[U-Boot-Users] [PATCH] mpc85xx: fix upmconfig

[Sebastian Siewior <bigeasy@linutronix.de>]

* Andy Fleming | 2008-07-14 19:32:56 [-0500]:

>> --- a/cpu/mpc85xx/cpu.c
>> +++ b/cpu/mpc85xx/cpu.c
>> @@ -71,8 +71,7 @@ struct cpu_type *identify_cpu(u32 ver)
>>
>>  static void set_lcb_clock(uint clkdiv)
>>  {
>> -       volatile immap_t *immap = (immap_t *)CFG_IMMR;
>> -       volatile ccsr_lbc_t *lbc= &immap->im_lbc;
>> +       volatile ccsr_lbc_t *lbc = (void *)(CFG_MPC85xx_LBC_ADDR);
>>        uint lcrr;
>>
>>        lcrr = lbc->lcrr;
>> @@ -352,8 +351,8 @@ void upmconfig (uint upm, uint * table, uint size)
>>                 i++, brp += 2, orp += 2) {
>>
>>                /* Look for a valid BR with selected UPM */
>> -               if ((in_be32(brp) & (BR_V | upmmask)) == (BR_V | upmmask)) {
>> -                       dummy = (volatile u8*)(in_be32(brp) >> BR_BA_SHIFT);
>> +               if ((in_be32(brp) & (BR_V | BR_MSEL)) == (BR_V | upmmask)) {
>> +                       dummy = (volatile u8*)(in_be32(brp) & BR_BA);
>
>This looks pretty good to me, but I'm not very familiar with this
>code.  Could you explain a little more deeply what is wrong with the
>old way, and why the new way is better?  I think I understand the
>problem with the BA_SHIFT (actually, it alarms me, a bit), but I'm not
the first part, changes the computation of the dummy address. The spec
[1] chap 14.4.4.2 referes to the dummy address as "...by a (dummy) write
transaction to the relevant UPM assigned bank." The address is assigned
in the relevant BRx[BA] register (bits 0-16 if not used extened
addresses) and therefore shift is wrong, logical and is correct.

>so sure about using MSEL on one side of the ==, and not the other.
BRx[MSEL] specifies the machines used (table 14-4, pdf page 631 in my
document). MSEL is the mask while upmmask (UPMC, UPMB, or UPMB) is the
content of the register. For instance, if your BR[MSEL] register would
have all bits set (what is reserved / not legal) than the old compare
method would match UPMA, UPMB & UPMC where is the new method would skip
it.

>Andy
Sebastian
[1] MPC8544ERM.pdf Rev1