> {
> unsigned int whateverthisiscalled;
>
> whateverthisiscalled = read_c0_brcm_whateverthisiscalled();
> whateverthisiscalled |= BMIPS_WHATEVERTHISISCALLED_BIT_X;
> /* disable "pref 30" on buggy CPUs */
> whateverthisiscalled |= BMIPS_WHATEVERTHISISCALLED_BIT_Y;
> write_c0_brcm_whateverthisiscalled(whateverthisiscalled);
> }
>
> ? I'm leaving it up to you to select the right names here -- just about
> anything will be better than the halfway-binary piece you have proposed.
These are not standardized registers in any form, which is why these are
in a halfway-binary form, they are not meant to be re-used outside of
two known places: disabling pref30 and enabling "rotr".
>
> FYI, we already have BMIPS5000 accessors defined up to ($22, 7) in
> <asm/mipsregs.h> so it will be the right place for the new ones as well.
>
> Maciej
>
--
Florian
